Chasing down a miss (HEI)

b4black

Well-Known Member
May 24, 2001
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Not all that many, I'm guessing 30,000 miles. It was a already replaced when I bought the car and I have no information on the quality of the build.

Since it's not the original engine, I'm likely going to pull it out and replace it. I have several directions to maybe go with this. I have a '83 turbo 3.8 short block, a complete '82 4.1 and a '82 turbo 3.8 block that needs a rebuild.
 

mikemcvaney

Active Member
Apr 20, 2009
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Sorry to hear that,figured it was a head gasket.Last time I blew one it sounded like a Jake break above 10 pounds of boost
 

Utah Blaine

Member
Jan 8, 2015
127
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Texas
My 79 doesn't have a puter but I had the exact symptoms and like Shawnr said, it was the cam. I wouldn't think at 30 thousand it would be worn that bad. My clicking/knock noise was the valve guides on the bad lobes. I had 71 thousand on it and didn't think that was a high miler. I put an oil pressure gauge on it and found out I had 5 lbs of pressure. That could have been a contributor to the problem.
 

gunzandgearz

gearzandgunz
Aug 24, 2015
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mustang oklahoma
Pull the plugs out of those two cylinders squirt some oil in the hole and check the compression if the compression goes up from what you originally read it's the Rings leaking if that doesn't change could be the valves leaking which you would need to run a leak down test to determine that
 

b4black

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May 24, 2001
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Well, just to be 100% sure it was a blown headgasket, I did a crude leak down test. I hooked up my air compressor to cylinder 1 (like when you are changing valve springs). As quickly as the air goes in, you could here it coming out somewhere. I checked the intake, the exhaust and the crankcase, but it turns out its all blowing out the number 3 spark plug hole.

I'm ok with this. This car was never as powerful as my '83 and now I know it's probably because I've had a turbo 4 cylinder for a while now. :p

I have everything off the motor already. Just need to separate the block from the transmission and it will be ready to come out. Maybe this weekend.
 

b4black

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May 24, 2001
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Engine is out and autopsy performed.

I was right, this is a NA engine. Crank does not have rolled fillets. Heads are 8445s, so that's good. Oil pan is baffled, so it's probably from the original motor. Odd thing is the block has no casting number. Not sure what that means. It has a knock sensor hole and a 14 bolt oil pan, so it should be a 1980-84 block.
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WarWagon

Caustic Cacophony
Mar 10, 2007
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Early even fire block. Casting # is on rear between the valley rail and the bell flange.
NA headgasket for sure.
 

b4black

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May 24, 2001
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You're right. It was there under the grime next to the knock sensor. 25506397 - seems it's must be a 1980 or 1981.

Knock sensor had thread sealant on it. :rolleyes:

It's a good NA shortblock. I have no interest in it, so it will be up for sale.
 

WarWagon

Caustic Cacophony
Mar 10, 2007
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397 casting is a turbo Riviera block '78-9
That's the block that I have currently in my blowthru setup that has problems and is coming out.
This casting had been a very tough one for me, it had the most nitrous and highest boost used on it of all my blocks. It's my hero block for sure. I've lost two 109 blocks that were beat on less.
 
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WarWagon

Caustic Cacophony
Mar 10, 2007
1,862
60
48
36
Fairmont WV
You're right. It was there under the grime next to the knock sensor. 25506397 - seems it's must be a 1980 or 1981.

Knock sensor had thread sealant on it. :rolleyes:

It's a good NA shortblock. I have no interest in it, so it will be up for sale.
Knock sensor could of had a thread locker on it to keep it tight and cancel false knock. 75% of new sensors already have a thread locker pre-installed on them.
 

Utah Blaine

Member
Jan 8, 2015
127
5
18
Texas
397 casting is a turbo Riviera block '78-9
That's the block that I have currently in my blowthru setup that has problems and is coming out.
This casting had been a very tough one for me, it had the most nitrous and highest boost used on it of all my blocks. It's my hero block for sure. I've lost two 109 blocks that were beat on less.
I does my heart good to read that.


Rich, are you rebuilding your own engine? I sure hope I get mine running before you do. I pulled mine months ago and sent it out to boot. I hope to have it on the road before spring. The key word is hope.
Is this your 82 and does it have a ESC controller like my 79?
 

b4black

Well-Known Member
May 24, 2001
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Aurora, IL
www.flash.net
I have an engine ready to go. It was going in my other car, but I think it's a better match for this car. It's a '82 4.1 V6 that will keep the draw thru turbo set up.

Both cars are '82s. They use an ESC module that works with an ECM (much like an 84/87 Turbo V6).

I'll be keeping the stock ECM for now, to get it going again by spring. Long term, I might go with a J&S Safeguard for knock protection and a ditch the computer altogether. Then set the carb up for E85.
 
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