Kelford Cams Safe Maximum Intake Advance?

taohawaii · Post by **taohawaii** » Thu Mar 24, 2011 6:58 pm

2003 RSX Type-S
K PRO
Kelford 179-A Camshafts (Stock valve springs)

I had my car tuned (with good top end results) only to discover after I began dissecting the calibration created by my tuner that the intake camshaft is never advanced beyond 40 degrees. These cams are supposed to have "a little more lift than the TSX cam". It seems to me that he probably did this because he was afraid of valve interference but he stated that mine were the first Kelford cams he had ever tuned. Was he being paranoid?

I already have the cams installed and running. Can anyone tell me if I can safely advance the intake cam to the full 50 degrees? I have the stock bottom end, pistons, etc...

eXceed · Post by **eXceed** » Fri Mar 25, 2011 7:30 am

Without getting your motor clayed there is no real safe way of knowing how much cam angle you can give. To be honest the tuner did right in playing it safe as you had no idea how far they could go and he had no idea.
Personally I would have either asked you to find the details out from the manufacturer or requested that you got the motor clayed (quite expensive). Chances are you can run more angle but id play it safe personally...

taohawaii · Post by **taohawaii** » Fri Mar 25, 2011 12:52 pm

eXceed wrote:Without getting your motor clayed there is no real safe way of knowing how much cam angle you can give. To be honest the tuner did right in playing it safe as you had no idea how far they could go and he had no idea.
Personally I would have either asked you to find the details out from the manufacturer or requested that you got the motor clayed (quite expensive). Chances are you can run more angle but id play it safe personally...

I have the cam specs but don't know how to translate that to interference clearance...
http://www.camshaftshop.com/home?page=s ... ory_id=125

Is there some sort of equation or algorithm that can be applied to figure out the maximum intake advance?

Post by **Hondata** » Sat Mar 26, 2011 1:46 pm

You always need to clay the engine because there are far too many differences from engine to engine to accurately predict the maximum cam advance. For example, the type of intake valve used, amount of valve seat recession/lapping, cylinder head / block decking.

Also, you should always use a mechanical stop in the VTC to limit advance.

taohawaii · Post by **taohawaii** » Sat Mar 26, 2011 2:21 pm

Hondata wrote:You always need to clay the engine because there are far too many differences from engine to engine to accurately predict the maximum cam advance. For example, the type of intake valve used, amount of valve seat recession/lapping, cylinder head / block decking.

Also, you should always use a mechanical stop in the VTC to limit advance.

I believe you because it sounds like you know more about engines than I do but I was hoping this would be an exception...

Referenced examples:
1) My intake and exhaust valves are the same as every other K20A2
2) My valve seats have never been reground they are stock.
3) Neither my cylinder head nor my block have been decked.

This is a stock motor. Just stage 1 cams. Not even the valve springs have been touched. I keep hearing "Wild cams" and "high compression" when people talk about claying the motor. These don't seem to be "Wild cams" to me and my motor is no higher compression than any other stock k20a2.

I read a procedure as to how to clay a motor and it says that you only have to clay one cylinder because all the others will be identical.

If all the cylinders are identical, my engine specs are known (to be stock), is there still no way to get an answer without claying the motor? It really, really seems like I should be able to crunch some numbers together and find out.

There are only 2 possibilities as I see it. 1) Every motor is inherently different due to wear and therefore no cam can ever be swapped safely without claying (even the same type). Or 2) With enough information I should be able to determine what the safe advance is.

For example, assume a toda cam has a centerline of "x" and an IPS cam has a center line of "x" + 3 degrees. Also assume the Toda cams have maximum safe advance (on any stock k20a2 motor) of 45 degrees and the IPS cams have a maximum safe advance of 35 degrees (again on any stock k20a2 motor). If my kelford cams fall right in the middle (between the toda and the IPS) in terms of lift and centerline I should have a maximum advance that is exactly half way between the Toda and the IPS cams. Theoretically 40 degrees right?

I failed to comprehend the connection between your reasons and my stock motor. Could you provide further explanation that would help me understand why it is not possible to do what I want?

Thank you for your time and effort!

Post by **Hondata** » Sun Mar 27, 2011 6:13 pm

Valve clearance is never the same, even between two stock engines, unless they came off the production line together. For example, machining the valve seats uses a tool which requires to be reset periodically as the tool wears - you can see how they are not going to be identical. Production engines have a lot of tolerance built into the valve/valve and valve/piston, but aftermarket cams are going to reduce this. There's really two answers - you can guess, or you can measure. Your choice.