Cylinder head repair

[86Shelby]

I disassembled my head today getting ready for the engine botom end rebuild. I was planning to get the crack by the freeze plug welded; hence the teardown of the head.

I found the outer cam bore was damaged on the exhaust side. The upper 1/3-1/2 of the bore is damaged. The cam journal should be able to be polished or otherwise repaired. Has anyone had this type of repair done to thier head? I can't see myself simply junking the head due to this. There is a good amount of money in porting, coatings, etc done within the last year to it. I'll pay to have it repaired vs finding and porting a different casting if there is a repair that can be done.

I did have an oil pump/int shaft failure; though I caught the gauge just before it hit bottom. I know why there's damage.

On another note, why was the upper portion of the bore damaged? The bottom, front, and rear of the bore are in great shape. I would have expected those portions to be damaged due to the pressure from the valvetrain and timing belt, especially the bottom/front portion.

[turbovanman²]

Yes, it can be repaired. I have shop near me that does it or search online to find some.

Upper bore damaged-weird. The rocker arms push down on the cam!

[Clay]

its all about how the cam is loaded by everything (belt, and followers), how that loading is released, and how the bearings are installed. If there is a fit issue with the bearing (ie loose, or too tight) this can also cause issues.

Best case, you may be able to polish it out, but I doubt it.

worst case: your going to have to weld up the cap, and have everything line bored.

clay

[86Shelby]

worst case: your going to have to weld up the cap, and have everything line bored.

It's a TIII head. The cams slide into the head like the cam in a traditional V8. There are no caps to weld and resize with line honing.

[Blue Iroc R/T]

Ray,
If it is just the outer bore, you could probably get the bore welded and the remachined. However, (I just looked and the head that I will soon be installing on my R/T) I notice that the thickness of the stock above the bore is very thin. There is a VERY good chance that welding the bore will disort the rocker shaft journal on the outer end that is just above the bore. Therefore, it might be better to bore the outer bore oversize and send your exhaust cam to Wallace (aka mopar2ya on TD.com) at Lonewolfperformance.com I think he can put a build-up on the outer journal and re-grind it to fit the bore. OR bore the outer bore oversize and sleeve it. IMO, either of these might be safer than trying to weld up the bore and causing more problems elsewhere.

[86Shelby]

I was finally able to drop the head off at the local aluminum head specialist. He took a look at it and thinks it can be polished out. The final say will be when I bring the cams in next week and he can gauge better. I'll let everyone know how this turns out. I certainly feel good about taking it here after the best general engine machinist in the area took at a look at it and said "go here, he's your man on this one".