71 Dart / 5.9 Magnum / Procharger

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rdakota340 said:
The bigger trans is going to rob some power but you get the converter right you will get the 60' down I'm sure how much boost is it making right now.
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I'm running 10 lbs of boost. Using the Wallace racing calculators I've added approximately 100 horse to the crank. Was hoping for an addition of 200 horse at the crank with 10 lbs. Again, hoping the exhaust might make a big difference.
 
Walker434 said:
I'm running 10 lbs of boost. Using the Wallace racing calculators I've added approximately 100 horse to the crank. Was hoping for an addition of 200 horse at the crank with 10 lbs. Again, hoping the exhaust might make a big difference.
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The centrifugal chargers tend to take a percentage of HP but a 100 horse power is a pretty good gain.
 
Time for an update. Took it to the track on Saturday. This is with the new TTI 1 7/8 Race headers. Had some good air, it went 7.16 at 96.97 MPH. Got to love the boost. The Fox Body Mustang in the other lane got me on the tree but when the boost kicked in I drove around him.

Dart 22.jpg
 
Yes sir it's coming around glad you are having some fun with it get a 2 step on it and see if that will help on your 60'.
 
Well, I've got bad news. Went for a Sunday drive in the Dart with my wife. Of course we had a few wide open blasts as usual. Got back home and the car was smoking really bad. Only out of the driver's side tail pipe. I currently don't have an X or H pipe so I'm sure I've hurt something on that bank. Still sounds great, not missing but I'm afraid I've broken a piston at the ring land on one cylinder?

That was my fear with this junkyard magnum shortblock. I should have taken the time to tear the engine down and open up the ring gaps. This is just a hunch but it's smoking BAD out of that one tailpipe. I'll do a compression check on all cylinders when I have time. That should tell me which one is having problems.

I'm glad racing season is almost over and the weather is starting to turn. Also, I've been planning a new stroker build anyway... one built for boost this time! I'll keep you guys posted when I do the compression check. Looks like I'll pulling this engine and trans this winter. Stay tuned.
 
Sorry to hear, my guess is #5 and I bet it detonated and cracked the piston Doubtful the rings butted.
 
That sucks! Pull the heads and see what happened. If not too bad, replace the piston (it that is what it is, and assuming the cylinder isn't trashed) with a stocker and slam it back together. You could still use it as a sacrificial motor to get your tune squared away while building your stroker.
 
Finally had time to compression check this afternoon. Passenger side bank was normal as expected. All plugs looked good and they went between 145 lbs to 155 lbs.

Driver is side #1 and #3 look pretty normal and were also in the 145lb range. #5 only went 100lbs and plug was very oil rich. #7 only went 100 lbs and was horrible looking! That thing is pumping oil, picture attached is #7 plug.

Thoughts?

#7 Plug.jpg
 
Time for tear down. Broken piston or ring would be my guess. How much blow by is in the crankcase?
 
I broke an exhaust valve head and when that hyper piston shattered the wrist pin hammered two holes in the bore. No more chevy rockers and hyper pistons for me. I went back to LA motor and forged assembly.
 
It will be a few weeks before I have time to pull this thing. Can't wait to investigate and see what happened. Hopefully nothing too serious because this engine is going into my wife's 65 Barracuda. Back to NA for her and my stroker will get the Procharger.
 
I bet you blew a head gasket like Dusted said that is the issue I had and it lifter galley side is the weak link it will blow before the rings butt together.
 
rdakota340 said:
I bet you blew a head gasket like Dusted said that is the issue I had and it lifter galley side is the weak link it will blow before the rings butt together.
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I hope you guys are right. That would be much easier than replacing a piston or two.
 
Time for an update: You guys that said head gasket were correct! Pulled the engine and transmission on Saturday and had time to pull the head. #7 cylinder. See pictures below. Wonder what caused this? Didn't think I'd have head gasket trouble with the ARP head studs and commetic gaskets.

Also, notice the in the one picture that the #7 piston looks washed around the edges? Would this be from sucking oil out of the intake galley?

Dart Heads.jpg


Dart Heads 1.jpg
 
Yet another blown head gasket. I guess it's a boost initiation ritual for us magnum guys.

I don't know the why they blow but my observation is that it seems to always include the outer most cylinders, like #1 and #7 or #2 and #8. Look at Dusted's pic above. I seem to recall that it is also those cylinders on the factory Magnum heads that tend to have the cracked valve seats between the exhaust and intake valves....or at least the cracks are the most severe on the far ends. I wonder if it's not a weak cooling issue on those cylinders? I'm convinced my head gaskets blew not long after I had a couple of over-heating issues on my build possibly weakening the gasket material.

I hope that's the extent of the damage and you're able to get it back together and on the road. -subcom
 
I wonder which way his carb hat is pointing? Seems like mine was facing away from the cylinders that popped. Make me think that these cylinders are going a little more lean with the air basically hitting the hat and funneling to those cylinders. Just an observayion. I know for a fact that the LS guy always have a problem on #7 and 8 and there the end cylinders makes sense with the way the Intake is.
Hopefully it’s not too bad and you can get it fixed and keep pushing the limit.
 
My carb hat is pointed towards the drivers side or the 1,3,5&7 cylinders. I built another engine for my Dart. LA this time, with forged crank rods and pistons. Indy TA heads and Edelbrock Victor 340. 414 cubic inches. All the head and intake porting was done by Brian at IMM Engines. Procharger will be going back in the dart with the new stroker. This engine is built for boost. 8.8 compression and cam on a 114 LSA. It made about 540 HP naturally aspirated so it should be a BEAST on about 8 PSI of boost.

This magnum engine will get a new head gasket and eventually be put in my wife's 65 Barracuda. The Junkyard magnum will live on! It will be naturally aspirated in her car so should live forever!
 
If I read it correctly, you had EQ heads and it did not burn the spark plug electrodes off. The piston looks to be in tact too, although I'd be curious to know if the ring lands held up. I wonder if the thin deck of the factory block, combined with small block Mopar only having four head bolts around each cylinder, simply allowed it to flex there and the gasket was doomed. No real fault of the gasket itself.
Very cool what you've been able to do with it up this point. Good luck with new combination. Looking forward to seeing updates.
 
Was any part of the head gasket over the edge of the cylinder wall allowing it to burn? Camera pics do funny things. I agree 4 bolts of the SBM is a weak area.
 
Walker434 said:
My carb hat is pointed towards the drivers side or the 1,3,5&7 cylinders. I built another engine for my Dart. LA this time, with forged crank rods and pistons. Indy TA heads and Edelbrock Victor 340. 414 cubic inches. All the head and intake porting was done by Brian at IMM Engines. Procharger will be going back in the dart with the new stroker. This engine is built for boost. 8.8 compression and cam on a 114 LSA. It made about 540 HP naturally aspirated so it should be a BEAST on about 8 PSI of boost.

This magnum engine will get a new head gasket and eventually be put in my wife's 65 Barracuda. The Junkyard magnum will live on! It will be naturally aspirated in her car so should live forever!
Click to expand...
IMO you're gonna need a NHRA license and more safety equipment with the new motor.
 
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