mtnman82

Tom - when you say clean up the exhaust ports do you mean clean the black soot off the liners? If so, what's the best way to do this? The liners look good to me, but there's the black soot all over them. A little bit flaked off (soot) in one place on one port and I could see the ceramic which looked good.

I called two of the local shops and they both want to see the head first. One of the guys was straight up and told me they have a guy they farm out the aluminum welding to and he's supposed to do a very nice job. He also recommended replacing the guides/seals and doing a valve job. I asked about porting and he seemed to think they do a great job at porting. I just need to find some time to take off work this week ...

mtnman82

Just dropped the head off with the guy who's supposed to be 'the man' in town. He's been around for over 30 years and two guys who used to work for him started one of the other machine shops here in town (the ones from above who told me they'd farm out the welding). The 3rd machine shop would never answer the phone and I was told they mainly deal with contract work from the Navy base here. He recommended not welding on it if it wasn't in a critical area, so I guess we're going that route. In addition to cleaning things up he's going to do a valve job and look at doing some mild intake porting/polishing. He's a one man operation now so I don't expect it to be done quickly, but I do think it'll be done right.

numbskull

In my parts receipts box I found the info for the shop that worked on the head a while back. Funny I just remembered they tapped a little anchor on the top as a signature.
http://www.precisionheads.com/index.html

Tom M'Guinn

Right, just hose them down with brake cleaner to see if the ceramic is in good shape or cracked. If the soot was uniform, that's a good sign. When the machine shop is done, it will be clean enough to inspect closely. The machine shop may not know about these exhaust ports unless they are familiar with the 951 -- so they may not know to check them and/or may not immediately realize the exhaust ports can't be ported.

mtnman82

I specifically told him the exhaust ports were ceramic coated and couldn't be ported. I also told him the exhaust valves were sodium filled - he seemed to be familiar with sodium valves. He's an old school guy who's been around, but one of my racing buddies that has all his engines done by the guy told he does his best to keep current. I'm not totally comfortable (a bit nervous) but we shall see... I don't think he's familiar with the 951, but also wouldn't be surprised if he was. There are a few 944's in town, but I've never seen another 951. I wanted to talk to him a bit more about things when I went back to drop off the valve seals but could tell he was getting annoyed (he's a bit ornary) so just let it be. The soot was uniform and I ran my finger across the ports and they all felt smooth. I certainly do hope he checks out the exhaust ports before he does any work.

numbskull - looks like an ideal place to take a Porsche head. Maybe I shouldn't have dropped mine off so quickly...

IanM

FWIW, I had some pitting on my head, and it never gave me any problems whatsoever. The pits were NOT in the area of the fire rings. Here's a pic, after being very lightly resurfaced at the machine shop. Interestingly, the pits were also around cylinder 2.

dp951

The proper way is to grind into the pitted area, weld and fill past the head surface ,then go ahead and mill the surface flat, leaving the pitted area un touched could latter on lead to sealing issues,
Ive repaired many heads like yours and it pretty straight forward when repairing the alum heads.

if you need additional info feel free to pm me.

pole position

You are overthinking it.....there is nothing special to a 951 head , anyone competent can easily deal with it and you will not get the "porsche tax" with your machinist.

mtnman82

Got it back today and am quite pleased. $150 out the door and he did the full rebuild - tanked, valve job, smoothed out the intake ports and drilled tapped for the steam vent kit. The pitting doesn't look near as bad as it did and nothing close to the fire ring, so we're going to just run with it. Even after skimming the head to clean things up, when I checked for wear it was still a tad over the 'new' spec of 24mm. I think he enjoyed working on it, as the few times I went back to talk to him he had more info like he'd been checking into the car. If (when) I do a blown944 stroker build I'll probably find another head and have him work it. I did see a cast iron sleeve sitting there but didn't get a chance to ask him if he sleeves engines. I'm not sure he would up for doing an offset grind on a crank. Pics of one of the intake ports below- they all look the same.

refresh951

Looks good. Excellent price also!

V2Rocket

Please tell if you find out if he does that sort of work...I have not had any luck with local shops down here, they are all afraid to touch free-standing aluminum cylinders...

numbskull

That's a real good price including the valve job. Good find.

Tom M'Guinn

Glad it worked out -- that's an incredible price -- they do a full valve job, surface it, and replace the guides and seals for that?

mtnman82

Spencer - I'll definitely share what I find.

Tom - yup, full valve job, surface, new guides and I gave him the new seals from the headgasket kit. I did have one bent exhaust valve, but Lart came to the rescue

Wifey was worried when I dropped it off without getting a price, and I was somewhat concerned - seemed like I was asking too many questions at the time. Then I was flabergasted when he said $150 (I gave him $160 and told him to keep the extra). I was starting to bum on it being down there 3 weeks, but am just tickled now. Just hope I can remember where the nuts/bolts I didn't bag go ...