Lukas018
Well-Known Member
Thanks mate. Have attached photo of the cracks we found. Are these typical failure locations for this head? Might need to zoom in mostly on cylinder 6 to 2.
Yep cracks to pre combustion chambers pretty normal. Also along the half moon shapes between the valves.
Lukas018
Well-Known Member
Cool. Got a cylinder head coming my way then case of putting all back together. Fingers crossed will start
.
Henry_b
Think outside, no box required.
Poor casting i'd put my money on..
Poor coolant system maintenance is mostly to blame i would think. Dissimilar metals with differing expansion coefficients may also play a part. Also the increase in running temp for emission control.
Henry_b
Think outside, no box required.
They chrome plated the face of the VM cylinder head(s) IIRC they were good units, the 6pot VM i would of put in the P38 instead of the M51.
Nothing againt diesels but the m51 has to be the most gutless and unbalanced 6 pot diesel i've experienced.
The VM 425 felt like it had more get up and go..
Datatek
Well-Known Member
I agree, the M51 is a heap of excrement. BMW managed something unique, a 6 cylinder diesel with bugger all bottom end torque that vibrate like a single pot Lister on a dumper. The Iveco 7.5 tonner I drove for a while had a much smoother 6 pot with way more torque.
My previous diesel was a 4 pot with balancer shaft, loads of torque and smoooth.
Henry_b
Think outside, no box required.
I test drove a Grand cherokee 3.1 diesel it was a lovely unit, great lumps of torque and really quite smooth, if it hadn't of been rotten i'd of bought it..
I'd have a diesel P38 if it wasn't for the m51.
Datatek
Well-Known Member
We are not allowed to play at engine transplants over here or I would have seriously looked at shoving the engine from my rusty Transit in the P38 with a 160bhp remap.
RangeRoller dt
Well-Sprung Member
+1 weight/cooling.
Some fairly big power from these engines on lighter track cars and they have souped up cooling systems to make it cope with a gigantic turbo
P38 rad is capable of desserts apparently so must be another factor?
Some fairly big power from these engines on lighter track cars and they have souped up cooling systems to make it cope with a gigantic turbo
P38 rad is capable of desserts apparently so must be another factor?
Just out of interest, did you have a power box fitted?
Lukas018
Well-Known Member
I don't think my P38 had a great life and I got the brunt end of it, it had a power box fitted, it was a PSI blue box?
I also got the apparently 'uprated' rad but looks cheap and nasty.
I am cacking it putting new head on etc and hoping it starts up as put a lot of work into it
RangeRoller dt
Well-Sprung Member
What uprated rad - bigger intercooler??
Take plenty of pics, anything out of place someone’s beady eyes will pick up on it.
Take plenty of pics, anything out of place someone’s beady eyes will pick up on it.
I don't think my P38 had a great life and I got the brunt end of it, it had a power box fitted, it was a PSI blue box?
I also got the apparently 'uprated' rad but looks cheap and nasty.
I am cacking it putting new head on etc and hoping it starts up as put a lot of work into it
I think those powerboxes cause heads to crack.
I hope the head you found is good - if not then I do have a spare early type one in my garage at the moment that I could possibly be persuaded to part with.
I think I agree with everyone else in this thread so far as well in terms of why they crack, although I’ll also add that a lot of other similar technology Diesel engines from the period are also prone to cracks e.g VW and even Peugeot XUDs can suffer from them. In both cases they aren’t as prone to going through to a water jacket though.
Good luck getting it going again, they’re a lovely car when working right even with the let down of an engine!
Rich
I think I agree with everyone else in this thread so far as well in terms of why they crack, although I’ll also add that a lot of other similar technology Diesel engines from the period are also prone to cracks e.g VW and even Peugeot XUDs can suffer from them. In both cases they aren’t as prone to going through to a water jacket though.
Good luck getting it going again, they’re a lovely car when working right even with the let down of an engine!
Rich
Lukas018
Well-Known Member
@RangeRoller dt what do you think?
Attachments
Lukas018
Well-Known Member
Thanks Rich much appreciated new head been tested etc supposedly always risk with 2nd hand parts but has no cracks!!
RangeRoller dt
Well-Sprung Member
Looks like aftermarket Ali coolant rad.
Pre EGR your Powerbox should be a ‘DA4419’.
Pre EGR your Powerbox should be a ‘DA4419’.
