Inliners International Forums General Discussion Blown and Injected 67 Camaro - Blown 250

Is it set up to be blow through?

You bet. Since we hit a new page I'll recap the externals:

A 4" Spectre filter feeds the CXRacing GT35 T4 .68 A/R turbo, and the air outlet will have piping to a front mount FMRacing bar/plate intercooler, then back into the bay past a Wyntonm 44mm BOV to the spectre hat with a Devil's Own stage 1 alcohol injector. Holly 4776 600cfm carb sits on an Offy 5414 intake. Exhaust flows out a stock 292 manifold with a 35mm adjustable SPA Turbo wastegate. At least that's the plan...

Ian

You're a braver man than I. I won't go turbo until I go EFI first.

I considered EFI initially but I figure once I get a grasp of the tuning it'll be a great setup. I've always liked the idea of having full control over air/fuel ratios with only a flathead screwdriver. Almost nothing to fail and gives a real old school feel to it. Plus the carb was only $110 (rebuilt).

Don't get me wrong though, the pros of EFI are quite clear and have a certain appeal. Maybe someday I'll...

Ian

Just found this:

"(CID X RPM divided by 3456) X (BOOST divided by 14.7 + 1)
You have to treat this as two calculations. Take a 350 Chevy turning 6,000 and stuffing 8 lbs into it for example:
350 times 6,000 divided by 3456 = 607 CFM
8 divided by 14.7 = .54
Add a 1 in front of the .54 to reach 1.54
Multiply 1.54 times 607 and find that the cfm required will be 934 CFM. "

(250x5500/3456) x (6/14.7 +1) = 557 CFM.

Actually your carb is the right size assuming 6psi boost. Note: vacuum secondary carbs don't work for turbos. You'll never open the secondary because you'll never have vacuum there.

Another website said you'll likely see 350 hp at the crank at 6psi. That should really make her scoot! Looking forward to seeing the video when it's done.

I'm new to the idea of turbo charging. Where does one get vacuum for the brake booster and vac advance? Weld a bung before the turbo in the inlet piping?

Pretty good formula... It's so detailed it must be right! I'm glad the math adds up to the carb being a good size. I had to learn early on the difference between vac/mech secondaries. The 4776 I have is mechanical secondaries which can be mechanically adjusted to open at any point.

350 HP would be very acceptable. I expected to need at least 8-9# to get there but 6 would be even better.

I'm not sure either about vacuum advance. Perhaps one of the carb ports but I can imagine the lack of vacuum under boost there so I'm not sure.

I was out cleaning the valve cover, side covers, timing cover, alternator bracket, oil pan and motor mounts today and noticed I wont have an air cleaner for the side valve cover hose. I don't want to buy a new valve cover (maybe some day) so can I keep the rear pcv, plug the side breather hole and replace the filler cap with one of those baby round breathers?


Old pics of my valve cover... Kinda.


The mini breathers I'm talking about (not specifically this make/model)

Ian

I've been running a breather like that for a long time.

http://i.imgur.com/25Pqvgf.jpg

you can see it there. In fact when I bought the car it had a breather in that location.

Interesting.. I was thinking I'd plug the the aide hole and replace the filler cap with a breather. You've never had trouble with oil in that breather before?

Lastly, I'm wondering where the PCV hose goes to on a turbo setup. I've looked at a ton of pics but can't see it anywhere. I would think the carb and intake would both offer a pressurized port under booat which would close the PCV... Perhaps that's OK for the brief periods of boost? Or perhaps I wrong all together.

Ian

If I were you I'd just put in another breather instead of the PCV. It's really just there for emissions. It pulls a vacuum out of the valve cover to suck out any exhaust gases that leak through the valve seals into the valve train.

I do get some oil leakage but not a lot. It's greatly reduced (maybe none now) since I replaced my valve springs and o-rings. I think I had a bad valve o-ring or 6 before. Now the PCV keeps enough suction to pull air in there rather than push it out.

I think Tom might make a valve cover that won't spit out oil as easily out the vents.

Yeah, I think toms cover supports breather adapters that come off the side and make a 90° curve to allow any oil getting up there to run back into the cover.

Doesn't the PCV also reduce moisture that causes oil sludge in the engine? I've read people mention an engine without a PCV will be a dirty one.

I like your setup with the side breather, but maybe I can find a universal 90° elbow to allow me to mount it upright. Might not look the greatest but upgrades like fancy valve covers, side covers, 2 piece timing covers, billet alternator brackets make great birthday and Christmas present ideas.

Ian

I just ordered a cover from Tom with a single hole on tp in the front. Ot appears to me he cuts some of the holes according to order. I bought what i belive to be a breatger with internal pvc. Now i wonder if that's what i really bought. Don't know shopping date, but will post when it comes in what it's like.

Why not just send him a PM here? He can clear it all up in a minute I'm sure.

I agree, Tom will sort it out. His email is on his website too, I've had lots of quick responses from him that way.

I'm outside today cleaning and painting. I managed to get the valve cover and oil pan cleaned and prepped for paint. However, its like 6°C outside and very windy... No problem...


I put a king size mattress bag and a heater inside my daughters wooden play house. Made myself a little painting shed.


It's a little cozy but it'll due. I'm using PlastiKote grey high heat enamel primer followed by VHT's high heat metallic black pearl engine enamel paint. I have some VHT grey Fireproof engine enamel paint for detailing.

I'll post some finished pics later when they're safe to handle.
...


Finished these two. Not my best work by far but passable on a daily driver with imperfect parts. I should have done one at a time as it was tough to spray tight angles in there.


The VHT black pearl paint has a great metal flake affect to it shows up looking like a layer of dust in this horrible indoor light conditions. I have plans to paint the raised script in flat grey.

This weekend the crank, cam, rods and pistons go to the machine shop. Things are moving along.

Ian

Hey, I'm emailing back and forth with CompCams about valve springs. They want to know what the guide size and pocket size is on a 250 head. I tried googling it with no luck. Anyone know?

Ian

I don't recall but these fit without a problem:

http://m.summitracing.com/parts/CCA-981-12/

That's the springs I installed.

In my experience with a turbo'ed 250 which have logged 2000 miles or so, your best bet is to use a system like this.

http://www.jegs.com/i/JEGS-Performance-Products/555/52210/10002/-1?parentProductId=924093

I run a fresh air breather on the front of the valve cover and the evac system at the rear. It is plumbed into the exhaust just as it straightens out under the truck.

Basically, the engine is able to inhale fresh air and exhale. The result is no imbalance of pressure.

Thanks! I relayed that to compcams and hopfully they can find me a similar set with appropriate max lift.


Yes! I like this idea. I think I'm going to use a screw in breather in the front, plug the side hole and use a push in pcv cap vented to atmosphere in the back. I like the idea of venting to exhaust but I intend to run a muffler and don't want it all gunked up. I suppose I could run it to the back end on a down slope in the exhaust but it seems pointless. A hose to a spot below the oil pan seems reasonable to me. I can't imagine I'll have much blow by with low boost. I can always change it later.

Dropped the crank, rods and cam off yesterday. He has instruction to tap the crank nose and replace the stock rod bolts with ARP ones. He advised me I should consider having the new forged pistons pressed on to the rods as the floating clip system is worse for wear (Low oil distribution there?) and more likely to get loose (clip break). If done correctly, I don't see this happening. Are they just trying to up sell me on connecting my pistons to my rods (aka wrist pin pressing) or is it better to have them pressed on?

Ian

For stock rods , it is better to retain the press fit design. Aftermarket rods are designed for a bushing in the small end.

The 981 springs from comp will swim around on the stock valve guide boss. It is best to control the spring on top and bottom for better valve control.
Look up videos on youtube for spintron valve springs.
My springs work great.

Does ARP make a press fit setup to use with these stock rods? Or should I just keep the stock bolts and not waste my time with aftermarket?

I sent you an email about your valve springs.

Ian

Its always best to replace rod bolts with better ones, at the very least the stock ones are pushing 30 years old. You'll likely have to recondition the rods if you change the bolts, but its money well spent.

What kind of power/boost will the stock head gasket take? I'm already getting the Sealed Power 260-1005 complete gasket kit. Do I NEED to get a Fel-Pro Performance 1025 head gasket instead of the one in that kit?

Ian

...Sometimes I think I spend too much time typing and not enough time thinking.

I just ordered another mother load of stuff, including the Fel-Pro performance gasket that I hummed about. Also grabbed the CompCams crank/cam gears, valve lapper, valve spring compressor, 11/32" valve umbrella seals, piston ring filer, piston ring compressor, digital caliper, base/dial combo, 11" timing wheel, front oil breather cap, rear oil breather/PCV, turbo oil supply/return lines, and the sealed power complete gasket set.

All that and I still need a new fuel line. I know the dual feed line I bought has a 3/8" hose fitting but I plan to swap that with a 3/8" NPT to -6AN fitting but I need one at the pump end. I can't remember what size fitting I'd need on the Delphi MF0051 mech pump. My question is, what fitting do I need to adapt the stock pump to AN? ?/? NPT to -6AN. I used the stock bent metal line when I installed the pump. I'm away from the pump for the holidays and would love to spend the time searching for a matching fuel line but can't confirm the size. Anyone know?

Ian

Rebranded all my stuff as I've decided to document everything on my website and YouTube. Was Ian67 but now go by Turbo Camaro everywhere. Since last update I received the new 0.070" over pistons from Tlowe and got them to the machine shop. Everything was done there and got it all home last week.


Block sanded, cleaned and painted. Video on Youtube


Stripped and repainted the valve cover + new breather/PCVs installed

Going to check clearances and install the cam/crank next week. In the mean time, I want to have the surrounding parts ready to install.

Is there a good, or best place to drill in the oil pan for the turbo's oil drain line? I read within the top 1" of the pan and near a bearing cap? Don't want to do it and regret the hole later. It's an oil drain AN fitting and the connector is a 45° hose fitting.

I drilled mine about 4 inches back from the front of the pan in the middle vertically on my 292 can post a picture tomorrow mine is jic

A picture would be great. I've seen a few online but a lot of the inline threads have broken picture links.

I did what CNC recommended and had the rods reconditioned and bolts Swapped for ARP. The machine shop took it upon themselves to press fit my pistons to the rods. I still have the bag of Spirolox retainers. If I look at either end of of the wrist pins I can see the empty groove where the Spirolox would go. Should they have installed them as well? Is a press fit better than the Spirolox only setup? I didn't expect them to do that for me but it's welcomed if the result is better.

No, leave the spirolox out with press fit rods. The pins will hammer them out because the pins are fixed and can't move freely on the rods.

Exactly what I needed to know. Thanks for making it so clear.

Assembling the head tonight. Ordered a set of umbrella seals. Do they just sit on the valve stem or do you press them over the guide? Looked everywhere but can't seem to find the answer.

Edit: I didn't look everywhere as I reworded my search and found it right away. Install on stem above guide. Seals move up and down with the valve.

Thanks

Alright, I've searched high and low and don't think I'll find an answer to this. My built up 250 is running now and everything is good to go with the exception of the exhaust (pipe isn't connected to manifold yet) and valve lash.

I broke the motor in for a solid 30 minutes with no issues but when I started it the next day I could hear (over the loud lack-of exhaust) an obvious clacking. I shut it down immediately and found one of the rockers had come so loose it turned sideways! The nut for it had almost fell off the end of the guide. The rest seemed firm and slackless. I tightened it back down but I can't hear a damn thing over the loud exhaust. To make it more interesting, I think 1-2 or more valves are clacking already, so how do I get the valve lash setup? I wanted to learn how to do it while the engine was running as it seems easy (loosen till you hear clacking, tighten till you don't and then tighten another 1/4-3/4 of a turn).

Any suggestions? Should I pull the spark plugs and just attempt it (again) by manually turning the engine and using a feeler? I need to drive this thing to the shop on Tuesday to get the exhaust done but I don't want to do any damage on the way there.

Thanks

I have only ever adjusted valves using a feeler gauge. Its been awhile as most engines i play with now have hydraulic setups.

Your post helped me significantly. It prompted me to research the different methods of setting valve lash (didn't realize there was different methods for different lifters/setups) and discovered I did it wrong initially. I do have a hydraulic cam/lifter and I used a feeler gauge to give it 30 thousands clearance when it looks like I should have got it to 0 lash and then tightened the nut an additional half turn. So with that clearance I expect they are all too loose, which is why I'm hearing all kinds of clacking. Phew, At least I didn't over tighten and bung up my rods/lifters.

I'll be redoing the lash in this manner with the engine off later today. Thanks again.

I always set the valves with the engine off.
Mark the balancer at TDC and 120 and 240 degrees. Start on #1 TDC and adjust both valves by watching the pushrod hitting the lifter cup. Once it has fully touched, then tighten down another 1/2 turn. Turn crank to the next cylinder in the firing order (153624), Which is 1/3 of a turn to crank and repeat the process until you are done.

not a problem, i'm looking forward to seeing youre car get turbo'd. I've been studying your site and really appreciate the videos you post. lots of good stuff.

I'll be doing it this morning and following this fairly close. Thanks for confirming the process. You wouldn't happen to know of any posilock nuts that fit under the stock 250 valve cover? I'll probably continue to use the stock ones for now but it might be a good future upgrade.


Thanks for the feedback on the site, I'm glad to hear someone finds it useful other than me. I'm rushing to get the car back on the road so I can get it to the in laws house where I have access to a welder to mount the turbo. The turbo could be hooked up as early as this weekend. However I won't be putting any boost in it until it's got a few more miles on it.

As an interesting side note, the wastegate I chose last year (SPA Turbo 36mm Compact Adjustable) had a discontinued proprietary "S" flange that made it a concern to buy, but for the price I didn't sway. Turns out a distant relative had a waterjet cutter and was able to cut my turbo, wastegate and wastegate downpipe flanges. They turned out great and made that wastegate worth buying after all. I was going to have him make me a few of those "S" flanges but I doubt anyone else buys discontinued parts like me

Alright.. The lifters are set and she purrs like a kitten. I knew I was running rich but after hooking up the wideband today it turns out I'm running 13ish at idle with the mix screws almost all the way in and as soon as I tap the gas I go as rich as 8-10. Revving the engine brings it down from 13 to 8 every time. I get lots of dark blue smoke too. But she sure does drive nice.

The carb is a rebuilt (by me) Holley 600cfm 4776 DP - Primary main jets 65, Secondary main jets 75, Power valve 6.5, Primary Nozzle 31, Secondary Nozzle 32.

I need to be able to drive it a ways to get it to the in laws where I'll mount the turbo.

I'm pretty sure it's going to be jet sizes, so I'm hoping some carb guru could make a educated guess on a jet size to get me to around 14 when cruising. Also, is there a trick to lean out the idle more than the idle screws allow?

I was thinking of getting 58's for primaries and putting the 65's for secondaries... that sound good or should I go lower?

13 is good at idle with these engines. I have tried going leaner to 14 on mine and it did not like it.
The jets you have listed should work fine. If you aim for 14 at cruise, it will get bucky and bumbly. You will see what I mean.

Blue smoke is not a good thing, are you sure it is not black? That carb is a double pumper and can throw a lot of fuel in with the double accelerator pumps.

I know your using it for the future turbo setup. Normally, that would be too much carb to use for a N/A engine. As it has manual secondaries.

Yeah I'm fairly happy with the 13ish idle but it requires just the slightest feathering of the gas to watch it bomb to 10.

The smoke is definitely blue but it's not the typical haze I've seen, it's darker... Almost navy. My theory is I'm flushing the cylinders with excess fuel and it's burning up all oil in there. It only does it when accelerating off idle as idle and cruise are transparent. The engine still only has about 45 minutes on it so I tributed some of it to it still being new. If it doesn't go away once I get this richness sorted I'll have to check plugs and compression I guess.

I'm going to lower the fuel bowl level and see if I have any smaller nozzles as perhaps my pumps are just too aggressive.

It wouldn't be so bad if I didn't have to order in jets from off Island with a 36 hour arrival time. Plus holley doesn't make a jet kit that covers the 55-64 jets I need to play with.

Not trying to be bearer of bad news but blue smoke from accelerating off idle sounds like a valve seal leaking.

Well if you're right, that's a lot better than rings which is my fear. I used umbrella seals. I had a difficult time figuring out how they are supposed to go on. I put them with the big opening facing down and they seem to fit into the lower Groove on the valve stem right above the guide. That sound like I put them on right at least? The Rings were properly gapped and I'm quite confident I didn't put them in upside down, the instructions were clear.

None of the local repair shops carry jets so I ordered a size 58 today.

As for lowering float levels, does it have any side effect other than leaning out the mixture?

Lower grove on the valve stem? I think they go lower than that and a small o-ring goes on the lower groove. Which I guess is to keep the seal down? Also keeps the valve from being able to fully drop into the chamber if such a slip were to happen.