bradthebold

I think I've decided to do the valve job and started getting the head off. Even with the good leakdown, turning the boost up on a 30 year old gasket didn't seem like the best idea.

Do the exhaust valve look okay/have normal buildup and would be reusable? Looks like a couple leaks too.







Then I'm trying to decide whether o-ringing is worth it or not. I could do the valve job locally for a lot less than shipping to Lindsey to do it and o-ring I'm sure. I'm concerned if I do blow an o-ringed gasket and need to deck the head again, it could be an issue. Or if I should deal with pulling the head studs and having the block decked for a cometic would be worth the hassle.

fast951

Brad, have you checked the ceramic liners in the ports. The first picture you posted is showing what looks like flaking (maybe the junk on the port vs. the ceramic)?
I would clean (by hand) the exhaust ports down to the ceramic before doing any work on the head.

bradthebold

I mostly cleaned up that one you were concerned about, and I think it looks good. There was a lot of stuff built up on it, which is what the others looked like too vs being a depression from it flaking off.

fast951

Congrats, the port seems to be fine.

bradthebold

I changed the rod bearings out and they didn't look too bad. #1 had the most wear, but looked ok. I put the oil pan gasket on Van style lubed with oil and want to make sure it looks ok before I have an issue after putting everything back together. There is some minimal squish out the sides, but nothing like the pictures others have posted. I tightened the bolts in probably 15 steps.





Then I started working on getting the head off and ended up getting stuck on a water housing bolt. Ended up stripping the hex head, pounded in a torx then snapped the bolt. I've been spraying it with penetrating oil and tried some heat with vice grips but can't get it to move. Anything else I should try, or should I just leave it for the machine shop to remove?





And finally, I'm probably going to drill the AOS and use a catch can. Is the Saikou Michi the only good choice? It looks like it's almost doubled in price since it became popular ($180+shipping). And what size would I need, 3/4"?

bradthebold

I got the head off, but not without more seized/snapped allen bolts. I'll soak them in penetrating oil for a while and hope I can get it off with vise grips. Any idea what size/part number these are? I don't see it in the PET and Pelican's says it should be one allen and one hex head. Mine were both allen.




The head gasket was kind of gross looking with a bunch of build up over the water ports and some of them were torn.



The head has significant buildup on it too.





A few scratches, but nothing I can feel or catch with a fingernail. #1,3 and especially 4 have horizontal discolorations though. Is #4 ok?

#1



#2


#3




#4

bradthebold

Do cylinder walls look ok? I don't want to start replacing seals if I need a new block. No leaking past the rings audible during the leakdown test on #4.

And how can I get those broken bolts out? Vise grips just spin. I bought some nuts to double nut it, but they just spin past the threads instead of tightening. Most of the water pump bolts feel like they're going to break when I tried to loosen them too. Anyway to prevent it or I'm going to have a lot of corroded bolt halves to try to remove.

Tom M'Guinn

Hard to say about any cylinder based on photos, but those look fairly par for the course. If the leak down numbers were good, then I'd probably run them unless you are up for a complete tear-down and rebuild. No guarantees a used motor will have better cylinders. As for the broken or soon to be broken bolts, they tend to just get brittle and chalky in those positions. You can try vice grips or the like, but don't be surprised if they just disintegrate or break further down. The only thing that's every worked for me is to drill them out and helicoil them. Making up a jig to center the drill bit will help a lot and help avoid holes in the wrong place. Or a good machine shop can remove them with an EDM machine. Or you can try Alum chemical trick lighting up youtube lately. Or, if Van were on this thread, he'd suggest welding a nut on and removing it that way, though when I tried it on these bolts, the bolt always just crumbles apart under the weld.

p.s., Do NOT try an EZ-Out. It will snap off in there and make the problem exponentially worse.

bradthebold

Thanks, that makes me feel better at least. It feels ok and just looks like stain/discoloration, and the good leak down number makes me feel ok then. If it is an issue, then I'll tear it down and go 2.8L probably.

I felt lucky getting through the exhaust without breaking anything, but now half the water related ones I can just feel stretching apart until they snap in half. There's plenty of thread to weld a nut on, so I might borrow a welder and try that first. Otherwise I'll try to figure out how to make a jig and drill them and learn how to helicoil. I am scared of damaging the block though, so I may just haul it somewhere once I get everything off and let a shop get all of them out and fix that alternator mount.

ealoken

Im replacing all the nuts in the water system that mounts on the block / head with studs. So i wont have this problem again.

bradthebold

I'm trying to find a shop to do the head work and it's proving difficult. I called the main Euro shop in town and called the shop they use for machine work, but the guy said he had no idea what the head looked like. After describing it, he said it sounded like a rabbit head and he should be able to figure it out. Not very confidence inspiring, especially after Dougs951S had his head cracked by a machine shop. I called the local Porsche dealer and asked their service guy who they use, and he said they don't use a machine shop, so he wasn't sure. I asked what they do when they need machine work and he said they've never needed any machine work. What. Otherwise the service manager at my mom's work called around and found a place 1 1/2 hours away they said they could do it. I called and one guy said they've never done one, but they could figure it out. The guy who does them called me back and said he has done it and it wouldn't be a big deal. He said it would be $810 just for labor though, insane. The first guy told me $230-240. I think I'm just going to go with him and bring a copy of all relevant factory service manual information about the job and go over it with him first. He's been doing it for 30 years and worked on Euro stuff, so I would hope he can handle it.

ealoken

What needs to be done to the head?

bradthebold

Just a valve job and replace guides and seals.

Humboldtgrin

I would clean ALL the exhaust ports ALL the way down to the ceramic like stated already and look for hairline cracks. It look like there's two long hairline cracks in the port you cleaned. I threw away my last 951 head because I found two exhaust ports that had hairline cracks in them and I had to clean them better then you have cleaned the one pictured. Ask Dave or Mike Lindsey about these 951 exhaust ports if they have the time, they have tossed some 951 heads to date. And IMO I would pass on an o ring head and use a Cometic head gasket instead. The head and block just need to be prepped smoother and flatter for a Cometic.

bradthebold

Here's a cropped pic. Where does it look like cracks?

I was planning on letting the shop clean and inspect it, but I could do it this weekend and see first. To use the cometic, I would have to at least take the studs out, clean more hoses/wiring out of the way, and transport the block? Is it worth the extra expense and pain to replace the studs? I was just going to clean up the block and run a stock/WF gasket.