Head reseal job, found missing metal on top of intake valves

[turbotransporter]

I'm working on a 1985 Vanagon with a stock 1.9L gas engine. It was "remanufactured" by VW about 50K miles ago. It began leaking a bit of coolant over the last couple of years and a few months ago it began leaving 4 to 5" puddles on the shop floor. I decided to remove the engine to R&R the heads because I was going to replace the exhaust system as well and I know it's much easier to access the head and bolts for both projects.

I've got the engine on my bench, the heads removed and cleaned but I'm stumped regarding the condtion of a couple of the intake valve tops. There are small areas of missing metal that looks like a coating of some sort. One valve (#4) has just a few 1/8" pieces missing and the other (#1) has perhaps 20% of the coating missing in various sizes but none larger than 1/8". The missing metal in on the outer, flat part of the valve.

Can anyone shed some light on this condition? Is it fatal? I'd like to get at least another 50K out of this engine without pulling the heads again!

Thanks,

Andrew

[ProvoCyclist]

Pictures would be extremely awesome about now. For real.

It sounds like somethings been banging around in there. Not good.
_________________
Clark
Current: 1986 Tintop GL 2wd, stock 2.1L, manual trans, Flash Silver LP7Y.

Past: 1985 Sunroof GL, 2wd, Subaru 3.3L, manual trans, resprayed to Diamond Silver L97A

[Terry Kay]

Andrew,

I think you'll find it to be a real good idea to replace whatever you find to be broken, damaged or plainly messed up, while you have the engine out and apart.

There's no sence trying to figure out why--if the valves are screwed up, replace them.

Stainless or titanium valves are a good replacement option for long term durability.
_________________
T.K.

[Terry Kay]

Andrew,

I think you'll find it to be a real good idea to replace whatever you find to be broken, damaged or plainly messed up, while you have the engine out and apart.

There's no sence trying to figure out why--if the valves are screwed up, replace them.

Stainless or titanium valves are a good replacement option for long term durability.
_________________
T.K.

[tencentlife]

The way you describe it it just sounds like the kind of carbon build-up one typically sees on the valve heads. It's so fused to the valve it seems to be part of it. It will hardly ever be completely even.

Anyway, that's what I think you're describing. Put up some pics and we can be sure.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[DrDarby]

Looking at the pictures, the valves look like the cheap AMC (Spanish) valves, I'd replace them. Since the heads are pitted I'll assume they are original VW heads as the AMC heads don't seem to pit.

Speaking of pitting, what are you going to do to get rid of it? Normally pitted heads get tossed but a friend of mine has had great luck bead plasting, coating of JB Weld and them having them surfaced.
_________________
Midwest Autosavers, Inc. Woodstock, IL

[turbotransporter]

I have some pics though they're not great.

I doubt there's been any foreign matter banging around inside. There's no obvious damage on the softer head metal or on the tops of the pistons.

thanks for your consideration,
Andrew

[tencentlife]

OK, well, it's not carbon. There's none in there at all. You're right, if something had rattled around in there you would see the same dings all over.

Plenty of pitting on those heads. They must be VW. Like DrDarby said, the AMC's just don't pit like the VW castings do. Must be a different alloy. The VW's were pretty inferior if you ask me; I'll never put one on one of my new engines. I hardly ever find any that are serviceable without welding anyway.

In your 3rd and 4th pics, where that intake on the right looks to be the worst, there also looks to be some combustion pitting along the right rim of the chamber. I don't know what causes this, but I see it from time to time. It has to be some kind of chronic chemical surface reaction taking place during combustion. The fact that it shows up in one cyl but not the others makes me think there could have been some coolant seepage into that cylinder, and over time the burning off of the glycol in that area eroded the metal. I dunno.

You said this was a VW rebuild 50k ago. That probably means the VW of Canada shop. I've torn down several of those recently, and have seen that their work can be pretty spotty; they weren't above cutting some corners. My guess is that those intakes were ones they recycled, and the pitting happened in their last incarnation. There's nothing wrong with regrinding intakes within their margin specs, so that by itself isn't necessarily a bad thing.

Don't know if you're planning a valve job, or to replace the heads, or just to put them back on as just a reseal job. What to do with the heads depends on your intentions. If I were in your shoes, and could afford to drop some more dough on the job, I would get some new AMC's, or at the least some of the reconned heads from VanCafe or Boston Bob.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.