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Oldsproject · 05-07-2007, 05:10 PM

Thanks for all of your help guys. As it turns out it wasn't an operator error after all. I rechecked the timing using the centerline method, was able to get the #1 Piston at 107 (reccomend was 106) but when I put it on #2, I got 96 on the center lobe. I broke down and called Comp Cams and sure enough and after some pursation, found out that they were not aware of the 45 degree banks on the "67" 425's and the grind was for a 39 degree bank (They were insistant that all 67"s were 39 degree until they found an ole timer that worked there, he set them straight). I pretty much wasted all day yesterday and today, my hands are sore as heck from turning the motor over so many times in the last couple days. I told my wife I probably put 50,000 miles on it while on the motor stand

. The good news in the whole thing is I have becoming a timing degree expert of sorts and Comp Cams does have cores they can grind for the 45 degree bank in the 270 or 280H. So we live to fight another day. Thanks for your help on this and I hope whoever reads it learns a lesson on 45 and 39 degree cam bank angles. Check, check, check ( I thought the machine shop would!)

Now then, another question for my Olds experts. Reading through all the olds engine rebuilding articles Mondello says there's a 3/8" plug in the rear of the block that was originally equiped with a .040 hole in it (behind the rear freeze plug). Claims the Cam and Distributor will wear out prematurally if it isn't reinstalled? I asked the guys at the machine shop if they replaced it or used the old one. They said they replaced it but didn't put the hole in it as it is no longer required (according to some software they have). Can anyone tell me IF they are correct or do I need to have the hole drilled in? Thanks.

05-07-2007, 05:10 PM	#6 (permalink)
Oldsproject Member Join Date: Mar 2007 Posts: 55	Thanks for all of your help guys. As it turns out it wasn't an operator error after all. I rechecked the timing using the centerline method, was able to get the #1 Piston at 107 (reccomend was 106) but when I put it on #2, I got 96 on the center lobe. I broke down and called Comp Cams and sure enough and after some pursation, found out that they were not aware of the 45 degree banks on the "67" 425's and the grind was for a 39 degree bank (They were insistant that all 67"s were 39 degree until they found an ole timer that worked there, he set them straight). I pretty much wasted all day yesterday and today, my hands are sore as heck from turning the motor over so many times in the last couple days. I told my wife I probably put 50,000 miles on it while on the motor stand . The good news in the whole thing is I have becoming a timing degree expert of sorts and Comp Cams does have cores they can grind for the 45 degree bank in the 270 or 280H. So we live to fight another day. Thanks for your help on this and I hope whoever reads it learns a lesson on 45 and 39 degree cam bank angles. Check, check, check ( I thought the machine shop would!) Now then, another question for my Olds experts. Reading through all the olds engine rebuilding articles Mondello says there's a 3/8" plug in the rear of the block that was originally equiped with a .040 hole in it (behind the rear freeze plug). Claims the Cam and Distributor will wear out prematurally if it isn't reinstalled? I asked the guys at the machine shop if they replaced it or used the old one. They said they replaced it but didn't put the hole in it as it is no longer required (according to some software they have). Can anyone tell me IF they are correct or do I need to have the hole drilled in? Thanks.