Oil level rising - exhaust valves?

JVY

JVY

Active Member
Hi, I got my first P6 ('75 2200TC) earlier last year. Although she has ran fine over last summer and I love her dearly, I wanted to take a look at a niggling engine problem before it gets any worse:- at idle and low rev's, there is a lack of power and idling is not very smooth. Have checked/set carb's, dwell, timing and plugs and all seems well. However, I have noticed that the engine oil level keeps slowly rising. For example, after an oil change, I set the oil level on the dipstick at the halfway mark. After driving 100 miles or so, the level is up to MAX on the dipstick and I have to drain some oil or do another oil change to prevent the level from rising too much.

Also, I have noticed that the oil seems thinner when I do an oil change - there is no sign of water or discolouration. Additionally, if I remove the oil filler cap while the engine is running, there is an exhaust/petrol smell. There is no sign of coolant contamination and no blue exhaust smoke - so I tend to think cylinders/pistons and head gasket are OK (have not done a compression test though). When I checked the valve clearances, I found the inlet valves where OK but the exhaust valve clearances where only about half what they should be!

Do these symptoms sound familiar to anyone please? My theory is that I have worn exhaust valves/seats? I was wondering if, due to the exhaust valves opening too late and closing too early, exhaust gas and unburnt fuel could be getting pushed down past the piston rings?

I plan to remove the cylinder head to see what I can find. So, before I start, any advice on where I can get a good gasket set from would be appreciated? Also, where would I quickly be able to get a set of exhaust valves if my suspicions are correct? Is it normal to have to replace valve guides/seals if you fit new exhaust valves? Finally, my engine number ends in ‘A’ – does this mean I need a steel head gasket (Haynes manual says ‘G’ in engine number means asbestos)?

Any advice welcome please :)
 
If your exhaust valves are too tight, it is normal not to run smoothly at idle. The problem is that if you drive a lot (and hard) like this, probably they will burn out. There is a way to adjust valve clearances without removing the cylinder head. It is described in the workshop manual and you need to find (or make) some spacers. To decide whether your valves are still OK, you should do a compression test, or more preferably a leak down test.

However, your oil problem is something different. From what you describe my guess is that the oil becomes contaminated with petrol, and the only way i can think that this can happen is through fuel pump failure, that allows petrol to leak into the crankcase and sump. So, check this out first.
 
Demetris said:
However, your oil problem is something different. From what you describe my guess is that the oil becomes contaminated with petrol, and the only way i can think that this can happen is through fuel pump failure, that allows petrol to leak into the crankcase and sump. So, check this out first.
Click to expand...

I would agree Demetris' fuel pump theory & if you continue to run the car in that state the oil will end up so thin that there will be no lubrication thus causing internal damage to the engine & also in extreme cases the petrol in the oil can detonate which is very unpleasant. Another thing which can cause this though not usually to such a large extent is a lot of stop starting & running on choke for lenghty periods as you get a build up of unburnt fuel which finds it's way into the oil but if it's running sweetly enough with no missfiring then the fuel pump is your culprit

Regards Colin
 
Demetris/Colin, thanks for the replies.

For the exhaust valve problem, I am thinking that I shall do a compression test before I remove the camshaft or head (I have a compression gauge but not the equipment to do a leak down test). I took a look at the manual and saw what you said about using spacers to remove the cam - will see if I can make some spacers from some copper tube. I guess it makes sense to just remove the cam and see what shims are fitted on top of the valves, as swapping them for thinner ones might solve the clearance problem without removing the head etc.

As for the suspected petrol in oil problem, the theory that petrol is escaping into the engine sounds good and I think I remember reading somewhere about this being a problem on P6s. So, shall remove/dismantle the fuel pump to see if there are any indications (like cracked diagphram or suspect seals?). It would be good to find the problem as it would save me changing oil every few weeks :? :? With any luck, my wife will let me out to play in the garage in the next day or two - will let you know how I get on.... Thanks, Steve.
 
Hi Steve a fuel pump overhaul kit is only about £25 but have a look on ebay as there is one on at the minute. The only problem I have found in the past is changing the valves in the pump without squashing them so it may be worth just putting the diaphragm in

Regards Colin
 
JVY said:
- will see if I can make some spacers from some copper tube.
Click to expand...

Mind you that you torque down the cylinder head on these, i doubt that copper is the most suitable material. If you can't make some steel spacers, you can always buy some suitable sized nuts to use in couples as spacers. They are cheap too!
At least this is what i did.
 
Colin, just bought a fuel pump repair kit on eBay (only 10 quid) - if I don't need it this time, probably shall one day!! Demetris, thanks for copper tube warning - steel nuts do sound more sensible. Thanks again, Steve.
 
Removed & dismantled fuel pump this evening. There seemed to be oily petrol in lower half of casing (i.e. below diagphram where there shouldn't be any). I could not see any obvious problem with diagphram/seals - but I suppose it only takes a slight leak to cause petrol escape. Will clean up pump and fit bits from overhaul kit when they arrive.

One thing I noticed was that two diagphrams had been fitted, the two being stapled together on the little orientation tab that protrudes between the lowe/upper halves of the pump case - so wonder if previous owner had a problem??

Steve.
 
JVY said:
One thing I noticed was that two diagphrams had been fitted, the two being stapled together on the little orientation tab that protrudes between the lowe/upper halves of the pump case - so wonder if previous owner had a problem??
Steve.
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Sounds like a big bodge for some odd reason there and the source of you problem. If you're doing the valves and don't know when the last time the head gasket has been changed may be worth doing that at the same time. Would save messing about with spacers although is more work (not much, p6 head is easy to get off). Just thinking would allow you to visually check the valves to be 100% sure. Just an idea. :)
 
You also need to make sure that the diaphragms are compatable with unleaded fuel. NOS probably won't be.
 
Guys, thanks for advice. On closer inspection of fuel pump diagphram, it does seem to have been manufactured with 2 diagphrams (labelled as an AC part - same make as pump :oops: ). Also, shall try to confirm repair kit is OK for unleaded - I use fuel additive but not sure if that would make any difference to the parts inside the pump?

If I get bored waiting for repair kit to arrive and have time (always the big if!!), I will maybe have a go at the camshaft/head removal.

As someone new to P6 maintenance, I truly appreciate the advice :D
 
JVY said:
As someone new to P6 maintenance, I truly appreciate the advice :D
Click to expand...

If your going to be doing the value gaps try to source some spare shims. I was lucky, there was an old boy on eBay a while ago selling some bit's he found in the garage, part of these bits was a tin of P6 shims. He was pleased to sell just this for a tenner.
 
As someone new to P6 maintenance, I truly appreciate the advice
Click to expand...

I suggest that you beg/steal/borrow/buy (delete as applicable) a workshop manual and familiarise yourself with the intracasies of the p6 engine before you take it apart,otherwise you will end up fishing for bits that you've dropped in the sump :shock: ,

Usually the chain tensioner foot and spring,...eh Richard :roll: :LOL:
 
Speaking of fuel pump kits.........
Many unbranded or aftermarket fuel pump kits DO NOT CONTAIN the circular neoprene oil seal which is supposed to stop oil filtering from the actuating valve area into the petrol area.

It would be a good idea to ask any supplier if their kit contains the valve.

A kit that I bought from a reputable supplier did not contain that seal.

I pounced upon a kit on eBay where the parts of the kit were all displayed in a photo. I bought the kit but no oil seal was contained within. When I whined/whinged/complained, the vendor sent me that seal by separate post - no charge.

Summary: always ask if that seal is included. :)

Eric
Canada
 
Thanks for advice on checking fuel pump kit should contain neoprene oil seel.

This evening, had a bit of time and, as I still haven't received the fuel pump kit, decided to start on camshaft removal. After checking over procedure in Haynes manaul, started by removing rocker cover and set about locking flywheel and camshaft. :( :? Almost straigtaway ran into a problem - managed to lock the flywheel on "EP" mark but then found that the slot on the camshaft crank didn't quite line up with the camshaft locking pin?? It almost lines up and, although I could turn the camshaft a little to take up the slack on the timing chains, it still wouldn't quite line up. Therefore, reckon camshaft is lagging the crank by maybe 1 degree or so?? Is the a common thing? Should I be worried? I read another post where someone was bemoaning fact that there is not a vernier to make small adjustments on valve timing. Is this why?

I am thinking that I can remove the cam without locking it - just so long as I make sure I put it back with no. 1 exhaust valve fully open and keep the flywheel locked?


Also, I am heading the warnings about being careful not to drop any bits down the timing chain casing.
 
I don't want to start an avalamche of expenditure for you, but could this be evidence of a stretched cam chain? If you are stripped to this degree, might it not be sensible to fit new chains and new tensioning slippers? Mileage of the engine might be an indicator - high? or low?

Harvey and I had an interesting difference of opinion some time ago where I contended that poor attention to detail in the production process and consequent minor cam timing error was a possible explanation as to why very early 2000's (say up to about '66 / '67) have a reputation for being much stronger on power than later ones. He discounted this on the basis of experience in overhaul of few problems of the nature you describe. Another explanation that surfaced recently was crankshaft windage due to more restrictive engine breating on later cars.

Chris
 
JVY said:
I read another post where someone was bemoaning fact that there is not a vernier to make small adjustments on valve timing. Is this why?
Click to expand...

There is a vernier adjustment built into the camshaft sprocket.
 
Replacing the chains is not a simple thing.
When I completely rebuilt my engine and was adjusting the chain runners, click--THUNK down into the sump went the 7/16ths socket.
I fished extensively with a flexible shaft and magnet,and pondered if I dared leave that item down there.
Eventually I raised the engine off its stand, reluctantly removed the sump, and retrieved the socket.
At least I don't have THAT to worry about
 
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