SwayBar

Jean-Louis is running a Euro in his racecar at 5-lbs of boost with zero problems - 375 rwhp, so that's a good choice for your current setup

Petza914

That's next on my list and I'll go from there.

GregBBRD

Allow engine to cool down.
Remove spark plugs.
If the problem is not obvious by looking at the spark plugs:
Install pressure tester.
Apply pressure to cooling system and allow it to leak down 2-3 times.
Have someone crank the engine over, while you observe the open spark plug holes.


Any sign of "Old Faithful" is bad.



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dr bob

Pete --

If you don't already have one of those little bore-scope cameras with the webserver attached (typically <$30 on Amazon...) here's a great time to add one. Coolant in a cylinder will wash a plug, but that may or may no be obvious depending on how white they are in normal driving. The top of the piston, however, is an easy telltale for lots of combustion issues including detonation and coolant leaking. Both are of serious interest in your supercharged car. Coolant leaking into the cylinder will quickly steam-clean the piston tops to shiny metal, while the "normal" cylinders will have tan to dark grey deposits. Detonation offers a radial bloom from the common point of detonation, sometimes with what look like BB or ball-peen hammer impacts. Among the look with the camera, the plug inspection, a compression test and the coolant system pressure/leakdown test, you'll have enough hints to ID the failure and location.

If you don't have the schedule available for a DIY repair, your best option may be to have the car transported back to Carl for the whole reseal/refresh effort. That virtually eliminates possible issues with having all the supercharger bits go back on correctly. Carl mentioned in the electrical-fire thread that he's headed to Arkansas this spring with the race car and transporter. If he makes a right instead of a left on his way home, he'd wind up in Clemson to pick the car up. According to my from-the-farthest-corner-of-the-lower-48 nav skills anyway.

Petza914

How new a motor could I run with the rest of my current setup as a plug and play? Would a 4.7 L-Jet work and provide even more power or does it need to be a K-Jet whether US or Euro? Are the electrics the same like wiring harnesses and such?

Seems like if I'm pulling the motor anyway and then the heads and might have to machine the block and refurb the heads that I could do this same work to a different motor with other advantages, if there are some. Maybe upgrade the headers at the same time.

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Wisconsin Joe

1 - Not super critical as long as it doesn't get worse.
2 - No. The coolant isn't actually burning, it's just vaporizing to steam and going out the exhaust pipe.
3 - Yes, it could. Maybe. Or maybe not.
4 - Maybe. If you see that the top of one piston (or maybe more than one) is clean, while the rest have the normal carbon, that would be a good indicator. As noted, pulling spark plugs which you'd have to do to do this, would likely tell you the exact same thing.
5 - Maybe one side, maybe both. See below.

You also asked if this can be done with the motor in the car. For a 16v motor, it's rather difficult to get the cam tower off with the motor in. Passenger side worse than driver. General rule for cam tower is that one can be done with motor in, but if you are doing both, it's easier to pull the motor. Not sure if getting the cam tower off gives enough room to get the head out 'easy'.
In this case, I would guess that you've 'failed' a HG. Coolant in the cylinder (coming out the exhaust) is a fairly definitive indicator.
As was noted, I hope you didn't warp your head(s) when you got it hot. Although that generally results in a more catastrophic HG failure.
The big question is whether or not you've damaged both HGs. And if one is still intact, is there damage that hasn't 'let go' yet? Did you weaken it enough that it will fail in the future. It would really, really suck to fix one side and then have the other fail in a few weeks.
Have the HGs been done in the past? Or are they original?

If they are original, I'd suggest biting the bullet, yanking the motor & replacing both HGs.
If they've been done fairly recently, that will be a tougher decision.

Standard disclaimer: My $0.02, worth what you paid for it, not a professional mechanic, didn't even sleep in a Holiday Inn Express last night, use at own risk, close cover before striking, contains flammable gas under pressure.

Edit to add:

Nope. There's probably 600 miles or so of Tennessee & North Carolina in the way.

GregBBRD

Yes. Any engine that got as hot as you described is probably going to need more than just head gaskets:
The decision to drive it a "few more miles" was the exactly the same decision as pulling it out and attempting to rebuild it....even if you didn't recognize it, as such, right at that moment.

The "Fat Lady" has sang, left the building, gone home, and is already sleeping.

Any of the '78/'79 US engines are "plug and play", obviously. Any '78-'83 Euro engine is also "plug and play". (Although the odds of finding any '78-'83 engine that is good enough to just drop in and supercharge are very, very low.)
Every other engine will require modifications to the electrical and fuel system.

Petza914

So Greg, how's your schedule?

GregBBRD

As always, very busy.

When trying to do things as perfect as possible....one "little snag" can set us back weeks.

Seems like everything we have seen for the last six months has multiple "little snags".

The reality of working on older cars is that we don't see many cars for routine service things....almost everything we do is something that no one else can figure out how to fix or some sort of major trauma.

928 GT R

So --- We skip the diagnostic steps entirely and simply jump to a GB rebuild?

Or --- new GB motor?

If you do not want to start it again, at least pull the plugs and report the findings. Photos would help create a reference.

Some of us want a confirmed diagnosis before ripping our motors out or apart... Geeezzzzzz


.

SwayBar

An LS engine would go perfect with your drivetrain!

Petza914

Nah, we'll be doing all of that, hopefully this week - at least the pulling the plugs portion and boroscoping into the cylinders (I have a mobile phone boroscope, which probably isn't great, but should do).

Just trying to understand options providing the problem is what everyone including me thinks it probably is. Doesn't seem like there are too many ways to make a coolant cloud on start-up which never once happened prior to the overheating event, and has now happened twice in the same week. Same situation for that glug glug sound I hear on shutdown now, which I thought might be air trapped in the cooling system since I had refilled it, but now think it's coolant running into the head and the air it's displacing rising in the system.

There are a few things all pointing in the same direction, but will pull plugs to confirm and post what they look like.

In the event it is the head gaskets, if I found an M28/10 K-Jet motor (Euro), how.much of what I already have on my engine that is new and known good could move over to it, specifically the CIS fuel distributor, air sensor, WUR, crank pulley for the SC, 200 amp alternator, a/c, etc. I know the spider manifold and legs are different and larger on the Euro.

If I end up sourcing a new motor, does it matter if it was the version for a 5-speed manual or for an automatic (M28/10 vs M28/09 or M28/11 or M28/12)?

j.kenzie@sbcglobal.net

Hi Pete. Sorry about your problem. There is a kit that tests for combustion gases in the coolant system. I forget exactly how it works, but not too expensive and supposedly very sensitive.
Maybe this is the one I got.
Good luck,
Dave

Petza914

Thanks Dave. Adding that to the test arsenal to help confirm the diagnosis. I'll try to pull plugs tonight and do the coolant test Thursday or Friday when I'm back home again.

BRB-83-911SC

I just posted this in the other Head Gasket thread. At the beginning of my thread below, I describe the symptoms I encountered, which sound similar to yours. Further into the thread you can see the forensics of the gasket. I got lucky and didn't have any corrosion issues to deal with. It has been 7 years and 16k miles since, with no issues.

EDIT - my car never overheated, so the fact that yours did may present issues other than the gasket, as you know.

https://rennlist.com/forums/928-foru...s-back-on.html