jdblock

Hi guys.

I'm building up a high compression NA GSR. 12.5:1 pistons, forged rods and GSR crank. I've got an engine running already in the car with a complete Supertech valve train, including flat faced valves. I also have S2P1 cams that have been degreed. I'm planning on installing the built head onto the built engine.

The question is, do I have to degree the cams again for the new short block?

Any help on this would be appreciated. Plenty of info about degreeing cams, but couldn't find anything about my question.

TomCat39

I can't say I'm familiar with your setup, however, I am not sure how you could assume the blocks are going to be the same, unless they are the same/built the same. Then I don't think you would need to go through everything again.

I would think you would need to both clay and degree the cams if you move the head to a new block if the new block is built differently. Just seems like common sense to me.

That being said, I could be mistaken as I'm not a master by any means, what I've stated is just my initial thoughts on what you've provided.

JRCivic1

Degreeing the cams is a necessary step if you do ANY of the following:

Change block
Deck block
Change cylinder head
Deck/mill cylinder head
Change head gasket
Change or remove timing belt... change or loosen tensioner
Cam change
Crankshaft change.
Align hone crank main journals or camshaft journals

jdblock

Thanks for the responses. Guess I'll be adding this to the to-do list.

B20VtecVillain

I agree with everything else on your list, but why would you need to degree the cams again for changing the timing belt? If the head and block stay together, the camshafts and cam gears stay in the head, and you just set to TDC, remove & replace the belt, assuming you are using the same belt, why would they then need to be degreed again? The whole purpose of decreeing a cam is to make sure you know exactly where it is, and this would not change at all if you do not move anything while changing the belt. The only thing I can think of is that a used belt would perhaps be stretched/worn more than new, but 9 times out of 10 your going to have a fresh belt on a fresh build, meaning when the cams were initially degreed it was done with a new belt, so replacing with an identical belt should not change it one biT. If it does constitute the need for degree, then theoretically your saying this should be done every so often anyway as the belt stretches over time as well? Not saying your wrong, I just have never done this practice for just changing of an identical belt so I would like some light shed on why this would need to be done.

JRCivic1

Villain, my statement with regards to a change in timing belt or tensioner holds true with a handful of exceptions. IF you were to degree a set of cams on a fresh engine with a brand new timing belt, and you were to replace the timing belt sometime thereafter with the same BRAND timing belt WITHOUT loosening the tensioner... you would be correct in that it is unlikely that the relationship between the cams and crank would change... so equally likely that degreeing the cams would be un-necessary. However, if your timing belt replacement process includes replacing or adjusting the tensioner, then cam to crank phasing can be altered and degreeing should be checked for maximum power.

You are also correct in that the theory of belt stretch altering the cam settings has merit. The easiest way to test for this is to strap the car to a dyno and advance both cams ever so slightly (and equally) and see if the power increases.