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Compression

TexasNomad

FTFS Designated DRINKER!
Well I finally got around to doing a comp test on my 460 and it wasn't good :(

140/30 PSI on 1 through 4 and going do to 90/100 psi from 5 through 8
Would have never known it from that way the runs and the power it makes..
Looks ike I wont be doing that 460 swap after all :rotz:
 
1,320
82
Rebuild the thing. Won't cost you much if you can find a decently priced machinist. While your add it you could throw some go fast goodies in it. If you know where to spend your money and base it off a proven combo you could make almost 400hp and 500 ft/lb. torque for around $3000.


Or you know.... You could just send the motor over to me. :)

smilieIagree << Even he agrees with me.
 
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TexasNomad

FTFS Designated DRINKER!
I aint got 3 grand!
SO i'm just gonna sale the truck for what ever the hell I can get for it.. :(
OH well... Life's a ***** and then you eat Communist cheese...
 

bowtiehatr

Certified Ford Tech
since it is not skipping, you probably have head issues. the old heads are bad about valve seats coming apart and the valve sinking into the head which can cause low compression even a skip if bad enough. pull a valve cover, remove the rocker arms and put a straight edge on the valve stem tips. if they go up and down, then you found your problem.
 
140/30 PSI on 1 through 4 and going do to 90/100 psi from 5 through 8
i know nothing about compression tests other than you want a good amount of it.

so 1-4 you got between 90 and 100 on them.

what does 140/30 mean? do you mean 130 to 140? or does 140/30 mean something special?

not being a jerk, just curious.
 

Fellro

Moderator
Staff member
since it is not skipping, you probably have head issues. the old heads are bad about valve seats coming apart and the valve sinking into the head which can cause low compression even a skip if bad enough. pull a valve cover, remove the rocker arms and put a straight edge on the valve stem tips. if they go up and down, then you found your problem.

thing is, not all of the seats will fail in a head at once, so that would show up as only one cylinder low, I have seen head gaskets do things like that though with no loss of coolant or such.
 

TexasNomad

FTFS Designated DRINKER!
i know nothing about compression tests other than you want a good amount of it.

so 1-4 you got between 90 and 100 on them.

what does 140/30 mean? do you mean 130 to 140? or does 140/30 mean something special?

not being a jerk, just curious.

I mean from Cylinder 1 through 4 the compression is 130 to 140 on all 4 cylinders not going any higher then 140 and not going lower then 130 :)
 

bowtiehatr

Certified Ford Tech
thing is, not all of the seats will fail in a head at once, so that would show up as only one cylinder low, I have seen head gaskets do things like that though with no loss of coolant or such.


thats true that they wont fail all at once, but they will all slowly fail overtime. i just replace my windsor heads due to the seats, and 11 out of 16 were toast and the truck ran great, didnt skip, and power was ok.
 

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