Thread: 350 issues

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Hey there everyone! Ive got an issue that if I had hair, I'd have pulled it all out by now. So I'll try to provide all the relevant info I can at this point. Hopefully those more knowledgeable than I can help me end this misery.

The Car: 79 Camaro RS beater (it's been mistreated)

The engine : 1973 block with 2.02 1.60 heads (bought as set) bored .040 over. Crank is GM 3932442 3.43 stroke. Cam is an Erson, though exact numbers are unknown to me. I could not locate any info on cam. Rods and lifters were in place already and all I can say is they are roughly 7 3/4 inch , no burs and all straight lifters were also pristine (micced all of them). This motor was assembled, but had sat for nearly 15 years. I pulled it apart to check everything out, clean it , added new rings, kept the pistons as they were clean (minor ignition signs; looked practically new). Re-honed / crosshatched the cylinder walls, reinstalled everything in the order it was removed. topped the block and heads off with the Torker2 intake that was with it and am feeding it with a Holley 4160 C (brand new) Set Harmonic at 0 deg verified TDC and Valve position, stabbed distributor (HEI GM) 5:30 position. Everything is torqued by the numbers (e.g. intake 35) If I can manage to keep it running Vacuum gauge shows no deviation and stays at center of 9 - 10 PSI. I have tried every trick I can think of to get this motor to start from key turn but it just wont do it unless I feed it fuel repeatedly and when it does start it will not stay running. I have even gone as far as to pull the valve cover and set the distributor to 10 -14 deg BTDC. Nothing is working for me. I have adjusted the Carb from lean (all the way in) to 2 and a half turns out for a richer mixture, all to no avail. At this stage I am about ready to pull the whole thing out again and start over as I just dont know what else to do. So with what little info I have here does anyone have any suggestions or ideas where I should start looking or what I may be missing. I will add that the battery, distributor, water pump, fuel pump, wires and plugs are all new. There is a fuel pressure regulator installed to keep the Holley fed w/o overfeeding it. Initially the pump was feeding 10 -12 PSI and Holley recommends no more than 9. I did this when I realized the Carb was feeding alot of fuel, checked the fp and saw nearly 12 psi.
Thanks in advance for any helpful ideas.

As I am not aware of what type cam I have could that possibly be my issue?

I probably don't have more knowledgr than you but, since no one tried to help I will put in my 2n cents.
Sounds like you have everything working except fuel. You have 9 lbs. FP. Recomened by the carb co. Seems like it should be 4-5 as most posts I've suggest.
Won't start unless you force feed it fuel.
Sounds like the problem is the carb. Do you have a known good working carb you could swap on just to try?
If not try to read all you can on your carb and then see if it is doing what it is supposed to do.
I am only familiar with the Rochester.
Problems with them would be blocked passages for idle circuit preventing fuel from entering the venturi and not startingWill start if you pump it but won't stay running.
Hope this helps. Bob

Well – first let’s have a cup of coffee! It sounds like you may have several issues and they need to be diagnosed/healed one at a time.

First, I would echo the fuel pressure recommendation, i.e., get it down to 5 PSI.

If you don’t have the Holley manual, download here: http://www.holley.com/data/Products/...l/199R9881.pdf

The 4160 has a lot of connections. All of them need to be either “connected” or plugged. Refer to the picture below and make sure that you have everything hooked up correctly. Pay careful attention to numbers 3a, 4, 7a and 7b - if you’re not using them, plug them. Also #5 is the only port the PVC should be connected to.

Unless you have one “killer” cam, your vacuum needs to be higher. Would hope you have at least 17 inches at idle, 20-22” is better. Measure your vacuum at 7a. Your current reading tells me there is a vacuum leaks or something open somewhere.

Give this a go and let us know what the results are.

Good Luck,
Glenn

I actually only have 3 vacuum ports on this newer version of the carb. According to your diagram they equal Ports 5, 7a/7b and 3a/3b. 5 has the PCV connected, 3a/b has the vac advance connected and finally 7a/b is capped. I felt that the vacuum was definitely too low but without it running steady its hard to figure out exactly what the vac pressure is. The key to me is just getting the car to idle correctly. I tore the top end down again, new gaskets and seals and re torqued everything again. I have checked all hoses (not a lot to check really) carb gasket, etc. I am nearly at witts end with this.

Jon, since Bob and Glenn are covering the carb, I'll move on to some other areas.

You said you pulled the top end down. Did you retain the intake gaskets? If so, examine them closely for being compressed (pinched) all the way around each and every intake port. You could have an internal vacuum leak that you would never find by spraying a flammable material on the outside of the motor in an attempt to find a vacuum leak. Here's a tutorial I wrote for the wiki on another forum.....
http://www.crankshaftcoalition.com/w...ad%2C_internal

The other thing that comes to mind is the valve adjustment. Valves could be too tight, particularly if you used the "twist the pushrod" method of adjusting. Follow this procedure and see if it helps.....
Bring the #1 piston to TDC on the compression/firing stroke. Do this by removing #1 spark plug and rotating the crankshaft clockwise by hand while holding your thumb (or your buddy's thumb) over the spark plug hole until you/he feels compression as a result of the piston coming up the bore with both valves closed. Continue rotating the crank while watching the harmonic damper. When the TDC notch on the damper aligns with the timing tab on the front cover, indicating TDC, stop. Back off the nuts on the intake and exhaust valves on #1. Move the pushrod around a little to make sure it is seated in the pushrod cup of the lifter plunger and not up on the face of the plunger. While holding the rocker arm tip down against the valve stem tip, jiggle each pushrod up and down while you tighten the nut down to zero lash. Give the nut another 1/2 to 3/4 of a turn. Adjust both intake and exhaust.

On the front face of the harmonic damper or on the face of the crank pulley, use WhiteOut to make four marks. One at 12 O'Clock, one at 3 O'Clock, one at 6 O'Clock and one at 9 O'Clock. This stuff ain't rocket science, so the marks don't have to close to the nearest thousandth or anything. Just eyeball them like you would a clock face and get them close.

Turn the crank 90 degrees clockwise (1/4 turn) so that the mark you made at 9 O'Clock comes up to 12 O'Clock. Adjust both valves on the next cylinder in the firing order (#8). Turn the crank 1/4 turn so that the mark you made at 6 O'Clock comes up to 12 O'Clock and adjust both valves on #4 cylinder. Continue doing the rest of the valves in the firing order (1-8-4-3-6-5-7-2). To adjust all the valves, you will make 1 3/4 revolutions of the crankshaft from your starting point at #1, rotating the crank 1/4 turn (90 degrees) clockwise each time between adjustments.

For those wondering about adjusting both valves on one cylinder at the same time.......
There are 720 crankshaft degrees of rotation (2 complete turns) to go through a complete firing of all 8 cylinders.
With the piston at TDC firing, the intake valve closed about 140 degrees ago and won't open for another 330 degrees, so the intake lobe is on the base circle. The exhaust valve closed about 340 degrees ago and won't open for another 120 degrees, so the exhaust lobe is also on the base circle.

Now, all this valve adjustment business assumes that the harmonic damper inertia ring hasn't slipped on the hub and still is valid for TDC as relates to the hub (crankshaft key). It also assumes that you are using the correct timing tab on the front cover for the harmonic damper used. There are 3 different timing locations used on a small block Chevy, 12 O'Clock, 2 O'Clock and 2:30 O'Clock. So, if you had a 12 O'Clock damper and a 2:30 O'Clock timing tab on the cover and/or the inertia ring has slipped, it is possible that you could be off the base circle when trying to adjust the valves. Of course, if that were the case, the valves would be too loose and thus noisy like solids. Here's another tutorial I wrote to validate the damper inertia ring as it relates to piston TDC.....
http://www.crankshaftcoalition.com/w...op_dead_center

Thanks tech! I will give your method a shot. I did adjust valve lash based on the "wiggle" method as I have previously. I know at least one valve was over tight by about a 16th as I got a bit of oil blow by on start up. I went back in and readjusted again for that. I hadnt even thought that the valves being a bit snug could cause my issues. Since I have ruled out the carb intake and head gaskets and fuel pressure (I made a response for the above pressure but for some reason it had to be approved by moderator before it will show up)as well as ignition, fire, etc; I will give your method a shot tomorrow. I had read your guide before (very well done I might add) but just did not really think it could be the issue here. Nothing like learning a new method Thanks for the assist! Keep those ideas flowing guys!

tech I did as you suggested, got the car running and idling though its lopey as all get out and sounds like its missing. I had to turn the carb mixture screws out 3 turns, as well as set the throttle all the way in to get her to idle. Its "running" so to speak but nowhere hear where it should be. The harmonic definitely needs replaced, thanks for cluing me into that one no rapping of valves and no blowby of oil so I am going to assume that the valves are right now that I have corrected the harmonic issue with your insight. while idling I re-attached the vac gauge, 10 is the highest it gets at an idle of 2000 rpm. I did notice that when I fed it gas the needle would damn near bottom out then pick up. I figure that in itself can be a huge clue where I need to go next to find the issue. I checked the manifold with your directions as well as the old intake gaskets. Everything is meshing well so I can rule out the intake to head seals. I'm at a complete loss here. Ive checked the vacuum lines, the intake, the carb gasket; I'm just lost now.

You've gotten great direction on here so far.
I have a question about where is the lash set at and it is possible that since the specs on the cam are unknown, is it possible it's a solid flat tappet and the lash you are sitting at now has your engine struggling to run?

Great question, if I knew the answer it would be even better There are no markings on the cam, and no color of any kind either. I would not know the nuances of one versus the other to know the difference. Its funny though now that you mention it, It ran a little better initially , but I heard tapping from the #2,4and 8 cylinder's valves the first time I ran her. At that time it idled better , but the pressure was still low. I could not take the tapping, so I pulled the valve covers and commenced to do the ol twist and tighten method. the first time I knew I was over tight as I had oil blowby, I readjusted again and got rid of the blowby. Now it definitely struggles to run. I had half a mind a few days ago to throw on the 305 heads I have that I know were fine when I pulled them. I decided against it because they are the nasty GM swirl heads and although they were ported about a year ago, I did not honestly feel I would get much benefit from them as the valves are 1.84 / 1.5. Not knowing my cam has left me uneasy to begin with, throwing a different set of heads on could further worsen my dilemma.
Is there a way to tell via casting what the cam type may be? like cranks?

I would think that if you had solids lifters you would have a set of bent pushrods,and/or pulled rocker studs by now. I would suggest backing off the lash by a 1/4 turn each and see if things get better. If you get to the point of clatter,you might just have way too much cam. You didn't mention exhaust, I hope you have headers and low restriction mufflers. You mentioned fattening up the idle mixture, try jumping up the jet size and see if it helps. Hank

Headers are hooker, exhaust is 3" all the way out true dual, no Cats.
After further research, I have discovered that what the vacuum gauge does is normal so my mind is a bit more at ease there. I did however learn that for higher elevations will cause lower readings on the gauge. Anyone know what the specifics are for say the Mile High City? I'm going to pull the carb and blow the metering blocks to make sure there is no trash there, throw on a new gasket for kicks and see if any of that helps. The only other potential issue I could find for low readings is cam timing. Once again it wakes me wonder if I should just throw a new cam and lifters in. The cam was in it when I got this motor, the timings gears are double, and there was absolutely no slack in the chain nor was there any chipped or broken teeth. I know now the Harmonic needs replaced and intend to order maybe a TCI rattler or something similar. Now because I am new to this whole gig, exactly what determines cam timing? Anyhow .... back to the garage for some more playing. Thanks for all the ideas so far guys

ya know as I am reading over this and what you have done so far and the fact that that you don't know about the cam maybe try adj the valves as solid lifter say 10 and 12 tho. and see what happens kind of like chicken soup couldn't hurt just a thought .....ted

Originally Posted by ted dehaan

ya know as I am reading over this and what you have done so far and the fact that that you don't know about the cam maybe try adj the valves as solid lifter say 10 and 12 tho. and see what happens kind of like chicken soup couldn't hurt just a thought .....ted

I was thinking along the same line except I'd start at 30/30 and go from there.

i have never heard the term oil blowby. not trying to be a smart ars, but do you mean oil coming out of push rod?

You can expect vacuum to be about 2" less here around Denver.... I'm pulling 5" with a pretty big cam

What is the state of the carb? Have you torn it down, cleaned it and rebuilt it? Sounds like the idle circuits aren't working if you have to crack the throttle plates open to get it to run.

-Chris