Ok, I have 79' international scout traveller that i changed over to a chevy 350. Everything that could have gone wrong has, and so far I have over come it. The engine was in bad shape when i got it. Had it bored out, lined honed, It had two different heads and they were junk, so I bought some Goodwrench heads from the machine shop i used for $400.(they have a reputation for excellent work). Casting #83417368. He had completely rebuilt them, with new valve, new guides, new springs, the works. Any way after getting it running i took the truck for its first drive. It had a horrible whine in the rear end, and i almost run it out of gas.(in just one mile--dang the luck) it ran like crud on the way back, only about 1 mile. It was missing and ticking when i got it home. I found both intake and exhaust push rods bent "one broken" on the #4 cylinder. So I replaced them. Taped the valves with a brass hammer and they both worked fine. Then it run fine. After i rebuilt the rear end I took it for another drive and it did fine. Then it was idleing in the drive way and it started ticking again. I shut it off and checked the valves. #2 exhaust push rod was bent. The rocker was sliped off the valve and onto the spring. In fact all of the rockers have trouble with staying straight. I know i am adjusting the valves right, and i checked for spring binding. .060 feeler gage goes in fine. Cam has lift of around .450 or so. What could cause this? I did use the old push rods in the rebuild. Any ideas?

#1, did the machine shop use the right springs and the right open spring pressures? if they have stupid high spring pressures on stock push rods it might do it.

#2 are you sure you are adjusting them properly? describe how you run your valves.

#3 have you checked to see that your push rods are the proper length?

#4 do the heads have screw in studs and guide plates?

#5 you can get some decent chromo push rods from www.enginekits.com for around 40 bucks.

what cam do u have. i got a edelbrock cam and lifter set and it did the same thing. talked to them come to find out they had a whole buncha bad lifters. sent me a new set and no more problems.

i would definetly be in contact with the machine shop. sounds like a sloppy job on there part.maybe they will double check things for you.

Ok, well lets see......

1. The heads were built for a standard chevy 350 for a car dealership that never used them.

2. I put the engine at tdc and adjust the proper valves (acording to the chiltons). I tighten them to untile there is resisance on the push rod while spinning it in my fingers (zero lash) and then add 1/2 turn.

3. no I did not, they were the original push rods. I will have to check them just in case.

4. no they have stock studs and no guide plates

5. hey thanks for the tip on the chrom molys....

Next Thread. I Have a Comp Xtreme 4x4 Cam # 12-231-2 and lifters that cam with the engine kit from EngineTech. And you say Edlebrock had defective lifters?... was it always the same push rods that bent?

you have checked the spring to see if there is bind with a feeler gauge, but have you checked to see if the bottom of the retainer was contacting the top of the valve seal?

that one just drove me insane myself, i bent 16 pushrods figuring that one out. i was using a similar sized cam and vortec heads.

edit: that cam should not require chrome moly pushrods. not that i dont like them, im just saying that that cam is not aggressive enough to HAVE to have them. keep looking for bind, or silly high spring rates

Do your heads have slots or big holes where the pushrods go down to the lifters.I wonder if your heads are the later style that take the self aligning rocker arms.Basicly the pushrods use the slots as guide plates to keep them in line with the rocker arms and valve springs.The heads with the holes use the self aligning rocker arms to keep everything lined up.Self aligning rockers have little ears under the rocker by the valve springs.It might be as simple as that.Seems like the machine shop would have given you the self align rockers if the heads needed them.Hope this helps.Jon

That is exactly what i have suspected myself Jon. The rockers keep flopping around and falling off the valve stem and onto the spring retainer.
The heads are casting #33417369...(90-up...350....Gen.I Goodwrench crate motor,"Hecho en Mexico", 76cc) They are for the 86' and earlier blocks. But the holes for the pushrods are not slots. They are .465 dia cast holes and the push rods just slop around in them. I have searched to the self aligning rocker arms but have not been able to find any yet. Any idea where i can find them. Thanks Travis

you need guide plates

Look in summit or jegs and you will see the self-aligning rockers. Also, type self aligning into ebay and a few sets should pop up too.

Darren

http://tdogamadog.tripod.com/international_scout_traveller_79/

I put the engine at tdc and adjust the proper valves (acording to the chiltons). I tighten them to untile there is resisance on the push rod while spinning it in my fingers (zero lash) and then add 1/2 turn.


I too think you should use some selfaligning rockers.

Your statement here about valve adjustment bothers me somewhat.

You should be turning the motor in the direction of rotation watching the exhaust valve. When it starts to lift adjust the intake using the method you already described. Next, watch the intake valve. When it rises and is almost all the way back down adjust the exhaust valve.

Something is haywire for it to do what you describe. I also wonder if the timing chain is installed correctly?

Alright thanks guys, I got some new rockers ordered and we'll see if they work.

Wait a second - you said "adjusted the valves" - do you by chance have poly locks on the rockers, that allow them to be adjusted? Some factory rocker nuts are not made to hold a setting without being torqued to factory specs. If you are adjusting with these type of nuts, they will back off and break pushrods.

Nope. They are just your standard GM rocker for an 83' 350

My father and I had sort of the same problem on his rebuilt 350. Come to find out the cam had been put in wrong.

Well, I got the self adjusting rockers on today and not only did it fix to problem of the rockers slipping off the valves, but the engine realy tightend up when you rev it. Major improvment. Also one other note. When I was installing the new rockers i noticed one of the valve keepers on the #8 exhaust was missing! :eek: Glad I caught that before i dropped a valve:D

My father and I had sort of the same problem on his rebuilt 350. Come to find out the cam had been put in wrong.


as in off the timming mark??? it only goes in one way.