Oil pouring out bottom of bell housing!

[Stevejames]

My 1973 spitfire (just acquired) has had the engine rebuilt about five years ago by a garage. The engine has not been used and the sump had not been filled. I filled with oil yesterday and this morning, having removed the distributor and drive gear, I primed the oil pump and using a screwdriver end attached to an electric drill, turned the oil pump in order to get oil into the bearings before turning the engine over. Unfortunately, the oil managed to escape from the back of the engine pouring out at the bottom of the bell housing! I didn't notice until I had lost nearly all the oil. Took about 1 minute to empty.  It is now engine or gearbox out to inspect. Anyone have any ideas where the oil might be escaping from? Is there an oil blank off at the bell housing end perhaps? Cheers, Steve

[Wendy Dawes]

Darren says  probably rear crankshaft seal  so hopefully should be able to get at it by removing the sump and replacing the seal and a new sump gasket.  Quite common when an engine has been standing and the seal dries out and tears when the engine is started again 

hope this helps 

Edited November 6, 2022 by Wendy Dawes

[JohnD]

Not an argument, but an alternative, from personal experience - which I am ashamed to admit to!

To empty the sump in a minute or two through a leaking rear crank oil seal, really isn't possible, especially as you didn't run the engine.   The other clues are 1/ rebuilt engine, never been used 2/ only the oil pump used to fill the oilways, so no splashing of oil onto the back of the crank - even in a sump full of oil, it doesn't reach the lower edge of the oil seal.

 

The same thing happened to me, on a six-cylinder engine after a rebuild, when I forgot to replace the plug at the back of the oil gallery!  Rapidly enlarging pool of oil under the bell went I went to start the engine.  Doh!!

I fear that you will need to remove the engine, the flywheel and the rear engine plate to get at the back of the oil gallery, but you would need to do that anyway to get at the rear oil seal.

When you do find what filled the bell housing with oil - for it surely will have got almost half-way up! - do not forget that your clutch has been sitting in it.     A complete degrease of the pressure plate and the flywheel will be needed, and a new friction plate.   You could degrease and use the oily one, but would that be wise??

Good luck!

John

[RobPearce]

I suspect JohnD is pretty much on the mark here. Another possibility is the welch plug behind the camshaft (looks like a water passage core plug because it's exactly the same technology) wasn't fitted. Same dismantling required for that.

[Stevejames]

Thanks for your helpful replies. JohnD I suspect you are right! Cheers, Steve

[standardthread]

To save chasing your tail and doing jobs not needed if it were me I would look very carefully at everything as I dismantled it to find the source where the oil first came from, before you clean any dismantled part.

As to clutch driven plate, visually you will see if it is shot because any oil on it will show as darker patches. Trichloroethylene used to be a solvent used to clean oil off driven plates but now it's a no no, carcinogenic! 

[Wendy Dawes]

2 hours ago, JohnD said:

Not an argument, but an alternative, from personal experience - which I am ashamed to admit to!

To empty the sump in a minute or two through a leaking rear crank oil seal, really isn't possible, especially as you didn't run the engine.   The other clues are 1/ rebuilt engine, never been used 2/ only the oil pump used to fill the oilways, so no splashing of oil onto the back of the crank - even in a sump full of oil, it doesn't reach the lower edge of the oil seal.

 

The same thing happened to me, on a six-cylinder engine after a rebuild, when I forgot to replace the plug at the back of the oil gallery!  Rapidly enlarging pool of oil under the bell went I went to start the engine.  Doh!!

I fear that you will need to remove the engine, the flywheel and the rear engine plate to get at the back of the oil gallery, but you would need to do that anyway to get at the rear oil seal.

When you do find what filled the bell housing with oil - for it surely will have got almost half-way up! - do not forget that your clutch has been sitting in it.     A complete degrease of the pressure plate and the flywheel will be needed, and a new friction plate.   You could degrease and use the oily one, but would that be wise??

Good luck!

John

I said to Darren I thought either the engine out or gearbox, flywheel and backplate would need to come off as well as checking the clutch condition 🤷🏻‍♀️

oh well, I’m only a woman lol 

[JohnD]

Please don't say that, Wendy!

[Wendy Dawes]

39 minutes ago, JohnD said:

Please don't say that, Wendy!

Just my sense of humour  😁

[Nick Jones]

As John says, almost certainly a missing or very loose gallery plug (missing seems more likely given the rate of loss!) at the back of the engine.  Assemble with a decent sealant as this plug can also be the source of large and persistent leaks.

Nick

[standardthread]

20 hours ago, Stevejames said:

I primed the oil pump and using a screwdriver end attached to an electric drill, turned the oil pump in order to get oil into the bearings before turning the engine over.

Is there an oil blank off at the bell housing end perhaps? Cheers, Steve

Much thought overnight.

Did you reverse your electric drill? The oil pump/distributor run anti-clockwise, I don't know if oil pumps are bi-directional!

If your electric drill runs at 1400+ rpm that's equivalent to just under 3000rpm for the engine speed (ratio of timing gears).

The description attached (it's of an early Herald engine) gives oil flow and potentially the need for the cam etc. to be rotating, if not, potentially more increase in oil pressure.

Then you come to the machining of the block, see the second photo of the core plug at the end of the cam shaft. This is a Herald 13/60 block.

When I first run engines I take the plugs out, disconnect the fuel and turn it over on the starter and watch the oil pressure on the gauge, but before that I put oil in the oil filter.

There is a massive build up of pressure in the crank case, not as great for you because the distributor was off, because early Heralds, Spitfires etc. had a crank breather tube on the side of the block (shown in the drawing).

 

Edited November 7, 2022 by standardthread

[RobPearce]

If you run the drill "forward" - and hence the oil pump backwards - then it tries to pump out of the oil galleries and into the sump. This rapidly empties the galleries and pumps air. Plenty of sump aeration but no particular risk of oil loss.

Not having the cam rotating does not affect oil pressure. The pressure is still governed by the PRV. All that happens with the cam stationary is you don't get any oil to the rocker gear, which isn't a problem because the cam isn't rotating so the rockers are stationary.

In fact, running the oil pump with a drill means the distributor's not fitted, which actually means there's a big leak where the distributor pedestal should be, and you get very little oil pressure. However, that leak is well within the crank case and will pour back into the sump without worrying the bell housing.

Given that, and the shape of the rear of the block meaning that both the gallery plug and the cam plug are behind a gasket, I'm slightly leaning back towards Darren's theory... except that the rate of oil loss is way too high for a mere bad seal. I'd not be surprised if the OP dismantles it to find the seal holder is missing and there are no bearing shells on the rear main.

[standardthread]

Steve,

Exactly where is the oil coming from, is it in front of the rear engine plate, or, from the joint between the bellhousing to rear engine plate?

32 minutes ago, RobPearce said:

Given that, and the shape of the rear of the block meaning that both the gallery plug and the cam plug are behind a gasket, I'm slightly leaning back towards Darren's theory... except that the rate of oil loss is way too high for a mere bad seal. I'd not be surprised if the OP dismantles it to find the seal holder is missing and there are no bearing shells on the rear main.

Rob is mistaken about a gasket (see the extract from my 13/60 parts manual) but is probably right about the cam core plug because that is OUTSIDE the engine. All the covers the core plug is the rear engine plate, in fact from memory I think it is open to the atmosphere at the bottom and would show oil in front of the plate.

The only gasket at the back of the engine (item 31 in the drawing) is the crankshaft to oil seal to block gasket.

 

 

[RobPearce]

51 minutes ago, standardthread said:

Rob is mistaken about a gasket

You're quite right, I was misremembering. There should be no fluids behind the back plate so no gasket, unlike the front plate, which has the camshaft poking through it. But your question is a good one - if it's the cam plug or the oilway plug then the leak will be from between the engine and backplate, and as likely to pour out the side as it is through into the bottom, but quite unlikely to flow through the bell housing.

[standardthread]

If you're like me Rob, it's an age thing! Whatever the cause is it looks like Steve will have to have the engine out.

[Nick Jones]

15 hours ago, RobPearce said:

but quite unlikely to flow through the bell housing.

Experience suggests that it does. Though my experience is only as a fairly minor leak rather than full-on gush as here. IIRC the backplate is drilled at the point where the plug is so there is a path through.

Nick

[RobPearce]

3 hours ago, Nick Jones said:

IIRC the backplate is drilled at the point where the plug is so there is a path through.

Oh. Something else I'd forgotten? It makes sense, I suppose, as it means the plug doesn't need to be flush, which makes assembly easier with it being a taper thread.

[Nick Jones]

2 hours ago, RobPearce said:

as it means the plug doesn't need to be flush, which makes assembly easier with it being a taper thread.

Yes, good point, that’s probably why they do it.

Been a while since I did a 4 pot so can’t remember whether they have different threads in the front and rear of the oil gallery like the 6 pots do. It’s an irritating detail.

Nick

[Stevejames]

Thanks for all the replies. JohnD was spot on. Oil plug at the back of the camshaft gallery was left out by a garage rebuild 5 years ago. New one ordered plus clutch plate as the old (new) plate was covered in oil. 

[JohnD]

Thanks, Steve!    You can't be a guru without validation!   But I knew because of my own idiocy!

[standardthread]

1 hour ago, Stevejames said:

Thanks for all the replies. JohnD was spot on. Oil plug at the back of the camshaft gallery was left out by a garage rebuild 5 years ago. New one ordered plus clutch plate as the old (new) plate was covered in oil. 

A garage to avoid?

[Stevejames]

JohnD Not idiocy! Just the way the brain works. It is easy to overlook a step in a process without realising! Cheers and thanks for you replies. Steve