Head repair question

[karlak]

The tIII head does not use cam bearings. If the bores are worn to the point that you dont feel good about just sliding the cam back in and crossing your fingers, what are your options? Welding and align boring would be costly. Align boring and installing cam bearings seems to be easy enough. What is the standard fix for this problem?

[86Shelby]

I'm still looking into finding bearing inserts for this issue, but finding a federal mogul catalog is actually kinda hard without spending a ton of money on it. Maybe I can find one at the swap meet this weekend.

[turbovanman²]

No one makes drop in bearings. Your going to have to scour cataloques as mentioned or get ahold of a bearing company and have them made. Jackson posted a link to a bearing company, forgot the name and they could make some. I should get my azz over to my machine shop friend and try to see if any V6/V8 cam bearings could work.

[Directconnection]

I have the federal mogul books at work. I highly doubt that we would get lucky and find one that will give the right clearances. Diogo or someone a few years back had this done.

I have line bored cam bearings to size in a Volvo TMD63 big diesel engine (PITA!) They are designed to be bore to size so the bearing has enough babbit to be removed.

What you would need to have done is line bore the head for the correct press of the bearings to be used, then line bore the bearings after being pressed in, and to size. PITA as well... but I planned to do just that if I got ahold of any junk T-III heads. (simon)

[turbovanman²]

I have the federal mogul books at work. I highly doubt that we would get lucky and find one that will give the right clearances. Diogo or someone a few years back had this done.

I have line bored cam bearings to size in a Volvo TMD63 big diesel engine (PITA!) They are designed to be bore to size so the bearing has enough babbit to be removed.

What you would need to have done is line bore the head for the correct press of the bearings to be used, then line bore the bearings after being pressed in, and to size. PITA as well... but I planned to do just that if I got ahold of any junk T-III heads. (simon)

Exactly,

Its being used right now for some TIII products I am bringing out but after that, I promise I'll send it out to you.

[Directconnection]

Exactly,

Its being used right now for some TIII products I am bringing out but after that, I promise I'll send it out to you.

Coolio. Good things come to those who wait then

btw...updates on your van? spring is right around the corner.

[turbovanman²]

Coolio. Good things come to those who wait then

btw...updates on your van? spring is right around the corner.

Nothing yet, have to get the racebike done first, fully sponsored this year so its my first priority,

[86Shelby]

Well, worst case senario I'll have the bores line honed, then have the cam journals machined to match. Right now my cam journals need to be welded up to be useable. Why not just go a little oversize to match the larger bores when they are machined? Sound reasonable?

[Directconnection]

Line honing aluminum usually doesn't want to work as it loads up the stones and makes it near impossible. plus... alot of $ in welding up the cam's journals, and hen grinding them to a larger size. Might as well do it right.

[turbovanman²]

Well, worst case senario I'll have the bores line honed, then have the cam journals machined to match. Right now my cam journals need to be welded up to be useable. Why not just go a little oversize to match the larger bores when they are machined? Sound reasonable?

That would make sense if the head had removable caps, but if you line hone now, you'll make the bores oversize and the cam will wobble around causing oil pressure and cam issues.

[Clay]

if you know any old school machine shop people, especially precision roll grinding people (fat chance), then they can put new babbit on the old surfaces, and the you could have it line bored.

but, the ones Ive see dont look like there is actually babbit on these cam bores, it just looks like aluminum.

[Directconnection]

Babbitting is very expensive and not sure if they can do it to aluminum. Usually, the bearing shells are steel.

Line bore the cam housings in the head to accept actual bearings, then bore those afterwards to size.

[Warren Stramer]

I can think of two possible solutions that problem, but not having the head on my bench to personally inspect I could be way off...........search bearing supply companies for roller bearings like are commonly used in V8 race motors. Or bore to accept aluiminum sleeves press fit in bores then honed to size. does not neccessarily have to be babbit cam brgs (cam runs on plain aluminum from factory anyway) Could be common aluiminum tubing slices for that matter. I would have to have a head to measure to be certain. Send me the head and ALL your money and I will make it like new.

[Directconnection]

Cam journals probably wouldn't hold up to a roller bearing.

As easy as it gets, press in a cam bearing from a different application, then line bore them to size.

[iTurbo]

I sent a PM to Wallace, he says Absolute Auto in Topeka has done this before but will need my cams for proper clearance setup. So it's definitely possible but I don't know if an off-the-shelf bearing was used or what. I'll give AA a call on Monday and let you all know what I find out.

Also, why wouldn't a roller bearing work? Sounds pretty trick.

[Directconnection]

I believe the cam's bearing surface isn't up to the task due to not being heat treated for that intended use.

[karlak]

I can think of two possible solutions that problem, but not having the head on my bench to personally inspect I could be way off...........search bearing supply companies for roller bearings like are commonly used in V8 race motors. Or bore to accept aluiminum sleeves press fit in bores then honed to size. does not neccessarily have to be babbit cam brgs (cam runs on plain aluminum from factory anyway) Could be common aluiminum tubing slices for that matter. I would have to have a head to measure to be certain. Send me the head and ALL your money and I will make it like new.

Cool..... did not know $5 dollars would go so far

[Warren Stramer]

Unless the TIII cams are made of junk, roller brgs. should not wear the journals. It is done all the time on V8's as a upgrade, and as far as I know they use the very same cam cores without any special coating or heat treatment. I would also say that there is no measurable performance benefit. I only mentioned it as a alternate fix.
Having said that, I agree with Steve, simply installing regular cam brgs. and hone would be easy and affordable. that would be my first choice also.

[turbovanman²]

Unless the TIII cams are made of junk, roller brgs. should not wear the journals. It is done all the time on V8's as a upgrade, and as far as I know they use the very same cam cores without any special coating or heat treatment. I would also say that there is no measurable performance benefit. I only mentioned it as a alternate fix.
Having said that, I agree with Steve, simply installing regular cam brgs. and hone would be easy and affordable. that would be my first choice also.

Exactly, they offer roller cam bearings as a hp freer upper when going for the last HP in all out engines and also if going with heavy valve springs and big cams, helps stop from wiping out cam bearings.

I don't see an issue trying to match up the cam with some common cam bearings and having the head bored to match, thats why they do with aluminium blocks,

[86Shelby]

I sent a PM to Wallace, he says Absolute Auto in Topeka has done this before but will need my cams for proper clearance setup. So it's definitely possible but I don't know if an off-the-shelf bearing was used or what. I'll give AA a call on Monday and let you all know what I find out.

Also, why wouldn't a roller bearing work? Sounds pretty trick.

It's Tuesday night, 18 months later. Were you able to get ahold of them?