how much compression should a std B16A have?

2slow · 22nd April 2007, 05:09 PM

did a compression test on the CRX (B16A1) the other day, it came up at about 180-190psi in each cylinder.
The mechanic said that was pretty good, but I felt the engins was not in as good a shape as it once was (it gets a hell of a hard life).
Is this good, bad or pretty average?
I was planing a re-build, but am wondering weather to just throw in some cams and cam gears, and leave the rest as is for the time being.

Logger · 22nd April 2007, 05:15 PM

Nominal reading for a gen one B16 is 185psi and minimum is 135psi although I regularly see B16's with at least 200psi compression. Mine has a shade over 225psi but thats with the B16B pistons.

Oh and I suggest you tear the motor down and tickle it up. I'd be happy to help.

2slow · 22nd April 2007, 05:36 PM

did you end up using machined B16A1 rods or did you go for B16A2 rods?

Logger · 22nd April 2007, 05:37 PM

I used B16A2 rods but they had to be machined anyway, which was odd as I thought they would fit without machining? It eas only 80 dollars anyway.

2slow · 22nd April 2007, 05:54 PM

Is that mahined at the piston end or the big end?
how much chunkier are they at the piston end than the B16A1 rods?

Logger · 22nd April 2007, 05:56 PM

At the piston end, I think it is only a matter of a few millimetres. Do you have new pistons and rods?

2slow · 22nd April 2007, 06:35 PM

I've had B16B pistons sitting in a box for about 5 months and all the parts for the quads for over a year!

Logger · 22nd April 2007, 06:39 PM

Good stuff. Now you just need to throw them in and beat me.

Horny_Devil · 22nd April 2007, 07:45 PM

compression readings are really only there to tell u if one cylinder is down in compression compared to the others. the reading all depends on the temp of the motor, intake temp, the gauge u use how many times u crank it etc etc. heaps of variables that can change the reading.

u should use it to see if there is a difference of more than 20psi between cylinders.

mr.sky · 23rd April 2007, 07:04 PM

the actual number value means SFA really. Too many variables. You only need to worry when there is a significant difference between two cylinders.

dragon · 2nd May 2007, 09:35 PM

Quote:

Originally Posted by mr.sky

the actual number value means SFA really. Too many variables. You only need to worry when there is a significant difference between two cylinders.

Would a 15 psi difference be significant enough to be worried about?

Cheers

chuckles2 · 2nd May 2007, 09:50 PM

Quote:

Originally Posted by dragon

Quote:

Originally Posted by mr.sky

the actual number value means SFA really. Too many variables. You only need to worry when there is a significant difference between two cylinders.

Would a 15 psi difference be significant enough to be worried about?

Cheers

if its 15psi between highest and lowest dont worry.

Ben, pull the head off it, and the sump, wack the pistons in with new rings, then wack head on with spoon head gasket and new valve stem seals new gaskets etc. that will make a huge difference

2slow · 4th May 2007, 06:54 PM

I just have a few too many options and not enough money!
My mechanic is trying to talk me into turboing it, am still contemplating a B20A, but would really like a high compression, 10000rpm, 1600 that can scare the crap outa V8's on the drag strip!!!

I guess I could just build up 1 of each after I win the 12 mill lotto on saturday!
Maybe I should just squeze an NSX motor and box in the back and have a n/a pro import?

Dionysus · 5th May 2007, 09:30 AM

Quote:

Originally Posted by 2slow

Maybe I should just squeze an NSX motor and box in the back and have a n/a pro import?

Ha I have dreams about doing that. Mid engined hatch back powering the rear wheels!

22nd April 2007, 05:09 PM	#1 (permalink)
2slow Senior Member 3,000rpm (Grandma Drag) Join Date: Jul 2005 Posts: 282 Location: Motueka	how much compression should a std B16A have? did a compression test on the CRX (B16A1) the other day, it came up at about 180-190psi in each cylinder. The mechanic said that was pretty good, but I felt the engins was not in as good a shape as it once was (it gets a hell of a hard life). Is this good, bad or pretty average? I was planing a re-build, but am wondering weather to just throw in some cams and cam gears, and leave the rest as is for the time being.

22nd April 2007, 05:15 PM	#2 (permalink)
Logger Senior Member 8,000rpm (B Series Redline!) Join Date: May 2004 Posts: 5,998 Location: Christchurch	Nominal reading for a gen one B16 is 185psi and minimum is 135psi although I regularly see B16's with at least 200psi compression. Mine has a shade over 225psi but thats with the B16B pistons. Oh and I suggest you tear the motor down and tickle it up. I'd be happy to help. __________________ J's Racing Work Wheels Xtrucking.com

22nd April 2007, 05:37 PM	#4 (permalink)
Logger Senior Member 8,000rpm (B Series Redline!) Join Date: May 2004 Posts: 5,998 Location: Christchurch	I used B16A2 rods but they had to be machined anyway, which was odd as I thought they would fit without machining? It eas only 80 dollars anyway. __________________ J's Racing Work Wheels Xtrucking.com

22nd April 2007, 05:56 PM	#6 (permalink)
Logger Senior Member 8,000rpm (B Series Redline!) Join Date: May 2004 Posts: 5,998 Location: Christchurch	At the piston end, I think it is only a matter of a few millimetres. Do you have new pistons and rods? __________________ J's Racing Work Wheels Xtrucking.com

22nd April 2007, 06:39 PM	#8 (permalink)
Logger Senior Member 8,000rpm (B Series Redline!) Join Date: May 2004 Posts: 5,998 Location: Christchurch	Good stuff. Now you just need to throw them in and beat me. __________________ J's Racing Work Wheels Xtrucking.com

22nd April 2007, 05:36 PM	#3 (permalink)
2slow Senior Member 3,000rpm (Grandma Drag) Join Date: Jul 2005 Posts: 282 Location: Motueka	did you end up using machined B16A1 rods or did you go for B16A2 rods?

22nd April 2007, 05:54 PM	#5 (permalink)
2slow Senior Member 3,000rpm (Grandma Drag) Join Date: Jul 2005 Posts: 282 Location: Motueka	Is that mahined at the piston end or the big end? how much chunkier are they at the piston end than the B16A1 rods?

22nd April 2007, 06:35 PM	#7 (permalink)
2slow Senior Member 3,000rpm (Grandma Drag) Join Date: Jul 2005 Posts: 282 Location: Motueka	I've had B16B pistons sitting in a box for about 5 months and all the parts for the quads for over a year!

22nd April 2007, 07:45 PM	#9 (permalink)
Horny_Devil Senior Member 18,000rpm+ Honda F1! Join Date: Jun 2002 Posts: 12,526 Location: Auckland	compression readings are really only there to tell u if one cylinder is down in compression compared to the others. the reading all depends on the temp of the motor, intake temp, the gauge u use how many times u crank it etc etc. heaps of variables that can change the reading. u should use it to see if there is a difference of more than 20psi between cylinders. __________________ D Series Guru My Profile - My Website - My Build Thread V2.0

23rd April 2007, 07:04 PM	#10 (permalink)
mr.sky Senior Member 6,000rpm (Max Torque) Join Date: Oct 2003 Posts: 1,984 Location: Porirua	the actual number value means SFA really. Too many variables. You only need to worry when there is a significant difference between two cylinders. __________________ less is more EJ1

4th May 2007, 06:54 PM	#13 (permalink)
2slow Senior Member 3,000rpm (Grandma Drag) Join Date: Jul 2005 Posts: 282 Location: Motueka	I just have a few too many options and not enough money! My mechanic is trying to talk me into turboing it, am still contemplating a B20A, but would really like a high compression, 10000rpm, 1600 that can scare the crap outa V8's on the drag strip!!! I guess I could just build up 1 of each after I win the 12 mill lotto on saturday! Maybe I should just squeze an NSX motor and box in the back and have a n/a pro import?

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