.8mm of lift at the cam does not equal .8mm at the valve. The Evo uses a rocker arm type follower - that gives it a different motion ratio at the valve. So .8mm of cam lift actually generates a much larger lift at the valve.

 

EDIT: I understand now.

Thanks.

 

The cams are out of the RS right now. From the pictures you posted ogvw, I cannot argue with the facts that is surely looks as though it is going to touch.

I did go back and look at a head the other day, it was not the RS head obviously as it was together and on the car. The head I looked at was an assembled EVO head that was being shipped out. In my hurry of reading this post the first time I didn't notice the emphasis being put on the "STOCK RETAINER" part. The had I looked at has our spring/retainers in it which are shorter on the bottom than the stock retainer.

The EVO retainer is definetely overly thick on the bottom. As a side note, the 272's are in the RS and we have installed probably 50 sets in other EVO's that have come through here. No problems have been seen even if there is contact going on.

Something else that I think needs to be checked ogvw. The picture you have shows the lash adjuster pumped all the way up. When the EVO's are running it is uncommon that they ever make it to this completely pumped up stage, this would change the amount of lift at the valve and could cause this to hit on the bench with a test spring. When putting new lifters in a head if one sticks open (pumped all the way up) it is not uncommon to see the valve hit the pistons in the 1g/2g cars and bend a valve. The lifters have to be collapsed before installing them.

We are dropping the HKS 280 cams in the RS right now. After the belt is back on I am going to roll the engine over and take a look. I have to admit my quick check the other day was wrong and I apologize ogvw. The retainers on the head I looked at were not stock.

Give me a couple of minutes and I'll post what I find with the lifter in a "collapsed" position.

David Buschur
www.buschurracing.com

 

Oh, the HKS 280 cams are the same lift also, 10.8/10.2 as the others, just duration changed. Going to have to bump the revlimiter now, these babies are good for 10,100 rpm! haha

David Buschur
www.buschurracing.com

 

That is a very good point.

 

I'm back......

I was right.......

On the head in the car we looked to see if when the lash adjusters are collapsed if the HKS cams would hit. With the top coil being so tight you cannot tell for sure as you can't see. Right before the top coil closes it looks like it is going to make it but there was now way to check for sure.

There is a head here now that has the stock valve guides in it, stock springs and stock retainers. It has new Mitsubishi valve seals on it. I carried it over to the machine shop and asked them to figure out how much clearance there was between the bottom of the retainer and the top of the seal.........

We pulled the spring out and measured from the valve tip to the top of the seal then pulled the valve back out and marked it for the top of the seal. The retainer and keepers were then put back on the valve and the distance was measured. .471 That is more room than the HKS cams need even taking into consideration the rocker arm ratio. If memory serves me right the rocker arm ratio will bring the lift at the valve up to about .446.

Here are some ideas that might help explain the pictures that ogvw posted. If the valve guides in that head you showed were ever replaced and not set back to the proper height this could cause the problem you are showing. If the seal was not pushed all the way down on the guide it could be the problem, if the lifter, which it is in the picture, is pumped up all the way then that IS the problem. The EVO/DSM lifters do not reach that fully opened state while in the car, if they do they bend valves.

For those of you that doubted me, no apology needed.

David Buschur
www.buschurracing.com

 

so here we go again? Which is right? lol HKS are fine, or no they arent?

 

absolutely correct - I agree completely


we are both on the same page here too..... all of the heads I have tested are 100% factory original low mileage heads (as delivered from the dealership)

Im not sure I follow you here..... those pics were taken with the head off of the car - so there was no oil pressure. When installed the lifters will be presurised with oil (taking up any lash between the rocker arm and camshaft) and expand fully. So if anything the results we are finding will be exagerated under running conditions.

At any rate David, please dont take any of this as an attack on you or your business, we hold you in high regard and respect what you have done for the EVO/DSM community.

Jason

 

ditto....not in any way an attack.

Beau

 

I appreciate that ogvw, I am not attacking either. With the measurements we took though there seems to be enough room. Look at the picture you posted, see how the lash adjuster is all the way out, that doesn't happen in the car. The lash adjuster never completely pumps up. If it does then there are clearance problems and the valves (in the DSM's would bend). It wouldn't happen in an EVO as it is not a -0- deck piston like the old 4g63's were.

David Buschur
www.buschurracing.com

 

Ok, this is all good information, but i am still wondering why i get a loud ticking noise after i installed the HKS 272 combo. The ticking goes away after driving 20-30 minutes. I have not experienced any abnormal oil consumption. My car just sounds like a old peice of junk for awhile.

 

i think they all do. I have 272's as well...Mine does it too.

 

Its annoying to say the least, when i get from Iraq ill change the valve springs & retainers. Hopefully it will stop my car from sounding like something that is heading for the junkyard.

 

The ticking is from the cam profile - the noise you hear is the rocker arms/lifters/cams moving very quickly. We have tested many different profiles - some make noise, some dont. Its nothing to worry about really.

 

Let's see where we are now on the original focus of this thread. There have been instances where the stock spring retainer combination makes contact with the valve seals. We have an example of this occuring but how common is it and could it be due to variations in valve guide height as measured from the spring seat? I am assuming for the moment that it is not due to the lifters although that seems to be a possibility here.