Help please - P76 valve stem seal replacement

**mark2** · 27th January 2009, 07:14 PM

I've decided to have a go at replacing the inlet valve stem seals on a P76 engine I bought recently. It was blowing some smoke on startup and after idling. It still has the P76 heads.

Anyway, the new ebay valve spring compressor arrived today so away I went.

First drama was removing the cast rocker pivot thingys - the nuts ended up being whitworth! After removing the nuts, the cast pivot was broken - I dont know if I broke it by not undoing nuts evenly enough? Anyone have a spare one of these or know where I could get one?

The spring compressor worked well along with the leakdown tester to hold the valve up and one dual valve spring was soon off.

The existing seal was nothing more than a flat rubber washer which came off in the inner spring. Apart from it being fairly hard, I cant see it would seal well by design, given the tendency for it to ride up the valve stem.

I then managed to bump a push rod which promptly dissapeared into the valley

. I really dont want to have to remove the inlet manifold as it appears to use two gaskets per side, probably a sign of previous sealing dramas. Any ideas for getting the pushrod out, without removing the inlet manifold?

What would be a better type of stem seal? The valve guide has a step in it which would probably accomodate some type of boot seal, rather than the dodgy washer.

The valves themselves have a slight amount of side play in the guide, is some movement normal?

Thanks in advance.

**Blknight.aus** · 27th January 2009, 07:25 PM

a magnet on a stick should recover the gone rod, sideways movement is bad and a sign that you should be K-lining.

I dont remember the exact specifics of the p76 but every seal Ive had to play with thus far is more cup like than washer like, is there any chance the youve just got the top of the whole seal and left something behind?

**mark2** · 27th January 2009, 07:53 PM

Pretty sure the washer was all there was.

So no sideways movement at all? Whats K-lining?

**Blknight.aus** · 27th January 2009, 08:16 PM

k lining is a process thats used to put a sleeve inside the valve guide.

it means heads off to do it but its worth it as they generally last longer than the normal guide and is easier on the valve stem.

From the photos of the guides it looks like it was ment to have one of the boot/metal cup type seals on it and thats what Id be looking at fitting

**BigJon** · 27th January 2009, 08:24 PM

I am just having a look around the net, apparently Datsun 1600 valve stem seals fit.

**karcraft1** · 27th January 2009, 08:27 PM

Early P76 engines used a stepped valve guide and used Mini Cooper S valve stem seals (AEG327). Later engines used a straight guide which used a special bucket style seal made esp for the P76.

With regard to the valley cover gasket - the engine was originally fiited with a tin type valley gasket like the Rover V8. They had no end of troubles with this, so they bonded gasket material to the metal gasket to seal around the inlet ports which fixed all the problems.

Hope this helps.

Rangier Rover · 27th January 2009, 09:49 PM

One reason why I dumped the P76 heads for Rover heads. Have to strip block to drill oil hole

I have some good p76 rocker gear here if you need it.

If the heads are stuffed best to use Rangie or Rover V8 heads rather than spend a fortune on P76 heads.

Tony

**mark2** · 27th January 2009, 10:54 PM

I never cease to be amazed at my ability to c*ck up a simple job.

I've just dropped the valve - into the cylinder which happened to be at BDC.

It helps to keep up the air supply when the collets are removed.......

So the manifold is coming off, along with the head.......

**p38arover** · 27th January 2009, 11:21 PM

Originally Posted by Blknight.aus

k lining is a process thats used to put a sleeve inside the valve guide.

it means heads off to do it but its worth it as they generally last longer than the normal guide and is easier on the valve stem.

When I had the heads on my P38A serviced some time back, they fitted bronze guides.

When the engine was rebuilt by Bruce Davis Performance Landys, Bruce said he didn't like them (I forget the actual reasons) and fitted new OEM guides. They weren't that expensive.

This is a section from How to Power Tune Rover V8 Engines for Road and Track By Des Hammill which give the method the a good review:

http://books.google.com.au/books?id=...um=9&ct=result

mike 90 RR · 28th January 2009, 10:56 AM

Originally Posted by mark2

I never cease to be amazed at my ability to c*ck up a simple job.

I've just dropped the valve - into the cylinder which happened to be at BDC.

It helps to keep up the air supply when the collets are removed.......

So the manifold is coming off, along with the head.......

Always move / rotate the piston to the top of the head when working on IT'S set of valves .... so as to avoid losing the valve if dropped

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