leaky heads gaskets, I'm losing it!

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737jetdr

737jetdr

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Alright, My 360 La motor needed new valve seals. I happen to have all the components to switch over to magnum heads including a set of heads. I figure, Why not? I made a hybrid for my 67 Dart years ago and it runs well. I'll do the same for the old D100. So I tear the motor down. Scrape the block with razor blades twice, clean with acetone, wire wheel the block and clean again. Put it all together and I have a coolant trickle in the front lower corners where the heads and the block meets right above the motor mount bosses. Ugh!!
So I tear it apart again. Take the heads and have them resurfaced just to be sure. Repeat the cleaning process, put it back to together and bam!! Same exact leak! WTF!! I've built at least a half dozen small blocks over the years and have never had this issue, let alone twice in a row. What am I missing? I'm using tried and true Felpro 8553PT gaskets. Everything is clean. New head bolts. The 1st time I torqued to 105'lbs like my magnum book says. Second time torqued to 95'lbs like my LA book says. The old heads never leaked. I'm at a loss. Am I using the wrong head gaskets? to mate the magnum heads to the LA block? Any help will be appreciated.
 
Here are the head gaskets listed for the 1995 Ram 360 magnum:

Screenshot_20220503-210916_Firefox.jpg


Shows the Felpro 519SD
 
The magnum head gaskets have holes for the pushrods to go through. Can't be used on an LA block because the pushrod angle is different. I'm guessing the 521SD must be the ones I need unless someone else has a better suggestion. When I built my last LA/ magnum cross breed I think I used some white head gaskets but that was 10 years ago and I can't be sure what they were.
 
Thanks for the input everyone. I guess I'll tear it down again tomorrow. I'll be able to change head gaskets in record time when this is finished. It just sucks to do it again.
 
737jetdr said:
Am I using the wrong head gaskets
Click to expand...
Easy enough to check, put the gasket on the head, line up the bolt holes check all the passages.

Use the same gasket on the block do the same thing.

If all the holes are correct it's probably not the gasket.

Maybe you have a crack in the block that opens when the bolts are tightened?

Don't some of the head bolts penatrate the water jacket and need propper thread sealer to seal?

Could it be coming from the intake?

Are you giving any sealer a day or more to setup before putting fluids in?
 
Dana67Dart said:
Easy enough to check, put the gasket on the head, line up the bolt holes check all the passages.

Use the same gasket on the block do the same thing.

If all the holes are correct it's probably not the gasket.

Maybe you have a crack in the block that opens when the bolts are tightened?

Don't some of the head bolts penatrate the water jacket and need propper thread sealer to seal?

Could it be coming from the intake?

Are you giving any sealer a day or more to setup before putting fluids in?
Click to expand...
Hmm. Never overlook the Un-Obvious!
 
I have a couple sets of the white head gaskets that I have used before. They are Corteco, a company that bought Detroit Gaskets I think. Detroit used to make the orange composition gaskets for Mopar Performance. I have used them on conventional small blocks, but never tried them with magnum heads.
 
Were the heads magnafluxed? Also was the block ever Square decked? I had an X block that would drip in the center on each side off of the rivets using Cometic gaskets. As soon as it would get a little heat in it it would stop dripping. When freshening the engine and square decking it we found the deck on each side had a low spot . Check the deck with a good straight edge and a light source. Also have the heads magnafluxed. Just precautions to take so you know for sure that is not your issue.
 
When I hear guys using wire wheels or those Scotchbright divot diggers on gasket surfaces my skin begins to crawl.
 
pittsburghracer said:
When I hear guys using wire wheels or those Scotchbright divot diggers on gasket surfaces my skin begins to crawl.
Click to expand...
a brass wire wheel is much softer than cast iron. On Aluminum is a no-no. Get a piece of thick glass or a granite floor tile and glue a piece of 600 grit on its shiny face, nice and flat. Run this over the gasket plane a few times nice and easy and see if any area is getting missed, there is your low spot.
 
I pulled the heads back off today. Gasket residue is in all the right places. Nothing sticks out as being wrong. Head bolts don't go into water jackets. Magnum heads don't have studs going into water jackets either so those are eliminated. Not sure what the deal is. Thanks for everyone's input. The investigation continues.
 
My wire wheel is low speed on a milwaukee cordless drill. 3m roloc pads are a definitely a no no when cleaning a mating surface. And yes, I use green coolant. I will try the tile and 600 grit sandpaper trick to see what I come up with.
 
737jetdr said:
Alright, My 360 La motor needed new valve seals. I happen to have all the components to switch over to magnum heads including a set of heads. I figure, Why not? I made a hybrid for my 67 Dart years ago and it runs well. I'll do the same for the old D100. So I tear the motor down. Scrape the block with razor blades twice, clean with acetone, wire wheel the block and clean again. Put it all together and I have a coolant trickle in the front lower corners where the heads and the block meets right above the motor mount bosses. Ugh!!
So I tear it apart again. Take the heads and have them resurfaced just to be sure. Repeat the cleaning process, put it back to together and bam!! Same exact leak! WTF!! I've built at least a half dozen small blocks over the years and have never had this issue, let alone twice in a row. What am I missing? I'm using tried and true Felpro 8553PT gaskets. Everything is clean. New head bolts. The 1st time I torqued to 105'lbs like my magnum book says. Second time torqued to 95'lbs like my LA book says. The old heads never leaked. I'm at a loss. Am I using the wrong head gaskets? to mate the magnum heads to the LA block? Any help will be appreciated.
Click to expand...
Are you lubricating the bolt threads prior to torqueing them?
Of late I have been using Mahle head gaskets and Ultra Gray on the china walls and skim coat around both sides of the intake gaskets just around the water jacket ports and have had zero issues.
 
Lightly coat the threads with wd40 then wiping the bolts with a paper towel. Just so the threads are shiny. I made that mistake years ago with 2 much oil.
 
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737jetdr said:
Lightly coat the threads with wd40 then wiping the bolts with a paper towel. Just so the threads are shiny. I made that mistake years ago with 2 much oil.
Click to expand...
WD40 is a poor lubricant at best, it works well for getting bubble gum out of hair and that's about it. The factory service manuals will tell you to use SAE 30wt engine oil. Many apply ARP thread lube to the threads and the under side of the bolt head or nut. Improper torque may be part of your issue but I would lean more toward a mismatch of intake gaskets.
Good luck, keep posting
 
737jetdr said:
Lightly coat the threads with wd40 then wiping the bolts with a paper towel. Just so the threads are shiny. I made that mistake years ago with 2 much oil.
Click to expand...
too much oil? the excess will run off, if way too much will scrape itself off as you drop the bolt in the hole.
 
Unfortunately it doesnt run off. Excess oil rolls up the threads as you turn the bolts in, comes out the top and contaminates the clean head surface and ruins head gaskets. I like how there are pictures on line and in books showing people dipping their bolts in a cup of motor oil. Just enough to coat the threads is all I do.
 
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