Cam problem

Hi all,
I'm new to this forum. I have had a good search through the archives but I can't find the info I need in the 807 posts,I must admit I got to about 200 and gave up!!
I've got a 1980 P&M 1000 that I've been racing this season. I bought it last year having been sat in a barn for 33 years. It's got an un-numbered set of crank cases and it's been bored out to 1001 cc. It's got Yoshimura Pistons and cams that the original owner got of Pop himself!!. It also has 29mm vm's with some aluminium spacers that Pop recommended for increased tract length. The crank is welded and it has a close ratio gearbox. I stripped the top end down,honed the bores,replaced the rings with some that were for a Renault Clio 1.2 turbo. I didn't split the cases as I figured it wouldn't have done many seasons on new bearings at the time and I've had no problems in that area.
I have had an issue with cam noise though. The season started well but after the 4th race I noticed some tappet noise so I checked the clearances and most were slightly out but 2 were well out,they were also concave in shape and looked like they'd been turning in the bucket,they looked like they'd got hot too.,I was looking for 4 thou and I was getting 29 and 34 on them. So I replaced all shims and set them all perfectly to 4 thou. After qualifying on Sat morn the noise was back but I raced all weekend anyway and checked clearances again. This time all but 1 shim was way out,most of the cam lobes are no longer round and have 3 flat spots on them. I'm thinking the cams have lost there hardness over time?
So I need new cams. I have no idea what the lift or duration is. It's running shim over bucket.
Can anyone recommend replacement cams?
What do I require to convert to shim under?
Is it remove and replace parts?
I've read all about really hot cams tiddlywinking shims out but I havnt had that happening and I've been thrashing the hell out of it trying to keep with the 1260's!!!
Really appreciate any help as I've got to get this fixed ready for Brands Hatch.

Do you mean bored to 1100cc?
Sounds like the cams are badly worn and the hard facing is breaking up which will also hammer the shims as you describe.
There should be some markings/numbers on the cams which will identify what spec they are.
These marks are usually one the end or near the sprocket flanges.
If not, it is easy enough to work out the lift by subtracting the base circle measurement from the whole height of the cam.
As these are for fast road/race use it will be easy enough to find some Yoshi cams that are close or the same to what you have as they are still making them or you can get something similar from Joe Hooper at Pit stop Performance . Their PSP cams are similar to the old Andrews cams.
To convert to shim under you need to swap out the existing valve retainers and buckets with some from any Z650/750 four or GPZ1100 Unitrack.
Whereabouts in the UK are you.

Hi Zed,
No I meant it was a 903cc bored out to 1000 as that was the limit back then. I worked it out to 1001 based on the stroke and piston diameter but I might be out a tad.
I've had a chat with Ken @ Newman cams in Farnborough and sent them down to him as he reckons he might be able to regrind them and use bigger shims,so I can't look for any markings at the moment but I don't recall seeing any. He said the cams wouldn't lose their hardness. He wondered if it was the valve springs binding up. Are the inlet springs different to the exhaust?,they could be mixed up.
The most affected lobes are the middle 2 exhaust and 1,2 and 3 on the inlets.
A mechanic friend said it sounded like oil starvation which made me recall I had read somewhere something about the oil pump had to be shimmed and it was really critical that it was done correctly,can you elaborate for me please?
I don't know if it makes a difference but my oil strainer has been modified so it sits in the middle of the sump for obvious racing reasons. Then again if it was starvation surely it would be in a terrible mess after a few laps racing.
I don't know what to do. If the cams can be saved and I swap to shim under(which I'd rather not do really),I need to be confident it won't happen again.
I'm in Rugby btw,where are you?
Cheers Pete

Hi, I'm top end of North Lincolnshire near Goole.
Each 1mm o/s is worth approx 30cc so easy to work out capacity within a couple of cc's.
900 block will push to 71mm = 1045cc.
Might be 998cc with 69.5mm pistons which was common with Yoshi pistons.
valve springs are same on in and ex.
Could be that the valve collets are topping out on the guides ( you will see if the guide seals have been damaged) which is common with very high lift cams and may need shorter guides available from ape etc.
These pumps don't get shimmed, Only the side clearance can be closed up by using a thinner gasket .
Shim spitting is caused by very high lift cams sweeping right up to the edge of the shim and rocking the shim into the groove in the top of the bucket, eventually flicking them out like tiddlywinks.
Before shim under they used to fill the groove with silver solder to reduce the risk.
I've run plenty of fast road cams with shim over and no groove filling with no trouble and still do.

Ah,well I see a calculator off the web and got 1001 but as I've got 69.5mm pistons I must have 998cc .
I'll check the collets then,thanks.
What do you mean by side clearance of the pump,why would you do that?
Yes,my lobes can't be very high lift as they aren't near the edge of the shim.
Good to hear you havnt had trouble with shim over. I like to fettle but I don't want to be taking the cams out to change shims. I'll end up with stripped threads in the head.
What oil do you use btw?, I started with 10/40 synthetic but it seemed to pee out all over the place,I swapped to 15/40 mineral and its dry as a bone. The clutch didn't like synthetic either and it's much better on mineral. Speaking of which,I don't suppose there's a drawing on here of a plate I can make to convert the cable clutch cover to hydraulic is there because it is really heavy?
I've seen them on the Moriwaki site but I ain't paying £300 or whatever it is,robbing gets!
I was going to trace round the cover on a piece of mdf and keep filing/cutting/adjusting till it was right,transfer to 6-8mm ally,blue the pushrod for a witness mark and drill and cut for a master cylinder..

The oil pump will wear grooves in the flat plate where the drive gear shaft is. The trick is to sand it smooth with #600 paper on a sheet of glass.
Steve

Under normal circumstances you should not use fully synth oil.
Only use semi synth., the stock grade is 10/40.
However! for racing and high performance motors I use ROCK OIL TRM20/60.
This is fully synth but is formulated with long chain molecules specifically for use with roller bearing cranks.
I run this in 2 of my Z road bikes (one being supercharged and the other fast road/race spec) and also in a turbo drag bike (The 0rient Express).
Non of these engines have any trouble with the clutch.
As for the hydraulic clutch, I have made several mounting plates out of 10mm ally plate.
Use the existing cover to transfer the 4 mount holes to the plate and once mounted with some temporary spacers you can use the pushrod to find the centre point for the slave cylinder hole and go from there.

So I've sent my cams off to Newman cams,I've been told they can weld and re-grind so that's a relief.
He reckons by the look of them oil starvation is the problem. See pics below,click pic for full view.
What's the procedure for checking the oil pump?
Anything else I should be looking for?
thanks

Oil starvation? Cam bearings looking good.
I would say some shims have lost the surface hardness why ever.
It could be someone grit them down to get the correct valve clearance or poor hardening process of the manufacturer.

Oil pumps rarely give trouble.
Early ones (with the screw on strainer) could suffer from air locks and the cure was to drill a tiny hole at the highest point on the body , this is well documented in most good manuals which you should get if you not have one already.
Look for radial wear on the pump cover plate where the gears have been rubbing, this can usually be lapped out.
The manual gives a clearance figure for the gears. This is between the tips of the gears and the pump body and measured with a feeler gauge.
Any Z1/900/1000 pump is the same so maybe a newer less worn one would be the easier cure if yours is very bad.
The Later pumps from the non kickstart J/GPZ motors also fit but have a pressure release valve fitted on the body though which needs unscrewing and the threaded hole blanking off.
The earlier motors have the valve installed in the actual crankcase whereas the J/GPZ does not.
The condition of the cam shells and valve buckets look normal and indicate a decent oil supply otherwise the shell bearing surface would be torn to shreds and the bucket skirts blued..
Most of the shims look dished and knackered though.
Early shims were prone to dishing and cracking so maybe a combination of that and possibly poor grade oil have effected the lobes.
I've had some race cams with the same flats as you describe and just put it down to harsh race condition wear.

I've had the oil pump apart,all seems well,3 thou between gear and pump body. The gasket doesn't look like it has ever been changed,
There is no wear inside the pump body. I'm worried to just put it back together and race again though. The shims were brand new before the last meeting,they've done 40 miles!!
Will you pm me your number please zed for a chat?
I've attached pics of the pump and a closer look at a couple of cam shells.

I'm just thinking about air locks now,my strainer is held on with 3 posidrive screws. I imagine this was taken off the original mounting point which then had a plate welded on,then the race mod with the tube to the centralised strainer was added and the screen with the 3 screws was simply re-used in its new position. Could it be that when I add the engine oil an air lock occurs in the modified pipe before the oil pump gears get a chance to pump the oil?
Moving forward I ought to leave the battery disconnected and turn the engine over on my pit starter so the oil gets a chance to get round.