Inliners International Forums General Discussion Engines My 'new' 250 is alive!

The original thread about my engine is gone but for those who have followed my trials, here is an update. The engine was started last week and sounds great!!!! I ended up going with an original points style distributor just for looks.

Some of you may remember the head which had a lot of work done on it also had a broken boss. While some recommended great caution which I appreciate, I took the head to a couple local speed shops and had the head evaluated by their engine guys. In both cases I was told that there was 9/16" of threads holding the stud in place and with stock springs I should be fine. I did replace the aluminum spacer with a cast iron spacer so expansion rates would be the same. New springs were installed also.

I'm running an Edelbrock 500 cfm on the clifford intake. A spacer was made so the linkage would clear the manifold.



I also modified the rear tube header to turn 90degrees and pass under the back part of the oil pan. A heat shield will be installed but I still can drop the pan and now I will have mufflers on both sides of the car which is what the chassis was designed to accept.



It has been a long time since I heard an inline six on split manifolds but I have to admit it's a great sound!

One other problem I had was the slave cylinder for the 84 T5. It it the header tube so I cam up with a bellcrank style mount.



I'm eager to get the brakes and pedals installed so I can drive it around the block!

Thanks for everyone's help and advice!

GREAT to hear it's up and running. Looking Good

Ok, a few questions. Been working on the mechanicals of the car and got back to the engine. I noticed previously that the car had very little vacuum at idle. The valve cover was never put on so I tried loosening the rockers until the engine smoothed out and the vacuum came up. When I did that the lifters rattled but I had good vacuum. Motor sounds very solid. No smoke, no knocks.

What I think I have is a big overlap cam. VERY lumpy idle, pretty much needs to be about 1000 rpm to not shake the car. It was much smoother at lower RPM when the lifters rattled.

I'm running power brakes and need decent vacuum.

I suspect this indicates a cam change. Any suggestions as to what cam is appropriate, where to get it etc. I'll change the lifters also. Remember this motor has some fairly significant head work with V8 valves, Clifford Tube headers and Clifford Aluminum intake with Edelbrock 500 cfm carb. Currently has 1.5 ratio small block rockers.

I want as much power as is reasonable but need driveability more. It's a driver not a race car. This is a 2200 lb 5 speed manual car and I don't want to have to feather the clutch at 1500 rpm to get it to move.

Also, I have a cheap set of guages on the car with a capillary tube oil pressure guage. Once it gets up to temp, the oil pressure at slow idle (800rpm) is very low...probably 5psi...runs about 40 psi at fast idle, 1250 or so. A friend suggested that it might have race bearings (double groove. When I had the pan off I didn't pull a cap so I don't know. I'm getting plenty of oil on the top end. When I was adjusting the lifters I was splashing oil everywhere even with the anti splash clips over the oil holes.

A set of Rhodes lifters might improve your bottom end with out having to change the cam. The theory behind rhodes lifters is that they don't pump up till you start to get into rpm. They also will eliminate some of the lope and better torque. I'm sure there will plenty cam suggestions.

Do you have a mechanical oil gauge you can replace the sender with temporarily? The thread is 1/8th pipe.

Larry

i would suggest getting rid of the power brakes. my car is 3650 lbs and i have manual brakes, it stops on a dime. then you could keep the existing cam. your car should be able to easily stop with manuals also.
the 250 should have plenty of tq to get that light car moving , especially with the T5 trans. it has a faily low 1st gear.

what weight oil are you running?

i suggest setting the valves properly and running it as is. tom

The roadster has Corvette C4 front and rear discs. Not sure they will work without power assist.

I'm running 10-50w. Thought I might try some straight 50W.

I'm not happy with the idle so something has to change. The Rhodes lifters are interesting. I googled them and read a bunch of forum discussions. Seems the noise is the only complaint. I can probably live with that as they will sound solid and therefore 'old'. Remember I'm building an art deco style roadster... something out of the late 30's.

The oil pressure gauge is mechanical. It has a plastic tube direct from the fitting on the block.

Kerry Pinkerton

First off I think your biggest issue is the Rockers,
Our L6 rockers are 1.75s That 1.5 is WAY!! to small Put the stock rockers on and then see how it runs.Or if you have a set of
BB rockers they are 1.7s and will work a 100% better then the
SB 1.5s

Do you know what the cam specks are?? Secondly seeing some of
the oter problems you have ran into.I wounder if someone Built
your motor with V8 rods This can cause a oiling problem if the
crank Or rod was done right You would have more bottom end bleed
off.????

But personaly I'd deal with your rockers first. And most cams
OVER a RV type like a little more idle rpms (then stock 800 rpms)
Hope this helps.

I'm confused Larry. I thought that going to a 'smaller' rocker would decrease lift. Obviously it won't change duration much. The motor originally came to me with BB lifters but some of them were 'wallowed' out in the pushrod area. I bought some SB 1.5 lifters thinking that would make the big cam effect less severe. I do not know the specs on the cam other than it was supposed to be .600 lift. I measured 3.3X on the cam lobe with a dial guage (think that was what it was..I posted it on the site but all the old messages seem to be gone.)

If it's not obvious, I'm not a master engine builder. I've built several engines but all stock. Never done any performance stuff at all.

The motor is supposed to have V8 rods (283) but I don't know for sure.

I believe you are talking about rocker arms not lifters?
Yes, going to a lower ratio rocker arm will decrease lift & duration.

You need BBC rockers or ones made for the 6 cylinders 1.75 ratio.
1.8 ratio.
The duration difference will not chage your idle that much & I do not believe running a SBC 1.5 ratio rocker arm will have correct rocker arm geometry. (I do not think they will work)

If it has 283 rods,then you are loosing oil pressure there because SBC rods are narrower on the big end therefore it will cause excessive oil slashing all over the crank & rods.

Did you decrease the hole outlet on the tube that directs oil to spray/drip on the cam gears? If not,that might bring up some oil pressure.

MBHD

I thought the original owner told me they were SBC rockers and that is what I ordered. When they would not fit over the studs (7/16?) I went down to the engine shop and we talked about it. When he looked at my original rocker arms he said they were 1.7 BBC and that no one made a 1.5 BBC rocker. However, he suggested I enlarge the slot in the SBC lifters which is what I did on my Bridgeport, using the nuts and rocker washers that were on the engine when I got it (they fit fine in the sb rockers). They appear to fit fine. No interference, no rubbing of the pushrods on the holes in the head and the end of the rocker is on the valve.

Did I say I don't know what I'm doing???

You keep referring to your rocker arms as lifters,makes me think you are not too familar with parts of an engine??? Don't know.
Anyways,,, I would think you must have bad rocker arm geometry running SBC 1.5 ratio rocker arms.
The rockers arms must be hitting on the edge of the top of your valve stem???? (Really easy to see w/a roller tip rocker.)
It should be hitting the center of the valve stem,easier to see this when you have roller tip rocker arms,which I would recommend anyways,because the six cylinder has short valve guides & have a dendency to wear more (the guides)+ with better rocker arms you get more even lift, not like the factory stamped units.
They are supposed to be 1.75 ratio, but they are not accurate,some could be 1.6,1.68 ,1.72,,,etc.
Comp cams sells roller tipped ones that are not too much if you are on a budget.

Not sure what type of answer you are looking for,but I would definately not run 1.5 ratio rockers arms,the geometry has to be off. Not contacting the the top of the valve correctly.

MBHD

Kerry,
Try using Crower SS roller rockers. They make them for the 194-292 series six cylinger engines. They're the correct 1.75:1 ratio and the geometry is right, plus they're smaller than aluminum rockres and more durable, and they're available in both 3/8 and 7/16 stud sizes. Crower has an online catalog if you want to take a look at them on line. I'm going to be ordering a set of them for my 194 as soon as I put another couple paychecks in the bank to pay for them. You can get them from Summit racing. Don't screw around trying to make BBC or SBC rockers work, they won't ever really be right.

Hey 64NovaWagon
Just for the record I want to let you know I ran Cranes Gold BB 1.7 rockers for the better part of 17 plus yrs on my 250 with a 583/607 lift cam and ran that motor as much as 8000 rpms and I never had a issue with the tip of the Valves Nore have i ever had to replace any parts due to useing Those rockers. And I had asked Mike Kirby If it was worth the money to get a 1.75 rocker
and he told me if i wasn't having any problems with what I had on the motor IT wouldn't be worth the cost to buy new ones NORE
would i see a difference in the motor.

But yes there is a difference in a 1.7 to a 1.75 But kerry if you
can get your hands on a good Used set of 1.7s from a BB (for cheap) WE have Harland Sharp make rockers for US That are a true 1.75 and are also machined for Big lift cams & Large DIA springs
(meaning they have been machined for push rod clearances & Springs also 1 & 12 have machined to clear the valve cover.)
You can get them from myself Or MrHotRod6

Hank, I know the internal parts quite well. I'm just bushed. We've been keeping my month old granddaughter this weekend and sleep deprivation is kicking in.



If I get out in the shop today, I'll take some photos. They appear fine to me but I understand what you mean about the geometry.



What I'm looking for is suggestions for a cam or other solution if there is one. Given I don't know what this cam is, I'm not sure it makes sense to dink around with leak down lifters. Especially if I end up going to 1.75 rockers. The Rhodes lifters on 1.75 rockers would probably put me pretty much where I am today with the current rockers in terms of duration and lift at idle.

If I replace the cam, I'll replace the lifters and rockers to what is spec'ed for the cam.

I have no idea what was in the other thread you referred to.
Are you sure you don't have solid lifters/cam?
If you adjusted hydraulics to 1/2 or even a full turn past zero lash, you should not have that big a change in vacuum when you backed them out to zero lash.
If you adjusted solids as hydraulics, then the vacuum would go to hell real easy at anything below zero.

Several months ago I had a thread about this motor. It's gone with everything else. A bunch of folks including Larry, Frenchtown flyer and others had made posts. there were some cam recommendations in the original thread also but they are gone now and I didn't copy the specs...

Definitely hydraulic lifters....had some out. Vacuum increases (and idle improves) as lifter adjustment is BACKED off...thereby decreasing valve lift/duration but making the lifters rattle.

Hi Kerry,

Your original thread is still available, we didn't lose anything. In each forum, go to the bottom of the page and set your display options to go as far back as you wish. I have them set so they won't load years worth of threads each time the forums are viewed by default for performance reasons. Each BB member can set up their own computer according to interest.

Tim

Kerry,
It sounds like whatever cam you have in your 250, you aren't too happy with it. As far as a recommendation for a different cam that would give you more vacuum, take a look at the Comp Cams website. I think their 260H cam and kit would probably do about what you want for a street engine. Cam specs are: powerband - 1000 to 5000 rpm, advertised duration 260 degrees (212 degrees @ .050 lift), .489 lift with 1.75:1 ratio rocker arms, and 110 degrees lobe separation. The also make a 268 degree cam which gives you more power, but you lose some of the vacuum. Check out their website at http://www.compcams.com and take a look at their online catalog. They also have springs, lifters and timing gears to go with the cam.

As I said in my introduction a few months back...I'm a metalshaper more than a mechanic and I'm afraid this has bit me.

I'm a dumb ass and I've probably trashed my motor and wasted a grand and a bunch of time. I ordered a new cam from Clifford for my 250, one of their 264s based on their recommendation. The cam that came out of the car had a thrust plate AND a tapped hole with a bolt and washer to locate the cam. The new cam did not have the tapped hole and I didn't think anything about it. Froze the cam and pressed the timing gear on, installed, etc. Motor ran for about 10 minutes and started backfiring through the carb.

I quickly shut it off, pulled the valve cover and noticed #4 pushrod was about 2" below the rocker...pulled the side cover and found a lifter broken in half...bottom half and internals in the pan.

The cam walked backward and the lifters got off center lobe and a couple lobes are wiped. Called Clifford and they said there is supposed to be an allen screw behind the rear freeze plug on the cam gallery that determines the forward location for the cam and the thrust plate determines the rear location. News to me and there was NO paperwork or instructions with the cam....still it was my fault. No warranty of course but whatever I do it won't be another Clifford. I expected some instructions at least but I
should have called them with questions.

I'm still using the head with the repaired boss and stock springs. Clifford said I needed 125# springs anyway and I'm not sure the head will hold up to it so I'm not sure what to do. I have no idea what stock SB springs rate and don't have a way to test them.

Haven't pulled the block yet so there may or may not be damage in the innards.

I'm thinking I basically wasted a bunch of money on this whole thing...I've got three choices as I see it.

1- IF my short block is good, I could get a new head. I'd like something better than the stock head especially since I have the Clifford intake and a 500 cfm Edelbrock and tube headers. I do want a very streetable motor though...something the wife can drive without having to slip the clutch at 2000 rpm to get it moving. What kind of head work do you think I'd want, cam to go with it. Who builds such things and what kind of price would
the loaded head run me?

2- IF the bottom end is ok, replace the cam with a milder version that will work with the stock small block springs (new).

3- I found on ebay an outfit in Washington state that offers a totally rebuilt 292 for $1000 + $175 shipping + $175 core and it has a 7 year 100,000 warranty. Everything new. http://cgi.ebay.com/ebaymotors/ws/eBayIS...%3DOp2%26ps%3D5
Ever heard of them?

Would my intake and exhaust manifolds work or be overkill on a stock engine?

Looking for options, insights, and advice. This happened this morning and I was so happy I just cut the grass...

Regards

Kerry Pinkerton

The Clifford intake is not good for the street especially on a 250 or smaller engine low compression,bad gearing & so-on.

Poor gas mileage,poor low & midrange.
You will need to slip the clutch more with that intake over an Offy.
Talk w/twisted6 for your head work suggestions.
Stock SBC springs can be 70-100 lbs @ the seat,IIRC?

If you are going with standard dished piston 250 I would look for a smaller chamber 194 head.

Go with a zero deck on your next engine.

Two cents thrown :-)

MBHD

I plan on building a similar motor soon (292). Want good drivabilty. Are you saying that an Offy 2x1 or 3x1 would be a better option over a 4bbl intake, or an offy 4bbl intake would be better over a clifford 4bbl?

I have quite a few option for used intakes right now and I'd like to select the best one. Plan on using a mild RV cam, split headers, TH350 trans w/ stock converter, 2.78 rearend. Would like to get the most bang for my buck. I'll probably look at head modifications down the road.

Built plenty of performance V8s, but seems like the rules change with I6s.

And for what it's worth on the topic at hand. Bad valve train geometry sounds like the main culprit of what was happening. I'm not sure what the difference is between the valves but you said your heads had SBC valves, maybe whoever originally built it was using the SBC rockers to compensate for valves with a different stem length.

I wouldn't be too concerned about a broke lifter. Probably just smoked your cam and lifters. I would put money down that said the rest of your motor is fine, unless you cracked the block. I've seen lifters explode a few times in V8s and none were catastrphic enough to ruin the engine or block. Might check the lifter bore for serious scoring though.

Take the cam out and rotate everything. I doubt it's froze. Probably just locked by the cam and lifters being out of alignment. Was there any head damage due to push rod dropping? If not, you'd probably be ok.

WELL first off what the guy at clifford said is a load of Crap.
There is no allen screw Or anyother type screw. What locates the cam Or keeps it in it's place is the retainning plate on the front of the cam and the cam Gear itself.
Now as to the intake Yes the offey is better for the street because of the runner size. It keeps the air flow up even on a ported head. Where as with cliffords larger runners size It was ment for mid range to upper rpms OR air flow. The best way to fix
It's low end air flow issue would be to install a lump port kit.
This will help make that intake More street friendly. But i have
seen and know guys who run this intake on the street and do not seem to have any issue with it. Mind i have not driven their rides personaly But I can only tell you what they have told me.

But if you have a head that the boss has been removed and are running a clifford intake and do have low end problems One of two
things can be done 1) swap to a offey Or 2) install a lump port kit.

A stock spring (esp a used stock spring) will not live very long
even with a very mild RV style cam. I know Personaly Been there
Done That. For most mild hyd cams with up to about a 530-550? lift The Z28 Sb springs will work.

But anyway Kerry I'll finish reading your Email and get back to you. Let us know what you find out on your block if it still good or not.

Does somebody sell Lump Port Kits? Or is this more of a machining process. Everything I have read points to a metal additive process that requires lots of grinding and experience. Some sort of a bolt-in or weld-in "kit" would be nice.

Sorry for lack of experience, this is an honest question... Thanks.

Sigh...

Well crap, this is the gift that keeps on giving.

Dropped the pan and found all sorts of chunks O Lifter in the bottom but no apparent damage. Until I ran my finger down in the broken lifter bore... Really rough and a good lifter won't go down it. Lifting the car this is what I see from the bottom:





You can't really see the scoring but the bottom part of the bore is pretty chewed up. Don't know if this can be saved or not but I doubt it without some heavy duty machine work. I could hone the bore but I expect the lifter would wobble and soon wipe the cam lobe.

Given everything else I'm leaning hard toward just buying a rebuilt, warrantied long block 292 and be done with it.

Ya pays for your education one way or the other. I've now learned that you ALWAYS need to replace the aluminum cam gear when you replace the cam because the press fit has to be tight enough not to let the cam slide backward. If I had drilled and tapped the cam for a bolt I'd have been OK.

Any thoughts and comments appreciated.

From what I know about SBCs, a heavily scored lifter bore usually equals a scrapped block. Not sure about I6s

Is there a way that you could bore the lifter bores larger and use a different lifter that is slightly larger in diameter and make up for any height difference with a over/under sized push rod? Just an idea, I'm not a machinist.

Considering what you've already spent, I'd try my other options before tossing a bunch more money at another engine. By the pics, it still looks like you have a ways to go to finish your ride. So what's the hurry on the motor? Maybe you could use the spare time while working on other parts of the car to track down another block and move everything over.

If I was in your position, I think I'd give my machinist a call and explore some options.

If you do end up going the route of a rebuilt crate motor, and still plan on using the head off your current engine, I might be interested in buying or trading for the head off the crate.

Was thumbing through Leo's book and on page 78 saw that it is apparently possible to use larger diameter lifters.

Chevy Diam= .842"
Ford Diam= .875"
American Motors= .904"

Says: "The larger Diameters are used when the rules specify flat tappet, but prohibit mushroom lifters".

So you must be able to bore the lifter bores and use bigger lifters.......

Yes you can bore the lifter bores bigger if you need to.

MBHD

trump I sent you a message in regaurds to the bolt -in lump kits.
Kerry that does not look so good and i am so sorry to see that happen to anybodys motor

"I plan on building a similar motor soon (292). Want good drivabilty. Are you saying that an Offy 2x1 or 3x1 would be a better option over a 4bbl intake, or an offy 4bbl intake would be better over a clifford 4bbl?

I have quite a few option for used intakes right now and I'd like to select the best one. Plan on using a mild RV cam, split headers, TH350 trans w/ stock converter, 2.78 rearend. Would like to get the most bang for my buck. I'll probably look at head modifications down the road. "

I personally have not used the two 1 barrel intake or the 3-1 barrels.
Between those two, the 3 1 barrels would be a better choice.

I would run the Offy 4 barrel intake over all of those choices.

If you are going to build a new engine & head, you should really intall some lump ports now,,not later down the road.

With the Clifford,you are losing a strong signal to your carb,low velosity of the Air/fuel entering the intake ports.

The Offy 4 bbl intake will give you a better signal to whatever carb you use,possible better gas mileage,more low end torque.

As I always said, the best bang/best HP ,best torque for carburated (SP) use three side draft Webers DCOE's & the Clifford side draft intake manifold.
It is pricey,but that will give you the most out of a carburated engine. Especially for a street car.

I have personally have used both the Offy & Clifford four barrel intakes on my 250's.
I have used Quadrajets,Thermoquads, Carter AFB's AVS's Dual jet two barrels,Holley double pumpers,vacuum Holleys ,two barrel Holleys.
1,2" spacers,open hole , 4 hole spacers.
The Offy is by far a better street friendly manifold.

But that's just my two cents thrown.

Goodluck & any more q's just ask away.

MBHD

Looks like you have forged pistons in there, what ones are they?

MBHD

Hank, they are TRW aluminum forged pistons. I posted a photo of them earlier...before I wiped them off.



I'll pull the engine tomorrow and Monday I'll check with some local machine shops on sleeving or repairing the bore. If I can save the short block I have considerably more options. New head or just new cam with the existing head...

Ok,
I believe I have those pistons & those are really low compression pistons.

Not really good for high boost supercharging or turbocharging ,the top ring land is too high up. Can easily see detonation on your top ring & expose it & cause failure.

Not sure if you want to super or turbocharge?

If not, I would definately look into gettng a small chamber 194 head,which would give you around 9.3-9.5to 1 IIRC.

Install some lump ports & zero deck your block.
Take a measurement now to see how far down the hole your pistons are before you take it apart.
Part of the reasons why the newr LS1's & LS2'S can run higher compression is because they all have a positive piston height of .003.-.005 above the deck surface.Pistons sticking above the top of the block.

If you are going above 5000 RPM, definately look into getting an aftermarket damper V-8 style.

MBHD

Hank I did a CC and came out about 8.5:1. The top of the piston is .100 below the deck. I don't plan on turbo or supercharging.

.100 below the deck,,,that is not good.
There is no quench action going on there.

Are you sure it is .100 down & not .010 seems a bit excessive??

That would mean you would need to wake off .100 off the block to get zero deck.

I believe I have those pistons you have & milled them to be flat tops w/no valve relieves.

After the milling I did , now I would have to mill the block/deck down .103 to have a zero deck.

I can look @ the PN on my pistons to see if they are the same as yours,it's been a while since I looked @ mine.

MBHD

You're right Hank, it was .010...dang decimals always jumping around.

The number on the top of the piston is 2255P4. There are probably other numbers inside that I won't be able to see until I tear it down.

.010 sounds about right. :-)
I would have the deck resurfaced another.010 so you can get a good quench area going for you,this has less tendancy to detonate.

I ran 12.to 1 compression ratio , 220 PSI cranking compression It did not detonate w/91 or 92 octane. Mainly because I had a positive deck of .002 to .003 pistons coming out of the hole.

Goodluck @ the machine shop.

MBHD

OT and Sorry for the hijack.

Hank, what cam and intake/exhaust setup did you have that let you run that wild of an engine on pump swill (oh yeah, what engine was that)?

The engine is a 254 CI inline 6, intake bosses removed,& had my upper lumps installed.
It has been a while & several camshaft swaps, but the cam was about 236 degrees duration @ .050 lift was around .560 lift, lobe center of 110.
When you can have 220 PSI of cranking pressure,you know the cam was not that big in the duration department.

Exhaust were Clifford dual headers into a y pipe into single 2.5" to the rear. 3" would have been better.
Muffler was a Dynomax 14" muffler mandrel pipe inside muffler perforated to quite it down,it was pretty loud IMO.

I was running the Clifford side draft manifold w/three 48 MM DCOE Webbers. (Too big BTW) better to use 45's
It was a hard running engine,really torquey, I never went to a track but I would have to say it ran around 13 flat in the 1/4 maybe high 12's if I had just set it up for track use.

Car weighed 3500 lbs front & rear anti sway bars,Koni shocks for better handleing. So it was never set-up fot track use.

MBHD

Progress,

Got the lifter bore sleeved so the short block is good to go. Ordered new Competition Cams 260H and lifters. New head from Tom Lowe on the way....bosses removed, lumps, big valves and the correct springs for the cam. New timing gears.

Anyone want to trade an Offy 4bbl intake for my Clifford?

Glad you could save the block.

Not sure why you would want the Clifford intake over the Offy, but to each his own. Goodluck!

MBHD