Author Topic: Cracked cam bearing cap (Read 28944 times)

land_shark · « **on:** June 08, 2005, 12:06:07 AM »

I cracked it when I over-tightened one of the bolts...

Is there any way I can fix this?

land_shark · « **Reply #1 on:** June 08, 2005, 12:15:22 AM »

before I get ahead of myself, that isn't the cover that cracked, is it....fixed the post subject, etc.

cjb1214 · « **Reply #2 on:** June 08, 2005, 01:07:16 AM »

It looks like you cracked the actual top of the motor where the bolt goes in.

Red01 · « **Reply #3 on:** June 08, 2005, 01:14:55 AM »

As I said in your same post in the torque wrench thread...

Quote

That damage is in the cam bearing cap, right?

Talk to a machine shop and see if they can weld it up and rebore & tap the hole for you.

If the crack doesn't extend too far into the piece, you may be able to save it with a heli-coil.

land_shark · « **Reply #4 on:** June 08, 2005, 09:57:50 AM »

Here is a better look after I took the head cover off this morning:

http://www.grundstad.com/images/cracked3.jpg
It's on the intake side of the #1 cylinder. This has to be something I can replace...

PitterB4 · « **Reply #5 on:** June 08, 2005, 11:26:13 AM »

Quote from: "land_shark"

This has to be something I can replace...

That's what I thought when I stripped mine last month. I was surprised when Bike Bandit and my local Suz shop couldn't get one for me. My machinist explained to me that each one of those is machined specifically for it's head. He said that if the heli-coil didn't work or if he couldn't get one, my options were a new head and matching cam brackets (yikes!) or taking the head off and having him custom machine something (can I get another yikes?!?). I sure hope someone chimes in with better news for you. That looks nasty.

land_shark · « **Reply #6 on:** June 08, 2005, 11:31:42 AM »

Quote from: "PitterB4"

...my options were a new head and matching cam brackets (yikes!) or taking the head off and having him custom machine something (can I get another yikes?!?)...

........

land_shark · « **Reply #7 on:** June 08, 2005, 12:00:47 PM »

I called my local dealership, and their resident expert gave me the same answer. I probably won't be able to find anyone who can weld a precision aluminum part, and I can't just replace one bracket. I have to buy a new head.

There is a head for sale on ebay for 275 at the moment, but it's for a 2004 (I have a 2000). They have slightly different part numbers, so I'm not sure if it'll fit.

JB weld has helped me out before. Is there anyone out there who can back be up with a "Yeah, that might work, try [insert instructions here]....". What about using some kind of sealant to reinforce the gasket on that corner of the cover?

PitterB4 · « **Reply #8 on:** June 08, 2005, 12:22:24 PM »

Mine was totally different - I just stripped out the threads rather than splitting it but JB Weld and Permatex Thread Repair were of no help. The threads are too fine. They would just pull loose.

GeoBandit · « **Reply #9 on:** June 08, 2005, 01:45:44 PM »

JB weld in the engine - I would not even go there. If it fails and causes more damage, you will just have to shoot yourself. Do not take that risk. Yes there are people that can fix it, locating them is hard. I was a Aviation Mech. for 20+ years. If anyone know hows to weld exotic metal (alum) an aviation machine shop should.

I used a trq wrench everyday. Deflection type are not allowed in aviation. The click type is the only allowable type. It had to be calibrated on a regular sched. Opperating one is not as simple as uust grabbing the wrench and putting it to use. You have to measure run on torque (that is the resistance to threading, mostly in self-locking). The wrench has to be treat correctly. Do not drop, bang, hammer with or any abuse. It must be stored in the "zero" condition. Walk the torque up, this does two things; it ensure even tightening, no worping, and lubricates the wrench. The worst thing to do is set it to the max torque allowed and tighten. The first time it is operated it takes more force to operate the "click" mech. You are over torqueing at this point. I own a couple for area where I want more than German torque (Good-En-Nuf). But for the real acurate and critical places I went/borrow from the local tool store.

Bob Holland · « **Reply #10 on:** June 08, 2005, 02:28:02 PM »

I have known of people getting those caps used, the cap being in tolerance and working. But there use to be a shop in Calif that would line bore the cap on the head, but you would have to take the head off and send the hole thing.. I sent someone in the Houston area one from an old head that I have, last year, never did hear if it worked.

land_shark · « **Reply #11 on:** June 08, 2005, 06:07:30 PM »

possible solution. I'd like some feedback (good or bad) before I actually try this...
"A friend of mine thought up this solution.

Here is a crappy artist's conception...

http://bandit.eng.uiowa.edu:8088/~jgrundst/cam_cap_fix.JPG
Ok, let me have it

snofrog · « **Reply #12 on:** June 08, 2005, 06:22:02 PM »

if you u.p.s the cap to me i will weld it for the cost of return shipping .i do fussy welding all day. M

Red01 · « **Reply #13 on:** June 08, 2005, 09:20:58 PM »

Quote from: "GeoBandit"

I used a trq wrench everyday. Deflection type are not allowed in aviation. The click type is the only allowable type.

That's not true! Dial Indicator types are allowed, too.

Quote

German torque (Good-En-Nuf).

I always thought that German Torque was "Goot-en-tite"

Quote from: "land_shark"

possible solution. I'd like some feedback (good or bad) before I actually try this...

I have an in with the machine shop guys here at the U of Iowa Engineering department, and they thought up this solution. 1) shear off the top collar 2) make a plate with a new collar on it that fastens under the cap mounting bolts. here is a crappy artist's conception...

That'll work!

And is probably the safest option short of any option that involves head removal.
I know you said it's just a crappy artist's conception, but don't forget the valve cover boss is not centered on the cap.

I would be VERY, VERY reluctant to trust a cam bearing cap from another head without at least checking the bore alignment with the other caps.

land_shark · « **Reply #14 on:** June 08, 2005, 09:35:27 PM »

Quote from: "Red01"

That'll work!
And is probably the safest option short of any option that involves head removal.
I know you said it's just a crappy artist's conception, but don't forget the valve cover boss is not centered on the cap.

That makes me feel much better about this

The piece is going to be finished tomorrow (off-centered, of course), so I should have it installed soon after work. I'll probably put it in, let it idle for a bit, and open it back up to see if there are any obvious signs of wear. Maybe check after a 2-3 mile ride, and so on. Either way, I'll try to keep putting up photos of anything interesting.

"Look out below, 'cause here we go..." -C.W. McCall