Hi, I'm in the process of building a Turbo 300D.
I've read through a mess of posts on here but have not yet found my answers.

I just got my rebuilt 617.952 back from the machine shop
The head was cracked so machine shop used a 617.912 head and installed the .952 valves
They thought they were the same heads other than the exhaust valves
They're not...

The .952 prechambers will not fit in the .912 head
The .952 prechamber has a slightly larger bore at the bottom (about 16mm)
I no longer have the .912 prechambers and haven't yet found a detailed picture to determine what the differences are, other than the bottom bore size.

My questions:

If I were to buy 617NA prechambers, would it work?
IF so, Does anyone have any used ones for sale?


Should I have the machine shop bore out the .912 head so that the .952 prechambers would fit? This seems to be a logical solution to me. Perhaps I'm missing something?


Or, do I need to find a .952 head?
IF so, Does anyone have a used or rebuilt one for sale? (I found a couple of folks on here with heads for sale; I've already emailed.)


Any advice is greatly appreciated.

Darren Morrison
info@darrenstunes.com
Christoval TX
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I'd not post your phone number or email directly on the thread! it's best to use PM's to give out the info to members.

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Christoval TX

No.

The Pistons have to match the Prechambers they are used with.

Since the Shop made the Mistake they should get you the correct Cylinder Head. They are supposed to have Insurances for such mistakes.

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84 300D, 82 Volvo 244Gl Diesel

you can machine the head to fit the turbo pc's no problem. I did this for my 240 when I added the turbo.

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1977 240D turbo

Thank ya'll for the advice!
I appreciate it and have located the correct head.

Here's what I've learned about the differences in a 1980 617.912 and a 1985 617.952 cylinder head:

On a close visual check, the combustion chambers appear to be the same. I don't have the instruments to be sure (or the knowledge to use the mic I have.)

The cam is the same (same part no.)

The turbo's exhaust valves are sodium-filled.

The prechamber holes on the .952 head are about 2mm larger at the bottom than those of the .912 head.

In addition, the little shoulder where the top part of the prechamber rests is different. One is more square, one is more rounded.

In other news, I'll soon post a thread to sell body parts and interior on the Texas 1985 300d and misc engine parts from the 1980 300d, including the rebuilt head, manifolds, and short block core (spun bearing).

--Darren Morrison

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Christoval TX