Needing advice on 360

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Walker434

Walker434

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Ok so this past winter I did a 360 magnum junkyard build. Tore an 80,000 mile magnum 360 down and everything looked great so I left the bottom end alone. Put Mr. Gasket 0.28 head gaskets on to up the compression a bit. Went with the stock uncracked heads and put on the Hughes 1110 springs becuase I went with a comp custom grind cam. Basically mimicked the 380/360 magnum crate build.

The swap went as planned this Feb and I have been having a blast in this car with this budget build until a few days ago. I was on a lonely road working on my holeshot becuase I was getting ready to take it to the drag strip for the first time. Holeshot went good shifted into 2nd about 5,500 and then it started blowing white smoke out of the passenger side tailpipe and blowing antifreeze everywhere.

I shut the car down and assumed I had blown a head gasket. There was antifreeze everywhere under the hood and it seemed to have gotten compression in the cooling system becuase it blew my water pump gasket and my over flow tube. I then towed the car home and planned on replacing the head gasket.

Last Sunday I finally had time to work on the car. Pulled the passenger side head and to my suprise the head gasket looks fine. So, I'm thinking that maybe it cracked that head. I couldn't visually see any cracks so I took the head to have it tested. The machine shop tested the head and says it's fine.

So could I have blown the head gasket on the driver's side and it blew white smoke out of passenger side? I hope I didn't crack the block but I can't see any cracks and the oil is not milky. I guess my next plan will be to pull the driver's side head and check it out when I have time.

Just trying to pick some FABO brains to see if someone has run into this before. Now is probably time to upgrade to some better heads I'm just trying to make sure I haven't screwed anything else up.

Thanks in advance for the help.
 
I'm not really sure what would have caused this but I don't believe the smoke came from the other side. Could be wrong.
 
Wow! Never experienced something like that, but it certainly does not sound good. Best of wishes to you..... and post what you find....
 
Are they the factory heads? Check between the valves, they are known to crack there, sometimes they hit water. Sometimes they don't. Magnums are beasts aren't they?!
 
I assume the machine shop magnafluxed the entire head. What did the intake gaskets look like? Could you have sucked coolant into the right bank from a bad intake gasket?

Drain the oil out and see if there is any antifreeze in it.
 
burdar said:
I assume the machine shop magnafluxed the entire head. What did the intake gaskets look like? Could you have sucked coolant into the right bank from a bad intake gasket?

Drain the oil out and see if there is any antifreeze in it.
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Agreed. If the head gasket was ok, and the head checked out ok, then I would next go to the intake gasket.
 
PoisonDart74 said:
Are they the factory heads? Check between the valves, they are known to crack there, sometimes they hit water. Sometimes they don't. Magnums are beasts aren't they?!
Click to expand...

Yes this thing was a beast until the problem. They are factory heads which is why I assumed it was a crack between the valves but the machine shop magnufluxed it and said it was fine.
 
burdar said:
I assume the machine shop magnafluxed the entire head. What did the intake gaskets look like? Could you have sucked coolant into the right bank from a bad intake gasket?

Drain the oil out and see if there is any antifreeze in it.
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You are on the same track as my Dad. He said if the head checked out fine it could have been the intake gasket. Wonder if I should pull the driver's side head just to be sure it checks out as well?
 
I would. It's already torn down this far.
 
You said it blew your water pump gasket too? When you say overflow tube, are you talking about the puke tube from the radiator neck to overflow can? A couple other engine builders here have said don't stop with a mag check for cracks-ask them to do an actual pressure test. And just because you don't see anything physically wrong with the gaskets doesn't really mean they aren't sealing 100%...

When you pulled the intake was there coolant/water in the ports? Carb? Intake runners?

My own experience with magnum swaps...I tried to use the .028" gaskets on my 5.2 build and it didn't take well...it started leaking coolant into the oil as soon as I fired it up, and it let some out of the pipes too, but with an X pipe, I couldn't narrow it down to a side, so I just replaced both. I went with the Fel-pro magnum gaskets (which are probably .045") and just rolled with it. At the time, I figured there was just enough warpage/planar issues on the decks/heads that the .028" gaskets just couldn't reconcile. After swapping to the thicker gaskets it's been fine...at least until I stored it about a year ago.
 
txstang84 said:
You said it blew your water pump gasket too? When you say overflow tube, are you talking about the puke tube from the radiator neck to overflow can? A couple other engine builders here have said don't stop with a mag check for cracks-ask them to do an actual pressure test. And just because you don't see anything physically wrong with the gaskets doesn't really mean they aren't sealing 100%...

When you pulled the intake was there coolant/water in the ports? Carb? Intake runners?

My own experience with magnum swaps...I tried to use the .028" gaskets on my 5.2 build and it didn't take well...it started leaking coolant into the oil as soon as I fired it up, and it let some out of the pipes too, but with an X pipe, I couldn't narrow it down to a side, so I just replaced both. I went with the Fel-pro magnum gaskets (which are probably .045") and just rolled with it. At the time, I figured there was just enough warpage/planar issues on the decks/heads that the .028" gaskets just couldn't reconcile. After swapping to the thicker gaskets it's been fine...at least until I stored it about a year ago.
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Yes the compression went back through the cooling system and blew the side out of the water pump gasket. The pressure also seems to have blown out the puke tube from the radiator to the overflow bottle. I wish I had paid more attention to what the intake gaskets looked like right when I pulled the intake. I am not sure if there was water in the ports or not.
 
Those thin gaskets need a really flat surface to seal, unless you had the block and heads decked my bet is on the head gaskets.
 
Well, you already have the one side off...might as well remove the other side, inspect, and if you don't find anything immediately obvious, I'd recommend checking the mating surfaces for warpage/flatness, or other imperfections. If it checks good, and the heads don't leak (pending machinist inspection), put it back together with some stock magnum head gaskets (yeah, they are a little different) and press on. Yes, you'd drop a little bit of compression, but the loss would be essentially insignificant for your purposes.
 
before you remove the other head put compressed air in each cylinder and check for leakage with rockers removed or valves closed. also look at the top of the pistons and plugs. The cylinder that blew will probably be steamed cleaned and shiny. Mr gasket thin head gaskets are not .028 compressed. I measured the gaskets that were removed from my brothers engine and they mic out to .034 compressed. I also measured new ones and they were .039
 
That sucks to hear. I would have the heads pressure checked & magged..I,m thinking intake gasket ,myself. The post above about the leak down ,a great idea. Yes ,Magnum's are beast's.
 
With enough pressure in the cooling system to blow out the water pump gasket it could have also blew out your intake gaskets as well. An intake gasket alone is not going to put compression in the cooling system.
 

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...because one guy says they are? Ehhh, not terribly convinced...

....this is from magnumswap.com

Head Bolts
The Magnum uses different head bolts than the LA engine — all of the long bolts on a Magnum are the same length. Additionally, some of the Magnum engines used Torque To Yield bolts, and as such are not reusable. Fortunately, ARP makes stronger-than-stock head bolts for Magnum engines.
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It's not just one guys opinion, Patrick did it too.

Oh boy, I better get out there right now and switch out my re-used head bolts, shes gonna blow up! :violent1:

But since your there, switch em' out, it's cheap.
 
Ha Ha! That's on you man-I never once said the head bolts would snap, and I've personally reused TTY bolts when I had no alternative, but it's not a choice I was happy with...the engine never came apart or anything, but it's like not a prudent decision if you're already there.
 
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