Please, please help!

[karlcouchMM1952]

I have recently been rebuilding my engine (Series MM, Type USHM2 - with thermostat).

After getting everything together needed to start the rebuild; new head gasket set, painting the head and buying a replacement exhaust manifold (which some kindly sold me via this forum) I set about putting the engine back together with my friend and fellow Morris Minor enthusiast Steve over the last few days.

Everything was going well and we were looking very pleased with ourselves until last night, when we completed the rebuild and tried starting the car.

1, The car failed to start. (No timing , ignition or carb changes made – but have checked everything methodically).
2, There is a water leak on the front right side of the head gasket. (44 pound torque used and checked).

After trying and trying, we decided to add a little touch of oil to the bores in case decarbonising the head had some effect on starting only to find that the car had blown the oil out of the exhaust manifold gasket. It looks like the replacement manifold does not fit the car. The original one was a Qualcast manifold and has rounded edges to the inlet section of the manifold where as the replacement one does not.

Has anyone had any experience of this or can offer some advice. I would really appreciate it.

[mike.perry]

If the engine has a thermostat then it is a USHM3, as well as a water pump or blanking plate and an alloy water jacket.
Have you checked the compressions?
Remove the spark plugs and spin the engine on the starter until you have good oil pressure.
Check the sparks on all the plugs.Check firing order 1342 anti-clockwise
The ignition timing could be out. Slacken the distributor slightly and rotate it slowly whilst pressing the starter to see if the engine will try to start. If not then move the plug leads one position and try again until the leads are in their original position

[karlcouchMM1952]

Hi Mike,

The engine has a thermostat (Qualcast) head. There is no water pump however but there is an alloy water jacket on the other side of the engine? It run like this for the last 5 years at least? The car also has a heater.

I haven’t got a compression tester... however, we did throw the engine over a few times to prime the engine in the first place. There is about 20lbs of oil pressure when the engine is turning over and trying to start though.

Checked the spark plugs and double checked checked the firing order... there is a spark at each plug, the points are sparking with a nice blue spark as well.

We have tried moving the dizzy slightly to check if it could possibly be the timing but to be honest we marked it up prior to taking it off so nothing should have changed timing wise.

The only thing we can think of is that the replacement exhaust manifold is not sitting on the block straight due to it touching the thermostat housing? It certainly blew out the little bit of oil we added to the bores. It came straight out of the exhaust manifold gasket, which made us think that there isn’t enough of a seal there and it could be sucking air. When we took the air cleaner off there didn’t appear to be much suction through the carb... could that be the reason?

The manifold not fitting correctly is the only conclusion we could draw in our minds? What do you think… really desperate!

[MarkyB]

Is it just an exhaust manifold or combined with the inlet?
You could be getting a big air leak if it isn't seating properly.
Chuck an egg cup full of petrol down the carb and see if there are signs of life then.

[Pikey]

I don't think putting more petrol into the carb throat, will have much affect. The carb is fitted with a tickler, and I held it open in an attempt to flood the carb. We've got loads of petrol at the carb, but none of it is getting through to the cylinders. Oddly cylinders 3 +4 would soak the plugs but 1 + 2 always remained dry.

I think we've got a huge air leak because the manifold isn't sitting squarely against the block.

The manifold on the engine now consists of a cast horizontal tube with core plugs in each end. We believe its meant for a non thermostated engine.

Now we've fitted it to an engine with a thermostat housing the square ended tube of the manifold seems to be fouling on the underside of the thermostat bulge on the head, and thus allowing air to enter the ports via the gasket joint instead of its proper route through the carb.

Has anyone experienced the none compatibility of the manifolds before.

Karl
I think we may be in luck with your old manifold its cleaned up fairly well, but one end looks like we've salvaged it off the titanic.

S

[karlcouchMM1952]

Please see the photograph of the replacement manifold (straight inlet section).

It would be great to hear from someone who knows if this manifold is used on non thermostat engines??[frame][/frame]

[karlcouchMM1952]

Hi Mike, please see a photo of my engine (no water pump)? [frame][/frame]

[mike.perry]

The manifold is the type fitted to the USHM2 non water pump engine. It has 4 round exhaust ports and 2 square siamesed inlet ports. The later manifold for the USHM3 engine has the same ports but the inlet ducts are curved. The early manifold for the USHM2 engine cannot be used on the later engine as it fouls the thermostat housing causing leakage problems.
The Ford side valve manifold has the same port spacings but has all round ports and takes a different carb.
The engine in the photo is a USHM3 with a blanking plate replacing the water pump. Where is the heater hose connected?

[Pikey]

The new look engine:



Sorry not sure why the side of the photos have been chopped off.

Cheers
S

[mike.perry]

If the manifold is not seating properly then try a couple of extra gaskets

[ian.mcdougall]

karlcouchMM1952 and Pikey how does the heater work without a water pump it looks like the other heater pipe goes to the connection on the side of the block do you get heat out of the heater

[karlcouchMM1952]

Hi Mike, I did think of adding another gasket or two to the manifold, however we were concerned that there may not be enough stud showing to get the nuts on as there isn’t a great deal left with only one gasket on there.

Are you saying that my engine should have a water pump? The heater currently works without one? In fact I had water leak on a rubber elbow connecting to the heater a few years ago and I got hot water all over my feet… so there was plenty of hot water getting to the heater?

Do you have any idea of way the new head gasket maybe leaking on the front. Does the copper gasket need to go through a heat cycle to anneal maybe? We used 44lb of torque and the head looked fine before going back on. I am really worried that water is coming from the head gasket even before the engine is started and unpressurised.

I really appreciate all advice.

[mike.perry]

Where did you get the head gasket? Was it hemmed over around the outside and the water passages? Did it drop smoothly down the studs and on to the head?
The water pump was an option as part of the heater kit, see section S of the workshop manual

[TvdWerf]

maybe not the best way, but I start engines, who did not had run for a long time, always with LPG gas, from my propane service kit.
first disconnect the (electrical wire from the) fuel input, then put the propane head in the air filter.
in that case you disconnect carburetor problems, and is it possible to let an engine run till 1500 rpm.
perfect to run warm, and when it runs ok, then switch on the fuel again.
With the MM this is possible to connect the electric fuel pump during running on LPG.
As soon the petrol is there, stop the LPG input, you can hear it on the engine reaction, and look if it runs well.

[MarkyB]

Sounds OK unless it back fires through the carb when things could get a bit explosive.
How do you control the amount of gas?

[TvdWerf]

[frame][/frame]With this one...
A pressure regulator, and a hand-grip, are enough...

[karlcouchMM1952]

Hi MIke, yes. I bought the head gasket online a couple of years ago but I cant remember where. It seemed to sit down OK before I put the head on. We did grease it though... I'm guessing thats the right thing to do isit. I was thinking it may be the manifold obstructing or holding the head up possibly... although I think that maybe wishful thinking.

[mike.perry]

I have never put grease on a head gasket. Try tightening the head down before fitting the manifold

[TvdWerf]

What I always do, and also did on my engine, is clean the thread (today checked, and the result was dirt and rust).
All the nuts and bolts should be clean till the end, and on my own engine, also the M10 thread should be cleaned complete.

When the thread is not clean, you think the head is fitted with the right tension, but a lot of force goes in the dirt and rust.
Because I have some spare-parts, I have spare nuts in better condition.

So clean taps and nuts always before fastening, to be sure no leaks are there.
And a little bit oil or grease on the nut before mounting it.

[colin addison]

Karl
I have a manifold exactly the same as the one in your photo, fitted to a USHM3 engine (no 156255). Originally my car would have had a USHM2 (1950). In the boot when I bought the car was a spare manifold again exactly the same, I guess from the original engine. I also have a spare cylinder head. So it was presumably one of the later engines, actually 65952.
Hope this helps
Colin