Posted by Dan in TN [172.68.73.36] on Friday, August 25, 2023 at 18:50:46 :
In Reply to: Re: Help With Vacuum Fluctuation posted by Vaughn [172.69.140.179] on Friday, August 25, 2023 at 16:02:01 :
Thanks, Vaughn. I did the reassembly myself, so there's no end to the number of things I could have done wrong...
Tappets were all new, with no additional machining before installation.
Valve clearance was set cold to INT .010, EXH 0.012.
Reading is taken from the NPT port on the intake manifold near cylinder 6.
I had the distributor rebuilt by Advanced Distributors. I did not double check the points gap before installation. Spark plugs are gapped at .032
Timing is set for 10 degrees BTDC. With the curve Advance Distributor put on they recommended up to 16 degrees BTDC.
I'll look into increasing the EXH valve clearance to .014 dropping the gap down on the plugs and double checking the points gap, and decreasing the timing. From the link you provided it looks like my probable causes are ignition related or my vacuum gauge not having a damper. I'm leaning away from the loose valve guides because the machine shop checked them and installed new guides in cylinders 2-5.
Appreciate the help!
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