Page 1 of 1
cam install overlap ?
Posted: Sun May 20, 2018 7:15 pm
by sjre
Degreeing cam in a bbc mild solid roller intake opens at 19 btdc . Cam is 244 at 50 107 lsa.Usually use the open at 50 then check lift at overlap.Checking this with lifters on #1 cyl. usually ends up with the intake lifter higher by about .030 .On this one the exh is higher by about .060 WTH?.Double checked-verified tdc and open at 050 but this doesnt make sense.Please any suggestions.
Thanks Joe.
Re: cam install overlap ?
Posted: Sun May 20, 2018 8:10 pm
by John Wallace
Degreeing cam in a bbc mild solid roller intake opens at 19 btdc
That's open at .050"?
What does the exh open at?
What are the specs on the cam card?
Re: cam install overlap ?
Posted: Sun May 20, 2018 8:15 pm
by amc fan
Most cams... not all are ground split overlap at tdc on exhaust stroke in that case .060 higher on exhaust would be retarded.We have seen an Olds cam and a SBC cam over the years... with exhaust lobes ground 20 degrees late! I do not know if it is an easy mistake that happens when they are being ground but they do run hot and start to get black death on the pistons.The Olds was a hydraulic flat tappet street cam, the SBC was a solid roller in a oval track stock car.
Re: cam install overlap ?
Posted: Sun May 20, 2018 8:27 pm
by sjre
Yes sorry at .050, exh opens at 56 bbdc at .050.
Re: cam install overlap ?
Posted: Mon May 21, 2018 6:36 am
by Geoff2
Maybe the cam is a dual pattern, with extra exh duration....
Re: cam install overlap ?
Posted: Mon May 21, 2018 5:24 pm
by paulzig
Geoff2 wrote: ↑Mon May 21, 2018 6:36 am
Maybe the cam is a dual pattern, with extra exh duration....
Looks like its a 244/250@50thou 107LSA 103ICL 111ECL...
If its 19° for the Intake then its 4 degrees advanced.
Re: cam install overlap ?
Posted: Mon May 21, 2018 10:02 pm
by F-BIRD'88
Why not check the .050" open and close events onstead of making this a guessing game.?