OM636 Engine problems

[Steve Beard]

Hi,

I have just bought a Seamaster 30 on the river Medway and we have had continuous problems with then engines in the two weeks we have had it.

On the first run last week, the engine overheated after about an hour and steam started coming from the engine compartment. When we got back, the closed cooling system was dry, but the wet system was ok. We refilled the closed system. It is unclear how the closed system was dry. We noticed one of the injectors was leaking. (see pic with white arrow)

On the second run this week which was short, we took it easy and the engine seemed fine. the closed cooling system retained its water.

Before the third run, the mechanic tightened the injector and noticed the rocker head bolt was broken. He tightened that bolt as best he could. On the third run yesterday the engine dropped its revs, there was lots of loud knocks from the engine so we turned back and slowly crept home. In general, the engine was very noisy and vibrational. We got it back to the marina and the mechanic had a look. The bolt on the rocker cover that goes through to the cylinder head had snapped off in the cyclinder head. The engine had been firing on 2 cyclinders we think.

The mechanic managed to get the snapped part of the bolt out of the cylinder head and we are going to order new bolts.

I am after peoples thoughts on two things:

a) Is it likely that a broken bolt on the rocker cover would cause the engine to misfire on 1 or 2 cylinders. I am not sure how the broken bolt could cause that issue.

b) Given the age of this engine, the problems we have had already, the fact is has hardly any power and it is very noisy, would it just be better to bite the bullet and replace the engine? If so, what would we replace it with? If we replaced that would be quieter and reliable? Any idea of costs for this? I did look at a new Mitshubishi engine as an option.

Any advice greatly appreciated.

Note: I can't seem to attach the pictures.

 

[Tranona]

If going new with something like a Beta 43hp you are looking at £10-12k installed provided there are no nasties in the installation. Secondhand and DIY With something like a Lancing Marine Ford of similar HP you could potentially halve that.

Having your existing engine reconditioned is also worth considering. There is a company in Lancashire (name escapes me) that specialises in these engines.

 

[Bru]

There is a company in Lancashire (name escapes me) that specialises in these engines.

Westfield 4x4

Manfred is very helpful and can supply all the parts plus good advice at sensible prices

And he does complete recon part exchange engines for a lot less than a new engine

 

[Bru]

Link (oops!) http://westfield4x4.com/

 

[volvopaul]

A man called Paul Gardner builds my rally cars BDG cosworth engine, when I was last at his workshop he was talking about all the OM 636 engines he has built over the years, I'd give him a call.

Paul Gardner Engineering he is in Lancashire. Sorry I don't have his number

 

[ffiill]

Mine is coming up 40 years old.
If there is no water in the freshwater system check for leaking hoses and the water pump.
Mine has a refillable oil lubrication reservoir and if you dont keep it filled it will fail.
Mine did this on the Crinan Canal a week after buying my motor sailer.
Basically the engine is a very reliable long stroke slow revving work horse owing its origins to the Mercedes diesel with which the Panzers invaded Poland.The OM636 as such was developed post war and remained the standard Mercedes Diesel in their cars up to about 1970.It also powered up the original go anywhere Unimog as well as powering Thermo king refrigeration units on lorries for many years.
Westfield 4x4 is really good if you need bits etc.

 

[Steve Beard]

NEWS!

Having watched videos on you tube, read the manual and looked at my cyclinder head with the rocker removed I can clearly see that the front half of the camshaft is missing along with 4 of the 8 rocker covers and pull rods.

They must have all broken when we were going along the river we then had to come back on 2 cylinders.

So, my question now is

a) what could have caused it all to break
b) Is it possible to repair myself?

I am assuming all of the bits have found their way into the crankcase and are sitting on top of the pistons.

Any idea of costs?

 

[Steve Beard]

Doh Doh Doh!!!!

What an idiot. The mechanic had already removed all the parts I thought were lost before I took the photo I was looking at! They were all in the rocker cover.

It seems clear that the broken bolt has caused the problems now that I have looked at it. I probably should not have got involved trying to understand it and left it to the pros.

The long bolt from the rocker head to the cylinder head holds what I presume is the rocker arm in place. As it had sheared off at the cylinder head the rocker arm must have been out of place and that caused the issue. The loud bangs (they were very loud) must have just been a misfire rather than anything breaking.

Apart from making an idiot of myself at least there is good news that it is only going to cost a few quid to fix.