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MG MGB GT V8 Factory Originals Technical - Rover Valve Guide Seals

When I rebuilt my Rover 3.5 to install into my MGB I was told that the 69 Rover 3.5 doesn't use valve seals. Now after the car has sat for a period of time when I start it up it blow out blue, I guess from oil entering the cylinders through the valves. If it does not need (or use) valve seals then what keeps the oil out of the cylinders? A tight fitting valve guide?


Bruce
Bruce

Bruce,
As far as I know all engines up to 1993 should have simple tap washer type seals (P/N ERC7865A) on the inlet valves only. From 1993 seals were fitted to both inlet and exhaust valves (P/N ERR1782). The valve guides are different so you canít fit later seals to an early engine without changing the valve guides.
This doesnít answer your question but if your car has no seals at all it is just the fit of the valve in the guide, although the seals are not much more than a deflector anyway. Make sure the engine breathers are OK so that crankcase pressure isnít forcing oil down the guides.
Geoff
Geoff King

I used a Mr. Gasket valve cover breather in each rocker cover to allow the engine to breath, I'll check those to see if they are plugged. Actually even in the manual I have for the Rover 3.5 it doesn't show any valve seals!

Bruce
Bruce

Bruce,
I guess my knowledge of these engines only goes back to the SD1, mid 70's. This must be one of the rare occasions that I am not old enough.
The heads are different and the valves are smaller on the early engines but you could probably fit the SD1 seals.
You rebuilt the engine; did it smoke before? What did you change during the rebuild?
Geoff
Geoff King

Yes I totally rebuilt the engine but I never had it running before I rebuilt it. I had the crank checked, Isky cam, cylinders rebored and new pistons, rings, bearings, Edelbrock intake and carb and block style headers ceramic coated, new rockers and shafts timing chain and such. Radiator from a 63 Ford Falcon with a 3000CFM fan and a Carter Performance Electric fuel pump P4594 7psi. Along with a T5 tranny from a Camero. I contacted the factory and my engine was manufactured in August 1969 and was fitted to a P6B with a compression ratio of 10:5:1. I was told when I went to buy the parts for the engine that this particular engine didn't take valve seals. The fellow who did the heads (and he has been machining heads for a long time) was pretty surprised.

Bruce
Bruce

Bruce,you could probably fit an aftermarket umbrella type seal wth the heads still on the car.Check with your machinist,he no doubt has boxes of misc seals.Just make sure they fit inside the spring and there is dequate guide to retainer clearance.
Dale Spooner

Bruce,

I have done a little homework; the early Range Rover and MGB GT V8 didnít have seals and your P6B engine wouldnít have had them either. All SD1 engines had simple washer type seals on the inlet valves and these could probably be fitted to your P6B heads without any modification. The later top hat type seals wonít fit pre 1993 engines unless you change the guides to suit.

If you decide to fit seals it would probably be quicker to remove the heads rather than try to rig up something to hold the valves while the collets, springs, etc were removed. It can be done but I would remove the heads. If you can find a pair of later heads (1976 on) the engine will breath a little easier, they have larger valves and a better gas flow.

Geoff
Geoff King

Bruce,

I had a simular problem with my engine, it turned out that i had fitted my rocker shafts the wrong way round [didn't know it matterd ]. If you don't know the left hand shaft [looking from the front] should have a knotch facing forwards and upwards, the right hand shaft should have the knotch facing the rear and upwards. When i had fitted mine the wrong way the rockers were being flooded with oil, too much and some was finding it's way down valve guides,worth a check.

Graham.
graham

Bruce,
I wish I could provide you more specific technical information on your vintage engine, but I can share an experience I have had with the 3.9 litre engine. On my 1991 Range Rover, I had experienced what I thought was unaccepable oil consumption (20W-50) at 15K miles on the car/engine. I would consume 1 qt of oil in about 1200 miles. I complained to Land Rover. Apparently, they knew there was a problem with the pre-1992 model intake valve seals. They replaced the seals using seal kit UKC-7012K. They did this under warrenty, and the problem went away. The engine now has 257K miles, and the oil consumption is now about 1 qt/ 1500 miles, and I think that is more from leakage at the rear main seal.
Charles
Charles Clarke

graham

Just checked the rocker shafts. They don't have a notch. Probably because I had to replace the original ones when I rebuilt the engine.

Bruce
Bruce

Bruce,
I am sure there will be a notch [or maybe a slight score] at one end of the shaft, all new shafts have this mark [as far as i know] to enable you to fit them the right way round. A quick check you can do is remove your rocker covers and start your engine you should see very little oil flowing, in fact you should only see the oil dripping slowly off the end of the shafts and seeping slightly between the rockers. When i had fitted mine the wrong way round as i said the oil was flooding out way too much.
I would check again for the knotches [or marks], unless of course somebody knows any different, maybee i am wrong [but it worked for me], let me know how you get on Bruce.

Graham
Graham

Graham
I am sitting here on the computer looking at the old rocker shaft for a notch (the wife is not impressed that I have car parts in the house) and yes I do see a notch. Now that I see it I will again pull the rocker covers and check for it as you suggest. I will also start her up without the rocker covers and see how much oil is coming out.
Thanks for the info.

Bruce

Bruce

Graham

Checked out the rocker shafts again. One was right and one was wrong, now corrected. I don't know if the problem is solved or not. I started the car, but I am in the middle of chasing an oil leak so was concentrating on that instead of looking to see whether or not it blew smoke on start up. But I am sure having the shafts the right way around will help.
Thanks

Bruce
Bruce

When rebuiding my 1982 SD1 engine i used the wasker type of seals. Recently i opened my rocker cover (after 15000km) and found 2 broken laying around near the valves. I don't think these seals help a lot.
Regards
Peter
peter van de velde

Bruce,

Glad to help, hope it solves your smoke problem. What you will have to remember is that it will take a few miles to get rid of any remnants of oil before you will know,

Good Luck,

Graham.
Graham

This thread was discussed between 18/06/2001 and 29/06/2001

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