Cleaning up Cam/Crank Journals

[lsfourwheeler]

My camshaft and crank journals have some slight wear, but nothing I believe would require them to be machined (Can't feel anything with a fingernail). What's the best way to clean these up? There seems to be some very mixed opinions in most places about this. Micron paper, requires machinist, do nothing?

MVIMG_20180211_112348.jpg

[NAZ]

First full disclosure: I'm not professing to be an expert on your engine but I have quite a bit of experience with a variety of split case bearing journals and can give you some general guidelines on how to deal with this.

Check the repair manual for a wear spec before attempting to clean up these surfaces. It's easy to damage these surfaces when attempting to "polish" out some minor imperfection that is perceived as a problem -- so don't be in a hurry to fix something that is not really broke. The surface finish is seldom an issue. It's common to see some minor fretting on the surfaces where the bearings nest. It is almost never a problem unless the wear is enough that the bearing will not nest properly. I see nothing in the photo to indicate a spun bearing -- this is the most common cause of damage I've experienced. If all you're dealing with is minor fretting then clean the surfaces with a soft cloth and solvent. When you install the bearings make sure they are nesting fully. Follow the repair manual reassembly procedure which should include installing the bearings and assembling the case halves without the crank to measure the bearing I.D.s for concentricity and proper clearance. Use a bore gauge for this it is much more accurate than the plastigauge most DIY hobbyists use.

Good luck.

[SixStar]

You'll want to bolt those back together and have your engine builder check the alignment before you do anything. About 50% of the engines I see at work need to be line honed to be 100% correct.

ProTip: you should NEVER EVER remove the OEM case half pins on these engine, not for any reason ever. You'll also need all new engine case bolts if the halves need line bored/honed.

[lsfourwheeler]

First full disclosure: I'm not professing to be an expert on your engine but I have quite a bit of experience with a variety of split case bearing journals and can give you some general guidelines on how to deal with this.

Check the repair manual for a wear spec before attempting to clean up these surfaces. It's easy to damage these surfaces when attempting to "polish" out some minor imperfection that is perceived as a problem -- so don't be in a hurry to fix something that is not really broke. The surface finish is seldom an issue. It's common to see some minor fretting on the surfaces where the bearings nest. It is almost never a problem unless the wear is enough that the bearing will not nest properly. I see nothing in the photo to indicate a spun bearing -- this is the most common cause of damage I've experienced. If all you're dealing with is minor fretting then clean the surfaces with a soft cloth and solvent. When you install the bearings make sure they are nesting fully. Follow the repair manual reassembly procedure which should include installing the bearings and assembling the case halves without the crank to measure the bearing I.D.s for concentricity and proper clearance. Use a bore gauge for this it is much more accurate than the plastigauge most DIY hobbyists use.

Good luck.

Great, so what about the cam journals? I understand not doing anything to the crank journals because they're not actually a bearing surface so that makes sense but the cam journals are. Any recommended options on those besides nothing or taking it to a machine shop?

[turbomacncheese]

I see nothing in the photo to indicate a spun bearing -- this is the most common cause of damage I've experienced. If all you're dealing with is minor fretting then clean the surfaces with a soft cloth and solvent. When you install the bearings make sure they are nesting fully. Follow the repair manual reassembly procedure which should include installing the bearings and assembling the case halves without the crank to measure the bearing I.D.s for concentricity and proper clearance. Use a bore gauge for this it is much more accurate than the plastigauge most DIY hobbyists use.
Good luck.

I'll second this. As for the cam journals, how does it feel with the cams lubed and torqued in? Any slop? Any wiggle? Do you have pictures of the wear pattern in the journals and on the cams?

[lsfourwheeler]

I'll second this. As for the cam journals, how does it feel with the cams lubed and torqued in? Any slop? Any wiggle? Do you have pictures of the wear pattern in the journals and on the cams?

Here's a picture of the cam journals, it's not as good but you can see some of the wear lines. My real concern is the journal caps that for a couple of them have a scratch or two in them from what looks like mishandling on the part of a previous owner. I don't have pictures of the caps though.

MVIMG_20180127_132400.jpg

[NAZ]

Like I said, I'm not an expert on your engine but do have relevant experience with similar engines. What does the repair manual say about wear limits? If these journals are beyond service limits then you're likely looking at an extensive repair. You should seek help from a engine builder that specializes in these boxer engine cam journal repairs. Some of the repair methods I know people have used to repair aluminum cam journals (not necessarily on your engine) is to bore the the journals oversize and add speedy sleeves on the cam; or build up the journals by welding and re-bore them. A shop that specializes in this repair may have some trick repair method that is cost effective.

[lsfourwheeler]

Like I said, I'm not an expert on your engine but do have relevant experience with similar engines. What does the repair manual say about wear limits? If these journals are beyond service limits then you're likely looking at an extensive repair. You should seek help from a engine builder that specializes in these boxer engine cam journal repairs. Some of the repair methods I know people have used to repair aluminum cam journals (not necessarily on your engine) is to bore the the journals oversize and add speedy sleeves on the cam; or build up the journals by welding and re-bore them. A shop that specializes in this repair may have some trick repair method that is cost effective.

Thanks for the info! My heads are already at a machine shop so I'll have them take a look at the caps too and see what they think about them.

[turbomacncheese]

I agree with NAZ on verifying the service limits. As far as the aluminum goes, it's hard to tell from the picture...but if it's only as bad as it looks in the picture and the diameter/roundness is in spec, I'll say I've run worse on other engines (no experience with Subarus except the one I just built...which has yet to see it's first start attempt). That being said, I AM something of an idiot and it was NOT a high performance engine, so maybe don't look to me for gospel. Whether or not it scored the cam is also important, but if it doesn't hang up your fingernail like you said, oil will likely fill the low spots as it should.

[lsfourwheeler]

I agree with NAZ on verifying the service limits. As far as the aluminum goes, it's hard to tell from the picture...but if it's only as bad as it looks in the picture and the diameter/roundness is in spec, I'll say I've run worse on other engines (no experience with Subarus except the one I just built...which has yet to see it's first start attempt). That being said, I AM something of an idiot and it was NOT a high performance engine, so maybe don't look to me for gospel. Whether or not it scored the cam is also important, but if it doesn't hang up your fingernail like you said, oil will likely fill the low spots as it should.

Yeah, I'm not going crazy with the power numbers for my build so I think I'll just roll with the moderate amount of wear that is on them. Thanks for the tips!