350 Chevy Engine issues - any suggestions

[Co4416]

Hi all, my dad and I have been working on rebuilding a 69 Camaro and have hit somewhat of a wall with the engine. Due to our lack of knowledge(we're new to this ), as well as me being ~200 miles away at school last year, we had a reputible local engine shop build up a 350 and then had a family friend install it at his shop. That process was completed back in February... or so we thought.

From the get-go the car was plauged with excessive oil burning and a noticeble lack of power below 3000rpm, as well as just not feeling as "fast" as it should. After multiple trips back and forth, talking with the engine shop etc, we came to find out at the end of August that our friend(who has his own repair shop) set the timing way too high, as in 61*.
During this time we put about 2000 miles on the car(another ), partially due to the engine builder's assurance that the smoking would clear up. It became apparent that the smoking wouldnt go away, so the car was taken to the engine builder and they discovered the timing mistake, and said the engine needed to be torn down to make sure there was no damage.

This brings us to the current situation. The engine was torn down and rebuilt under warranty, then re-installed by the same shop that did the initial install. We picked up the car the beginning of this month and this past Thursday took it to the shop that built the engine to allow them to do a once over and make sure nothing was out of line. Turns out the total timing was yet again set way too high, 56* this time.

The car still isnt running right, even after adjusting the timing. The builder set it at 40* when I went, and suggested larger squirters in the carb and a larger fuel filter to promote better flowing.

The same problems are persisting, with a few new ones added on. It idles fine, but down low the car is stumbling over itself from idle to 2000rpm. It keeps stalling, is backfiring through the carburator, and the header tubes on cylinders 2, 4, and 6 are glowing red. And now the intake is starting to leak coolant.

Neither shop has been able to get this car running right, I kind of feel like im banging my head against a wall. I love the car and other than getting the engine straightened out all thats left right now is finishing redoing the interior and getting it painted, but right now am extremely frustrated. Its currently just sitting there as I dont want to do any further damage by driving it until I can hopefully figure out whats wrong. Does anyone have any ideas to at least point me in the right direction????

[Project69]

Sounds to me like the engine was never broken in properly (rings never fully seated) As for the stumbling part, what size camshaft do you have, need some info on the engine.

[Co4416]

I agree that it seems like the rings never seated, any idea why that wouldnt happen. I kept it under 4000rpm for the first 1500 miles, did some idle to 4000rpm and back in first gear jumps, didnt really beat on it at all during that time.

The cam is a Lunati Voodoo cam .489/504 lift duration @50 227/233 LSA 110/106. It has 10:1 compression. Erm... what else do you need?

[Project69]

If you dont have atleast a 2800 stall then its gonna fall flat on its face when you punch it from a stop (happened to me).

Couple reasons why the rings arent seating would be, not a proper break in, cylinder walls have to glaze busted so the rings will seat. Idle to 4000 seems kinda rough, i usually hit it from a 2500 roll to maybe 3600, just a short burst, nothing to prolonged.

[Co4416]

ah, forgot to mention im running a 4spd, not an automatic. Plus its not just when you punch it from a stop, its just trying to get moving. If you dont bring the rpms up relatively high and feather the clutch it'll die or barely chug forward.

[Vegas69]

Your carbuerator needs rejetted. Popping through the carb is a lean condition. Pull your spark plugs and see if they look lean. I would also check for a vaccuum leak with some carb cleaner. The water leak needs resealed. If it is still burning oil you can look at the intake valve while you have the intake off to see if they are sucking oil. What type of crankcase ventilation do you have? Improper setup of the crankcase ventilation system can cause oil burning as well. Feel free to PM me if you need help or have specific questions.

[Co4416]

Thanks for the help guys I really appreciate it. I'll check the plugs and for a vaccum leak ASAP. I cant believe it, but I also forgot to mention that the car is dieseling pretty badly. Its not all the time, and not uniform either. Sometimes it does it sometimes it'll shut off no problem... That can be caused by the lean condition as well right?

[Project69]

anti dieseling happens when the throttle blades remain partially open when you shut the engine off, which gives your hot engine enough fuel to run without spark (like a diesel). Just check the throttle blades close fully when your not on throttle.

And yes a lean condition will make that happen also.

[shep]

Dieseling is caused by pre-ignition. Meaning that there are hot spots in the combustion chamber causing the engine to fire out of time. Lean carburetor or too much timing can cause this. Since the headers are only glowing on one side I would start with that side. like stated before check for a vacuum leaks.