cam advance

1967JMG

Well-known member
i have an isky 262H cam. its rpm is 2000-5000. could it hurt to advance it 4 degrees? what would that lower the powerband to?
thanks guys
 
1967JMG":1g46f2uz said:
i have an isky 262H cam. its rpm is 2000-5000. could it hurt to advance it 4 degrees? what would that lower the powerband to?
thanks guys

I think the only harm you could do is if you built the engine with more than 9.8 to 1 compression or so.
If the compression is stock, you won't hurt a thing from advanceing it.
 
Yes advancing the cam timing it would gain some low end torque and lose a bit of the top end!
 
bubba22349":2a9wdwzg said:
Yes advancing the cam timing it would gain some low end torque and lose a bit of the top end!

8) not necessarily. advancing the cam as a rule of thumb is supposed to increase the low end performance at the expense of top end performance, but that isnt always true.

but to answer the question, there is no harm in advancing the cam 4 degrees. any more than that though, and you want to degree the cam and closely check valve to piston clearances to prevent interference.
 
All these guy's know a lot more than me. But I used a Isky 252H and told the builder to degree it 4 advanced. He said he tried and the geometry was off. Had to install it straight up. Don't know if it was built into the grind or what. Might be worth contacting Isky. He's been building engines for 50 years and while I trust him, he could have been wrong. Used a double roller timing set from CI so it was no real reason for him not to do it unless it was valve clearance as rbohm suggested.
 
8) explorer some cam companies grind their cams a few degrees advanced to allow for timing chain stretch. comp cams in particular does this. your engine builder probably degreed the cam and found this to be true.
 
Isky states the 262 supercam power range is 2000-5500.

Advancing it more than the 2 degrees recommended by Isky will give you a little more low end, but at the expense of some top end.

In fact the recommended 2 degrees just compensates for the load put on the timing chain.

The cam is mild enough i would just go with 2 degrees advance.
 
Put it in straight up, you already have a 109 L/S and its only 208/208 at .50, the milder the cam, the less I would advance it,I seriously doubt it is good for power to 5500, probably more like 4500 in reality. Interesting cam profile though,will be interested in how it runs. When i thought I was going to run my bronco N/A, I had a cam made up for me at 210/210 @.50 and 110L/S and .496 lift each, trying to split the best of both worlds, still have it and never tried it.
 
Broncitis":1kndjovf said:
Put it in straight up, you already have a 109 L/S and its only 208/208 at .50, the milder the cam, the less I would advance it,I seriously doubt it is good for power to 5500, probably more like 4500 in reality. Interesting cam profile though,will be interested in how it runs. When i thought I was going to run my bronco N/A, I had a cam made up for me at 210/210 @.50 and 110L/S and .496 lift each, trying to split the best of both worlds, still have it and never tried it.

Broncitis who did you get to grind that cam & what kind of valve spring pressure is required to keep the valves from floating.
That lift is real decent for the short duration. What rocker arm ratio did you use to get the .496" lift??
Thanks
 
I was made by bullet cams, 662-893-5670, grind #F6 260/260-10HF, I believe the closed spring pressure was 110, I was going to use a set of clifford springs I had laying around, wound up using them anyway on the blown cam, it was based on 1.6 ratio rockers.
 
For every 2 degrees of advance the power band will drop approximately 500 rpm. Therefore, if the power band is currently 2000-5000 rpm, advancing it 2 degrees would lower to 1500-4500 rpm, 4 degress 1000-4000 rpm. Personally, I wouldn't go more than that. I might even leave it where it's at, but that would depend on what type of driving you do most. If you spend a lot of time on the highway and/or open road, it might be better to leave it where it's at, to maintain the top end power for passing. If you do a lot of city driving, light to light, than it would be better to advance the cam.

One of these days we plan to make adjustable cam gears and billet timing covers. The timing covers will be two piece, with a removable inspection hatch for adjusting the cam gear. This would eliminate pulling the balancer and timing cover, making cam timing adjustments quick and easy.
 
Almost all of my driving is in city. Every once in a while i go on the highway but not more than about 20 miles maybe. I think i may go 2 degrees
 
It wasn't a Ford six, but I've had a good chance to compare cam settings on an otherwise unaltered motor over the past year. Adding nearly four degrees with an offset key definitely made the car more tractable in city traffic. Seems to run cooler, too.

This especially helped as it is a manual transmission and you can "creep" more readily as the queue moves along. Realistically, I wasn't going to miss the top end drop as it still does (a noisy) 100MPH if required.
 
Back
Top