390 oil leak

[Petrolhead]

Hi

In a previous post I mentioned that my '62 has a bad oil leak, around 1-litre of oil for every 100kms (60 miles) or so.

Everything underneath has an oil slick on it.

I checked the usual suspects - valve covers, rear of intake, front timing cover, loose oil filter etc, no joy

I had the workshop that was doing my generator repairs (all sorted, working well now) track down the leak - I suspected rear main seal.

But no, it's leaking between the head and block!?

I've never heard of this happening before. I guess I'll be pulling the intake and heads off this week, but has anybody experienced this and can let me know what I might find when I pluck the heads?

Cheers

Alistair

[KULTULZ]

Hi


I had the workshop that was doing my generator repairs (all sorted, working well now) track down the leak - I suspected rear main seal.

But no, it's leaking between the head and block!?

I would think that most likely the oil leak is between the intake and lifter valley. Look for a deformed/damaged rear valley gasket after you remove the intake.

Does this engine have a road draft system or PCV? Make sure either is operational.

[Petrolhead]

Thanks - I will check that - good idea. The head/block leak was the workshop's diagnosis and haven't poked around myself

It's road draft tube, I guess it's working as there's plenty of smoke/fumes chuffing out when it's idling and hot.

Cheers

Alistair

[scumdog]

Almost put money on the rear gasket between intake and block is shot/been improperly put on.

Could fix it the bodgy way - hit the area with degreaser, let it dry and smear gobs of silicone sealer over the area.

50-50 chance it will work - and I wouldn't do it 'cos I just KNOW I'd have to do again about one day later and properly this time.

[KULTULZ]

It's road draft tube, I guess it's working as there's plenty of smoke/fumes chuffing out when it's idling and hot.

If it is smoking, either it is non-funtional or you have excessive blow-by. Excessive crankcase pressure will blow seals and gaskets. Consider performing the PCV update as shown on this websites tech page or if you want to keep it origional, consult your shop manual as how to properly service the road draft system.

[Petrolhead]

If it is smoking, either it is non-funtional or you have excessive blow-by. Excessive crankcase pressure will blow seals and gaskets. Consider performing the PCV update as shown on this websites tech page or if you want to keep it origional, consult your shop manual as how to properly service the road draft system.

Cool, thanks. The car arrived from the US and sat for almost two years while I had body, paint and some mods done, I didn't touch the drivetrain. I only got it going four weeks ago, and already have a list of things to sort out - a positive crankcase ventilation system is on that list. On the first drive the road draft tube fell out. There was no O-ring where it pushes into the back of the intake, somebody had tried to glue it in with silicone. The two small spot welds that secure the tube-to-bellhousing bracket were broken. Judging by the way the car goes I'm guessing the engine's worn and it's blowby smoke - there's quite a bit of it.
Will do the tube tonight following the manual as you suggest - thanks.
Scumdog, I too am leaning towards the rear seal, all responses I've had agree. I used silicone rather than the gasket when installing the intake on my 302W and it worked a treat. I'll pluck the intake and fix it right.

[Petrolhead]

if you want to keep it origional, consult your shop manual as how to properly service the road draft system.

Hi Kultulz
I removed teh intake last night and found that the road draft tube is loose in teh manifold, no o-ring, just dollops of yucky blue silicone.

i looked at my '62 shop manual. There is a detailed cutaway illustration showing how the road draft tube works, but nothing on servicing it. There is a chapter on servicing the PCV though.

I can't actually see anything to service - my car's tube is exactly that -a hollow length of tubing with nothing inside it at all, apart from oil residue and sludge. Is something missing?

I think i'll do a PCV conversion.

Cheers

Alistair

[Petrolhead]

Almost put money on the rear gasket between intake and block is shot/been improperly put on Could fix it the bodgy way - hit the area with degreaser, let it dry and smear gobs of silicone sealer over the area. 50-50 chance it will work - and I wouldn't do it 'cos I just KNOW I'd have to do again about one day later and properly this time.

Scumdog, you should have put money on it - pulled the intake last night, the seal is stuffed and somebody had already wiped great dollops of silicone on the back of the intake/block to try and stem the flow.
I've posted a pic on my other post re the road draft tube.
Just got to decide whether to go with the gasket, or just use a bead of silicone on surgically clean surfaces.

Cheers

alistair

[Guest]

Where is the gasket that belongs on the block? Looks like someone did a quick fix. I never had any luck with just silicon when puting an fe manifold on. They always leaked.

[Petrolhead]

I'd taken the gasket off , that goopy silicone had been applied from the outside of the engine. Not pretty.

Thanks for your advice re silicone.It's a tough call whether to use silicone or a gasket. Opinion on the Fe forum is split pretty well 50/50, I'd hate to put it all back together and up with another leak

[scumdog]

Run an even bead of RTV silicone on top of the block where the valley gasket goes, (after cleaning & wiping with paint thinners/acetone) place gasket on it and put a bit of pressure on top of the gasket (but carefull not to move the gaske while doing so!)

Wipe off any silicone that has ooozed into the inside of the valley.

Leave it 24 hours then place a bead of silicone on top of the gasket, place head-intake gaskets in place (with a dob of silicone at each end of the manifold/head gasket)

Place manifold, torque down and (most important) leave it at least 24 hours before filling the radiator and running the engine.

Has worked 100% for me on a variety of engines.

[KULTULZ]

Hi Kultulz

I removed teh intake last night and found that the road draft tube is loose in teh manifold, no o-ring, just dollops of yucky blue silicone.

i looked at my '62 shop manual. There is a detailed cutaway illustration showing how the road draft tube works, but nothing on servicing it. There is a chapter on servicing the PCV though.

Actually, on this particular system, the air inlet filter (oil filler cap) is about the only part needing regular service. If this plugs up, the system has no fresh air source. The PCV conversion will help immensely.

On that RTV, the blue glue is not good for this type of application, try to find RTV Black. The problem usually with the rear gasket is that it moves while lowering the intake spoiling the seal. Just make sure it is in place correctly before torquing the intake down.

[Petrolhead]

Scumdog, Kultulz - thanks! Will follow Scumdog's method, just not looking forwrad to lowering that weighty cast intake accurately into position. On my 302W I used a couple of studs threaded into the heads to locate the intake (plus it was an aluminium intake) , but seeing as the 390's bolt holes are at 45 degrees that obviously won't work.

[KULTULZ]

On my 302W I used a couple of studs threaded into the heads to locate the intake (plus it was an aluminium intake) , but seeing as the 390's bolt holes are at 45 degrees that obviously won't work.

Maybe studs front and rear on just one side (try it dry first). Make sure you have fairly large dabs of RTV at the corners where the valley gaskets tie into the intake gaskets.

Check gasket integrity once the manifold is placed and during torqueing down (gasket may move).

You might want to place it with a engine crane.