What kind of cyc. compression result are people getting with 84mm 9:1
07-22-2008, 11:39 AM
#1
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What kind of cyc. compression result are people getting with 84mm 9:1
did a compression test and number seem to be low . range around 155psi on all 4 cyc.
07-22-2008, 11:42 AM
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I have that type of compression on a 8.4:1cr motor.
i would say you probably should be around 180psi go do a leakdown test and see what condition the motors in
i would say you probably should be around 180psi go do a leakdown test and see what condition the motors in
07-22-2008, 12:05 PM
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depends on alot of factors which include, what head, what gasket, how much material has been machined off, and what cams you have. etc etc
I'd do a leakdown if your worried.
Modified by sewell94 at 1:14 PM 7/22/2008
I'd do a leakdown if your worried.
Modified by sewell94 at 1:14 PM 7/22/2008
07-22-2008, 04:25 PM
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Re: (hotrod99)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hotrod99 »</TD></TR><TR><TD CLASS="quote">I got 180 across with 84mm 9 to 1 pistons and .056 headgasket which calculated to 8 to 1 compression</TD></TR></TABLE>
your a tad bit high for a 8:1 compression motor.
your a tad bit high for a 8:1 compression motor.
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07-22-2008, 06:47 PM
#10
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Re: What kind of cyc. compression result are people getting with 84mm 9:1 (hbyrd8701)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hbyrd8701 »</TD></TR><TR><TD CLASS="quote">sorry to thread jack, I have 81.5 9 to 1 and my compression is about 220 across</TD></TR></TABLE>
i have the same thing only pumping 155 !
maybe your guage is off (to the OP)
have you tried a differant tester ?
i have the same thing only pumping 155 !
maybe your guage is off (to the OP)
have you tried a differant tester ?
07-22-2008, 06:54 PM
#11
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Re: What kind of cyc. compression result are people getting with 84mm 9:1 (DaveF)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaveF »</TD></TR><TR><TD CLASS="quote">
i have the same thing only pumping 155 !
maybe your guage is off (to the OP)
have you tried a differant tester ?</TD></TR></TABLE>
im not sure if the guage is off but i will try another one and see. maybe do a leakdown test while im at it.
i have the same thing only pumping 155 !
maybe your guage is off (to the OP)
have you tried a differant tester ?</TD></TR></TABLE>
im not sure if the guage is off but i will try another one and see. maybe do a leakdown test while im at it.
07-22-2008, 08:15 PM
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Re: What kind of cyc. compression result are people getting with 84mm 9:1 (eg:R)
Honestly, if all cylinders are equal, and leakdown is minimal, you're probably just fine.
07-23-2008, 06:06 AM
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Re: (2redstars)
also do you have it wide open when cranking?
i run 9:1. b16 head itr cams, gsr block 84mm with ls crank. i see between 190 and 195 compression, 6 cranks hot motor when its wide open
i run 9:1. b16 head itr cams, gsr block 84mm with ls crank. i see between 190 and 195 compression, 6 cranks hot motor when its wide open
07-23-2008, 03:46 PM
#17
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Re: (Kevin)
ok i did another compression check and leak down on my motor. 7 cranks with fuel shut off and wide open throttle for compression check. NO oil was added to cyl. TDC for every cyl. test on leak down. motor was warm up before all testing.
compression test cyl. / leak down
#4- 157psi leak down- 50%
#3- 145psi leak down- 65%
#2- 160psi leak down- 40%
#1- 157pis leak down- 40%
compression test cyl. / leak down
#4- 157psi leak down- 50%
#3- 145psi leak down- 65%
#2- 160psi leak down- 40%
#1- 157pis leak down- 40%
07-24-2008, 05:45 AM
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Re: (vesperfx)
where was the air leaking down from? was it coming through the valves or the crank breathers? if it was the valves...are you dead sure your timing is on?
07-24-2008, 12:50 PM
#21
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Re: (blackeg)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackeg »</TD></TR><TR><TD CLASS="quote">where was the air leaking down from? was it coming through the valves or the crank breathers? if it was the valves...are you dead sure your timing is on?</TD></TR></TABLE>
i didnt check where the air was leaking from. the timing was on tdc on every cyl. before leakdown. are the leak down test results normal? when the engine is on idle i can see some white smoke coming out from crank breather of valve cover.
i didnt check where the air was leaking from. the timing was on tdc on every cyl. before leakdown. are the leak down test results normal? when the engine is on idle i can see some white smoke coming out from crank breather of valve cover.
07-26-2008, 10:05 PM
#23
Re: What kind of cyc. compression result are people getting with 84mm 9:1 (eg:R)
Im 84mm at 9:1 and I have 195+ psi on a COLD motor across all cylinders. Im very happy with the ring gaps I did on this motor. I was 180+psi on the last build, same bore and CR.
07-27-2008, 11:17 AM
#25
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Re: What kind of cyc. compression result are people getting with 84mm 9:1 (A.E Motoring)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by A.E Motoring »</TD></TR><TR><TD CLASS="quote">u do it when the motor was warm?</TD></TR></TABLE>
yes the engine was warm and ring gaps were gap to spec from the box.
yes the engine was warm and ring gaps were gap to spec from the box.