FYI: Interesting head bolt torquing experience.
#1
04-05-2011, 09:12 PM
FYI: Interesting head bolt torquing experience.
So nothing groundbreaking here (because you expected there would be, right? haha), but I just did my first ever head bolt REtorque, and thought I'd share some interesting results.
Different people will tell you different things about whether or not you need to retorque your head bolts after a day of running a rebuilt engine (new head gaskets). Views on the matter when I asked ranged from it being aabsolutely necessary, to completely without worth. I wasn't sure, so this time I tried it.
Last week, using stock head bolts, with the threads and heads oiled, and following the correct torque sequence, I torqued them all to 105 lbs. I did it in 3 step ups, and double checked them all at the end, for 4 total passes, ran the truck for a few days, about 80 miles, and the temo was around 40 degrees out when I torqued them.
Today, I popped off the valve covers, undid the rockers, and tried it again, and every single bolt popped between 90 and 105 lbs, and needed to be tightened a dozen or 2 degrees, and it was about 50 degrees out.
I didn't see any steam in the exhaust, or anything like that to indicate that the bolts were problematically loose, but the whole thing did seem to tighten up or compress with either time, or temp changes. The engine is a 400, .030 over, 9.2 compression, and stock heads, and the gaskets are Felpro.
Just figured I'd add my experience to everybody's search results when they go to do their project. The retorque does seem to matter....
AleX
Different people will tell you different things about whether or not you need to retorque your head bolts after a day of running a rebuilt engine (new head gaskets). Views on the matter when I asked ranged from it being aabsolutely necessary, to completely without worth. I wasn't sure, so this time I tried it.
Last week, using stock head bolts, with the threads and heads oiled, and following the correct torque sequence, I torqued them all to 105 lbs. I did it in 3 step ups, and double checked them all at the end, for 4 total passes, ran the truck for a few days, about 80 miles, and the temo was around 40 degrees out when I torqued them.
Today, I popped off the valve covers, undid the rockers, and tried it again, and every single bolt popped between 90 and 105 lbs, and needed to be tightened a dozen or 2 degrees, and it was about 50 degrees out.
I didn't see any steam in the exhaust, or anything like that to indicate that the bolts were problematically loose, but the whole thing did seem to tighten up or compress with either time, or temp changes. The engine is a 400, .030 over, 9.2 compression, and stock heads, and the gaskets are Felpro.
Just figured I'd add my experience to everybody's search results when they go to do their project. The retorque does seem to matter....
AleX
#2
04-05-2011, 09:36 PM
So nothing groundbreaking here (because you expected there would be, right? haha), but I just did my first ever head bolt REtorque, and thought I'd share some interesting results.
Different people will tell you different things about whether or not you need to retorque your head bolts after a day of running a rebuilt engine (new head gaskets). Views on the matter when I asked ranged from it being aabsolutely necessary, to completely without worth. I wasn't sure, so this time I tried it.
Last week, using stock head bolts, with the threads and heads oiled, and following the correct torque sequence, I torqued them all to 105 lbs. I did it in 3 step ups, and double checked them all at the end, for 4 total passes, ran the truck for a few days, about 80 miles, and the temo was around 40 degrees out when I torqued them.
Today, I popped off the valve covers, undid the rockers, and tried it again, and every single bolt popped between 90 and 105 lbs, and needed to be tightened a dozen or 2 degrees, and it was about 50 degrees out.
I didn't see any steam in the exhaust, or anything like that to indicate that the bolts were problematically loose, but the whole thing did seem to tighten up or compress with either time, or temp changes. The engine is a 400, .030 over, 9.2 compression, and stock heads, and the gaskets are Felpro.
Just figured I'd add my experience to everybody's search results when they go to do their project. The retorque does seem to matter....
AleX
Different people will tell you different things about whether or not you need to retorque your head bolts after a day of running a rebuilt engine (new head gaskets). Views on the matter when I asked ranged from it being aabsolutely necessary, to completely without worth. I wasn't sure, so this time I tried it.
Last week, using stock head bolts, with the threads and heads oiled, and following the correct torque sequence, I torqued them all to 105 lbs. I did it in 3 step ups, and double checked them all at the end, for 4 total passes, ran the truck for a few days, about 80 miles, and the temo was around 40 degrees out when I torqued them.
Today, I popped off the valve covers, undid the rockers, and tried it again, and every single bolt popped between 90 and 105 lbs, and needed to be tightened a dozen or 2 degrees, and it was about 50 degrees out.
I didn't see any steam in the exhaust, or anything like that to indicate that the bolts were problematically loose, but the whole thing did seem to tighten up or compress with either time, or temp changes. The engine is a 400, .030 over, 9.2 compression, and stock heads, and the gaskets are Felpro.
Just figured I'd add my experience to everybody's search results when they go to do their project. The retorque does seem to matter....
AleX
Was this the first time the head bolts were re-used and are the head gaskets Fel-pro Perma-torque?
#3
04-05-2011, 09:52 PM
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Curious myself about the bolts.Oil is not a good agent for a head bolt(or any mid to high torque bolt),but thread lube is.Caterpillar engines that I work on regularly run torques of 420 lb ft.Thread lube is the only thing that will give consistent torques in that range.Mains are even higher.
#4
04-05-2011, 10:12 PM
I heard that just regular old motor oil was exactly the way to go for head bolts, or anything on these engines?
Anyway though, yes, this was the first RE-use of the bolts, and I'm not sure if the gaskets were Perma Torque. I got them from the parts store in a complete engine kit. I doubt they were anything special.
Anyway though, yes, this was the first RE-use of the bolts, and I'm not sure if the gaskets were Perma Torque. I got them from the parts store in a complete engine kit. I doubt they were anything special.
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