Has anyone broke a valve? Well, heads up if your using topline valves. I just snapped an intake valve where the keepers lock.

The valve dropped and dented the piston pretty good, no holes or cracks in the piston, thank god!. The valve bent and got jammed in the guide. The guide cracked and has to be replaced.


This sucks <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> man, I just put that head in! <img src="/forums/images/graemlins/angry.gif" alt="" /> It was a rebuilt unit from Wilson machine shop in New York. First I snapped a valve spring on the #2 intake now the #4 valve breaks and ruins my new-rebuilt head... What's next? F&%$!

Does anyone know where I can find an oversized guide? Help Please!

Shoootz!

Ton

Ton any good mach shop be able to come up with an oversize guide it is an 8mm stem , but your first job get rid of those vlvs all of them , lay you 10 to 1 they are made in a place that start with the letter C and i don,t mean north of the border here,2 years ago i ordered 6 cyl heads at one time from a very large cyl head supplier whom i won,t name , got all the cyl heads and the vlvs to go with them the very first 3 i sent out, one broke an exhaust vlv in less than 300o miles , ask Curtis Johnson about this ones damage, the second one at 1500 miles was allready burnt on the exhaust , got hold of my customer who had the third head all ready installed and it was not running correct , sent him a new head only this time it had the factory vlvs in it the truck is still running , i immediately trashed canned all the rest of the vlv s and assembled the rest of the heads with the isuzu vlvs not one has been back , those vlvs from the "C" country cost 4.50 each, the ones from isuzu costs about 20.00 each, but they don,t burn and the heads don,t fall off, anyway when the guide broke did it tear up the head if not a stock guide should work fine ,anyway now you can get a brand new heavy wall casting , isuzu cyl head complete with all new vlvs, springs and cam shaft, all new rockers and rocker arms ready to bolt on completely assembled for right around 550.. freight paid in most places Jerry

Thanks Jerry!
I'll keep you in mind when I need that new head assy.

When the valve let go, I was just warming up my truck. It's a good thing I heard something give and shut it off quick. If I was on the road or at the strip, for sure the damage would of been worse.
I was able to press out an old guide from a spare cracked head. It fit ok, with a little play. So I used a punch to re-shape the ends of the guide bore. I also used some lock-tight to help secure the guide in place.
Got everything back together last night and ran the motor about 5-miles. I wish the Isuzu dealership here carried parts. I would of spent the extra cash for genuine valves for sure!

I think the valve let go becasue of the spring/retainer combo I was using. When I first re-built the motor, I used Toyota 22r springs/retainers. The #2 Toyota spring that snapped was due to slight spring bind. I'm hoping the valve that snapped had to do with the spring bind too.

I replaced all the springs/retainers with the combo I had on my 2.3 motor, Dual springs this time!

Hope to make a few passes without ruining my bottom end...

Ok Zu gurus this ones for you...

Need a source for shims... I would like to shim the rocker arms, so that the tappet hits directly on the valve. Got a couple of them that are slightly off center. I know this has something to do with valve rotation and such. But, since I'm building it for racing I won't be needing the rotation that much. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Huh? You don't have tappets anywhere in that 2.6L engine, unless you consider the noises it makes with a maladjusted valve train. <img src="/forums/images/graemlins/smile.gif" alt="" />

The rotation you are talking about is for engines with tappets or lifters. The offcenter contact with the cam allows them to rotate in their bore. This is good for wear and lubrication.

I *think* you are talking about the rocker arms where they contact the valve stem. There is no way to get them to hit in the center all the time. Because the arm moves in an arc and the valve stem just moves vertically, the arm will move back and forth (relatively) on the valve stem.

Michael

Haven't listened to your fuel injection much have you? <img src="/forums/images/graemlins/pfft.gif" alt="" />

won't lash caps help out a little by providing a slightly larger contact surface?

That's the one! <img src="/forums/images/graemlins/notooth.gif" alt="" />

I guess nobody tried it yet huh?

Pucci, can you elaborate more on those lash caps?

shoootz!

Ton

I don't think lash caps will do much either. They install on the valve tip to help with wear issues, and some valve train clearance issues.

But, there is nothing you are going to do to relieve the relative angles between the arc of the rocker arm and the position of the valve. Draw it out. The arm moves in an arc and no matter where it is, the lash adjuster will move laterally across the valve tip during the cycle of valve action.

Even more simply put, I think there are better things you could spend your time chasing and better things to throw money at. <img src="/forums/images/graemlins/smile.gif" alt="" />

Good Luck,
Michael

lash caps:




I remember you mentioning the cam profile you run required you to relocate the lash adjuster lock nut to the under side of the arm in order to have the threads fully engaged. with these caps you should be able to put the adjuster nut back on the top of the rocker arm making adjustments a little more convenient.

and just the nature of the cap sitting on & around the stem tip expands that surface area a wee bit: