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1986 2.8L to Turbo 3.4L to turbo 4.0L to 4.6 Turbo Stroker MJ....


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Sorry for the huge delay! They're having problems with the front brakes locking up so they haven't been able to make much progress. I'm hoping for it to be done by the end of the week. We'll see! I'm anxious to drive it!

 

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Funny story for everyone! So it's tuned and ran fantastic for 10 minutes. A number of factors came into play but long story short I blew a head gasket, I'll have it fixed by the end of the weekend! But just my luck! OH BY THE WAY 311hp @4400 288tq @3600 the rpm ranges are not to scale with the tire size or gear ratio though.

 

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So is this blown head gasket going to be a recurring problem or is it something that is preventable? Nice numbers too, great job!

It is preventable. It was a combination of excessive coolant pressure, (above 27psi) because I had an overflow tank that was completely sealed (aluminum tank with screw on cap). Me running 10psi of boost, and it was probably horribly weekend from the multiple times I tried to tune it prior!

 

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So is this blown head gasket going to be a recurring problem or is it something that is preventable? Nice numbers too, great job!

It is preventable. It was a combination of excessive coolant pressure, (above 27psi) because I had an overflow tank that was completely sealed (aluminum tank with screw on cap). Me running 10psi of boost, and it was probably horribly weekend from the multiple times I tried to tune it prior!

 

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Um, this sounds like the result of a combustion leak... Wether there's 10psi or 20psi in the intake none of it should be making its way to the water jackets.  I'll go with your idea that it was damaged during your initial tuning attempts.  

Interested to see what you find when the heads are off.  

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So is this blown head gasket going to be a recurring problem or is it something that is preventable? Nice numbers too, great job!

It is preventable. It was a combination of excessive coolant pressure, (above 27psi) because I had an overflow tank that was completely sealed (aluminum tank with screw on cap). Me running 10psi of boost, and it was probably horribly weekend from the multiple times I tried to tune it prior!

 

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Um, this sounds like the result of a combustion leak... Wether there's 10psi or 20psi in the intake none of it should be making its way to the water jackets. I'll go with your idea that it was damaged during your initial tuning attempts.

Interested to see what you find when the heads are off.

On a 60 degree v6 like the 2.8, 3.1, and 3.4 there is, the intake manifold is part of the heads. I'll try and take a picture tonight, it's a goofy motor.

 

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So is this blown head gasket going to be a recurring problem or is it something that is preventable? Nice numbers too, great job!

It is preventable. It was a combination of excessive coolant pressure, (above 27psi) because I had an overflow tank that was completely sealed (aluminum tank with screw on cap). Me running 10psi of boost, and it was probably horribly weekend from the multiple times I tried to tune it prior!

 

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Um, this sounds like the result of a combustion leak... Wether there's 10psi or 20psi in the intake none of it should be making its way to the water jackets. I'll go with your idea that it was damaged during your initial tuning attempts.

Interested to see what you find when the heads are off.

On a 60 degree v6 like the 2.8, 3.1, and 3.4 there is, the intake manifold is part of the heads. I'll try and take a picture tonight, it's a goofy motor.

 

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Huh?  

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I've messed with a bunch of these leakers out in the field.

 

As far as I can figure, the only route for boost (or vacuum) to get into the water jackets via the intake manifold is the bank-to-bank coolant passages that are sealed up with the intake gaskets (2 spots I believe)... any other manifold leaks will either suck oil (from the valley) into the chambers or pressurize the crankcase when you're under boost; not cooling system issues.  This is assuming the intake isn't cracked of course.

I'm willing to bet you were pushing boost into the water jackets through the already blown head gaskets; you just finished them off with that good tune and the hard dyno pulls it took to get there.   :yes:

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Funny story for everyone! So it's tuned and ran fantastic for 10 minutes. A number of factors came into play but long story short I blew a head gasket, I'll have it fixed by the end of the weekend! But just my luck! OH BY THE WAY 311hp @4400 288tq @3600 the rpm ranges are not to scale with the tire size or gear ratio though.

 

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Slap some stock tires on the back for the next dyno pull. I would like to see what it is really putting down.

 

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I've messed with a bunch of these leakers out in the field.

 

As far as I can figure, the only route for boost (or vacuum) to get into the water jackets via the intake manifold is the bank-to-bank coolant passages that are sealed up with the intake gaskets (2 spots I believe)... any other manifold leaks will either suck oil (from the valley) into the chambers or pressurize the crankcase when you're under boost; not cooling system issues. This is assuming the intake isn't cracked of course.

I'm willing to bet you were pushing boost into the water jackets through the already blown head gaskets; you just finished them off with that good tune and the hard dyno pulls it took to get there. :yes:

That's a good theory aswell, yours sounds more knowledgeable than mine!

 

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Was the block machined and heads gone through and resurfaced? On thing that could cause this is a warped head. Did it overheat at all during your tuning?

 

 

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Yeah, they were resurfaced block was machined and had a valve job. When I was on the highway it jumped from 189 to 290 and I pulled it over.

 

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three things.  Get MLS gaskets if you can. Have the head surface machined for said MLS Gasket (requires a smoother finish), and use some head studs.  Every boosted engine I have ever built and driven had this combination, or at least as close as I could get.  At minimum do the head studs.  The number one cause of blown head gaskets on boosted motors is the heads lifting off the block from bolt stretch, and head bolts aren't as accurate for clamping force as you fight the thread resistance.

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Unfortunate news. I'm running out of funds and time (need a reliable vehicle soon) for this project. So it's up for sale make an offer and if it's the right price it's yours.

 

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Scratch that, just figured out all of my problems and received some funding.

 

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So today marks the 4th time pulling the heads off, it's beyond tedious but I'm sucking it up. The piston rings were damaged in the overheat. So Tuesday night I'm going to put new rings on and with the ARP studs new coolant routing and better knowledge of what the hell is going on; all should be well. Next little project will be installing a Ford IAC to control the idle better!

 

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  • Pete M changed the title to 1986 2.8L to Turbo 3.4L to turbo 4.0L to 4.6 Turbo Stroker MJ....

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