Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
1977 454 Quadrajet Secendary issue, pop back fire rough running.
Cliff Ruggles:
Absolutely and for sure you must run good USA made lifters or the cam just isn't going to make it. Cam failure is directly related to using cheap offshore tappets. It's greatly accelerated by running WAY too much spring pressure combined with ultra-quick lobe profiles.
All the other stuff we read about like not having trace metals in the oil and improper break-in procedures, for example aren't the root cause of the issues.
A very good practice to get into is to paint a white line on the top of your pushrods that will be visible when the valve covers are removed. Once you are done running the engine in after the cam install remove the covers and start it up so you can see the white lines. Make sure to have it idling as slow as possible to minimize the mess.
They should all be spinning nicely. If you have any that aren't spinning might as well pull it right back down and throw that cam out because it's doomed.......
Jeff K:
Thank you so much! I will mark the push rods. So far everything looked clean. I put about 40,000 miles on it so far.
I'm going with one of those cams you spec'd. You know more about engines, cams then anybody I know.
Does anybody sell good hyd lifters anymore?
The motor came from a brand new demolished 1978 C-50 work truck that the previous owner picked up in a tow deal back in 1978. When he saw the brand new 454 he bartered it from the insurance company for the price of the tow. Took it apart and stashed it in oil a few decades..
Cliff Ruggles:
Good luck with finding good lifters. The best will come from Hylift Johnson if you can find them.....
Jeff K:
Crower has some interesting flat lifters. I wish they would explain what they did ...
https://crower.com/lifters.html?cat=414
77cruiser:
Top quality stuff here.
http://jonescams.com/
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