Camshaft bearings

[AJ'S 88NA]

I have a spare head that has some damage to the camshaft bearing surfaces. Has anybody tried to maybe open those cradles and caps up enough to put a replaceable bearing in those areas?

[GrimJack]

How much damage? Scoring in there is common and doesn't matter unless it's really severe.

Got any pics?

[AJ'S 88NA]

How much damage? Scoring in there is common and doesn't matter unless it's really severe.

Got any pics?Yeah it was bad enough to use another head. Happened after a stock rod let loose. Would you think that enough material could be taken from the cradles to put a bearing in that area? The reason I ask the question is that the head in question had a lot of time put in in P&P. The head I have now has a lot more done to it and if something goes wrong I'd like to be able to maybe salvage it. I know a lot of others have had the same problem and it would be nice to be able to save them some way if possible. I know it would take some research to find the right size bearings and have a machinest line bore the cradles to fit the bearings. It would be nice if there would be enough room to put a needle bearing in, but I don't think there is enough material.
Another option would be to turn the bearings surfaces on the cams, but then if you have a good set of cams then they are no good for any other head.
Anybody else tried this or done it?:nono:

[Poodles]

they can weld material on and remachine the journals

[AJ'S 88NA]

they can weld material on and remachine the journalsI guess that's possible. Anybody done that out there? I wonder if it would hold up?

[mkiiSupraMan18]

Thats what.... 3x the amount of bearings to spin ? :icon_bigg

[AJ'S 88NA]

they can weld material on and remachine the journalsIt's the cradles not the cam journals that get trashed because they are alum. molded right into the head.

[CRE]

You might want to ask IJ. He's cut a head in half before to do some investigating, if he's still got it he may be able to give you an exact answer.


BTW - i got the package... crap GM parts? lol, what make MAP sesnor you running? :icon_razz Oh, and THANKS!

[supra_ed]

i actually thought about the same thing (getting bearings machined in) last year during my first rebuild. i called titan and hpf for some input. both said too much work and not necessary. my machinist (has built 1000hp supra and is currently building his personal 2j) agreed. seeing as how both companies own 1000+ hp supras, i didnt argue much. stock design is fine. just make sure u install caps correctly. as dumb as that sounds, it seems to be a growing problem. i personally have come across 3 diff. 7m heads with cam caps on backwards!......people r idiots.

[AJ'S 88NA]

i actually thought about the same thing (getting bearings machined in) last year during my first rebuild. i called titan and hpf for some input. both said too much work and not necessary. my machinist (has built 1000hp supra and is currently building his personal 2j) agreed. seeing as how both companies own 1000+ hp supras, i didnt argue much. stock design is fine. just make sure u install caps correctly. as dumb as that sounds, it seems to be a growing problem. i personally have come across 3 diff. 7m heads with cam caps on backwards!......people r idiots.I guess they figure it's not necessary because they have a lot of heads laying around:biglaugh: I was just thinking of trying to save the head if the cradles are messed up. Nice thought though don't you think..Roller bearings for the cams....they sure would spin nice:naughty:

CRE: Your welcome. Now get that damn MAF off there before it gets cold.:biglaugh: I've got the 3 Bar GM MAP.

[Poodles]

yes, if the clearance is horribly out of spec they can weld the craddles and remachine them.

I've seen worse damage repaired on an aluminum head, but the issue is money...

[suprarich]

No need to weld them. You just mill .003 from the head and the cap surfaces and then line bore the head, assembled and torqued, back to the oil clearence you want. Of course, i assume you head is still straight.

[Poodles]

oh, damn, forgot you could take material off the cap :slap:

a machine shop should be able to fix it, if they can't, go elsewhere IMHO...

I've seen some SERIOUSLY fucked up aluminum heads repaired. It's not a big thing for our engines as finding another head is easy, but when you have a rare engine...

[suprarich]

Best way is to take a little from the head too, not just all from the cap. Of course you will need to re-shim the cam.

[Poodles]

yeah, but it's not a huge issue...

I remember seeing this discussion about billet cam caps for 2J's... most people didn't know how to get everything in spec...