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PostPosted:Mon Mar 29, 2021 8:17 pm 
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Guys,

My 1850HL loves being in a cosy workshop and keeps finding reasons to stay there. The latest thing is coolant in the engine oil - never a good sign. The first thought is head gasket - but the car has recently had a major cylinder head overhaul, carried out by a well respected machine shop. The head was checked for flatness and 4 thou removed with a fly cutting tool. It came back immaculate. I fitted a new head gasket and diligently torqued it down, the engine ran well.

So due to the very recent top end work, I am wondering whether it may be caused by the water pump...? The water pump was last replaced probably 14 or 15 or years ago. There is no visible coolant loss from the window in the block where coolant usually leaks when a WP fails - but I'm wondering whether anybody has had this snag before and can share their experience?

Any thoughts/suggestions welcome

With best regards


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PostPosted:Mon Mar 29, 2021 11:40 pm 
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There are 3 ways water can get into the oil on a slant motor, head gasket (obviously) water pump seal, this is Triumph slant/V8 specific and note that the water seal to atmosphere which exits through the block slot is not the same seal that will allow coolant into the oil, and the 3rd and worst case scenario is a cracked block. I've seen 3 of these and Mad Mart encountered one on a Sprint engine a couple of years ago. So not common, but does happen.

Diagnosis! A head gasket failure is often characterised by overpressurization, steam everywhere, rough running and overheating. The oil contamination is an almost insignificant side effect. But the other 2 causes don't cause such dramatic symptoms as they don't involve combustion pressures in the cooling system. The oil gets contaminated and you lose small amounts of coolant slowly, but the motor runs well otherwise. Also, because the coolant leak into oil territory passes into unpressurized gravity oil return pathways in both cases, neither will exhibit the reverse cross contamination of oil in the water system that the Rover K series is famous for.

So having eliminated the HG, there is no good way of telling which of the other 2 faults you have. At this point logic and common sense comes in, a water pump is a lot cheaper and easier to change than a cylinder block, try that first!

HTH Steve

Edit, here's the rub, When Mart had his encounter he did the HG 2 or 3 times and the water pump more than once too. Because he was beginning to doubt his own abilities and those of his cylinder head specialists, who had pressure tested his head(s). If Mart, who is probably one of the most experienced slant engine builders alive today, can fall into this trap, anyone can! Either you trust yourself and your chosen specialists and look for something else wrong (definition of futility......) or you don't trust them/yourself, in which case why are you/they doing it? I had to politely remind him of this (gotta lot of respect for him) and was able to correctly indicate a cracked block by PM for him (what else could it be?)

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted:Tue Mar 30, 2021 8:33 am 
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Basically, I thought the whole point of that air gap and the hole in the side of the block was to prevent the possibility of water running into the oi that way. Am I wrong in that?

Here's the cross section through the pump from the Triumph slant-four engine training manual, where I've highlighted the air gap between the water and oil in red. It don't show very well, but the right hand end of that gap is open at the side of the block. I've not cut a block up to check, but I'd guess from the way they are cast, the gap has to be wider in height at the front than the back, so the bottom face of the slot ought to slope down to stop water pooling in the back of it. That's not shown in this drawing though.

Image

So I can't see from that where there's a path from the water impeller chamber to where the jackshaft runs without either running down the side of the block in vast amounts or that someone has deliberately filled that gap to stop it running down the block. I have seen that done, but it's kind of obvious when it has been.

Hence, if water runs down either the outside of the brass cage, or down the drive shaft, surely in both cases it has to cross that airgap to get to the oil?

Is there a path or mechanism for water to get past that air gap without it coming out the side of the block that I can't see?

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted:Tue Mar 30, 2021 9:09 am 
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If the pump is leaking you will see evidence of it around the slot...
You say the head has been diligently torqued down?
How many times?
I normally find it takes at least 5 retorqued over quite a few heat cycles before the gasket stops compressing and becomes stable.
My preferred sequence:
Fit head and sit overnight.
Retorque before it's run for the first time.
Run with no coolant in for a few minutes until the head is warm.
Sit overnight, retorque in the morning.
Fill with coolant, run to temperature.
Sit overnight, retorque in the morning.
Then retorque at 50, 100, and 250 miles.
I find until you reach the 50 mile mark everytime you retorque it's surprising how much it pulls back down..
If you have not retorqued the head it won't be sealing.
.


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PostPosted:Tue Mar 30, 2021 9:11 am 
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One possibility is a faulty gasket at the rear of the cylinder head. This is also a place where oil and water can mix. There are 2 different gasket part numbers for this so its important to get the correct one.

One other thing I found on my 1850 ( particularly if you have to wrestle to get the head off ) is that water that remains in the head / block finds its way down the oil ways and into the sump and it takes a day or so to show up on the dipstick. A change of the oil and filter and it was cured. ( I shall always be grateful to Jonners for this advice. ).

Tony.


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PostPosted:Tue Mar 30, 2021 11:21 am 
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I had the same problem with my Sprint, rebuilt the water pump with no further issues.


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PostPosted:Tue Mar 30, 2021 8:16 pm 
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Guys

Thank you for all of your contributions. Matt, interesting method for cylinder head torqueing - I pulled it down gradually, initially set to 25 lb ft, then 40 then 55.

Ran the motor till it warmed up. Left it for a day. Ran it again, left it overnight, 3 or 4 times, then re-torqued it again to 60 lb ft. I will re-torque it again now I've seen your method.

I've ordered a reconditioned water pump today from TD Fitchett, I wasn't turned on by the prospect of Rimmers £270 plus carriage for a new one. The recent parts spend on this car is already eye watering - and it keeps on demanding.

Removing the old WP tonight was both a battle and an eye rolling FFS moment. The WP coming from TDF is a 6 vane, that's what I thought was in it - turns out it has a 12 vane. So now I need to source a 6 vane cover! The old WP didn't want to come out - fighting like a cornered she cat every step - the impeller got damaged in the process, so it's pretty unlikely it will be suitable for exchange.

Anybody have a 6 vane WP cover in their shed, hanging off a strategic nail...waiting for a time to be useful...?


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PostPosted:Tue Mar 30, 2021 8:26 pm 
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Location:Over here...can't you see me?
I have spare 6 vane covers, but you'll need to know whether it is an early or late 6v in order to source a cover to properly match...sorry to add to your woes!

I can also probably find you an impeller which swapped for your damaged one would allow you to get your exchange surcharge back...it matters not how many vanes on that as all other components are identical...


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PostPosted:Tue Mar 30, 2021 9:00 pm 
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Thank you so much XVI - that is very kind.

I believe it's a late 6V pump, the car is 1981 registered, the guy at TDF acknowledged how late an 1850 it is when sourcing the replacement WP.

I will speak to them tomorrow to verify - and PM you to make the arrangements for the cover and the impeller. Thank you again for your kindness.

With best regards


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PostPosted:Wed Mar 31, 2021 1:44 pm 
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Fellas - thinking about the responses you've kindly given to this seemingly endless period of Dolomite duffness - with the engine out of the car, I want to cover and eliminate all possible causes of this problem, before the lump goes back into the car.

I now have a reconditioned WP, to eliminate that as the cause of the problem.

Shaun in your reply, you mentioned that you had the same problem and changing your WP cured it. Please could you confirm whether or not your failed WP leaked coolant externally - or just internally? Thank you

Mig Wielder - you mentioned getting the HG type right. When I had the head off recently, I ordered a HG from Fitchetts, who supplied me with one for a late 1850HL - which mine is. Thinking about it though, my Dolomite had a short motor change several years ago (the old block has thread damage on one of the main bearing caps) so the block it has now, is maybe from an earlier Dolomite.

If I dig out the engine number, are you able to determine the part number of the correct HG that it should have please?

My thanks in anticipation


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PostPosted:Wed Mar 31, 2021 3:10 pm 
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The gasket that Mig Wielder is referring to is not the head gasket - Theres only one type on an 1850. He's talking about the cover plate on the rear of the cylinder head, facing the bulkhead. There are indeed two types, but the visual difference between them is very obvious, I can't imagine you would fit the wrong one. But if you've never had this cover plate off then it's worth seeing if that gasket has failed - there's an internal divider in the gasket that seperates oil and water so it could conceivably be your problem. I would have thought that would have shown up in the cylinder head test though - Id be very surprised if it was not replaced as part of the head gasket job, it usually comes in the kit.


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PostPosted:Wed Mar 31, 2021 6:58 pm 
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Thanks Matt - I know the plate you mean at the back of the bead- and feeling slightly ashamed to admit, that when the head was off, I did not replace the gasket. (I bought the gaskets individually and omitted that one)

It's something I will check out tomorrow. I have the engine on a stand, the sump gasket was leaking for England so I removed it and all the other ancilliaries to try and get as much coolant contaminated oil out of the motor as possible.

Rotating the engine on the stand, I saw clear evidence of an oil leak from the rear of the head on the corner closest to the rearmost lower exhaust manifold bolt. The head is now off and shows the oil leak was actually over a wider area.

This is mystifying given that the head has been checked and confirmed flat. I haven't has the face of the block checked for flatness, but thinking that may need to happen.

This car is proving to be an itch that won't be scratched...


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PostPosted:Thu Apr 01, 2021 6:53 am 
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So it's definitely a head gasket leak, not water pump or anything else. That narrows it down. The heads been checked and is ok, the block is ok so that leaves a poor quality gasket or inadequate torquing.
What make of gasket did you use?


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PostPosted:Thu Apr 01, 2021 8:39 am 
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Thanks Matt.

The HG was supplied by TD Fitchett, I didn't specify a brand...but think maybe I should have...? Do you specify which HG you want?

About the torquing down, I have a brutally expensive 3/8th drive Snap On digital torque wrench, which, when I think about it, started not working properly when I was pulling the head down. So I reverted to an old torque wrench - it's definitely possible that the change of wrench affected the torque sequence - and possibly the settings...

The Snap On item has gone back for repair and recalibration, it's due back, so I will have something to rely on for the re-fitting.

Also, I noticed that the HG just removed was partially obscuring the main oil gallery at the back of the head - not by much, but enough to notice and think 'maybe that's not right'. Thoughts?


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PostPosted:Thu Apr 01, 2021 9:18 am 
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I've given up with modern repro gaskets. All crap.
I bought a batch of old stock ones at Beaulieu Autojumble a few years ago for 50p each. No idea what make they are but I've used several on different engines and they have been fine.
I still have about ten left....
Payen is the best, if you can find one.
I still think the re-torquing is the key to your issue.
You have to be mindful that because of the angled studs it takes a few heat and cool cycles before the head finds its exact position and the gasket stops compressing - and the newer gaskets seem to have more compressability which makes it worse. What I'm getting it is it's not so important how accuratly you torque it initially, as how often you torque it. It needs repeating and repeating as stated above. It's not a "one shot" job like a modern engine with stretch bolts.
Also what sequence did you use? The original sequence was unconventional, you did the studs first, starting in the centre and radiating out, then the bolts. This was later revised to a conventional pattern like most engines where you simply started in the centre and worked diametrically outwards. I personally use the first sequence, studs first then bolts, not the revised sequence, as I think it makes more sense with the materials and design involved. Opinions on this vary though..


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