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Kent engine valve stem seals question.
RoadkillUK - 31/8/02 at 04:55 PM

Just putting my head back together seeing as I've just run out of welding gas ;( and its so long ago that I've forgotten what it looked like in one piece.
I've just given my valves a good grinding and I'm putting 'em back in, thing is I can't remember how the stem seals sit on the head.
Do they just sit there with nothing holding them in place or do I have to push them on so they overlap the little lip ?
It doesn't seem right just leaving them sitting there with only the force of the vacuum produced to hold them but the only other way seems totally wrong as the springs will catch 'em, are these the correct seals ?

Come on fellahs help me out here its a mental block/short-circuit


theconrodkid - 31/8/02 at 08:20 PM

Yup thats how they go


RoadkillUK - 31/8/02 at 08:33 PM

Which one? The one on the left is pushed over the the lip and the one on the right is just sat on it.


paulf - 31/8/02 at 09:26 PM

They just sit loose on the valve stem, I have heard them discribed as umbrellas. They only really stop the oil from running directly down the valve stem and do not act as proper seals.
Paul

quote:
Which one? The one on the left is pushed over the the lip and the one on the right is just sat on it.


JamesS - 31/8/02 at 09:53 PM

If you are using double valve springs, those rubber washers dont fit and break up. Use the much better VW 8 valve motor stem seals. They are small rubber seals with a spring clamp at the bottom to hold them on. The other option I'm told is mini stem seals but these aren't as good.


RoadkillUK - 1/9/02 at 01:14 AM

Thanks lads, we put them on loose, hope that's right. They are single spring not double thanks James.


JohnFol - 1/9/02 at 07:03 PM

Don't grind the inlet valves!!! (Well that's what Haynes says but without the exclamation marks). This is the stage I am at, cleaning up the engine. I'm trying to decide what I need to do to get the engine converted to unleaded before re-assembling the head. Have you done this?


johnston - 1/9/02 at 07:13 PM

any ideas y ur not to grind the inlets????


paulf - 1/9/02 at 08:37 PM

Most ford valves are supposed to have an aluminised coating on the seat which would obviously get removed by grinding. However if the valve needs grinding there would not be any coating left , Ihave always ground them in with no problems.
The only option is to fit new valves and then you are supposed to lap the seats with an old valve which never seems satisfactory to me.
Paul.

quote:
any ideas y ur not to grind the inlets????


johnston - 1/9/02 at 10:25 PM

always thought the idea for grindin in new valves were so they sealed wit the seat


so if ur grinding in with the old valve (which will be worn)

howz it gonna help the new valve seal????

any way never had any hassle wit my old fiesta anyway


JohnFol - 2/9/02 at 07:49 AM

Paul, that was the word I couldn't remember.

I guess it's so the seat is 'automatically' ground in just through usage.

I can't see the harm grinding it as if the coating is removed it's just a palne odl metla valve that can be ground


paulf - 3/9/02 at 08:29 AM

That is my point, I always reface the valve and grind in as normal and have never had a problem. It sounds like a way to sell ford valves.Obviously if the seats have been cut with a hand type cutter then they have to be lapped, there are some seat grinding machines that are accurate enough to allow a valve to fit without grinding however.
Paul

quote:
always thought the idea for grindin in new valves were so they sealed wit the seat


so if ur grinding in with the old valve (which will be worn)

howz it gonna help the new valve seal????

any way never had any hassle wit my old fiesta anyway