Olds 350 high compression timing
May 21st, 2024, 07:47 PM
#1
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Olds 350 high compression timing
So I yanked the 350 out of my car and went thru it
I did a compression test and I got around 190-195 psi per cylinder and when I pulled the heads I found forged flat top .030 over pistons in it
there were no numbers on the cam so I’m still not sure what kind of cam is in there. One of the main reasons I pulled it out was because I was having problems w pinging before
under some advice I replaced the edelbrock I had w a Holley 850 street hp and replaced the stock distributor with a MSD. I bought the ready to run msd and have it hooked right to the msd coil
I put everything together and popped the distributor in and hooked up the vacuum advance and fired her on the stand and it ran pretty bad til I bumped the timing down and played w the carb a little but it still not running great
my question is what should the initial timing be or a ball park
I’m running 93 octane pump gas
I did a compression test and I got around 190-195 psi per cylinder and when I pulled the heads I found forged flat top .030 over pistons in it
there were no numbers on the cam so I’m still not sure what kind of cam is in there. One of the main reasons I pulled it out was because I was having problems w pinging before
under some advice I replaced the edelbrock I had w a Holley 850 street hp and replaced the stock distributor with a MSD. I bought the ready to run msd and have it hooked right to the msd coil
I put everything together and popped the distributor in and hooked up the vacuum advance and fired her on the stand and it ran pretty bad til I bumped the timing down and played w the carb a little but it still not running great
my question is what should the initial timing be or a ball park
I’m running 93 octane pump gas
May 21st, 2024, 08:16 PM
#2
'72 Cutlass ragtop
Join Date: Jun 2016
Location: Tampa, FL
Posts: 956
Others will likely respond but it may arguably depend at least in part on the cam specs -required initial timing may essentially need between 12-15 degrees depending on what your cam may like, and all in around 34-35 degrees.
as an example, I'm running a roller cam 350 that Mark Remmel built - his cam has mid-500 lift specs and it really likes 16 degrees initial / 34 degrees total timing. In my case, I'm running a Pertronix Ignitor II electronic distributor and I had to experiment with the limiters that it came with to achieve the above-stated timing specs.
Also, make absolute sure your distributor is aligned with the #1 cylinder - even a tooth off can screw with your timing.
as an example, I'm running a roller cam 350 that Mark Remmel built - his cam has mid-500 lift specs and it really likes 16 degrees initial / 34 degrees total timing. In my case, I'm running a Pertronix Ignitor II electronic distributor and I had to experiment with the limiters that it came with to achieve the above-stated timing specs.
Also, make absolute sure your distributor is aligned with the #1 cylinder - even a tooth off can screw with your timing.
Last edited by 70sgeek; May 21st, 2024 at 08:26 PM.
May 21st, 2024, 08:51 PM
#3
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Location: Phoenix, AZ
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As noted above, the total advance should be around 32-36 degrees. The initial is total minus mechanical.
On a high compression engine, higher initial advance can cause slow cranking speed especially when the engine is hot.
You may need to adjust the mechanical advance to achieve around 32 total with the initial low enough for easy hot start cranking (likely around 8 to 12 degrees).
On a high compression engine, higher initial advance can cause slow cranking speed especially when the engine is hot.
You may need to adjust the mechanical advance to achieve around 32 total with the initial low enough for easy hot start cranking (likely around 8 to 12 degrees).
May 22nd, 2024, 02:14 PM
#5
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May 23rd, 2024, 05:26 AM
#6
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Sorry missed that, 93 is what you need. Honestly the factory MSD curve should be good, not too aggressive and 21 total mechanical advance in by 4000 rpm. Set you base at 13 to 15, see what runs best. If it has vacuum advance, no more than 10 degrees. I prefer manifold vs ported but see what is likes.
May 23rd, 2024, 07:10 AM
#7
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Location: northwest indiana, near gary
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Sorry missed that, 93 is what you need. Honestly the factory MSD curve should be good, not too aggressive and 21 total mechanical advance in by 4000 rpm. Set you base at 13 to 15, see what runs best. If it has vacuum advance, no more than 10 degrees. I prefer manifold vs ported but see what is likes.
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