P38A Engine overhaul.

Hi all,

As some of you know my #5 cylinder was blowing into the coolant on my 2.5 DT. The head is off awaiting pressure testing and I am wondering what else I might as well do while she's apart. Timing chains and sprockets seem sensible at 170k miles.

How about turbo refurb? I think @Mark Piercy said you could get replacement internals that just slot in but which are reliable? I don't want something made of chinesium. Anyone tried any? Or is it better to send to a refurb place? Recommendations?

That then brrings us to injectors. They all looked OK to be honest but is it worth sending them to be refurbed? Again, any recommendations?

Anything else? The FIP is a refurbed one and not that old. Water pump is maybe 10 years old but it is the metal one. Same with the stat. Glows are Beru and still look new.

@Slooby got a kit to refurb your own turbo for under £20

Defo. on the injectors, Diesel Bob is a good Egg.

While its all apart, why ever not? Sounds like an ideal time to take care of these things. Good Luck with the rebuild.

Quixote said:

Defo. on the injectors, Diesel Bob is a good Egg.

Click to expand...

+1^^^^^^^^

Id have injectors checked and a new coolant cap, new clips on hoses ect,
Sounds silly but iv seen heaps of caps fail and not release/regulate pressure,
Isnt the turbo on the m51 a fairly low failure item?

@Grrrrrr, if in doubt get a fully refurbished turbo with a guarantee

Bloody Diesels always causing trouble

Henry_b said:

Bloody Diesels always causing trouble

Click to expand...

Pfff. Only when dropped in water
Where as yours is dropping water... Err coolant

stustrong said:

Id have injectors checked and a new coolant cap, new clips on hoses ect,
Sounds silly but iv seen heaps of caps fail and not release/regulate pressure,
Isnt the turbo on the m51 a fairly low failure item?

Click to expand...

Yes but I reckon there's been ever so slight a whine when cold recently. I'll take it out and give it a waggle as per Dopey's suggestion.

Henry_b said:

Bloody Diesels always causing trouble

Click to expand...

My drive is turning into a RR graveyard at the moment. Need to get a few running again!

Head is scrap. Apparently there are different M51 heads (I knew of 2) and they have different valve stem sizes: 6mm, 7mm and maybe 8mm. I think the 6mm valve stem is the later head. Being a '95 I bet mine is the 7mm.

You don't need the special tool RAVE says you need to get the cam out. Just ease all the nuts off a little bit at a time.

I don't think I will refurb the injectors at this point. I am wondering what state the head on the scrapper is like. It is a lot of work when I don't really have the time to spare. PITA!

Grrrrrr said:

Head is scrap. Apparently there are different M51 heads (I knew of 2) and they have different valve stem sizes: 6mm, 7mm and maybe 8mm. I think the 6mm valve stem is the later head. Being a '95 I bet mine is the 7mm.

You don't need the special tool RAVE says you need to get the cam out. Just ease all the nuts off a little bit at a time.

I don't think I will refurb the injectors at this point. I am wondering what state the head on the scrapper is like. It is a lot of work when I don't really have the time to spare. PITA!

Click to expand...

Are you putting the scrapper engine then? I wouldn't lift the head on it if you are, only some can be scimmed. It all depends on how much is taken off as you know.. The head doesn't have much to lose either...

Mark Piercy said:

Are you putting the scrapper engine then? I wouldn't lift the head on it if you are, only some can be scimmed. It all depends on how much is taken off as you know.. The head doesn't have much to lose either...

Click to expand...

BMW say the M51 head cannot be skimmed.

Datatek said:

BMW say the M51 head cannot be skimmed.

Click to expand...

I've spoken to a bloke in Pons but he wasn't so keen if it came to it hence the odds on it and it's a massive job to find out it didn't go so well!

Mark Piercy said:

Are you putting the scrapper engine then? I wouldn't lift the head on it if you are, only some can be scimmed. It all depends on how much is taken off as you know.. The head doesn't have much to lose either...

Click to expand...

Swapping the engine is a bit of a bind, not least because one is manual and one auto so some extra bits to do.

I was considering pulling the head off the scrapper as that means I don't have to source an engine crane However, the act of swapping it over over might cause it to fail if ir is a bit close already.

AMC Spain allegedly make replacement heads but I am told they are a sod to get hold of post+Brexit, cost has increased and they may have discontinued the early head. Look pricey on Turner's website.

Looks like Turners do a replacement head complete with valves which gets around the different valve sizes but it is a grand. Don't know if the stud pattern matches either. I might give them a ring on Monday.

Grrrrrr said:

Looks like Turners do a replacement head complete with valves which gets around the different valve sizes but it is a grand. Don't know if the stud pattern matches either. I might give them a ring on Monday.

Click to expand...

I have seen new heads for sale on Ebay for €800 but it was a while go.

Charles who sells the P38 spares sold me a good head for £250 about 5 years back. Not sure where he is these days

I'm slowly taking things apart and I have to say for an engine that has done 170k (fairly hard) miles it is looking remarkably good with few signs of wear.