Max Rpm
#11
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Re: Max Rpm
Originally Posted by SB
Even if they came with a spec, you need to find out. This goes with any cyl head from any manufacturer.
Without knowing this means you do not have any idea where the valvetrain will bounce and bust you up.
Therefore, no one can answer your 'where's my rpm limit' question. Not being a dick, but we just can't.
Without knowing this means you do not have any idea where the valvetrain will bounce and bust you up.
Therefore, no one can answer your 'where's my rpm limit' question. Not being a dick, but we just can't.
#12
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Re: Max Rpm
Originally Posted by SB
Even if they came with a spec, you need to find out. This goes with any cyl head from any manufacturer.
Without knowing this means you do not have any idea where the valvetrain will bounce and bust you up.
Therefore, no one can answer your 'where's my rpm limit' question. Not being a dick, but we just can't.
Without knowing this means you do not have any idea where the valvetrain will bounce and bust you up.
Therefore, no one can answer your 'where's my rpm limit' question. Not being a dick, but we just can't.
#13
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Re: Max Rpm
That's cool - same people hate when they get a 'I don't know' even if we don't know. LOL !!!
I looked up your valvespring:
p/n 12462970
Dual spring
140 lb/bs installed at 1.94 height
Rate 325 lbs (per inch)
solid height 1.20 "
============
Since these heads have been used for some time, and since they are apart I would just have the springs + heights checked. If one or more is 'soft' or not installed to waht your application demands, then now is definately the time.
I get paranoid over valvesprings so I even have new heads checked.
My rule of thumb is if the heads or head is off for any reason, let's check them out ! They get quite a beating in a marine environment.
I looked up your valvespring:
p/n 12462970
Dual spring
140 lb/bs installed at 1.94 height
Rate 325 lbs (per inch)
solid height 1.20 "
============
Since these heads have been used for some time, and since they are apart I would just have the springs + heights checked. If one or more is 'soft' or not installed to waht your application demands, then now is definately the time.
I get paranoid over valvesprings so I even have new heads checked.
My rule of thumb is if the heads or head is off for any reason, let's check them out ! They get quite a beating in a marine environment.
#14
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Re: Max Rpm
Originally Posted by SB
That's cool - same people hate when they get a 'I don't know' even if we don't know. LOL !!!
I looked up your valvespring:
p/n 12462970
Dual spring
140 lb/bs installed at 1.94 height
Rate 325 lbs (per inch)
solid height 1.20 "
============
Since these heads have been used for some time, and since they are apart I would just have the springs + heights checked. If one or more is 'soft' or not installed to waht your application demands, then now is definately the time.
I get paranoid over valvesprings so I even have new heads checked.
My rule of thumb is if the heads or head is off for any reason, let's check them out ! They get quite a beating in a marine environment.
I looked up your valvespring:
p/n 12462970
Dual spring
140 lb/bs installed at 1.94 height
Rate 325 lbs (per inch)
solid height 1.20 "
============
Since these heads have been used for some time, and since they are apart I would just have the springs + heights checked. If one or more is 'soft' or not installed to waht your application demands, then now is definately the time.
I get paranoid over valvesprings so I even have new heads checked.
My rule of thumb is if the heads or head is off for any reason, let's check them out ! They get quite a beating in a marine environment.
SB WHERE DID YOU LOOK UP THE SPECS FOR THOSE HEADS. I HAD CALLED GM LAST WEEK AND THE COULD NOT TELL ME WHAT THEY WERE. THEY TOLD ME MY CASTING NUMBER DID NOT MATCH ANYTHING IN THE COMPUTER. (I LOST MY SPEC SHEET)
#15
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Re: Max Rpm
GM Performance parts catalog. Yes, they have misprints too, so we always have to check.
Duke - why doesn't valvetrain matter for rpm limit ? I did answer on the shortblock too.
Duke - why doesn't valvetrain matter for rpm limit ? I did answer on the shortblock too.
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Re: Max Rpm
Originally Posted by SB
Duke - why doesn't valvetrain matter for rpm limit ? I did answer on the shortblock too.
#17
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Re: Max Rpm
I understand now. Thanks.
Didn't want to see someone rpm into valvetrain issues. Very common for this to not be looked at / considered.
Didn't want to see someone rpm into valvetrain issues. Very common for this to not be looked at / considered.
#19
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Re: Max Rpm
Check the springs - I found out the hard way. I had a Magnum motor set up almost identical to yours until I floated a valve at 5500 RPM. The valve took out the head, piston, 2 rods and split the block(junk). Ouch! - can you say new motor. It's worth the piece of mind.