bwoyat

After a couple of years now of getting my 89S4 Euro A/T in what I would consider very good shape. I've decided that I'm ready to add a little boost!

I've already upgraded the suspension with eibachs/bilstein's, 18" Carrera III wheels, new rubber, x-pipe no cats, Momo steering wheel, and bunch of other stuff. Also had new motor mounts installed about 20k kms ago.

I'm looking for some input on what I should check/do before I SC the engine. I think I'm leaning towards a Murf Stage III.

In the next couple of weeks I'm planning on pulling the engine and doing the following:

- Full Intake R&R/Valve cover powdercoating
- New intake needle bearings from 928MS
- wp/tb, looks like the pump has a small leak? Although this work was already done 20k kms ago?
- front/rear crank seals, seems like a little oil coming out the rear?
- Porkensioner
- silicone pan gasket, 928Intl
- solid steering rack mounts, 928MS
- upper A-arm bushings
- convert A/C from R12 to R134, new barrier hoses, o-rings, etc. Just ran out of gas
- new ignition and coil wires

These are the main things so I thought I would pull the engine to make it all go a little easier. I'm in no hurry, I don't plan on having it back on the road until April.

I'm wondering if I should replace the head gaskets, OEM or Cometic? And if I should look at the rod bearings? Inspect/replace? Although I don't want to pull too much of the top and bottom ends apart if I don't need to as I might never stop! Only what's really necessary.

Wondering if there is anything else I should do while I'm at it? Car has relatively low mileage. Only 43kms, but it came from Japan 2 years ago with 20k kms on it and no service records. I was suspicious about the mileage when I bought it but it was very clean inside, outside & underneath?

Brent

BC

You can only improve things with a cometic head gasket, as long as you are willing to properly surface both the block and the heads.

bwoyat

do you have to resuface the heads for sure or just confirm whether they are straight and smooth?

BC

Cometic requires a 50ra surface - basically what the aluminum and steel looks like that you buy from the metal stores when its been "blanchart ground" or ground flat. Then, of course, the flatness and straightness needs to be correct as well. My point is that it is well worth it, concerning the holding power of the MLS gasket compared to the 18th century fiber gasket that is sold oem.

BC

You can see shades of light in the surface - it has to be that smooth.

bwoyat

you think the OEM gaskets aren't strong enough?

hacker-pschorr

OEM gasket is all you need for the Murf Stage III kit.

Quite a few Murf cars are on their original head gasket - including Tim's Stage III test car.

toofast928

Sorry Brenden I disagree here. OEM gaskets have held up to 15psi of boost. Cometic leak coolant/oil.

Replacing the head gaskets is a good idea. I bet when you remove the head, the surface is pitted where coolant touched it. If you disassemble the head for the machine shop, probably the valve guides are worn. And so on and so on.............

bwoyat

Should I bother replacing the current OEM gasket then? Or is it a good idea to put in new ones to be safe while the engine is out? With the OEM gaskets I assume I wouldn't have to resurace the heads?

hacker-pschorr

They are not leaking on the three 928 engines I know using them.
It's a crap shoot.
Like I said, plenty of 928's are running around boosted with the original gasket installed. We also see 100% stock low mileage 928's that blow head gaskets.

I took my heads off since I was more interested in replacing the valve guides / seals before installing the supercharger.

If you are going to pull the engine any way, I would pull the heads, check the valve seats & valve guides, I would also check / replace the rod bearings. Hell, while you are at it, install 951 piston rings.

Or do a simple intake refresh & install the blower

bwoyat

I'm ok with replacing the gaskets but like you say, start machining, etc. and it never stops and gets expensive. I guess I'll have to wait and see the condition once I get in there.

davek9

I would check the chain and tensioner that run's between the two cams.
Oh.. as you are replacing seals.. do the oil pump 'O" ring and seal too.
Sounds like you have a good plan, please post some pic's!
Good luck!

bwoyat

I've been thinking about this for a while. I've built a spreadsheet with all the parts, vendors, costs, etc. that I'll need. I don't want to get part way through and forget something or get it back together and kick myself for something I should of done. I plan on posting pics of the whole project over the next few months.

p.s. - I just realized my Rennlist membership has lapsed but I just renewed my membership?

BC

Maybe when new. But you would need to resurface the head and block for any new gasket. Many may believe that its common practice to slap on a new gasket of any type over corroded and simply "scraped off" head and block surfaces, and this is pattentedly false.

BC

This has been hashed over here, and I am fine with my position, as are many others. We will respectfully agree to disagree. The MLS (Multi-Layered Steel) gasket is current technology. The Fiber gasket is based on old engine designes that had flatness and casting issues between heads and blocks. These are no longer evident, and can be machined out.

I will do it my way, and other's will do it thier's. But I will always give the advice I know to be true. The block and heads need to be decked properly and SURFACED properly - they can't just be planed with an old machine and slapped together.

The leaking is a remnant of IMPROPER BLOCK PREPARATION no matter who would like to come on here and blame the part, because he or she did not take the time for the research (not referring to you tony).

But I always get in trouble here when I talked about this because the old guard doesn't want change, and doesn't want to do research on what is new and correct.