273 commando Build

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that engine had all the oem parts in it , cam pistons lifters steele shim gaskets and appeared to have never been opened up until I rebuilt it. mopar did a lot of stupid things on the assembly line as we all know .
this 273 commando engine block I'm going to use to build this time around is the same.... all the oem internals were still intact when I disassembled it.
as longs as were are talking about the tops of cyl block machining ..I would suspect that those milling grooves could be a issue too because I can catch my finger nails in the grooves.. that is not a perfectly flat surface ..I can see that as a sealing problem. right ?
 
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Man....I'm trying to be silent on gaskets.....I know nothing I know nothing I know nothing.....
 
I'd have to look back but I think these are the ones I used but my deck was in a lot better shape than Stroker's.

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update update
well I removed the 273 from the 65 barracuda engine bay today and put it on the engine stand.. I did a check on the head bolts over #8 cyl that popped.. did a retorque and the 4 bolts over that #8 cyl loosened up ..... one bolt as much as 1/8 turn. all four bolts loosened up...

so went to check the remaining and some of them had loosened up also. this is with arp bolts 100 # and retorqued . disgusting !!!
 
stroker402 said:
update update
well I removed the 273 from the 65 barracuda engine bay today and put it on the engine stand.. I did a check on the head bolts over #8 cyl that popped.. did a retorque and the 4 bolts over that #8 cyl loosened up ..... one bolt as much as 1/8 turn. all four bolts loosened up...

so went to check the remaining and some of them had loosened up also. this is with arp bolts 100 # and retorqued . disgusting !!!
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Too long? Bolt holes not clean?
 
up date on the old engine that keeps blowing head gaskets #2 and #8 are what blew again . into the valley . first pic is #8 cyl

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Damn! I didn't re-read the thread, but I'm guessing either the head or block is not level.
Sorry to read, hopefully no other damage than blown gaskets?
 
up date up date

different 273 commando block will be used this time . 70K miles on that commando engine ... nothing abnormal on that engine. all the main and rod bearings looked good .
the block is all cleaned and prepped did not deck it.... but did check for flatness ..... looks good to go. standard block bore dimensions . 3.625
cyls honed and ball honed ...
standard crank is in with all new bearings and plasti gaged to specs.
new rings are installed on standard domed pistons .
new rod bearings and plasti gaged
next .... install pistons ...
winter weather is approaching here now. soooo
going to work over the heads this winter . just a clean up in the ports
 
4spdragtop said:
Damn! I didn't re-read the thread, but I'm guessing either the head or block is not level.
Sorry to read, hopefully no other damage than blown gaskets?
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yeah had that passenger head off three time already... block as a warp in it. both head were trued up last spring when it blew again . going with a different block now.... that is what I'm building now.
 
stroker402 said:
new arp bolts used and torqued to arp spec 100 ft lbs.
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The important thing is an approximate 3/4 thread engagement. @perfacar said at more that 85 ft lb of torque they were seeing block distortion. What bothers me is you were loosing torque. Maybe the ARP bolts are too long? I do know, when I ran 72 "J" 340 heads on my 273 years ago I torqued the head bolts to 95 ft lb and had no problems with Fel-Pro 340 gaskets, but I used original 340 head bolts. I think I'd run stock 273 head bolts at 85 ft lb anymore, maybe with hardened washers.
 
66fs said:
The important thing is an approximate 3/4 thread engagement. @perfacar said at more that 85 ft lb of torque they were seeing block distortion. What bothers me is you were loosing torque. Maybe the ARP bolts are too long? I do know, when I ran 72 "J" 340 heads on my 273 years ago I torqued the head bolts to 95 ft lb and had no problems with Fel-Pro 340 gaskets, but I used original 340 head bolts. I think I'd run stock 273 head bolts at 85 ft lb anymore, maybe with hardened washers.
Click to expand...

66fs said:
The important thing is an approximate 3/4 thread engagement. @perfacar said at more that 85 ft lb of torque they were seeing block distortion. What bothers me is you were loosing torque. Maybe the ARP bolts are too long? I do know, when I ran 72 "J" 340 heads on my 273 years ago I torqued the head bolts to 95 ft lb and had no problems with Fel-Pro 340 gaskets, but I used original 340 head bolts. I think I'd run stock 273 head bolts at 85 ft lb anymore, maybe with hardened washers.
Click to expand...
just measured the sb arp bolts and the stock head bolts .. approx 3/8" difference. arp bolt # 144 - 3602. so it appears stock bolts have more thread length and gripping forces.
Also , what did you mean by this Quote " I think I'd run stock 273 head bolts at 85 ft lb anymore, maybe with hardened washers. " ?

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stroker402 said:
just measured the sb arp bolts and the stock head bolts .. approx 3/8" difference. arp bolt # 144 - 3602. so it appears stock bolts have more thread length and gripping forces.
Also , what did you mean by this Quote " I think I'd run stock 273 head bolts at 85 ft lb anymore, maybe with hardened washers. " ?

View attachment 1716330250
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and yes these new Arp bolts were loosening up some bollts as much as a 1/4 turn on the torque wrench before I disassembled the 273. still have NOT found the smoking gun yet.
 
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