M20 Head Valve Seals Damage???

[bw86newman]

Hey everyone....rebuilding the head on my 1990 m20. When disassembling, I damaged one of the valve seats (I think). Wanted to get everyones opinion on if it should definitely be replaced or if it looks good to go? Here is a pic of the damaged one (1st pic) and a good one (2nd pic). Thanks.

[e30davie]

Thats a vale stem guide, rather than a seat. and my understanding is that the valve stem seal with the spring that does the actual sealing fits around that, or close to it.

Perhaps you might have gotten away with it if the valve stem seal (rubber doovy) still makes a nice seal on your damaged valve stem guide.

However if that copper/brass piece is available and is replaceably, id be buying a new one, cause otherwise if it leaks your engine will suck in oil and burn it:)

[bw86newman]

Thanks....that's what I figured... probably better to have machine shop replace with the stem seal repair kit....anyone have any suggestions on what brand kit to buy? Was going to get the victor reinz repair kit since that was the brand the seals I removed were.

[essi1553]

That is a valve guide, and noted above. They are replaceable, but must be done by a machine shop because they are press fit. A stem seal repair kit isn't want you need to repair it. I'm sure bimmerheads can help you out. Otherwise search m20 valve guide (you'll probably need oversized ones).

[bw86newman]

got it...thought the yellow bits here

https://www.ecstuning.com/b-genuine-...t/11349059172/

in this kit were the valve guides...obviously not...thanks

any suggestions on the seal brands?

[essi1553]

I like elring (same brand as OEM), but you can go aftermarket and get good results. I usually stay away from victor reinz (Ive heard horror stories about some head gaskets).

[e30davie]

For what its worth i used elring when i replaced all of my exhaust guides (i didn't do it personally, got a shop to do it).

Used Elring headgasket and all other gaskets too, no issues.

Just remember you never hear of all the success stories of victor reniz, only the bad stories.....

[yosh]

I'm no expert in rebuilding heads, but why not just take the head to a trusted machine shop and get their opinion?

Personally, I would take the matching valve for that cylinder, oil the stem up and slowly insert it. If any burr is present in the guide you'll feel the interference immediately and stop pushing the valve in and replace the guide. If the burr makes a microscrstch, at least it'll be in the area of the retainers. Who knows, maybe the machine shop can polish the inner surface of the guide to remove the burr.

[yosh]

Actually. Sorry, looking closer at the inner surface, you can see the square ridges from needlenose pliers, yeah, maybe replace your guide(s).

[TobyB]

Do the valves still fit?

I've found that the guides on anything with 100k miles are getting pretty worn-
likewise, the valves and seats themselves.

But that damage is cosmetic- if the stem goes in and the stem seal will go on, it'll function ok.

Me, if it was anything beyond daily beater, I'd take it to a machine shop for a freshening...

t

[ahlem]

If the damage doesn't go into the ID very far. I'd chuck a countersink into a tap handle and dress it (by hand) just enough to get rid of the burr and call it good. You could also use a tapered stone from a die grinder and do the same thing by hand without the die grinder.

[digger]

looks salvageable atleast from the pics without pulling it

[bw86newman]

Thank you everyone for the replies/suggestions....I will be taking the head to the machine shop tomorrow to see what they think.

[zaq123]

is is EX or IN side? If EX and original, I would replace them since there are out of spec most likely anyway. Honestly, I would replace them due to that damage anyway, who knows how mangled they are on the inside, can't see from that pic.
How did you manage to do that? Were you grabbing the seal with one side of pliers from the inside or something?

[bw86newman]

Back from the machine shop....machinist doesn't see it to an issue as long as the valve seats in there nicely and laps well, shouldn't be an issue.

The damage is only on the inside, just at the top. This was the first seal I removed on my first head tear down...used need nose pliers and obviously went too far down/did it incorrectly. removed the seals differently on the remaining ones and they are fine.