Bad Misfire

[KZJonny]

Not trying to stop you from doing your own cam journal adjustment, but relative to other things, how much are the cams worth?

Only suggesting that if BC cams has suggested a fix, and you go ahead and hone/polish the keeper, and that causes any problems at all like lack of oil, or burning up the bearing surface, you may not be in a good position to get a replacement under warranty. They'd have evidence that something wasn't right, and if you didn't have them re-grind to match the journal...

If they're not terribly expensive, then yeah, DIY sounds good.

Just a thought.

[Tehnation]

But I don't want to touch the cam.... hmmm I think I need some dye, toolmaker's dye, you spray it on the journals and let it dry, then bolt the camshaft in, spin it and you can find the high spots or where its touching, depending on that result I may or may not be able to work some magic. 

I'm actually a mech engineer, so I am familiar with a lathe and machine work. 

[KZJonny]

Gotcha!

I understood you wouldn't touch the cam, I guess I was just thinking if you take too much off the journal, and lose the correct gap = not the correct clearance for oil to stay in a film between the cam and journal = cam death.

As you point out, heads are reasonably cheap to just replace entirely, but I had the feeling the cams are spendy.

Despite it not being the 'correct way' to do the job, I entirely understand just getting a thing done. If you take your time and only work on it until you don't have any high spots indicated my the machinists dye, I suspect you'd be okay as well.

 

I'm a biochemist, but I've got a lathe and a willingness to make mistakes, so... I feel ya.

[m sprank]

I second the recommendation to seek MIkes assistance at AZP Installs in Kenilworth, NJ.  Mike will remember me, lol.  He used to be a very active member/vendor here and is still a huge asset to the Subaru community.  If you speak with him, tell him I said "hi".  I lost his personal number after my phone died and the shop closed. 

[Tehnation]

Its like 900-1k now it seems for a set, I think I got mine for like 600 directly from bc. They have already given me 2 i'm on the 3rd cam.... and I been waaay past warranty for like years now, so I think I am more a guinea pig! 

That place is like an hour and half away from me, plus all the tolls and traffic, the George Washington Bridge is a nightmare most times. Then spend lots of money cause their machine work isn't cheap, going to probably have to pay for a rebuild and line hone which is way more money than just getting a used head and starting over, I can rebuild the head myself if the valve seats are good.

At this point I would rather just go for broke with this head. BC said they would cut my cam but I don't think that fixes the issue, they would give me another cam with the same diameter for center and rear, but those journals should be relatively close cause they were bored at the same time, so shrinking it wouldn't really work especially if something else is going on. Easiest way to find out whats going on is to use dye.  

[Max Capacity]

Just thinking, why take the risk of doing it yourself, what is normally done by a machinist on a precision machine, that he works with all the time. 

In the long run, have it done right the first time...or is this the second time... or third...

m sprank, is someone we all listen too, he knows what he's talking about.

This is coming out to be one of those, pay me now...or pay me more later, things.

 

You wouldn't replace a crankshaft in a block without having the block line bored. I think I gave you my trusted machine shop's email before. http://eastwoodsautomachine.com/  you can email them, tell them I sent you. Contact them and ask your questions, Mark Eastwood is the owner, his brother Mark works there, their Dad (Olie) started the shop many decades ago.   Call them, at: (860) 749-2903 or (888) 203-2323 Toll free

You can ship the part to the shop, you don't need to drive there.

[Tehnation]

I'm just saying I at least want to know what the issue is or what's binding the cam. A 10 dollar can of dye can tell me where its binding, and if its a simple burr or something I can easily remedy that. I would rather diagnose it 1st before pulling the entire head off and assuming the worst. Could be something simple. 

[Max Capacity]

I hear you, I would think any burr you should be able to feel with your skin. 

Please post pictures of what the dye reveals. 

[Tehnation]

For an idea of what I am talking about with the dye, and fixing it, not a subaru but you should get the idea.

 

[m sprank]

If there is anything more than a small burr you will not be able to accomplish a line hone at home.  Its not as easy as "taking out a high spot".  I would inspect.  You can even use the dye for GP so that you know.  If its the cam cap I would replace it.  The cap, not the head.  If its the cam and BC has already offered, the ball is in their court. 

 

I did not watch the video.  But I can tell you in all honesty that the things I have done to a race engine I would NEVER do to my own car.  Lets think back...  hone a cylinder with a glass jar and a sheet of sand paper, drill holes in the crank to lighten it, port the head after the valve job, oh it get worse the more I think back.  "Winning isn't everything, its the only thing."

[Tehnation]

So after letting things percolate, I came to the conclusion measuring my journals would be impossible cause I could only do it by crude methods, and my bore gauge doesn't do anything under 2 inches. I figured I would polish things and hope for a better result but then I remembered I have a set of cams, my oem cams, that I can use to see if I get a different response! My old cams spin freely when torqued down so its a cam thing. So I am going to see what bc says cause I'm not measuring 1 inch journals with what I have. I told them if I have to send back my cam they just sent I might as well just send the oem cam with it and let them come to a conclusion with their fancy tech. 

Going to polish all my other journals and cams with some 1500+ grit, maybe like 2k-3k, all my old cams seem to have ridges so everything could use a good polish.  Edges on the cam mean edges on the journals, and since the cams move back and forth some what it creates a toxic relationship between the cam surface and cam journal. 

[Max Capacity]

So if your OEM cams work well...what is the O.D. of the BC cams bearing surface ? I'm they must meet the Subaru Factory spec... ?

What is the O.D. of "your" OEM cams bearing surface ?

Or is all that info back in this thread already ?

 

Unless BC told you it was ok, "in writing" I would not touch their cams bearing surface.

[Tehnation]

Didn't measure the O.D. I just tried it to make sure my journals were good, and when I torqued it down I was able to spin it by hand without the cam gear so I just stopped messing with it cause I think it just makes more sense to send my oem cam or both back to them so they can come to whatever conclusion. I will probably measure them myself to see the difference but its turkey time! 

Happy Thanksgiving!

[Tehnation]

BC is sending me a label so I can ship back the cam and my old oem cam so they can cut it to match!

Problem solved.... this is some amazing customer support I must say....

[Max Capacity]

Nice to hear about a company that takes care of it's customers.

[m sprank]

This is good news.  

[Tehnation]

I'm curious how do the heads come from the factory? Are they like the blocks with 1,2 and 3 for the crankshaft journal sizes? I wouldn't think so, cause the oem camshafts don't come in different sizes, or do they? Do they cut camshafts at the factory? I'm wondering cause they said my journals are probably on the small side, while the cam might be on the high side. All the other cams can spin by hand, so to have one undersized journal seems odd, but I don't know much about the factory build process.

[m sprank]

I believe Oem cams are not made by Subaru, they are made for Subaru like almost all parts.  Subaru uses over 260 "OEM" suppliers.  They do not come in sizes.  This is all very peculiar.  But with used parts (not new forgings or castings) lots of oddities can occur. 

Edited November 30, 2022 by m sprank

[Tehnation]

Does the fsm give the cam specs or the O.D. diameter and the range? I just saw the journal I.D. The journals have a specified tolerance.

Standard value mm (in)

Front

37.946 — 37.963 (1.4939 — 1.4946)

Center, Rear 

29.946 — 29.963 (1.1790 — 1.1796)

[Max Capacity]

Having worked in the Aero-Space industry, I can see where, "compound of tolerances" can come into play. I was always taught to shoot for the middle of the tolerance. You don't want to be just good enough, by just meeting the low or high side.

[Tehnation]

I need a new caliper. Mine isn't that accurate...

[Max Capacity]

The cost of a good one is probably more than you want to spend. 

[silverton]

27 minutes ago, Max Capacity said:

The cost of a good one is probably more than you want to spend. 

I looked in to buying the tools to measure clearances at home to assemble my own block, and yes... the cost of the tools to do my one block, accurately, was the same cost as taking it to a machine shop to be assembled.  If I was going to be doing it over and over again, I'd have bought them, but for just mine... I couldn't.

 

Here's alldata's info on the 2005 LGT camshaft, usually this stuff is straight from the FSM.

Edited December 3, 2022 by silverton

[Tehnation]

I could use a good caliper regardless, the one I have is good, just not that precise. I wouldn't mind spending 150-200 for one, I know I will use it down the road. My logic is a little bit different, I would rather buy the tools and do it myself if the costs are similar to paying someone to do it. Even if its only a one time thing, I would rather go the diy route cause I get new tools and more experience, so rather than pay someone else I would rather pay myself. Obviously thats not always the case but when its rational like this, I prefer to just invest in the equipment. 

[silverton]

Starrett and Mitutoyo seem to be the go to for quality and accuracy.