VM Mercruiser Cylinder Heads

[Converging]

I have a leak on cylinder 5 of my VM 3.6D Mercruiser. These engines have individual cylinder heads. Could anyone tell me if I can just remove one head or do I have to remove the lot? I am worried I could distort the adjacent heads by only removing one.

 

[tinkicker0]

I have a leak on cylinder 5 of my VM 3.6D Mercruiser. These engines have individual cylinder heads. Could anyone tell me if I can just remove one head or do I have to remove the lot? I am worried I could distort the adjacent heads by only removing one.

Not a problem. Just lift the one head.

 

[volvopaul]

Not a problem. Just lift the one head.

I am a great believer that if one leaks then eventually they all will.

VM mercs arent that easy to work on, look at the engine and study it carefully.

You have to remove the water rail from all heads, then the manifolds, look at the spacer under the bolts, each bolt secures 2 heads on each corner, as soon as the bolts loose pressure is off the gasket, the head is unevenly clamped down, it could distort the alloy head and displace the gasket, for the extra work and cost of gaskets as you will ahve to buy all new for the manifolds and water pipes its just not worth leaving them off.

If you are having them skimmed and I always do, make sure the machine shop take off equal amounts, otherwise you may get worse leaks than before.

There are also a few special tools you need to align the ex manifold to the heads as they move around on the face of the block when tighteneing up they need to be partially clamped to the exhaust manifold in order the get a good seal.

All sounds not as straight forward as a good old volvo eh.

Sorry Dave im so busy, otherwise id of come over and done the job for you.

Did you do a compression check, id do one before you strip it and get the valves checked and refaced if req while its all down.

 

[tinkicker0]

Converging. I bow to Volvopaul's experience on VMs. All my experience of motors with individual heads were gleaned on Merc V10s, Deutz's and the like; and is likely 20 years out of date.

These motors were relatively understressed compared to today's tackle and were not so requiring of special jigs and stuff.

Sorry if I got your hopes up.

 

[Converging]

Thanks for the advice.

I havent actually done a pressure test Paul. I backed off each injector and the fall on the engine is about equal. I am assuming this means there is a reasonable balance, but its definatly leaking oil from there.

Wish you could have come over as I enjoyed the revelations of our last chat!!!

 

[salty bottom]

I have a leak on cylinder 5 of my VM 3.6D Mercruiser. These engines have individual cylinder heads. Could anyone tell me if I can just remove one head or do I have to remove the lot? I am worried I could distort the adjacent heads by only removing one.

Did you manage to complete this repair and if so could you tell me where you bought the head gasket set from and also any pointers on any problems you encountered would be appreciated as I have the same problem and need to replace the head gasket which now seam to be a three or two cylinder gasket I think so you can arrange for a five or six cylinder engine.

Cheers Jonathan

 

[Converging]

Hi Jonathan,

This is still an ongoing project as I could not find an engineer in Cardiff, or the world for that matter, who was interested in doing it!!!

The heads are off now, and I just need time to reassemble.

The parts are no problem - Contact this company and speak to Shane:http://www.jnlengineering.co.uk/. He is a first class chap.

Your first problem is to find the thickness of your head gasket. This is indicated by a notch system on the head gasket. Zoom in on the top RHS of this picture and you will see it.
View attachment 5628
You are also correct that three head gaskets have now replaced single head gaskets.

Shane advised me that changing one bank of three was acceptable.

Doing it his way allows you to leave the manifold in position and I am hopng this will help me to re-alighn the heads when we put them back!!

Apparently these engines are Italian and were used in Land Rover Range Rovers. They were dropped due to poor reliability. Heads being one of the issues. Regular checking of the head torques has been widely recommend by my Land Rover Friends.

These engine have undergone many iterations so it has taken us a while to identify them but Shane is like Inspector Morse!! For instance neither of us could beleive there were no valve seals fitted!!

Volvo Paul was also real helpful in talking the alternatives through with me. Tried to get the buge**r to move Marinas but he wouldnt!!!!!!

Hope this helps and if you need to know anything else then please let me know

Dave

 

[volvopaul]

Hi Jonathan,

This is still an ongoing project as I could not find an engineer in Cardiff, or the world for that matter, who was interested in doing it!!!

The heads are off now, and I just need time to reassemble.

The parts are no problem - Contact this company and speak to Shane:http://www.jnlengineering.co.uk/. He is a first class chap.

Your first problem is to find the thickness of your head gasket. This is indicated by a notch system on the head gasket. Zoom in on the top RHS of this picture and you will see it.
View attachment 5628
You are also correct that three head gaskets have now replaced single head gaskets.

Shane advised me that changing one bank of three was acceptable.

Doing it his way allows you to leave the manifold in position and I am hopng this will help me to re-alighn the heads when we put them back!!

Apparently these engines are Italian and were used in Land Rover Range Rovers. They were dropped due to poor reliability. Heads being one of the issues. Regular checking of the head torques has been widely recommend by my Land Rover Friends.

These engine have undergone many iterations so it has taken us a while to identify them but Shane is like Inspector Morse!! For instance neither of us could beleive there were no valve seals fitted!!

Volvo Paul was also real helpful in talking the alternatives through with me. Tried to get the buge**r to move Marinas but he wouldnt!!!!!!

Hope this helps and if you need to know anything else then please let me know

Dave

Hi Dave, glad to hear your moving forward with it now, Cardiff is a really long way from the hamble where im sat now in glorious sunshine, even port solent was good today and I was working!!

 

[davedpc]

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