Cylinder head resurface, cam timing?

The timing numbers you indicate represent late timing. Leave the intake where it has 145psi and advance your exhuast one tooth. With no.1 on tdc the nose of the cams on no.1 will be divided equally by the valve cover mating surface. Once they are, the degree wheel will make sense when used to verify the timing.

Post edited by: nads.com, at: 2006/01/10 03:55

Thanks for suggestions.

When I have been sayng lift I mean how far the valve bucket moves down as measured by a dial gauge, or how far the cam lobe is pushing on the valve. Valve lash or valve clearance is the space between the cam lobe and the shim.

I have some adjustable cam sprockets on their way. It's clear the compression is affected by the current intake cam location, and I am almost certain it must be closing late, i.e retarded. Since compression jumped up when I advanced the intake cam by one link I think advancing the cam that is the right direction to go.

I don't know how much the head was milled and I didn't know to ask how much. It was probably more than .002 just recalling the appearance of the surface. If I pull the head off again at some point I will measure it. I was hoping the cam degreeing wheel would tell me how much the lobe centers had changed and then get an idea of how much to adjust. However I haven't been able to make much sense of it.

If I advance the cam 1 link that would be 12 degrees I think.

Nothing major to report yet. I should have the cam sprockets REAL SOON NOW.

Making some more degree measurements last night I think the cam timing is retarded about 4 degrees. I wouldn't have guessed that would have made much difference. I guess I will see when I can set it right.

Willo46 wrote:

Nothing major to report yet. I should have the cam sprockets REAL SOON NOW.

Making some more degree measurements last night I think the cam timing is retarded about 4 degrees. I wouldn't have guessed that would have made much difference. I guess I will see when I can set it right.

Hope you are not waiting on us as we are out of the 30t KZ sprockets.

Jay

APE Jay wrote:
Hope you are not waiting on us as we are out of the 30t KZ sprockets.

Jay[/quote]

Yes, I noticed - we've been waiting about a month to get some...

Go crack the whip Jay...

Just another thought.
On a car you compensate for lifter colapsing (hydralic). Is that the same for KZ's??? Dont the KZ's have solid lifters meaning no colapsing to worry about.

no hydraulics involved,just a shim!

So why compensate .050 into the degreeing

Snakebyte wrote:

So why compensate .050 into the degreeing

That is generally used in comparing different cams, if you want to compare the specs of cam A against cam B it kinda helps to be working from the same starting and ending points. If cam A has 230 degrees of duration on the intake at .010 and cam B has 220 degrees of duration at .040, cam B would actually have greater duration while appearing to have less. It's all about marketing.

I haven't reported back because putting these adjustable sprockets on has been really tedious, and I guess I'm only half done. Haven't had as much time to work on it as I hoped.

I think I have the exhaust cam set right finally and I'm continuing to work on the intake cam. I started off working on both and adjusting the sprockets a little, putting back in, checking compression and degrees. At the moment the exhaust is exactly right on degrees, figuring where the center line of the stock cams should be with factory specs, and the measurements repeat every time. I'll say visually the cam looks advanced over stock.

I'm using .050 lift. Will report back if this works or not.

Thanks!!!!

SOOOOOOOOO what happened??????
Did you get a chace to work on it?

Hi again. Thanks for the interest. I have been working on this and once I figured out my math was wrong on calculating the lobe centerlines it went a lot smoother. I was subtracting degrees when I should have been adding and vice versa, depending on whether the opening/closing points were ATDC and BTDC. After a number of adjustments on the cam sprockets, when I was thinking my exhaust cam was exactly correct, after I rechecked the math I was 20 degrees advanced over stock.

I started using this calculator for the math which helped a lot:
www.rbracing-rsr.com/camshaft.html

I have finally figured that the exhaust cam was 6 degrees retarded from stock to begin with and interestingly the intake cam was 2 degrees advanced. I set both cams back to stock 110/110 lobe centers with the adjustable sprockets. I only picked up about 5 lbs compression though, but actually the motor seems to be running better, idling better. I couldn't get the compression up to 145 without getting valve interference.

Since my compressions were still only in a 120 to 130 range, I also built a homemade leakdown tester and found the air was hissing out into the crankcase. I think the pressure loss is about 3 to 5% but since my homemade job is probably not accurate I wouldn't count on that. I redid the test with oil in the cylinders and there was virtually no pressure loss. I'm thinking now that the blowby may be the source of some lost compression and also maybe the oil is heating up from the blowby.

Considering the options at the moment.

Post edited by: willo46, at: 2006/01/25 14:40

Post edited by: willo46, at: 2006/01/25 14:41

Post edited by: willo46, at: 2006/01/25 14:42