Friends,

It looks like our 1994 940 NA, with about 250,000k miles, will need a head gasket. I have been reading the procedures in the FAQ, and looking at various posts--many of which offer great information--and I still have some questions.

I'm looking for advice about:

1. rebuilt heads: can anyone suggest reliable sources for a rebuilt head? Instead of taking the head to be worked on, I might try simply swapping it out.

2. gasket sets: if I get the head machined, will I be able to use the standard gasket? Are thicker gaskets available to make up for a deeper cut, if required?

Do people have advice on what brand of gaskets to use?

3 bolts: how often can one reuse the bolts? This head has been off just once, at about 150,000 k miles. At that time, the head was not shaved down, we just put a new head gasket on to solve a minor leak.

4. machine shops in Baltimore: can anyone suggest a good place to have the head cleaned up in Baltimore? or close to Baltimore?

Thanks in advance,

Paul
in Baltimore

Hello Paul,
I am a career toolmaker and have full machine shop facilities at my disposal. Last summer I trued the head of my '94 945 regina b230f. The head was warped .021, just slightly more than the Volvo recommended .5 mm. I re-machined it anyway and all is good. What I learned was this.

Gasket set From FCPEURO,

Buy new Head bolts. They are "torque to yield" by design, use once. inexpensive.

no, you don't need a thick gasket set as this valve design is a "no interference" design. IE: the valves will never hit the pistons

A youtube vid of my machining setup of my head

https://www.youtube.com/watch?v=k6hzwpuIvyM

I had to do mine on the 92 945T at about 250K miles a few years ago.

1. In my case my head had been "skimmed" already once by a previous owner and the machine shop could not take any more material off so I ended up buying a used head from another Brickboard member and installing that one. If you know yours has not had any machining you might just want to get it machined true and reinstall.

3. I bought and installed new bolts, seemed like a small expense for peace of mind.

4. I'll leave that one to Art. In my area, Fairfax Auto Parts in Merrifield VA just outside the beltway seems OK.

With a different head you need to do some shim measuring, calculating, ordering, and installing to get the valve clearances right.

Good luck!

Brian Mee
Manassas VA

" In my case my head had been "skimmed" already once by a previous owner and the machine shop could not take any more material off"

If truly only surfaced once in the past, someone took a lot off to not be able to do a second pass. This can happen when head gets badly warped (rare with our engines) but normally it is either a crappy machine shop or someone chasing 0.2-0.3 increase in compression.

Good point. However when you buy a Craigslist car for $1300 you don't ask too many questions.

Brian Mee

My comment was less for you than for others that might see this. As our heads tend not to warp much (almost none in NA applications that have not been massively overheated) the average resurfacing job is more to remove high spots or improve the surface smoothness than anything else unless a long term steam leak has eroded a path across the mating surface.

Most machine shops that have been doing this since the dawn of time rely on rules of thumb of .020-.030 or more because that will solve almost any surface irregularity and minor out of plane or warp. They do not care if that is the last time that head can ever be trued...they just want to make sure it is true in one pass of their expensive machine.

I would be surprised if about any B230F head ever need more than .015 removed. I am sure it can happen just likely to be the exception. Most could go with the minimum the machinist equipment can run (unless a very high end shop) or .010.

This comment is really useful--I'll try to get a "lighter" cut done!

"1. rebuilt heads: can anyone suggest reliable sources for a rebuilt head? Instead of taking the head to be worked on, I might try simply swapping it out."

Nope. If you really want the fast turn-around and a rebuilt head, get a second head from a PnP and have it rebuilt. They will charge you core charge anyway so return it for that.

"2. gasket sets: if I get the head machined, will I be able to use the standard gasket? Are thicker gaskets available to make up for a deeper cut, if required?"

Standard gasket is fine...the amount shaved should be minuscule.

Good point, thanks!

Somebody may chime in with more info...

Use the OEM style waffle type gasket.

Standard gasket will work on a milled head. The shaved head will just increase the compression ratio a bit. Doesn't effect valve or ignition timing.

Thanks, that is very helpful!

You can reuse the bolts a couple of times. Just curious: why the head gasket failure? Which coolant were you using?

Thanks for advice on bolts. I don't know what caused the failure. Maybe I will be able to learn more once I take the head off!