Fuel leak from metering unit - not the "O" ring

[Graze]

I have had a persistent fuel leak since I got the TR back.

 

I was sure it was the "O" ring between the metering unit and (let's call it) the pedestal for the distributor (because I didn't know it's correct name) which are bolted together with three bolts. So I replaced the "O" ring yesterday and at first I thought I'd solved it.

 

Then I find it's still leaking from a small hole on the underside of the pedestal, a hole which is obviously meant to be there, but (if my logic is correct) should not have fuel anywhere near it - surely it should stay in the metering unit and be sealed by the "O" ring?

 

So I need help with a diagnosis - what is the fault in the metering unit causing the fuel to leak through? Do I need a complete rebuild by an expert, or is it something a moderately competent home taught mechanic can fix with aid of the manual and some pro advice?

 

All help appreciated

 

Graze

[Jersey Royal]

Hi Graze

 

Have a read of this

 

http://www.lucasinjection.com/Lucas%20Mk2%20manual%20page%203%20CONTENTS.htm

 

The aluminum rotor has two further o rings around its body to keep the fuel between case and rotor. Plus there are other seals bung seals.

If fuel has leaked out due to o ring failure it would be prudent to replace the lot. If you dont feel confident to do this i would recommend you sent it to

Neil Ferguson K Raven Smith on the forum. If the history of any work done on the unit is unknown its probably even more of a good idea to get it sorted once and forget.

 

However , as fuel has leaked from MU and is coming out of a hole under distributor there are two further seals that need replacement, Pedistal Seals.

They can be a bugger

 

Hope this helps , and a search on the forum should bring forward posts on that

 

Cheers

Guy

[RobinTR6]

If its the small hole in the bottom of distributor pedestal between the MU and the dizzy then its supposed to be an overflow.

 

There are two seals in there (the pedestal housing), one to stop oil from the dizzy drive getting to the MU and one to stop petrol from the MU getting into the dizzy drive (and from there the sump).

 

It may be that the petrol seal has gone allowing too much petrol to escape. If you remove the Metering unit from the pedestal and the red drive dog you can see it. Unfortunately if it needs replacing its probably best to remove the dizzy pedestal from the engine and the MU from pedestal. I'd replace both seals as they dont cost much (a bit of a pig to drift or push out, patience and a bit of muscle required).

 

Dont ask me how I know...

[RobinTR6]

Given youre in Australia if its just the seals in the pedestal then you can buy them off Neil Fergerson and presumably they should'nt be too expensive to post.

 

It will take about 1/2 a day to remove the pedestal, do the seals and replace and redo the timing. Its not difficult just time consuming.Couple of spanners and something to poke out old seals is all thats required toolwise

[flatlandsman]

All correctly diagnosed re seals- one keep fuel out of the engine and the other keeps oil out of the metering unit with a tell tale holes just to let you know what's happening.....simples!!

It should take you ten minutes to remove the pedestal- that's what it's called. Turn engine to TDC with No 6 firing (see W/SHop Manual) Remove the distributor assembly by taking out the SINGLE bolt securing the adjusting clamp (the the ignition timing won't be upset). Remove mu complete by removing the 3 bolts, then take off pedestal by removing 2 x securing nuts (5/16unf). Remove single 5/16 bolt securing the conical cover on one end of pedestal assembly. Drive/puch out gear. Drive/drift out old seals using punch/old screwdriver -careful not to score the internals. Reinsert new seals carefully with punch or something similar aand make sure they face the correct way round! Reassembly is the reversal of dismantling as the saying goes- should be done within 2 hours in total. Honest!! Good luck

[Graze]

Thanks gents

 

Graze

[JohnC]

Hi Graze,

If you need somebody on your own timezone (nearly - he's in Sydney), try Peter Bower at http://www.bowerpower.com.au. Knowledgeable and helpful about all things PI. Pretty much any kind of fuel injection, not just Lucas MkII. He set up my MU to cope with a non-standard cam, and it runs like a dream. Also sold me the bits when I wanted to recondition a PI (seals & whatnot). As Robin & others have said, it's not hard to do. No connection with Peter Bower other than as a very satisfied customer.

Cheers,

John C

[Graze]

Thanks John

 

Good to know someone closer

 

Seems ok since I got the pedestal seals replaced although there is still a small leak

 

Cheers

 

Graze

[Denis]

Very lucky the vapour wasn't set alight by the Dizzy...happened to me once when the return pipe popped off!