Hks Step 2 Cams

[RB26zcar]

Hi, will installing a pair of HKS cams (EX280 10:01 - IN272 10:08) require all new valve tip shims (in general)?

I know they need to always be checked, I'm just asking, on average, do most guys with stock heads require buying all new thicker/thinner shims to install these cams?

thank you

j.

[DoughBoy]

It depends on the base circle of the cam as to whether you'll need the longer aftermarket buckets, but as for shim size pretty much after any cam swap you'll need to change/machine them for the correct lash.

[ylwgtr2]

i have them but in 264..... machine the head and re shim

[RB26zcar]

It depends on the base circle of the cam as to whether you'll need the longer aftermarket buckets, but as for shim size pretty much after any cam swap you'll need to change/machine them for the correct lash.

Reason I ask is I already installed a unknown brand of cams (264/9.7 - 256/9.7) and all the stock shims worked out perfect on that swap.

I've heard of some cam makers keeping the base stock so that the stock shims do work. Just wondering if anyone has installed the HKS step 2 cams, and if so, did they need new shims....?

thanks - j.

[WetGTR]

Shims should be meaured and adjusted for each valve. This must be checked with a feeler gauge. I wouldn't just swap and hope for the best even if they say its OK. You should be accurate to 0.01mm or very close to this.

Edited May 4, 2006 by WetGTR

[RB26zcar]

Shims should be meaured and adjusted for each valve. This must be checked with a feeler gauge. I wouldn't just swap and hope for the best even if they say its OK. You should be accurate to 0.01mm or very close to this.

I know all that.... I keep asking the same question but get answers to something else.

I ask, from someone who knows, in general, do you have to buy all new shims when you install HKS step 2 cams on a stock unmolested head?

I know I should check the clearnces "after" the cam swap. I'm trying to plan ahead and know if most that have done this ended up buying all new shims.

thanks again - j.

[ylwgtr2]

I know all that.... I keep asking the same question but get answers to something else.

I ask, from someone who knows, in general, do you have to buy all new shims when you install HKS step 2 cams on a stock unmolested head?

I know I should check the clearnces "after" the cam swap. I'm trying to plan ahead and know if most that have done this ended up buying all new shims.

thanks again - j.

and again.......i used HKS step2 264 cams with the same lift as yours........I machined releifs for the cam lobe....and reshimmed the valves.....how can they say you have to or dont have to reshim....all depends on so many variables....valve wear, seat wear ect

[RB26zcar]

and again.......i used HKS step2 264 cams with the same lift as yours........I machined releifs for the cam lobe....and reshimmed the valves.....how can they say you have to or dont have to reshim....all depends on so many variables....valve wear, seat wear ect

ok, so you bought 24 new shims. Thanks, thats what I needed to know...

[Mik]

ok, so you bought 24 new shims. Thanks, thats what I needed to know...

I'll make it easy

Case 1: Cams are standard base circle (32mm) - Which I think the HKS Step 2's are...but check

-> If you just drop the cam in, the clearance will be the same as it was before you did the cam swap, as the only thing that has changed is the camshaft. The only part of the cam lobe that determines the valve clearance is the back of the lobe, and this should not be worn.

HOWEVER, of course you should fit the cams and check clearance with a feeler gauge.

ALSO, you will probably find that on an old engine, the clearances will be a little on the high side due to wear on the lifters, shims and valve stems. But re-shimming is painful and expensive, so as long as the clearances are acceptable, you may be better off fitting the cams and setting the clearances properly if you ever pull the head off. Most guys that do heads don’t buy shims they just set the clearance by taking a touch off the stems when after they have cut the valves / seats.

Case 2: Cams are non standard base circle (32mm) – Tomei, Jun and others.

This is done so you can run big lift without flycutting the cylinder head. In this case, you will either need to reshim the entire head, or buy lifters with the correct offset for your base circle. If you use the right lifters, theoretically, your valve clearance won’t change, but there will be too many variables so you should reset.

[RB26zcar]

Thank You Mik. Everything should be ok unless the HKS cams indeed use a 31mm base circle. In that case I'd need all new shims 0.5mm thicker... correct?

[Mik]

Thank You Mik. Everything should be ok unless the HKS cams indeed use a 31mm base circle. In that case I'd need all new shims 0.5mm thicker... correct?

Spot on...

The clearances may be out, but they would have been vefore the cam change anyway...

[ylwgtr2]

no i didnt buy that many shims......fit the cams in the head....measure the clearance...write them all down in order take the shims out messure them then swap them accordingly......unless you have o clearance on any of the valves then you find the smallest shim you have and put the cams back in again and get a starting clearance from there