High altitude 403 build
#42
Too expensive. 🙂
In the Comp Cams case, you would only need to advance the crank 2 teeth and set the key back to 0 to get +5. Then with the cam adjustment you could get +3. I can make it work👍 . I'm sure I won't need that much adjustability. It seems like +2, +4 is an arbitrary choice and there shouldn't be much difference from +3, +5 as far as power is concerned.
In the Comp Cams case, you would only need to advance the crank 2 teeth and set the key back to 0 to get +5. Then with the cam adjustment you could get +3. I can make it work👍 . I'm sure I won't need that much adjustability. It seems like +2, +4 is an arbitrary choice and there shouldn't be much difference from +3, +5 as far as power is concerned.
#44
https://speedmaster79.com/Oldsmobile...ming-Chain-Kit
Even one of the reviews speak of improper markings. Curious of the quality, either way the cam should be degreed.
Even one of the reviews speak of improper markings. Curious of the quality, either way the cam should be degreed.
#45
I got my "new" cam bearings in and the copper color is showing. It's not only showing to one side like it's wear from being used, it's showing all the way around the bearings like someone removed the silver babbitt on purpose. On the one with the oil groove you can still see some silver babbitt in the groove, but there are sections of it missing there too (red circles in the pic). The cam can't touch there so it can't be from use, it has to have been removed by something else. I sent a message to Mahle about it and their response was:"Most sets that are offered now no longer have a babbit coating. They use copper matrix that is an upgrade & will be fine."It's hard to believe simply removing the top silver coating is an "upgrade". Do they just remove the top layer now because there's too much lead in it? Should I be okay using these?
Red circles are copper/missing babbitt.
Red circles are copper/missing babbitt.
#46
I sent them pictures and they sent this reply:
"Thank you for the photos. The date stamping helped us to answer your question. This is an older set that Clevite made back in the 90's when we still made our own Cam bearings. That's why the 4-91 is stamped on the bearing. Durabond makes all of our Cam bearings now. The good news is these are fine to use. The F5 Tin that was used back then when blended with the Copper & a small amount of babbitt & you end up with more of a copper appearance because the bearing surface itself did not carry an overlay plate. The silver color left in the groove was just residual from the blending of the F5 Tin & the small amount of Babbitt that was used back then . Basically just an older process that gives more of a Copper appearance. Just some older inventory made with a earlier process that was common for bearing construction in those years. You are fine to use these & they will cause no harm to your cam."
I've never heard of that, but if they say it's okay to use them I'll use them...
"Thank you for the photos. The date stamping helped us to answer your question. This is an older set that Clevite made back in the 90's when we still made our own Cam bearings. That's why the 4-91 is stamped on the bearing. Durabond makes all of our Cam bearings now. The good news is these are fine to use. The F5 Tin that was used back then when blended with the Copper & a small amount of babbitt & you end up with more of a copper appearance because the bearing surface itself did not carry an overlay plate. The silver color left in the groove was just residual from the blending of the F5 Tin & the small amount of Babbitt that was used back then . Basically just an older process that gives more of a Copper appearance. Just some older inventory made with a earlier process that was common for bearing construction in those years. You are fine to use these & they will cause no harm to your cam."
I've never heard of that, but if they say it's okay to use them I'll use them...
#47
I measured my heads at 88cc. Is that excessive? I found someone that said 83cc in 2012(my heads say 2019). I'll need to deck .105" for 67cc. That might help with any hood clearance issues.
#48
Those cam bearings should be fine if they measure correctly on the I.D. and O.D.
As for the heads, 88cc is big if that is correct; not only do you have to cut the heads quite a bit, you will have to cut the intake on the faces and the bottom of the end rails as well to match the shorter heads.
You need to check with your machine shop to find out if they are competent, capable, and what the cost of all this milling will be.
With aluminum, it is easier and softer than iron, but still, that is a lot of cuts and hoping that the cutters are all leveled correctly and sharp.
Vortecpro spent a long time to carefullly cut our iron heads and aluminum intake to match with a big cut like this and it came out immaculate, but that is not the typical attention that even a decent shop will give to other engines.
I have had heads and intake milled In the past and they did a rough job on the RA, and I never pushed a head gasket, but also wasn’t making a lot of cylinder pressure (Hp) either.
Last edited by Battenrunner; September 14th, 2020 at 08:10 AM.
#49
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September 18th, 2012 07:35 PM