[72SSConvertibleGuy]

Hey guys...I just want to thank everyone for all of their help so far--it's been a great tool to have in tuning and tweaking this car!!..

I have a couple more questions which I hope someone can assist with---Thanks ahead of time!!!

1) What should the initial/base timing be set at for the 72 396/402 engine? The service manual says 8 degrees, but the sticker on the car says 4 degrees. (I can't vouch whether the sticker is original or not)

2) When adjusting the valves while the engine is running, how much oil should be coming out of the rocker arm holes? A dribble? A steady flow? A gush? or a great deal of squirting?

If I need to provide some additional info, let me know...

Thanks again everyone!!!

 

[72SSConvertibleGuy]

Bump

 

[matt's66]

Original cam?

 

[72SSConvertibleGuy]

Hey Matt...Thanks for replying...Yes, original cam as far as we can tell.

 

[Jerry70]

It's very likely that the distributor in a 40 year old car has been replaced, rebuilt, or modified. If that's the case, the original specs may no longer apply. GM used dozens of different curves for different applications, rebuilders used generic parts, and guys like me revurved them. A distributor that originally had 30º of mechanical advance may now have half of that. You should start by setting it's total (36º is a good start for most engines). Keep in mind that many distributors didn't reach max advance until well past 4k, some past 5K, so be sure to check that advance is all in.

 

[matt's66]

It's very likely that the distributor in a 40 year old car has been replaced, rebuilt, or modified. If that's the case, the original specs may no longer apply. GM used dozens of different curves for different applications, rebuilders used generic parts, and guys like me revurved them. A distributor that originally had 30º of mechanical advance may now have half of that. You should start by setting it's total (36º is a good start for most engines). Keep in mind that many distributors didn't reach max advance until well past 4k, some past 5K, so be sure to check that advance is all in.

Very true. I would just give it as much timing as it will take without pinging itself to death. Assuming all components function as they should, start with 8 degrees and keep going up in 2 degree increments until it pings, then back off 2 degrees. There are a million posts on how to dial in your timing spot on, but this will make it run decent without spending any cash at the moment. Best to go through it though and find out what the total timing is, how much is in the vacuum advance and what your engine actually likes.

 

[72SSConvertibleGuy]

Jerry and Matt---Thanks so much for the help!! Do you guys have any experience with adjusting the valves and how much oil I should be seeing?

 

[matt's66]

The amount of oil you see actually varies from engine to engine and also from each rocker within the same engine. At least from my experience. Some will dribble oil, some will squirt and some will appear like there is nothing. I like to adjust my hydraulic lifters while the engine is idling, although some guys here hate that method. I adjust the idle pretty low (but still smooth) to keep the oil mess down. You can get a spare valve cover and cut the top out to keep from making a mess. There is also deflectors you can buy to place on the rockers. (Be sure to remove them when done!). Do each rocker one at a time. I back off on it until it starts to tick, tighten SLOWLY until the tick just disappears, then go 1/2 turn SLOWLY (180 degrees) more. Repeat for each one. Some guys will tell you anything from 1/4 turn to a full turn. Stock lifters and most aftermarket ones I've never had a problem with 1/2 turn.