Dizzy base filling with oil/leak

[PodOne]

Hi folks

I've mentioned this in another threat with other bits and pieces.

In summary newly rebuilt engine and dizzy from Dizzy Doc with oil leak from dizzy base/shaft where it inserts into pedestal. Pedestal and MU all reconditioned. A google search hasn't brought much up.

Replaced  "O" ring from my box of my spare O rings on dizzy/pedestal but it's still passing oil that seems now to be coming from the bottom of the dizzy housing. Presume there is a weep hole? I think that some how the engine oil is being pumped up and into the dizzy via the shaft. I'd expect no or very little oil pressure getting there.

Thinking that either;

1) My replacement O ring isn't thick enough but then why is the dizzy housing filling with oil or

2) The oil is being somehow pressurised to pass up the dizzy shaft - Increased crank case pressure - Then why its a new rebuilt engine with a clear breather in the cam cover it should be as Triumph intended. 

Its making a mess I hate mess and a rag tied round it isn't a long term fix!!

Any thoughts appreciated.

Andy

[John L]

From the picture you made on another topic,  I think your O  ring is too big, the distributor flange at its base should sit right down onto the locking plate, that should allow the o ring to seal.

John

[PodOne]

16 minutes ago, John L said:

From the picture you made on another topic,  I think your O  ring is too big, the distributor flange at its base should sit right down onto the locking plate, that should allow the o ring to seal.

John

Thanks John for the feedback.

So just to be clear should the locking plate sit flush to the top of the pedestal and then the distributor flange sit flush to the locking plate?

That said would this prevent the distributor body filling with oil?

Andy

[Waldi]

Hi Andy,

The cast iron bearing bushing in which the MU/dizzy gear is bearing is located in the oil gallery, and pressed in the engine block. It has a drilling trough which the bearing is lubricated (with (full) oil gallery pressure. Some of that oil can escape on top op the bushing, between the bushing hat and the gear. The end-float is set to (I think) 0.15 mm with gaskets (acting as shims) and this limits the amount of oil that can escape.

The excess oil then drains back to the sump via a small hole in the engine block.
The dizzy bearing is also designed to receive a splash from this oil I think.

My bushing was slightly worn (but not much), so I replaced it to minimise oil (pressure) loss. The new one had a slightly better fit. Are your bushing and axial clearance ok?

There are (at least) two versions of the bushing; mine (first picture) is from a early (TR5) block according to Neil Revington.

Waldi

[PodOne]

Hi Waldi

Thanks for the input.

My bushing is the early one which is no longer available to replace and the one thing I didn't replace reasoning that it's bathed in oil and there was none to be had anyway. The drive gear was missing from the engine so I sourced a second hand one so in short I don't know the clearances. The end float was set as per the work/shop manual with a couple of gaskets between the pedestal and block.

So from your description the large hole in the early bush sits within the oil gallery and oil goes up the spiral slot in the shaft and spills out along the slots in the on the "top hat" and the gear sitting on top and then back into the block through a return hole. Looking at the picture of your block there is an even bigger hole for it to return! Some of the pressurised oil must then pass up into the pedestal/MU drive to provide lubrication and then return by gravity to the sump.

The problem I seem to have is too much pressure some how finding its way all the way up and into the bottom of the distributor housing along its drive shaft. The O ring on its stem seals it to the block and must be holding as the oil is coming from above this point. There is no oil seal on the distributor shaft just a bush and has been rebuilt by Dizzy doc so I'd expect its running clearances to be good. 

If the bush in the block is worn it would by default deliver less oil pressure? 

Bit stuck on this one at the minute going to just ensure the dizzy is sitting fully down in its slot as John suggests. But I'm not confident this is the cause. Oil who needs it!

I'll feedback. 

Andy

 

[John L]

Andy,   Here is a picture of mine, I'm sure your o ring is too big, I think if you measure down on the dissy, I think you will find its the o ring holding.

Added just now,       Just reread your original,  so the oil is coming from the drain hole in the Dissy body?

John

it up. 

Edited September 19, 2023 by John L

[PodOne]

8 minutes ago, John L said:

Andy,   Here is a picture of mine, I'm sure your o ring is too big, I think if you measure down on the dissy, I think you will find its the o ring holding it up. 

Hi John

It does look different mines stuck up a little more than yours. Thanks for the picture.

Andy

[ntc]

55 minutes ago, PodOne said:

Hi John

It does look different mines stuck up a little more than yours. Thanks for the picture.

Andy

Andy just removed the plate and flatten it in a vice however I don’t think that will cure it my money is on the o ring 

[Waldi]

20 hours ago, PodOne said:

Hi Waldi

Thanks for the input.

My bushing is the early one which is no longer available.  

If the bush in the block is worn it would by default deliver less oil pressure? 

Andy

 

Hi Andy,

my “TR5 Bushing” came from Revington, worth asking.

I think you can machine a new one back to the old dimensions. Make sure it is cast iron. An additional advantage is the newer design has smaller holes drilled in it.

Maybe Triumph did this with a reason?

And yes, the excess oil that escapes reduces oil pressure, I gave no idea by how much.

Waldi

[PodOne]

23 hours ago, John L said:

Andy,   Here is a picture of mine, I'm sure your o ring is too big, I think if you measure down on the dissy, I think you will find its the o ring holding.

Added just now,       Just reread your original,  so the oil is coming from the drain hole in the Dissy body?

John

Hi John

Yes took the Dizzy out today and oil is definitely dripping out of the weep holes in the bottom of the Dizzy case. My dizzy was sitting higher than yours and I suspect this may have been due to the locking bracket position too high the bracket is slotted which I didn't realise. Released it and the Dizzy is now fully home with its base in contact with the block. The O ring I've replaced while I was there but in fairness the old one looked ok. 

Fingers crossed it solves the problem but I not convinced given the oil in the Dizzy base.

Andy

4 hours ago, Waldi said:

I think you can machine a new one back to the old dimensions. Make sure it is cast iron. An additional advantage is the newer design has smaller holes drilled in it.

Maybe Triumph did this with a reason?

And yes, the excess oil that escapes reduces oil pressure, I gave no idea by how much.

Hi Waldi

Seems you can get hold of the newer bush but I'm hoping the above fixes the issue. If not I'll be as sick as pig as getting the old one out is going to involve I suspect removing the engine and stripping the bottom end to knock it out. Unless there's a way of dropping the sump and removing the oil pump or somehow pulling it from the top.

That said there must be loads of cars running around with worn old bushes with no issues of oil passing up into the dizzy! I've searched the internet so far found nothing.

Suppose the actual drive shaft could be worn or the dizzy bushes out of spec but as above it's a recon unit. Think I'll give Martin a ring and see what he says. 

Andy

[Waldi]

Hi Andy,

your make a good point about the impact of a worn bushing / increased tolerance. Since no one else reports similar issues it is very likely not the cause of your leakage. So better to look for other possible causes.

Should you want to replace the bushing: I think I pulled it out from above, there are special pullers for this.

Waldi

[John L]

How was this resolved, just curious.

John

[PodOne]

12 hours ago, John L said:

How was this resolved, just curious.

John

Hi John

As you suggested in your photo my dizzy wasn't seated all the way down. It is now.

But I've yet to run her to see if it resolves the leak otherwise its back to square one!

I'll post back on the outcome.

Andy 

[trtechie]

On 9/21/2023 at 6:38 AM, Waldi said:

Hi Andy,

your make a good point about the impact of a worn bushing / increased tolerance. Since no one else reports similar issues it is very likely not the cause of your leakage. So better to look for other possible causes.

Should you want to replace the bushing: I think I pulled it out from above, there are special pullers for this.

Waldi

Hello sorry just read this and i have to say that i have had exactly the same problem and my dizzy had been to dizzy doctor, i couldnt find any info about it either, i fitted a Delco type dizzy and no oil leak, however this dizzy is not as well made as the Lucas

[PodOne]

Update

Distributor fully seated with New O Ring made no difference still leaking oil from the weep hole in the distributor body (no petrol smell or from dizzy or sump oil). Returned to Dizzy Doc for inspection hopefully there is an issue with the top bush.

Just in case the dizzy proves to be in spec what else could be the cause as I'm keen to keep using the dizzy? 

Bearing in mind it's a completely standard rebuild engine. Start up oil pressure 80 hot 50 and idle 20-25.

1) Would increased crank case pressure be a cause and if so how do I test and reduce it if required. Would fitting a pipe from the redundant blanked off fuel pump plate to the rocker work.

2) Have ally rocker cover should the cap have a hole in it to reduce pressure.

Thanks

Andy

 

 

[Mike C]

For the crankcase pressure just check that the vent hose between the rocker cover and inlet plenum is clear, and that the firetrap in it isn't blocked.

[stuart]

Ally rocker cover caps should have a breather hole plus obviously the cover itself has a breather pipe exiting from it too check thats not blocked for whatever reason.

Stuart.

[Waldi]

How to test it:

I remove the oil filler cap, let the engine run, and block the opening with my flat hand. If you hear “wush” when you remove your hand, the pressure is too high.

A bit subjective, I know.

Waldi

[PodOne]

Hi all

I thought I'd report back as this issue hasn't been reported as a problem and may save someone else some grief.

Checked all the above suggestions with no improvement so last week so I rang Martin (Distributor Doctor) who advised I send it in for a look and after 3 days it was back fixed with a diagnosis and explanation. Top service!

The top bush was a bit rough and had chewed through the nylon oil seal allowing oil to pass into the body now all replaced. After another 70 miles today she' ran well once warm up (Question to come!) and is nice and dry so well happy as I now don't have to consider removing the bush in the block - result 

Thanks to Martin and all for your help.

Andy  

[John L]

Well done to both Andy and Martin!

John

[Mk2 Chopper]

Always good to have a conclusion to a problem posted on here. 

Great service by the sounds of it. 

Gareth