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-   -   Blown/Damaged Head Gasket? (https://rennlist.com/forums/928-forum/1134055-blown-damaged-head-gasket.html)

SwayBar 03-19-2019 10:03 AM

If you score Euro heads, then also find some Euro cams too.
​​​​​​
They are more supercharger-friendly in that they'll lower the dynamic compression ratio of the engine, thus, help minimize detonation.

Classic failure mode of a supercharged engine is a blown head gasket, and usually caused by detonation.

Petza914 03-19-2019 10:20 AM


Originally Posted by SwayBar (Post 15713724)
If you score Euro heads, then also find some Euro cams too.
​​​​​​
They are more supercharger-friendly in that they'll lower the dynamic compression ratio of the engine, thus, help minimize detonation.

Classic failure mode of a supercharged engine is a blown head gasket, and usually caused by detonation.

Actually, it looks like my current compression ratio of my '79 US car is 8.5:1 and the lowest of all 928 motors, so should be as supercharger friendly as they come. In '80, the US cars moved compression to 9.0:1,and for the Euros to 10.0:1.

83/84 US cars were 9.3:1
84-86 Euros were the highest at 10.4:1
85-86 US cars were at 10.1:1
then everything after that, except the GTS was 10.0:1 with the GTS being slightly higher at 10.4:1

If I end up putting heads onto my block, I'm going to install them with upgraded gaskets from 928MS. If I end up installing the 4.7 rebuilt motor, I'm going to leave things assembled as they are and drop it in. That motor would have a compression ration of 9.3:1 which should be OK. Probably going to install new fuel injectors just to be save if I go that route, unless I also change over to the L-Jet fueling system that's available with that motor.

Any opinion on K-Jet vs L-Jet for supercharged setups - avoiding a computer and tuning manually with mixture seems easier.

j.kenzie@sbcglobal.net 03-19-2019 01:42 PM

I would talk to Carl about L-jet vs K-jet. He has experience with both .
good luck
Dave

jeff spahn 03-19-2019 01:47 PM


Originally Posted by polecat702 (Post 15709268)
I had head gaskets blow on the exhaust valve side in my blower motors in the Pantera. It stopped when we O ringed the heads. I'd do a compression test on each cylinder. They don't always pop where you get water in the oil. I've seen them let go and the exhaust gasses push all the coolant out thru the cooling system. BTW, I got my radiator cap from Roger, and I believe it's a 13 pound cap. Also Greg Brown says the head gaskets on these cars are failing due to age related problems. My 89 is supercharged, and I'll be changing head gaskets as a precaution when I do the top end refresh.

Joe
Call me when you do that. I'd be happy to come out and help you pull the motor and do the heads. It's easier with extra sets of hands.

Petza914 03-19-2019 02:15 PM


Originally Posted by j.kenzie@sbcglobal.net (Post 15714321)
I would talk to Carl about L-jet vs K-jet. He has experience with both .
good luck
Dave

Just did.

He says the K-Jet is a better fueling platform for supercharging providing it's in good shape (which mine is), so I'll be staying with what I have on that, but probably installing with new injectors and seals just to be safe, and some braided stainless fuel lines I've found.

AirtekHVAC 03-19-2019 09:21 PM

Pete, sorry to hear all this, hope it works out, and I hope you can get it done before SITM

Petza914 03-19-2019 09:35 PM

I bought the recently rebuilt 4.7L M28/19 motor today from user BC for very reasonable money - thanks BC! It was previously in ladybug's car.

So that's the plan...pull the motor and replace it with this 4.7 and then reinstall my K-Jet setup and supercharger onto it. Also going to install new injectors and Greg Brown fuel lines.

The motor will be starting the trip my way from San Diego sometime next week and I'll start doing prep work on my car in the meantime as I've now made a decent list of stuff I am going to do.

Hoping I can get it all put together in time for SITM.

If there's a good 16v Engine Pulling for Dummies (Rookies) writeup with step by step instructions someone could point me to, that would be awesome.

I'll pull the heads from my current motor after I get everything else done and decide what to do with it.

polecat702 03-19-2019 11:49 PM


Originally Posted by jeff spahn (Post 15714329)
Joe
Call me when you do that. I'd be happy to come out and help you pull the motor and do the heads. It's easier with extra sets of hands.

Thanks Jeff!!!!! I'll wait till you're snow bound and want to hit Vale on the way out. I wanna do the engine after we run down to 3rd coast, this year. Yank the motor, and get it back in before I have Tommy, paint the car. I'll have everything ready to do a quick swap. I have spares for almost everything. Plus all the new parts will be here too.

We'll tool around in the Pantera this time too. Gotta start driving it.

BC 03-20-2019 09:03 PM


Originally Posted by Petza914 (Post 15715304)
I bought the recently rebuilt 4.7L M28/19 motor today from user BC for very reasonable money - thanks BC! It was previously in ladybug's car.

So that's the plan...pull the motor and replace it with this 4.7 and then reinstall my K-Jet setup and supercharger onto it. Also going to install new injectors and Greg Brown fuel lines.

The motor will be starting the trip my way from San Diego sometime next week and I'll start doing prep work on my car in the meantime as I've now made a decent list of stuff I am going to do.

Hoping I can get it all put together in time for SITM.

If there's a good 16v Engine Pulling for Dummies (Rookies) writeup with step by step instructions someone could point me to, that would be awesome.

I'll pull the heads from my current motor after I get everything else done and decide what to do with it.

The motor removal is the hard part. Putting it back in is super fun. I stole the pallet from Costco today so ON SCHEDULE!

Petza914 03-20-2019 09:31 PM


Originally Posted by BC (Post 15717552)
The motor removal is the hard part. Putting it back in is super fun. I stole the pallet from Costco today so ON SCHEDULE!

Thanks BC !

karl ruiter 03-20-2019 09:35 PM

All easy stuff, especially on a CIS car.
Remove hood
Unhook exhaust
Pull fan and radiator
Unhook 14 pin electrical connector
Disconnect 2x fuel lines and throttle cable.
Disconnect driveline at clutch
Drop the clutch? (don't totally remember if I pull the clutch down or not. Probably makes the pull easier if you do as otherwise it has to come pretty far forward)
Bell housing bolts and motor mounts.
Pull baby pull.

WSM has a good write up, I think.

Petza914 03-20-2019 11:16 PM


Originally Posted by karl ruiter (Post 15717634)
All easy stuff, especially on a CIS car.
Remove hood
Unhook exhaust
Pull fan and radiator
Unhook 14 pin electrical connector
Disconnect 2x fuel lines and throttle cable.
Disconnect driveline at clutch
Drop the clutch? (don't totally remember if I pull the clutch down or not. Probably makes the pull easier if you do as otherwise it has to come pretty far forward)
Bell housing bolts and motor mounts.
Pull baby pull.

WSM has a good write up, I think.

Thanks for the outline. I have the WSM and will look that up.

Does the hood really need to come off, or can you just disconnect the struts and make it more vertical or pad it lay it back toward the windshield.

I'm planning to put it on the lift so I can access things from above and below as need be, then roll it off the lift so I can get a cherry picker with leveler under it to lift the motor out.


j.kenzie@sbcglobal.net 03-20-2019 11:22 PM

Hi Pete,
The hood comes off easily and one person can do it. I popped the struts, then laid blankets across the engine and fenders. Then I lowered the hood until almost closed, but I could still access the hinge bolts. Pull the bolts and walk around to the front of the car and lift the aluminum hood. Very easy, and the access is vast.
Good luck,
Dave

karl ruiter 03-21-2019 04:19 PM

Mark the position of the hood hinges with a sharpee. If you have fender service guards this would be a good time to use them as it is easy to bump the hood against a fender as you are lifting it, if you are doing it by your self.

SwayBar 03-21-2019 04:28 PM

Disconnect the engine at the torque-tube and bellhousing. Pull the engine with bellhousing attached.

Less is more at this stage.


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