Oil pressure getting past the long head bolt on drivers side oil galley

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HotRod20

HotRod20

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So we are priming the new 340 build with a hand drill , and turning the engine over by the starter with no spark plugs at the same time. Oil pressure gets to about 60 psi, when all of the sudden oil is leaking out from under the hex head of the longer head bolt that goes through the oil valley.
All head bolts are torqued to 90 ft lbs. What gives?? Is there a fix? head washer? crush washer? sealant? what do you think??
 
Bolt too long, bottoming out? I have had this happen with ARP bolts.
 
Head bolt holes were not cleaned, tapped and blown out with air. Or bolts to long . We always clean and run thread chasers in all threaded holes. Many times there is crud packed in the bottom of holes.

Take a long skinny screwdriver and twist it down in the hole while blowing it out and then thread chase it. Measure the depth of the hole and then the length of the bolt.
 
If they’re factory heads, that have been on and off a few times....... the top of the bolt bosses often get marred up pretty good.
I’d pull the leaking bolt out and have a good look at the area the bolt seals against.
If it’s ugly, I’d use a head bolt washer with some sealer between the head and the washer.
 
Must be that pesky head bolt that the oil goes through for the rocker oil.
 
I'll report back either tomorrow or Tuesday. Going to pull the bolt out,check the bolt hole seating surface,check the hole with a screwdriver for crud, measure the hole depth and bolt length.
I'll let everyone know what the plan is.
Thanks for your input.
HR20
 
HotRod20 said:
I'll report back either tomorrow or Tuesday. Going to pull the bolt out,check the bolt hole seating surface,check the hole with a screwdriver for crud, measure the hole depth and bolt length.
I'll let everyone know what the plan is.
Thanks for your input.
HR20
Click to expand...
When we rebuilt my 340 I cleaned all the holes with a bottom tap blew them out with brake cleaner and air, cover your eyes, and wire brushed all the bolt threads. Prior to torqueing the bolts I applied a thin film of ARP thread lube and a Mr Gasket hardend head bolt washer under all of the factory bolts.
You would not believe all the crap that came out of the bolt holes.
 
Yes I would. ! LOL!
Think you found the problem.
 
I'm not understandin' this. What head bolts are open to the oil galley? Or is the bottom cracked open?
 
67Dart273 said:
I'm not understandin' this. What head bolts are open to the oil galley? Or is the bottom cracked open?
Click to expand...
The oil passage from the block into the head intersects a head bolt hole.
 
??Then maybe it's leakin because the rocker passages are restricted / blocked?
 
Thanks to everyone for your input!! But........... the root cause of this is issue,was that the bolt hole register has been compressed, so that oil was leaking by the bolt head mating surface.
I have never seen this before , but sure enough. With the bolt out of the mounting hole, we ran a 90 degree pick up and down the hole and it caught at the top of the hole.
It went from a smooth hole to a lip at the top of the hole. It was determined that because this set of J heads are 50 yrs old, who knows how many times they were torqued down,or over torqued. Oh and Rusty RatRod, you are correct!! (Headbolt does intersect an oil passage)
The fix was a simple head bolt washer under the head bolt. We re-primed the engine and cranked it over at the same time with no plugs.. 80 psi oil pressure and No Leak!! :) Torqued to 95 ft lbs. we watched both sides of the rocker gear while turning engine over and oil is flowing nicely,...as it should be over the rocker gear, not under the headbolt to cylinder head mating surface. Thanks everyone.
(oh and Mopar Official..that was the next step...the spot face cutter!!)
HotRod20
 
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