p6 engine

V

vanguard55

New Member
Hi guys, The engine on my p6 is on its way out. Its droping num 4 plug, but this comes back after 40mph, its a 71 2000, but has the 2.2 engine single carb fitted. The engine is also pushing oil out. I had the plugs out, they are all looking fine, had the rocker cover off, nothing looks out of place, It did run really well before this, I parked it up one night, got her started the next day and She started on 3. I think it could be head gasket? or a valve, Can any member give me any tips on what this may be before I pull the engine out?. A friend of mine has an early p6 , a 67, with a geat engine, but it would be a shame to remove any parts from it. thank guys.
 
I would compression test your motor to work out what is going on. Do this with the motor warm with the throttle wide open. If you get any low readings on a cylinder then squirt some oil down that cylinder bore and see if the compression comes up. If it does then you have a ring issue on that cylinder. If the reading is the same then the cylinder is losing compression out of the valves.

Is the engine using oil at a rate that you have to top up the oil regularly? All British motors of that era leak oil to some degree. If they are not leaking oil then you have a problem as you have no oil!

What is the condition of you distributor cap, and leads?

If the bores are okay, then you could just re-ring the motor and do a valve regrind without pulling the motor. If it is a head gasket or a valve then you do not need to pull the motor, just the cylinder head. Make sure you get the tappet shimming in order once you put it back together. This is the hardest part of doing these motors.

James.
 
On the 4 cylinder engine, I know it is reasonably easy to change the big end and main bearings with the engine in situ in the car. Does anyone know if it is possible to pull a piston downwards past the crank? If that were possible you wouldn't even have to lift the head to re-ring!

Chris
 
Like James suggests, I would do the compression test. Also, check other basics things like valve clearance, timing and fuel mixture. The fact that no.4 is coming back at higher rev's could mean it's nothing more than a weak spark at low RPM on that cylinder? What do you mean when you say the engine is "pushing oil out"?
 
chrisyork said:
Does anyone know if it is possible to pull a piston downwards past the crank?
Click to expand...

It isn't, and even if it was, getting it back in with a ring clamp on it would take far longer than lifting the head in the first place.
 
Thanks guys, The engine is pushing oil out from the cap that covers the timing chain , I put some neat oil in the num 4 plug hole and it made the compression better, but still not a lot. The strange thing is it was fine when I drove it home but starting the next day on 3, and its played up ever since then, I think I will have to take the head off, cos I do love this old girl. I have just fitted all new brake pipes, New batt, new tyres, new carpet so I will have to mend her.
 
chrisyork said:
Does anyone know if it is possible to pull a piston downwards past the crank? If that were possible you wouldn't even have to lift the head to re-ring!

Chris
Click to expand...

Yes, it is possible. But you would ideally need to remove the bottom tensioner to give enough slack in chains to allow sufficient clearance from the bearings to swing the crank sideways. How easy/possible this is on a 2.2, I don't know, but if it looks like there's space, then there probably will be!
Probably better to get the head off for a re-ring though, IMHO, as a gasket is only a couple of quid, and you can check ring gaps so much easier (and also check for a stepped edge if the bore is worn).

All of the above is my little project over the next month, so depending on who gets there first, I'll post pics!

Michael
 
redrover said:
Yes, it is possible.
Click to expand...

Is that from experience or just guesswork? I don't think it is possible, but if you are so confident I think you should get your spanners out to prove me wrong.
 
Here are some of the rovers I have had over the last few years, The mustard and cream p6 is the one I have now.

2011_06060001.jpg


2011_04300013.jpg


2011_04300015.jpg


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RoverP6B1.jpg


RoverP6B11.jpg


RoverP68.jpg


RoverP69.jpg


RoverP6mk11.jpg


RoverP6mk12.jpg


RoverP48.jpg
 
That's quite a collection of P6s (& a P4). The cream/mustard combo is quite unusual - is the roof vinyl? Thanks for posting the pic's and hope you find the problem if you take the head off. I found taking the head off using the Haynes manual wasn't too difficult. Have you removed the head on one of these before?
 
The mustard p6 started off life being dsb, It was rebodied from a 3500, When I bought it it had a Dark brown roof as this panel was not changed, It did not look right and as I have painted most of my p6 roofs cream, this one got the same. I think it looks ok. There are other pics I will post when I can find them. the inside of the car is good, but could do with both front seats. I am told that the early mk2 p6 had the mk1 dash fitted but only on the 2000 model.
 
chrisyork said:
On the 4 cylinder engine, I know it is reasonably easy to change the big end and main bearings with the engine in situ in the car. Does anyone know if it is possible to pull a piston downwards past the crank? If that were possible you wouldn't even have to lift the head to re-ring!

Chris
Click to expand...

I do not think that it is possible to get a piston out downwards past the crank, and even if it was I would like to see how you would then measure the bores for ovality, and taper, and then hone them to remove the glaze with the crank in place.

James.
 
redrover said:
Yes, it is possible
Click to expand...

Whilst I've not actually tried it on a P6 engine, I think piston removal from underneath with the crank in situ would be extremely difficult with any engine. But as Harvey points out, getting the rings compressed, and piston back in from underneath would be near enough impossible. Besides if an engine needs rings then the top-end will probably require some attention too - at least a valve re-grind.

j_radcliffe said:
All British motors of that era leak oil to some degree
James.
Click to expand...

I've had many cars from the 60's/70's which didn't leak or burn oil, including triumph, morris and ford. My old 2000TC engine didn't actually use any oil either, just the bottom end was shot.
 
Only type of engine I know where you take out the piston downwards (and put it back) is on a 2 stroke as in a strimmer
Bore seems tapered to compress the rings as the piston goes back
But even then you have to take the barrel off the crankcase
 
Hi, usually the only type of engines where the piston can go down are small bore,
long stroke engines. Modern engines with their design roots in the 50s are large
bore, short stroke and so the crankshaft is closer to the bottom of the bore and
main bearing journals can be wider than the bore spacing. I fact in a lot of cases
the skirt is cutaway to clear the swing of the crankshaft.

Colin
 
I was basing the question on working on a W. O. era Bentleys, where the only way to take the pistons out is downwards, as the head is cast as a single unit with the cylinder block. Just about the polar opposite of a K series!At least there's no head gasket or head studs to worry about!

Chris
 
Hi guys, I am going to lift the engine out, strip it down and See what it needs. I will stick some pics on as I go. thanks for your help guys, John.
 
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