I'm kind of debating on whether to run my 292 Chevy naturally aspirated or with a blower.
If I went N/A it would have a Clifford 4bbl intake, lump ports, a Holley 570cfm carb, 1.94int. and 1.60 exh. valves, Ross pistons, long tube headers, and 10:1 compression. Here's the cam specs: 274* advertised duration, .320 cam lift,110* lobe center.
If I went with a blower it would have a Clifford intake, lumps, a Holley 600Cfm carb made for a blower, same valves, Ross pistons, Long tube headers, and stock compression. Should I run the stock cam or some kindof turbo/blower grind(recommendations?)
What do you think about one of the old diesel blowers like off a 6-53 Detroit? that motor is 318 ci, pretty close to a 292. I would go through and put all the needed teflon seals and stuff in it. Do you think it would work? I could play with pulley sizes.
(sorry for the double post,I wasn't sure where this should go...)
A blower cam will give you more power everywhere.
Specs,,,,all depends on how much you want out of the engine.
How much boost,etc.
You have stock rods? If so, that's going to limit your RPM & will allow you to chose accordingly.
For a blower for the street.
I would go w/about 144-116 lobe center.I like a smooth engine for the street,maybe a little lope to the engine idleing.
220 duration @ .050..500" lift or so,,,,like I said,all depends on your goals.
Thats just a guess w/the cam,but need to know what you want out of it.
My 250 had a solid cam w/specs of .540 lift, & 236 int. 246 ex. on a 115 lobe center,IIRC.
With this cam, you could definately here it lopeing @ idle.
Also,I had normally aspirated cams w/about the same duration & it never wanted to rev as fast or as far as it wanted to w/the blower installed,,it just wanted to keep reving & reving,,,the blower had a max RPM & I actually had to shift @ 7500 RPM,otherwise I would have over spun the Paxton & would have damaged it. It probably would have spun to 8000 RPM w/the correct sized pulleys for t Paxton, but this engine had stock,side grinded, polished & shot peened rods,,,it probably would have thrown a rod or 2?
This long block engine is still in my Car & still altogether,minus the intake & exhaust awaiting for my turbo stuff to throw on.
I ran about 10 psi @ the most & the engine would want to spin to 7500 RPM.
This was w/a Paxton SN 89 supercharger.
Estimated HP was about 400 HP @ the wheels & ran low to mid 12's in the 1/4.
This was my street car daily driver.
MBHD
I was thinking anywhere from 350 to 400HP and about the same in torque. I'm still in the planning stages so I'm going going to build around a 400HP/400ft.lbs point of view. I wasn't planning on going above 5500-6000 RPM for street use. What are some good rods for me or are the stock ones fine for this?
The reasons I Was wondering about the diesel blowers was because I have easy and, primarily, cheap access to them. Do you think they would be alright for this application?
i have a 4-71 on my 270 gmc. about all you have to do is find one in good condition. know were to look for wear on the rotors and up grade the bearings. and no teflon for a street blower
Now that I think about it I have a 6-71 blower on the shelf ready for street use, could I just gear that down to about 70% the speed of the engine? Theoretically that would put out around 298 ci.
(6x71=426x.7=298.2)
just saying because I have the 6-71 handy and it's freshly rebuilt.
Go for it man!!
Just remember to factor the abount of boost you want into your equation.
The tests Cart Car & other mags have done in the past comparing a 6-71, B&M 144,Weiand 142?, Paxton super chargers & so-on, when they slowed down the 6-71 blower for low boost of 6-8 psi IIRC?
The 6-71 made the least HP & really added a lot of weight to the car.
The smaller faster turning blowers all made more HP & were more effcient (SP).
MBHD
huh, you'd think the slow moving ones with big rotors would gulp more air than one moving fast with small rotors...
There is a guy on the H.A.M.B site running an 8-71 on his 270 six, and he says it can keep up with the stupid little ricers on the highway, so I was thinking my 6-71 would probably work fine.
I'm not looking for a full out race motor, but I want to be able to show those ricers what a real hot rod looks and sounds like
If I get 350HP and 350ft.lbs I'd be happy, It'll top at about 10psi boost and 6000 RPM, and It's going to be a daily driver anyway...
Hank, Or somebody, Could you please suggest some cam specs for me?
That'll have me running a Holley 600 (http://holley.com/0-80592S.asp), Clifford intake, lump ports, 1.94I/1.50E valves, Long tube headers, Ross Pistons, and the 6-71 Blower.
The 6-71 is a big boat anchor (I've read 65 lbs. without mag end plates, needs big brackets, high inertia to spin up) for your purpose, and although capacity is high running it slowly means high leakage at low RPM.
For a roots type (boost at low speed) a Weiand or B&M small GMC replica is a better choice if you can find one used ($$$ new).
The M90 is a bargain, but remember that no OEM Eaton accepts a carburetor - no flange, intake in the wrong place. IMHO an M90 could be converted to top-fill with some surgery, and rotated 90° to use side-draft carbs and keep the hood clearance.
All the centrifugals (Paxton, ATI) must be spun faster, and produce less boost at lower speeds - which may help if your static CR is too high?
I'd also be using a bigger exhaust valve, 1.56" or 1.60" if it fits (even if it means reducing the intake valve).
CFM: 292" @ 90% VE, 6,000 RPM (not with the stock rods!) = 502.
For boost, multiple by the pressure ratio (1.68:1 for 10 psi) = 843 CFM. You can use the 600, but your power valves may need some tweaking - the Holley lit says dual for a V8, or 1200 CFM.
I assume when you say "ricer", you're talking about those irritating little squids with the giant red katakana decals on their fart-can Civics?
A serious Supra is 1,000 hp.
ya, those fart-can civics, OH, don't forget the 3inch exhaust that drags on the ground, and the muffler that looks like it belongs on a dozer... all behind a little 4 banger... (that's what makes it a ricer, or a ricerocket, or a ricecar
.)
I am using bigger valves: 1.94 intake and 1.60 exhaust. they fit.
I really kind of want to use the 6-71, because I already have it and have poured money into it (rebuild) and it's left over from another project.
Couldn't I just play with pulley sizes till I find something that works? The old Detroits only rev up to about 3000RPM, so It'd be spinning twice as fast on my motor (depending on pully size)
I'm not trying to argue, I just want to use this blower? if possible?
Ooopps, senior moment - meant small size up from 1.60" may help.
I think tom Lowe said you would hit water soon after 1.94/1.60...?
Sure wish he(TLowe) would get on and say something, or Answer his email!!!
hint, hint, nudge, nudge
[quote=qparkerHank, Or somebody, Could you please suggest some cam specs for me?
[/quote]
Comp cams can grind what ever spec cam you want.
A cam with a range of 220-230 degrees duration @ .050.
A lobe center of 115-116.
Lift around .500" is plenty,you are forcing the air in there. You can look @ there SBC stuff for a blower cam & tell them you want a cam w/the SBC blower specs for your 292.
If all else fails,there tech dept can help you out.
I would not get any Clifford cam.
MBHD
a 2in valve can be installed but you really don't need it. On some of these old heads With the core shift that is in some you can Hit water just by trying to install a hardened seat Even with the USE of the shallow seats.You can even get into the water jacket if useing the wrong cutter (when under cutting for bigger valves)
You can get custom ground cams from most any cam company.
I combined Hank's info with a blower cam Engle had for their small blocks and came out with this:
lift@1.7:i).500"E).510"
Adv.duration:i)272*E)280*
Cam Lift:i)294"E)300"
lobe center:115*
Duration@.050:i)224"E)230"
What do you think? any adjustments?
Parker,
I have not seen any email from you in quite awhile. Answered them as they came too.
I think a 6-71 is going to be hard to drive off the snout of a chevy 6. The 6-71 is a beast, even for a V8. It takes quite abit of power just to turn it. Still think a turbo is the most efficient way to turn up the power.
You are on the right track with a cam. Clifford does not make turbo/ blower grind cams. I like Comp cams for custom grinds. Tom
I decided in the beginning of the build to do the bare minimum amount of business with Clifford. they lie and just want you to buy their products. I am going to have Engle Cams fill my order.
Thats weird you haven't gotten my emails...
Btw: how much is your turbo manifold?
I just like the simplicity of a blower, you don't have to fiddle with the carb for blow thru, mess with as much piping, and it's easier to mess with pullies than it is to mess with turbines/ housings. in my opinion. I still may go the turbo route, if Things get spendy with a blower...
As for the intake, should I use a 4bbl, a 3x1 or a 2x1? I'm already planning on doing alot of fab work, and if I went with a 2 or 3x1 I could put 1 to 2bbl adapters to make a bigger opening for the air to flow through, it'd probably increase velocity too...
???
How does an adapter make the opening bigger?
Bigger opening increases velocity?
look at this:
http://www.stoveboltengineco.com/acartpro/product.asp?productid=174the bigger opening in the top(2bbl) necks down to the small bottom(1bbl) You'll see what I mean...
You are still restricted by the single barrel opening. Also most turbo users have boost controllers so you can adjust the boost without going into the turbo. Easier than changeing pulleys.
I know what it is. How does it make the opening bigger?
The top opening(the 2bbl part) is bigger than the bottom(the 1bbl part) it goes from a 3x1 manifold to a 3x2 manifold...
think of a funnel, the top is bigger than the bottom. you can pour something in the top slow and it comes out faster at the bottom. if you move, say, 500 cubic inches of water through a 1 inch opening in 1 minute it doesn't have to flow as fast, but if you push it through a 1/2 inch hole, it has to flow a lot faster in order to get the same amount of fluid out in the same amount of time. Get it?
\~~~/\~~~~~/
.\~/or\~~~/
I hope you get it, kuz you're making me start to doubt myself...
I understand what your saying I just don't understand why you would want to cause a restiction in your intake tract. I would think you would want the boost in the cylinder and not hung up in the blower with no way out. I would free up the flow and use the pulleys to adjust boost.
There is already a restriction in it, it's an offy intake made for three single barrel carbs. I'm putting 1bbl to 2 bbl adapters so you could put three two barrel carbs on it. Technically the adapters are just funnels, so I'm funneling the air into the motor.
Maybe get a dual four manifold and adapt the blower to that?
Who makes those for the 292?
Check out prostores1.carrierzone.com IM-17 $289.00 made by Clifford.
That's more like it!!! Thanks!! I'd have never found that...
All Hail Harry!
Or this, but for $200more... Maybe I'll stick with the dual quads...
http://prostores1.carrierzone.com/servle...manifold/Detail
I think that one only fits the small 144ci style blowers. I think that the 6-71 pattern is different. You would have to build an adaptor plate to bolt on top of that. It could be done, I guess, but you'd be in it pretty deep in the pocket when you got done.
Who makes those for the 292?
Here is a blower manifold for the smaller blowers.
194-292
http://prostores1.carrierzone.com/servle...manifold/Detailhttp://www.34-chevy.com/MBHD
I think I'll just adapt it to the dual quad manifold and save $200
I think I'll just adapt it to the dual quad manifold and save $200
Sure, if you like to fab up parts & can make it happen,,,but if you want to bolt up a blower & save time & probably $$$ in the long end,there is a blower manifold available.
Plus I am thinking the blower manifold would deliver fuel better than running a dual quad manifold & then make an adapter & then stick a blower on top of the adaptor.
Just thinking out loud.
Two cents thrown ;-)
MBHD
I have ALL KINDS of scrap metal from previous projects that I can use, I'm a proficient welder, and don't mind fab work...
I think I'll just use the dual Quad intake, fab the parts, and be done with it.
I can just about pay for the water/methanol injection kit with what I save on using the 2x4 manifold over the blower one...
I agree, for me its always more fun to build it yourself. And if it works all that much better. Thats why I'm building my own water/meth injection system. Save some money for things I can't build.
I was going to do like you and build my own injection system, but i'd have to adjust the flow manually, where as with Snow's kit it's proven, it has a pressure sensor to adjust output, and/or I can manually do it...
The one I'm building will be controlled by my mega squirt along with a knock sensor.
Are Roller Rockers Really worth it for my application? They're $450+/- at comp cams and for $50 I can get "high energy" rockers for $50 at the same place...
What is your spring pressure over the nose? Under 350, you can get away with the roller tip ones. That's from Comp. Personally, I say buy the good stuff, so later, when you upgrade, you won't have paid twice for rocker arms, or worse, twice for rocker arms and twice for pushrods when you miss a gear, overrev and everything breaks and you have to replace it.
I'm not sure what the spring pressure will be, seems how I'm still in the planning stages of this build...
Do you plan on running a solid lifter cam, solid roller,hyd?
MBHD
Why are you posting new questions in 2 different places?
kuz I'm getting answers in both places.
the cam will be solid lifter, and after some searching&planning Here's where I'm at currently:
I'll be running a 292 with a 6-71 blower, lump ports, 3 1bbl rochesters, homemade manifold, 1.94 intake and 1.60 exhaust valves, Ross pistons, 8:1 compression, 10 pounds of boost, an MSD6 BTM ignition, water/methanol injection, 200,000 psi scat rods, cloyes timing gears, steel roller rockers, dual exhaust, and lots of chrome and SS, which will give it 10 more HP, I don't care what you guys say!
or 4... mostly for looks, I think a 4bbl just looks wrong on a six...
If you can tune it and keep it tuned right I'd say go with the multi carb Just for the Cool OMG factor from most people.
And, you have that big database of prior efforts using blowers and multiple 1 bbl. carburetors to fall back on.
Oh, wait...
Thanks for all the positive responses Panic, It really helps me, because I'm not going to base my build off a site on the internet where some one like you could load me up on BS, make me spend alot more $ than needed, and possibly loose power.
Thanks for the support larry!
Oh, and Panic, my mom always said if I didn't have anything nice to say don't say anything at all. Maybe you should try asking if I knew what I was doing instead of guessing that I was clueless. I've setup dual 500 holley 2bbl's on a blown 383 chevy, so, I do have some previous knowledge.
what sounds better?:
And, you have that big database of prior efforts using blowers and multiple 1 bbl. carburetors to fall back on.
Oh, wait...
or
It sounds like you may need some help, I'm sure someone on this board can and will gladly help you, if you need it.
Lets drop it at this, and go back on topic.
if I didn't have anything nice to say don't say anything at all
That's the way all the world's problems are solved, isn't it?
That was great advice from a parent to a 10 year old.
Now... not so much.
I've found that when I'm making a mistake, my friends will tell me ("don't connect those wires. they're still hot"), and my enemies won't ("his tire is flat - that's so funny"). Guess your mom didn't get to that part?
Since you find playing the victim much more enjoyable, and since anything but "wow, what a great idea!" isn't "anything nice", I agree. Make as many mistakes as you want.
The attitude and the general snottiness that masquerades on this bulletin board as wit and 'advice' precisely represents the reason that I and others I've corresponded with refuse to join II.
Although the only Inliner I've met in person is nothing like that, one cannot follow this bulletin board long without feeling that opting to join would amount to formalizing a relationship with people who appear to view the forum as a license for sarcasm and self-righteousness.
I would assume that this rationale for this bulletin board is discuss (the word discuss is used advisedly; it is not used to imply an obligation to receive pronouncements) our plans, hopes, thoughts, and to recieve gentle guidance, and through these interactions to recruit new members. I suspect that the all-too-common open belligerence is instead driving away potential members.
By "gentle guidance", you mean telling someone what he wants to hear?
The speaker decided to fault my motive and method, since he's not competent to rebut my statement (that 3 Rochesters leaves you in an empty field with no guidance, and starting off from square one).
I intended to wait to see if he wanted some more information, or not. I was right - he doesn't want information, he wants approval, and I agreed not to offer any more assistance.
What's more important: the quality of the information, or the little happy faces?
Your statement accusing me of attitude and the general snottiness rather suggests that your opinion on these matters is also something not to be criticized?
There are none so blind as those who only see themselves in the mirror. Rather than examining my willingness to face criticism, you should be reflecting upon your own.
Everybody on this board is a full and complete person, with a tremendous body of knowledge; that knowledge may not be in the same area as yours, but the very fact that a person is asking questions implies a commonality of purpose and interest. That commonality makes it nothing less than shameful when discussion is rewarded with sarcastic dismissal.
I'm sorry, but I would suggest that the quality of the discourse, that is, the ability to openly discuss, is more important than the "quality of the information" as delivered by any one individual. In an open forum, information that is agreed upon by a consensus of contributors is more highly valued than bombastic finalities, no matter how loudly stated.
Note to all readers...
The opinions expressed in this, and im my previous message are directed not as much to a specific offender, but more to all of the respondents who feel free to indulge in sniping, petty arguments, put-downs, self-promotion, and otherwise generally poor behavior. You are collectively taking all of the fun out what should be enjoyable discussions. After all, the people that know something wouldn't have much to talk about if those of us that are more ignorant in the field were unavailable to ask the questions.
Note to all BB Members:
I don't have the time or the patience to be a babysitter, every time a topic gets started it seems like someones feelers get stepped on. The typed word doesn't have the inflections to pass on the way things are meant, if you continually get told you are a jerk perhaps you should rethink your words, if you are being a jerk, STOP IT!
This Board is about mechanical things, not about egos or personal problems. Everyone here is entitled to ask questions, talk about their project, and give advise. No one is obligated to take that advise.
Let's keep on the subject of Inliners.
Tim
lets just drop it, okay? panic, if you want to give me or anyone else some info Please feel free to do so, but don't make us feel like a dumb a$$ while your at it.
For those who would actually like some help (even if it's how to avoid a costly mistake), tell us:
1. what the project is (engine, year, transmission)
2. what you've done (is it stock? Mods?)
3. what's wrong
4. what you tried so far, and what happened
5. yes, there are some stupid questions, like those already asked and answered 5 minutes ago (another is "why can't I bore my 216 out to take 454 pistons?"). A search can be very useful.
1)292Chevy Inline six cylinder 1969 block.
2)4x1 rochesters, 6-71 blower, Homemade intake, lump ports, 1.94Intake/1.60Exhaust valves, Ross pistons, 8:1 compression, dual headers, MSD BTM ignition, Snow performance's Water/Methanol Injection kit, and my custom cam seen below, with 10 pounds of boost.
lift@1.7:i).500"E).510"
Adv.duration:i)272*E)280*
Cam Lift:i)294"E)300"
lobe center:115*
Duration@.050:i)224"E)230"
3)just want general help, is there anything else I should do before the build?
4)Not much, just getting started.
5)There's no such thing as a stupid question, just stupid answers.
let's start over, Nice to meet you panic...
Thanks - I'd much rather talk about engines than argue.
My objection wasn't that you want traditional appearance, it's that you're making (what appears to me to be) extra work for yourself. The B (or M?) has too many variations to know which body casting is best, tuning parts not easy to get.
Repeating the math: 292" @ 90% VE, 5,500 RPM (adjust as needed), is about 460 CFM. 10 psi is 1.68:1 pressure ratio, makes 772 CFM just to get 1.5" Hg vacuum. If you're jetting is good, you could run even more area down to perhaps 1.0" Hg. Even 4 needs 193 CFM each, only the largest 230 & 292 1-3/4" models are that big. It does allow progressive to keep the idle and low speed clean, though - idle on a center pair with the outers as secondaries.
IIRC they have power valves and an extra-fuel passage, don't know if it has a jet or just a drilling. I'm not sure how to reference the power system except by drilling through the body casting (this information is well-known for Holley and AFB), or address the fuel curve for extra gas on boost. This is a very ambitious project, but as we all know they have a tendency to add 2 new thoughts to the end as 1 gets taken care of - it never stops.
Cam: looks good, may need some tweaking.
You're going to need some serious work on the pan just because of the high power - scraper, baffle, pick-up surround, potentially lowered sump and extended pick-up. This doesn't even really need to be done until after the engine is built, especially since it has to match the chassis.
Headers: BIG primaries, the size is based on the power output, not the cylinder or valve size. 400 hp ÷ 6 needs the same as 533 ÷ 8, you may need 2" OD.
The intake shape can be a big advantage. The most current 14-71 blowers have their manifold inlets near the front of the case (like an Eaton), not centered in the rotor length (as did all older GMC manifolds). This both increases flow, improves distribution, and lowers charge temperature. You may need to make a jack-shaft to position the nose drive where your crank pulley can reach it.
Exhaust:I was thinking about using a header like the one you see by the inliners logo, maybe 1.75 ID to dual 3" pipes, then a X pipe, then back to dual 3". maybe a set of flow masters, but that'll come later. LOUD & PROUD.
Carbs: I believe the big (1.75) 230/292 carbs are 180cfm, (180x4=720) after a bit of shaving and polishing, and I'd set my rev limiter at ~5000~ so it'd take (1.68x422.45=709.7) so I'd be a little big, which would be good. As for jets IIRC they're just holes in the casting, so I could just drill them out little by little until I get it right, or, if possible? I could drill&tap them for ?holley? jets that are wide ranging an plentiful.
Intake: I think since I AM going with the 4x1 setup I'll do the traditional rotor legnth set up. As for the nose drive I'll just move the manifold ahead so it'll line up the blower.
Pan: I can lower the sump about another 4"-6" max. same with the pick up.
Cam: what do you suggest I change? I'm looking for my power to top out at about 3500-4000. lots of torque, even if it means HP loss.
Glad we could get that behind us, It's Tons more fun to talk about engines like you said.
Exhaust: obviously your own decision, but 1-3/4" is smaller than I would use and gives up some power. The usual argument against (low exhaust velocity = reversion) is completely removed by the blower flushing the chamber constantly during overlap.
I could drill&tap them for ?holley? jets that are wide ranging an plentiful.
Exactly - if the "power" orifice is drilled, and you can interrupt it in the casting (some require drilling in 2 places, and routing the passage to outside - not fun), insert a replaceable jet. The tap size is based on wall thickness and OD, there are some very small jets out there, many thread sizes. My (still future) book gives many alternate jetting components by thread, tap and available sizes. In addition, Jenkins used a piece of fine wire draped through a small jet to make really small changes (like a miniature metering rod).
Pan depth: that will help a lot. Keep the same depth over the pick-up to lower the oil down from crank contact.
I'll just move the manifold ahead so it'll line up the blower
You have to be very careful here, because an error is very expensive to fix. Moving the plenum changes cylinder distribution quite a bit, and inserting dams and dividers is dyno work - long and painful. Agreed, that any manifold has some distribution problems (typically #3-4 run rich due to short runners), but a centered plenum is at least symmetrical front vs. rear. Most aftermarket manifolds have fair distribution, but the rotor discharge pattern bias (favoring the front) means don't expect the same with the blower. Moving the manifold introduces another variable.
Just a thought: you're going to make a transition piece to mount the carbs to the 6-71 intake, yes? Making multiple bolt patterns will allow you to move just the carbs back and forth without moving the manifold - not as good, but still worth adding, costs nothing. Just figure out your throttle plate width (1st to last, remember they can be 4 × 1 or 2 × 2) vs. blower case opening length to see how much wiggle you have.
Demon's new 2bbl carb is 205cfm, takes holley/demon jets and float bowls, has a 3-bolt (stromberg) bolt pattern. You would be able to take advantage of holley 4 barrel knowledge to do the manifold referenced power valve mods and any adjustments to pvrc sizing to fix fuel curves etc. Isn't there a multiple rochester faq in the tech tips?
And its just me but I really think you need more cam although I may be failing idiot gearhead here. Blowers eat cam. My SBC cam was 255/262 at .050 and idled at 850rpm. There was definitely no lack of bottom end power. Also according to Stahl and Lemon's, 400+hp 6cyl blower motor should have 2" primaries.
Demon's new 2bbl carb is... $$$$ × 4
and rochesters around here = little to no $...
I was thinking of slanting the runners foreward on the intake, I don't know if you knew what I meant... I may run 5x1 if the cfm requires it...
Maybe 2"inch primaries would be the way to go. or even bigger: 2.25? what do you think of me making the manifold like the one on the one by the inliners logo, but split? I'll run a X or H pipe, Which 'd be better? And would straight pipes help performance enough to speak of or should I run smitties or something, I DON'T mind noise...
What should I do to my cam, I want my power band from about 1000 to 3500-4000...
thanks guys!
Qparker,
I think for your proposed rpm goal, the cam needs to have closer to 220 duration @ .050.
What rpm do you want full boost in? What is the max RPM level?
I'd set my rev limiter at around 5200, and I'd want full boost by around 2500-3000, or so, This'll be a red light racer, and It may only see long streches of highway a couple times a year.
all in all, which of these rockers should I get?
http://www.summitracing.com/parts/CRO-73631-12/http://www.summitracing.com/parts/CRO-72831-12/http://www.summitracing.com/parts/CCA-1261-12/so basically, steel roller, aluminum roller, or stamped(like stock)
I kind of think of roller rockers as just something else to fail, but they have their uses.
I'm not particular to these exact rockers, in fact, I'd probally use a BBC set because it's cheaper for 8 than it is 6?!?
not sure of the spring pressure, but I'll be running 1.94&1.60 valves, and maybe
this cam:
lift@1.7:i).500"E).515"
Adv.duration:i)272*E)280*
Cam Lift:i)294"E)300"
lobe center:115*
Duration@.050:i)224"E)230"
I am not sure it's cheaper, but you can order from Comp cams individual (SP)sets of rockers that might be cheaper than buying a set of 16.
MBHD
because it's cheaper for 8 than it is 6?
Not sure what you mean.
The same rocker from the same manufacturer is going to cost more for 8 than 6. There are simply some rockers that are cheap and only offered for BBC, and even getting 2 extra it's less money, but it's not the same product.
I tried just selecting 12 individual ones and it showed up to be less than the cost of a pack of 12. and I also tried 16 individuals and they cost MORE than a 16 pack for a BBC. Maybe because BBC is so common? not many people buy rockers for 6's?
Besides, with a 16 pack I have 4 extras.
Should I go with the stamped ones, steel rollers, or aluminum rollers?
Should you buy apples or oranges?
bananas
really though...
are the rollers worth it? they're $100 more than stamped ones...
One of the surest, and most frequently followed paths to disappointment in engine building is to wheel the shopping cart down the aisle and buy shiney stuff when you're in the mood, and assume it must all work because it's expensive name brands.
The result is that you get smoked by someone who spent half as much money, and followed a plan. You're buying the dress before you meet the girl.
Think ahead: when do you actually need to install the rockers? About 20 minutes before you order the pushrods. Are you ready to do that yet? The project doesn't go any faster with big boxes all over the room.
Until the head is done, you don't know what you need for a cam.
Until that's done, you don't know what the springs are.
After that comes the rocker choice.
People with 10 years experience make the same mistake, sometimes they even realize it - but not enough.
Another fave is getting a great deal on a very nice piece ("Wow, a low mileage billet .800" lift roller cam!"), and designing the engine around it. The saying during the Civil War was "You found a horseshoe. Now, all you need are 3 more shoes, and a horse - and you're in the cavalry".
With your 5200 rpm limit you don't need to spend a lot on rockers. Stock type would probably be all you need. I have comp cam inexpensive roller tips on a small block that spins quite a bit higher with no problems.
Yep, listen to panic. Buy the cylinder head first. Then the cam, then the springs, then the rockers, then the pushrods. It's a series vice parallel evolution.
You need to have the cam specks In order to build the head(set the head up for the right springs and proper machine work is done)Why go back and have to redo the for the spring pads Or different lenght Valves So you don't end up with Coil bind.Because the springs were not set-up for the Cam(lift)
You also Need to know what compression your after So that If the head needs to be milled Or not.(for what ever CC's your after)
So you have to plain ahead (no pun) if your plain is to Buy a head before hand.
Just more food for thought & my2cents
Harry's right about your low RPM limit taking speed out of the equation as a variable, but rocker deflection is related to spring load. A cam with high accel rate (in .001" per degree of rotation) needs more spring for the same RPM.
A good replacement is fine with 250 lbs., but for 400 I'd use steel with a roller tip but a plain shaft. Ask the cam manufacturer about this, not the phone guy at Summit.
You might wind up with the same stuff anyway, but I always feel better knowing that nothing got past me, and helps diagnosis tuning stuff afterward.
okay, I won't go over .525 lift, and the CR will be 8:1...
I guess I was getting ahead of my self, again...
Another thing to add about stock type stamped steel rocker arms is that the ratio will be all different.
One might be 1.69,another 1.63,& 1.70 & so-on.
They are not exact ratios.
Non roller tip rockers will wear the guides out faster than roller tip.
And our 194-292 cylinder head guides are short & tend to wear out faster than a longer guide would.
MBHD
True - the quality replacements have closer ratios than factory. The original design (which was developed to reduce cost) was laughed at in 1954, but it turned out pretty well.
I use the Elgin nitro rockers on my nhra stocker. They are very accurate and tough. They easily go to 7800 with shubecks and STIFF springs on a 302 chevy. They aren't much cheaper than rollers so not a good option for this application though.
I have used Cranes gold rockers for 17 plus yrs and I never had one fail and they seen 8000 rpms more then once. BB 1.7s
guys, not saying I'll drop the 292, but ho!y sh!t I just got a Chrysler straight eight for free! It's all there, and I'm thinking maybe use it with the 6-71?? I don't know much about it, but I'll get some numbers and run them soon. It was in a crane and it says it's an industrial version...
What do you guys think? I haven't really started buying 292 parts yet so I can still change.
How did these motors hold up? I'm clueless on inline 8's, never worked on one, not even seen one till yesterday. Clue me in Please!!! I think this'd be awesome in my 49 pickup.
Or a steam engine.
Or 3 squirrels.
Or cold fusion.
Or...
Big & heavy,no parts easily available.
Can't handle that much power?
MBHD
I have used Cranes gold rockers for 17 plus yrs and I never had one fail and they seen 8000 rpms more then once. BB 1.7s
That's what I used all these years w/out any problems.
Another option:
http://cgi.ebay.com/ebaymotors/194-230-2...=item2c573a6501
But different; and different always justifys some additional trouble. I'd suggest thinking about how much additional trouble you're willing to invest for that different.
I'm just trying to figure some specs on it, I'm not dumping the 292, but I think this'd be a really cool motor to build and put in something (another truck?)
Okay, back on track with the 292, Should I still run manifold heat? Remember where I live (Interior Alaska), I'm making an aluminum water heated fuel block already...
This'll be run at temps down around -45°F on a regular basis, so It's not like So Cal guys...
Run the water heat and put in a valve to shut it off when you're racing.
Do I even need the heated manifold? The 6-71 will generate it's share of heat...
If I do, I think my aluminum manifold will cool pretty quickly with -30 below temps all around...
P.S. I'm having trouble posting, It'll make me log off then back on once or twice before I stay on(It logs me off automatically when I hit submit) so I have to copy the message so it won't get lost...
Anyone else having this problem??
Okay, I talked to Engle And Delta Cam Companies, and they helped me with a cam, Here's what I've got so far:
lift@1.7Ii).510"E).527"
Adv.duration:i)275*E)286*
Cam Lift:i).300"E)310"
lobe center:111*
Duration@.050:I)220"E)231"
Build Recap:
multi 1bbl's, homemade Intake, lump ports, 1.94/1.60 Valves, 1:7 roller rockers (alum), Ross 8:1 Pistons, 2.13" headers, Dual 4" Exhaust, MSD BTM, Water/methanol Injection, Scat 200,000 psi rods, maybe a whiff of Nitrous on down the road, 10 pounds boost MAX, and HEI Ignition goodies...
How much do you think I'll be putting out? Rough guess??
I think turning a big 6-71 is just going to kill making better HP than you could w/a smaller blower,but a 6-71 looks impressive!
That cam is OK, & you will hear the loping,if you want a smoother idle,widen the lobe center to 114-117 range.
Multi 1 barrells??? how much CFM?
If all tuned & running good,400 HP to the wheels?
Just a guess.
MBHD
If it helps it's a small bore blower, not a large bore...
I figured 5 rochesters off 230-292 trucks will equate to 830 cfm,
Here's my CFM Math:
(292x5200)/3456x(12/14.7+1)=798
(CIDxRPM)/3456x(Boost/14.7+1)=CFM
830CFM will give me a little room at the track to turn up the boost with high octane, and there's enough carbs I could setup the last few as progressive.
400 HP would definately make me happy, And loping is fine, I don't think I've ever had a smooth Idling Rig.
I'm now looking for a new block, I was letting some guys use my shop and while they were pulling a trailer in they failed to notice the stripped engine block on the engine stand, and first, knocked it over, then second, ran it over, needless to say, they gave me the $200 I payed for it, and said sorry multiple times, there's a huge chunk missing, and it made sorta like a spider web crack up the walls.
SO, if anyone in Alaska has a 292 block (head or no head, must have crank) I'd be willing to pay reasonably for it.
Luckily, I have not started to assemble any hipo parts on it, so I lucked out in that aspect.
UGH....
I'm up here (Alaska) every 2 weeks or so hauling freight from CA to Alaska so if you find one in between I can arrange delivery. Sitting in Barnes and Noble in Fairbanks right now using their wifi and reading Leo Santuccis' book.