Eric Lyublinsky

iTrader: (5)

I think I will just buy the new stock caps and do the studs and bolts.

ferrarokid

iTrader: (4)

Eric, not sure if you can buy just the caps ..... and even if you can the caps at the factory are a "matched set" thats why there are numbers on them ! ! the proper way to fix this problem is to machine the caps, and then line hone the camshaft journals !

Eric Lyublinsky

iTrader: (5)

I don't have a problem with mine. I just want to make sure not to have a problem with them when doing cams.

TurbotrixRacing

iTrader: (21)

stock cam bolts are fine, ( in my opinion) Dont fix what isnt broken. John shephard goes through the traps with the same head caps stock cap bolts at 9500 rpms. If they are working for him, im sure it will work for my 12 sec evo ...

my 2 cents



mark
turbotrix

superz

iTrader: (7)

My point exactly. The tick in the valvetrain after cams are installed is usually caused by not properly bleeding down the lifters, and therefore causing air to be trapped inside the lifters. I have never heard of a slightly bigger clearance in the camshaft bearings/caps causing a "loss" in oil pressure, at least not big enough to cause a noise.

Mike W

iTrader: (1)

The cam caps only crush when a gorilla over torques them.

So yes, if you plan on having a gorilla overtorque your cam caps, certainly do your self a favor and get some upgraded billet cam caps custom made and have them specifically line bored to match your head and install them with custom shoulder studs... or just torque your stockers to factory specs and you'll be fine to 9,500 rpm and 700+ hp.

Mike W

ferrarokid

iTrader: (4)

AS usual everything on this board of experts gets blown way out of proportion ! ! it was never said that this had to be done on every engine ! ! all the was asked if studs would be a good idea ! ! and they would .. as far as the ticking noise .. well yes when there is excessive clearance you will have a pressure loss .. but I guess you have already measured the cam to bearing clearance on some cars that have the noise ? ? funny after the caps were machined then lined bored and finished hone to the right oil clearances .. hmmm no more noise ! ! and guess what ? ? it has more oil pressure ! ! gee go fiqure ? ?

Eric Lyublinsky

iTrader: (5)

I agree with ferrarokid. When there will be a noise after cam installation the owner will have to go throw great expense and time down to get the head right. Again the noise is coming from out of spec cap and cam seat because of improper installation.

Mark Turbotrix,

You know these cars in and out. That's why you never have any problems with any install. I'm just trying to think out side the box as far as realiablty.

ERic

darkhorse

Just to add fuel to the fire..... The stock bolts are fine, and have been used for the production engines without problem. What Ferrarokid and Eric stated in the beginning is true, a stud would be a better solution, and to incorporate a locating shoulder on it so the you can get rid of those toilet paper locating holow dowels would be even tricker. It can be argued that its splitting hairs, but to use a nice and proper designed stud in that area would just make things a little more secure. If the cam caps are installed properly, the OEM stuff is fine. We just did a head that had cams installed and the caps were distorted due to improper torqueing. I had to clip all of the caps flat and square to be able to line hone the cam carriers again to proper size . In doing the job, I went to pull the hollow dowels out with a dowel puller and they are so flimsy that they collapsed during that operation. No big deal, you can buy new ones for about $1.00 each from Mitsubishi. The thing is is that if you had a nice strong stud, that had a locating shoulder on it, it would be better. The OEM bolt and hollow locating dowel is just cheap, and keeps costs down, but it works- unless you try and remove them. The other thing I had to do on the same head was helicoild a few of the cam cap bolt hole since when I installed a few of them and tightened them up, the threads pulled from the aluminum head. SO again, a stud would be better off there.

If the caps happen to get distorted, its possible to have drastic oil clearance between the cam journal and cap housing- this last head had some of them that were not only out of round and binding up on the cam when installed before the honing, but had cam to housing clearances of over .004. You dont even run half of that clearance on the main bearing to crank clearance. So yes, what ferrarokid says is true, in this instance the oil clearanc ewas so great that a large enough volume of the oil being fed to the head was dumping out around the cam bearings to starve the last lifters in the oil manifold and have it begine making noise when the temp came up and the oil thinned out. And also to verify what he said, after I rebuilt the caps and honed it, the cam not only spun so freely when installed, the engine was quiet as a mouse up top, and the oil pressure was not only increased, but steady as a rock.

The problem isnt necessarily the bolts that hold the cam caps, it was the install, but in rebuilding the head and having it apart, we looked at it and agreed that if we had studs there with the locator built into it, it would be a nice touch. Here are some pics.

darkhorse

heres the area that the cams sit where I rehoned them

darkhorse

.

darkhorse

this is what the surface of the cam bearing looks like after it honed back to proper size

Eric Lyublinsky

iTrader: (5)

Darkhorse,

Thank for the technical insight.

I have one question. When homd is the cam duration now higher because they now sit lower?

Thanks
Eric

darkhorse

No, the cam does not get moved that much lower, perhaps .001-.002 tops, and even if it did drop that amount, the hydraulic lash adjusters would make up for any devialtion in the cam posistion in terms of the clearance when the rocker is operating on the base of the lobe or on the heel.

Eric Lyublinsky

iTrader: (5)

Cool,

Man I learn so much from you Keep on posting your findings. You have the best technical posts out there.