Cam Journals Worn Outta Spec. Looking for a little bit of advice.

[shadowlurker]

Fairly recently i brought a head to the machine shop to get some prices and to get a feel for the place. So he looked over the head and inspected it. He saw the cam journals and checked if they were within spec. Which unfortunately they were not within spec. And the journals could not be honed out because his equipment needs a rod to go all the way through from one end cam journals to the other and connect. Which obviously wont work. Soo, I could look for another machine shop with the right equipment to get the honing done. But first i want to know if this is too much of a problem and if i should pick up a new head? Otherwise the head is in decent condition, its not warped in any way the mating surface looks nice still. Oh, and i dont have pictures of the cams sorry, in case that would help. The plan is to aftermarket cams anyhow. Thanks for your time!

 

[lewis15498]

I would look into contacting Rich from sip racing. I dont think he is too far from you. I'm like 99% sure he can do it. While I havent had him do any machine work, if I needed some done I would likely send it to him. I have done business with him before and he is A++. He even emailed me afterwards to make sure I was satisfied with the products I purchased from him. I'm pretty sure hes in the vendor section here, and his website is sipracingmailorder.com.

 

[shadowlurker]

Thanks for the recommendation! However i did pm him on here a while ago asking about this. But now that you mention it i dont think i emailed him on his private email. Woops haha. Ill definitely be contacting him soon then.

 

[supradjza80]

whow, just noticed you are in Green Bay. Is that Green Bay wi? If so who were you having do the engine work for you? I am looking to have some work done around here to my motor.

PS. I haven't checked clearances yet but my Cam Journals look quite similar to these.

 

[shadowlurker]

Yup green bay wisconsin. I was gonna get my machine work done by baril machine. Ive heard from several people that they do good work. I asked them a whole bunch of questions and they answered them all nicely. He also showed me the machine that would have done the honing on the cams and why it wouldnt work. I could pm you some prices i got from them if you are interested.

 

[supradjza80]

oh ok, Yeah, I have talked with Baril, but I decided to go with Bay Speed. Let me know if you ever need a hand with anything, Im in Little Chute right now.

 

[CyFi6]

How far out are the clearances exactly? If it is not much, you can simply shave the cap mating surface down slightly to get the clearance tighter. It wont be 100% round, but with the amount of load the cam deals with it shouldn't be a problem. I did the same thing and have been running like this for half a year now. Just food for thought.

 

[Supraflymk3]

If your cam journals get out of spec its recommended to just get a new head because there are no bearings to replace. The only way it would be worth it is if you had it honed and polished then you would have to order new custom cams with the right cam journal sizes. I like CYFi6's idea though, I might be resorting to that idea if mine are shot because I bought a Supra with a spun bearing so metal got recirculated through the whole engine and the journals are all scored. Otherwise I'll throw on my GE head from my Cressida which is in good shape.

 

[supradjza80]

Also, You may want to check with this machine shop in GB

http://www.polkdiesel.com/

My grandpa owns a semi repair shop and they do top notch work on the Big rigs among other things and should easily have a machine large/long enough for our head. I am calling them tomorrow with prices as I may go with them after my grandfathers advice.

 

[shadowlurker]

I do not remember how worn outta spec the journals were unfortunately. I'm currently outta town so I can't check. I emailed rich at sip, and he gave me some prices and said he could do it. Supradjza80 if you could let me know on. What info you get from polk diesel that would be great. Thanks for the advice guys!

 

[3p141592654]

If its just normal wear that's made them out of spec, the procedure outlined in post #7 works fine. Most of the wear is in the cap due to the spring pressure, so lapping the caps will make them more round than they are now. If the problem is abnormal wear with deep scratches or worse, then it is done for. The rears are typically worse than the fronts, due to the location of the oil feed up front.

 

[destrux]

The right way to fix it is to have the journals filled in with a TIG welder and bored back to factory size. Cutting the caps down will work OK, but you might need to cut the caps too much dependin on how far out of spec you are.

There is one other way... repair inserts (basically, they look like normal cam bearings)... but nobody I'm aware of makes repair insert bearings for the 7M yet, although there's a company called durabond bearings that makes them for the 5M and older M series engines. They machine the journals oversize and install the bearings to bring them back to original spec. Not sure why they don't make them for the 7M, I would think demand would be high with all the metal contamination these motors see with all the BHG and rod bearing meltdowns.

I've seen these inserts used to fix a 4G63 head and they worked well.

 

[supradjza80]

I called Polk and there pricing is good, Baril is F'ing rediculous price wise. I did not ask for what you are looking for specifically as I am not really 100% sure of your plan but you should give them a call regarding it. For the machine work I am doing they were quite good on the price.

 

[shadowlurker]

Ill give Polk a check this weekend. Ill stop over there and ask some questions. Ill probably send the head to rich though for the line honing of the cam journals. But for the block and crank ill see what Polk can do, plus its fairly close so that's always a bonus. Supradjza80 what are you having done? Machining wise.

 

[3p141592654]

You would line hone the cam bearings, or shells, in the head. The journal is the part on the cam.

If you do line hone the bearings in the head, how do you plan to bring the bearing size back to the factory spec to match the cam journals?

 

[TurboStreetCar]

If you cut the caps it would make the holes out of round, wouldnt line honing bring them back to round in the proper size for the cam?

 

[3p141592654]

The holes are already out of round because the wear is not even due to the nature of the cam loading. Next time you have a head apart use a bore gauge to measure the cam bearings. You will be shocked how bad they are. The journals, on the other hand, don't wear at all in my experience.

Also, it should be noted that to minimize oil-whirl so-called lemon bore bearings are often specified. However, I am pretty sure the factory did not ship lemon-bore bearings new in this application so this is a bit of a red herring, but I bring it up only to point out that there are applications where a perfectly circular bearing is not desired.

 

[IJ.]

The holes are already out of round because the wear is not even due to the nature of the cam loading. Next time you have a head apart use a bore gauge to measure the cam bearings. You will be shocked how bad they are. The journals, on the other hand, don't wear at all in my experience.

Also, it should be noted that to minimize oil-whirl so-called lemon bore bearings are often specified. However, I am pretty sure the factory did not ship lemon-bore bearings new in this application so this is a bit of a red herring, but I bring it up only to point out that there are applications where a perfectly circular bearing is not desired.

Genuine Clevite 77 Rod bearings aren't "round" pity you can no longer buy them for the M engines....

 

[shadowlurker]

woops got my terms all mixed up again, my mistake. But yea that's what I meant, as long as everyone knows what I mean haha. So the title should be cam bearings then?

 

[IJ.]

Nah it's cool I was just commenting on 3p's "not round" post