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Severe oil leak from front of GT6 block


Paudman

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I'm going to appeal for help with this one so if anyone can rack their brains and work out where an enormous oil leak is coming from on the front of my GT6 engine. I know you could tell better if you were here but take a minute to check the symptoms and see if it points to anything you've experienced.
If I leave the car overnight I get a pool of oil from the front of the engine directly below the front plate, a pool of maybe six inches across. It does not reappear if cleaned up, so points to a leak from after the engine has been running.
It does not appear to drip when the engine is running as I've run it for almost 30 minutes with no drips, but only after it's been turned off and sat for a time; I've never yet actually observed it dripping, but it's always there under the engine if parked for any length of time.
Going from the oil stains it's not the timing cover, nor the crank seal but appears to be the front edge of the sump itself, almost as if the sump was overfilled, which it isn't - I've checked. I've retightened all the front sump bolts using new locking washers to no avail. The centre bolt actually stripped threads from something which looked like a helicoil insert, so may need redone if this has contributed to the leak; however the bolts on either side are firm and there's no damage to the lip of the sump.
The impression I get is of something filling up with oil as the car runs, then draining slowly overnight to leave a pool. The MOT tester commented on it last year but it's worse now than ever.
Any thoughts as to a possible cause of an oil-leak from this area of the engine would be very welcome, as if I'm going to have to take the engine out AGAIN the only way to find out if it's cured is to put it back in again, by which time it's too late...

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Are you sure it's not the timing cover gasket or oil seal?

Another possibility: I once had a sump that had rusted and it would only leak when it got hot. It was only a slow leak until I pulled off the flaking rust then it suddenly became obvious where my leak was coming from. It took me many months to finally pin that one down, so it's worth a look to if yours is a similar problem, although it doesn't look likely judging by the photo.

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Steve_Curton wrote:
Are you sure it's not the timing cover gasket or oil seal?



No Steve, I've wiped both clean many times and when the oil has dripped there are no tracks around the seal or timing cover, only the front edge of the sump. I'm suspecting - possibly - the engine front plate or the aluminium sealing block. Are the aluminium blocks available in uprated form in the UK?

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490 wrote:
I've retightened all the front sump bolts using new locking washers to no avail. The centre bolt actually stripped threads from something which looked like a helicoil insert, so may need redone if this has contributed to the leak; however the bolts on either side are firm and there's no damage to the lip of the sump.


You've made your own diagnosis, but you need a little bit more to clinch it.   Put a magnet on that 'helicoil' - it's NOT steel.   It's aluminium.

The 'bridge-piece' across the front of the sump (aka "front sealing block") is made of aluminium, and should have been tapped with coarse threads, but Triumph, penny-pinching as always (they had to) didn't.  So the bolts that go into it are the same UNF thread as the rest of the timing cover bolts, and they strip out of the alloy with no trouble at all.

The result is a bolt lying in a hole that is just wider, at the bottom of the timing cover, which ciontian plenty of oil when you have run the car.  So it seeps out, probably helped by capillary action, but isn't there in the morning.

Steel bridge pieces have been produced, I think in the US:
http://www.collectorcarsforsale.com/parts/TR6-GT6-TR250-OR-SPITFIRE-RE-ENGINEERED-SEALING-BLOCK-For-Sale_260527045440.html

Or, of course get am old, unstripped block and fit it to yours - carefully!
The bolts should be little more than finger tight.

John

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490 wrote:
Going from the oil stains it's not the timing cover, nor the crank seal but appears to be the front edge of the sump itself,


If your sure the oil isn't coming from the timing cover nor crank seal, and your confident the sump is well sealed, then the next area to look at is the front plate lower edge which is level with the sump. It may be possible that with the engine running, some oil fills up behind the front plate and block and when the engine is stopped, the oil then seeps through a narrow gap making it look like its coming from the sump edge. The front plate should have a paper gasket fitted between it and the block so maybe there is a leak path there. Its a long shot but you need to try and see the oil as it first drips out after cleaning to confirm this. Also, don't overtighten the sump screws as that could also result in a leak due to distorting the sump flange.

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To add to what John says above, the screws which hold the sump in place are not all the same length. Those which are screwed into the front alloy block are shorter than the others. Now you can imagine what happens when the uninitiated takes the sump off, the screws all go into a pot, and are replaced in any old order. When the longer screws are put into the alloy block, they bottom out before they are seated against the sump. The threadform is torn out of the alloy blopck as soon as the screws are tightened beyond this point.

Cheers,
Bill.

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JohnD was probably doing the same thing I was while reading this:

"sounds like...sounds like...'I re-tightened the bolts at the front, stripped'...DOH!"

There's a guy in the US who sells a replacement for those in steel, at $75 a pop:
http://classic-technologies.com/sealing-block.php

Jeez, how many Spitfires and GT6s have I seen with insane globs of silicone or whatever sealer all around the front of the oil pan where people had the stripped sealing block issue and were trying to make it stop with goo in a tube.  It either drips, or you fix the sealing block.

re:  Rarebits' point about the bolts - the parts manual will give you the size/length of the bolts via the part number.

edit:  I do wonder about why Triumph made the part out of aluminum, since it seems it would be just as easy to cough it out with all the other iron & steel parts made for the car.  I wonder if the slightly softer aluminum works better with the wooden wedges.

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rotoflex wrote:
JohnD was probably doing the same thing I was while reading this:

"sounds like...sounds like...'I re-tightened the bolts at the front, stripped'...DOH!"

There's a guy in the US who sells a replacement for those in steel, at $75 a pop:
http://classic-technologies.com/sealing-block.php



The centre bolt did strip, but the threads were non-existent anyway as I'd only hand-tightened the bolt back when the engine was first rebuilt (the worst recon engine I ever bought from a supplier) and this was a desperate attempt to effect a better seal on the front edge of the sump. The oil leak was heavy for months before I ever went near it, and as I've said someone had attempted a helicoil repair on the front aluminium sealing block, rather than replacing it. (Did I say it was the worst recon engine I've ever bought from a main supplier?)
In any case it's an engine-out job (yet again) and I've invested in one of the metal sealing blocks in the hope that this will FINALLY cure this engine, which has turned out to be the worst recon engine I ever bought. Did I say that already?


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could you not have re tapped to 8mm or even up to 3/8unf, unc , eveyr leaker Ive seen has had the long bolts in th wrong place    and the wooden sealing pegs are often whacked in and broken   let us know how you get on with the metal replacement,, get the bolt lenghts correct ,  you can do all this with the engine in  its just  a bit fiddly    Pete

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Do you have to remove the engine to replace the alloy block? If you lift it slightly there's a good chance you'll be able to drop the sump and replace the wee block in situ. You'll end up covered in oil if you're anything like me, but it's easier than pulling out the engine.

Nick

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I looked at getting them made a few years ago. The guy who does my machining reckoned they were a doddle, but before committing to them, I thought I would see how well some perfect originals I had would sell through ebay.

You can guess the answer, so I never got them made.......

If it's not bling, Joe Public doesn't seem to be interested,
Cheers,
Bill.

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heraldcoupe wrote:

If it's not bling, Joe Public doesn't seem to be interested,


You would probably need to market them as performance parts. A Series centre main straps are not exactly bling, but there's a good demand for them as they are marketed as must-haves for the "serious" performance engine. As they are relatively cheap, they sell well just because of their performance connotations.

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Slimboyfat wrote:


10 minutes in a coordinate measuring machine, 30 min CNC programme, 95p material, say couple of quid plus the RAT each? How much did you pay?


Considerably more!

But would selling "new" ones affect the secondhand market detrimentally??

I would suspect that if you were to sell at a similar price to secondhand then most people would choose the new ones.

Minimum quantity from the supplier?? boxes of unsold ones for years to come???

Clever marketting required!

So when can we expect to see them on the website as your latest hot thing???

:-)

Colin

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  • 2 weeks later...

Slimboyfat wrote:


10 minutes in a coordinate measuring machine, 30 min CNC programme, 95p material, say couple of quid plus the RAT each? How much did you pay?


Okay - here's the ...well I was going to say the nitty gritty but as someone has deemed this phrase offensive for strange unknown reasons, here's the low-down. No offence intended to short people.

Item on eBay: £46 GBP. Courier to the UK £31. This I can live with if it cures the oil-leak and gets me through another MOT.

NOW: Parcel Force get their mercenary mitts on it when it enters the UK. HM Revenue and Customs - you know the ones, you can smuggle tons of heroin into the country and drive your car all day on red diesel, but a Classic Car part? - anyway they decide to slap £19.35 VAT on it.
Some sweaty bloke in Parcel Force has golden hands for they charge another £12.50 handling.

Result: almost £100 for a small metal piece in an envelope. Thank God the mounting screws are not supplied or I'd need a mortgage. This had better cure the oil leak or I'm going to start reusing stamps and recoup the cost.
By the way - due to my 3 - 1 manifold the engine has to come out as I can't get access to the sump bolts in behind it.



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good lord,  you got money to burn !!!!
why did you not  re tap in situ,!!!!
and then put sealant on the threads , just incase the bolts have gone thru the top,

even if you did not re tap, then a good clean off, and silicon sealant all round would have done,


you prob find when you take sump off, the alloy has been ..pulled down.. so bulging the sump gasket, maybe even broke it,

silicon would have sorted it,

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490 wrote:

Item on eBay: �46 GBP. Courier to the UK �31. This I can live with if it cures the oil-leak and gets me through another MOT.

NOW: Parcel Force get their mercenary mitts on it when it enters the UK. HM Revenue and Customs - you know the ones, you can smuggle tons of heroin into the country and drive your car all day on red diesel, but a Classic Car part? - anyway they decide to slap �19.35 VAT on it.
Some sweaty bloke in Parcel Force has golden hands for they charge another �12.50 handling.

Result: almost �100 for a small metal piece in an envelope.


B***** me, that's a lot! After you started this thread I decided to use one in my GT6 engine later this year. To my door in Australia it cost 67GBP - but Australian customs don't seem to chase tax on small items and usually there are no handling charges. Handling? That's what you pay for, it's called postage!

I've often seen people on forums (fora?) complaining about the cost of buying ex-US. By law US companies have to ship overseas using registered mail, which costs more and results in duty and extra charges at the other end. Marc Goldblatt, the guy selling these blocks seems like a nice guy and I'd recommend the blocks to anyone. But with those extra costs, he's facing an uphill battle selling to the UK.

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796 wrote:
good lord,  you got money to burn !!!!
why did you not  re tap in situ,!!!!


Well I HAD... the new lawnmower didn't cost me as much as I'd saved... so the extra went on the block.
I didn't want to try a bodge with silicone or sealer that might have got me through the season but would lead to problems maybe next year.
There's no guarantee anyway that this is where the oil is leaking from, but if the engine has to come out and the front plate is going to have to come off, I'll do the job properly. Totally sick of the oil pool under the car every morning.

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