Isky E-4 cam???


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By Klaus M - 12 Years Ago
Can it be true that a Isky E-4 (no. 301444) camshaft with a rollmaster chain set to standard, will read 6-7° in advance??(I will try to test it on cyl. 6 to see if its the same.)
By charliemccraney - 12 Years Ago
It's possible with any cam. That's why adjustable sets are good. The crank, both timing gears, and the cam have tolerances. They can stack up and result in the exact thing you are seeing.
It is possible that any one of those parts are machined incorrectly and out of tolerance, but I wouldn't be worried about 6-7 degrees with that timing set.
By Hoosier Hurricane - 12 Years Ago
I think some cam grinders put a little advance in their cams to compensate for probably slack timing chains. As Charlie said, tolerance stackup can make it even worse.
By 1955mainline - 12 Years Ago
I had this with my isky cam too. had to set the rollmaster as retarded as possible and it was still 2 degrees advanced....but I can live with that. I thought I was reading my degree wheel wrong but after 6 times I was pretty sure I was doing it correct. john
By Klaus M - 12 Years Ago
I have now installed it 4degrees retarded and my intake lobe centerline hits 105º i was trying to hit 104º after seeing this tread by Ted Eaton.
(Afraid I’ve got the Isky E4 in my 272 so can’t help you on the other two grinds. But the E4 literally boils the hides with it installed at 104° intake lobe centerline. The E4 is slightly more duration and lift than the factory ’57 cam but is ground on a 108° lobe centerline which makes for more peak torque than the factory grinds.)   
By charliemccraney - 12 Years Ago
The fact that you both have experienced this with the rollmaster makes me wonder if the timing set could be at fault. I have the Rollmaster as well and the best I could get was 1.5 degrees retarded. I had the same cam and timing set in a previous build of the engine which I did not degree, so I figured I'd go with it.
By Klaus M - 12 Years Ago
I can't blame it all on the Rollmaster, with a standard chain the intake lobecenter is 103º (E-4= 108º) and with the Rollmaster straight up it was around 101º.
By Ted - 12 Years Ago
Klaus M (4/16/2013)
I have now installed it 4 degrees retarded and my intake lobe centerline hits 105º. I was trying to hit 104º after seeing this tread by Ted Eaton.

I’m guessing you meant that the camshaft is advanced but have the crank gear in the 4° retarded position to get to that 105° intake lobe centerline reading? For street cars, I do like the camshafts installed with a moderate amount of advance. For those engines running in the higher rpms, I’ll typically install the camshaft closer to the ground lobe centerline value but still with a smaller amount of advance. It’s not very often that I find an engine that performs better with the camshaft retarded and when I do, it’s typically because the camshaft is too small for the application.

And Charlie is right about machining variances in regards to cam timing. It’s because of those variances that the cam timing must be checked. Here’s a past post on the subject of variances that lead to cam timing stackups.

http://forums.y-blocksforever.com/FindPost53787.aspx
By Klaus M - 12 Years Ago
Ted you'er right, the cam is advance and crank gear is 4 degrees retarded to get the result Smile The engine is going in a street F100.