Hey guys

I have a 99 B16A2, just did a compression test, all four cylinders are at 150! Took the same gauge in my buddies GSR, all four cylinders are a little over 200. I think B16 compression should be higher than GSR.

Now I have had a problem with my synthetic oil dissappearing, i'm thinking the valve stem seals, but no smoke comes out the exhaust and the car has always run perfect.


UPDATE - i tested it again with a new gauge. Throttle open, injectors unplugged. 150 across. I called up my buddy who has a turbo Si, he said his was about 145 ish. What do you think


-A


Modified by KURRRWA at 10:27 AM 11/11/2003

 

if you are in your vtec alot you will burn oil.

 

but what about the 150 compression, what do you have to say about that?

 

New is 185psi. 135 psi is the low limit for the B16. Difference between cyls should not be more than 28 psi. 150 psi is still diecent compression. When it drops below 135 then its time for a rebuild. Check for oil leaks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PhatOptimo &raquo;</TD></TR><TR><TD CLASS="quote">
Check for oil leaks!</TD></TR></TABLE>

What numbers have you seen when checking compression on 99-00 Si's?

My engine bay is clean, no oil leaks. I park my car in my driveway all day long. I lose about a quart between oil changes.

 

was the engine warm? I just did a CR test in a 99 b16a2 and it was 230 across.

 

You should find a factory honda manuel, It'll tell you the compression psi specs for your car, like phatoptimo said, as long as there all the same, you should be okay, your motor dosent feel low on power does it? oh, by the way, I have aquired the oil problem too, just within the past month, Im not seeing leaks either, but I dont have vtec, Someone help us!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by That Dood &raquo;</TD></TR><TR><TD CLASS="quote">was the engine warm </TD></TR></TABLE>

I did it right when the temp gauge got to normal

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KURRRWA &raquo;</TD></TR><TR><TD CLASS="quote">
I have a 99 B16A2, just did a compression test, all four cylinders are at 150! ...</TD></TR></TABLE>
that's too low. did you have the throttle open? recheck it, do it again. for 10.2:1 - that's too loow.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mathusala &raquo;</TD></TR><TR><TD CLASS="quote">
that's too low. did you have the throttle open? recheck it, do it again. for 10.2:1 - that's too loow.</TD></TR></TABLE>


I had the throttle closed - is it supposed to be open?

 

ya...crank it with the pedal to the metal.

 

Throttle needs to be open and the injectors disabled. The throttle to get the air to the cylinders to compress and the injectors off to keep from washing the oil off the cylinder walls.

And as a pet peeve that annoys me to no end. A compression test or leakdown test will tell you NOTHING about the valve seals. The valves are CLOSED when the test is done. If leaking seals were detectable with either test, the valves are not closing and you have a much bigger problem than simply seals.

There, I feel better now for having vented. Thank you for listening to my rant. Continue with your scheduled program.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mohudsolo &raquo;</TD></TR><TR><TD CLASS="quote">And as a pet peeve that annoys me to no end. A compression test or leakdown test will tell you NOTHING about the valve seals. The valves are CLOSED when the test is done. If leaking seals were detectable with either test, the valves are not closing and you have a much bigger problem than simply seals.
</TD></TR></TABLE>

Did you mistype that or something? The valves must open and close to do a compression test, otherwise no air will be entering or leaving the cylinders. In a leakdown, the valves should be fully closed.

 

But the valve seals do not hold in the pressure in the cylinder, the valves against the seats do. The valve seals never see pressure during the test, so you cannot identify a problem with them using a test that pressurizes the cylinder. Yes the valves open and close during a compression test, as when the engine is running. With bad valve seals, a running engine's vacuum pulls oil past the seals into the intake port and mixes is with the fuel and air. Enough oil and you will see smoke. Small amounts of oil will not show in the exhaust.

When doing a compression test, the pressure will rise on each compression stroke until it hit peak. The compression is being retained in the guage, not the cylinder. The guage has a built-in one-way valve to retain pressure. An interesting thing is that a rotary engine can be checked by taking the valve out of a standard guage and watching the needle bounce. Same bounce for each chamber and OK, one high and two low=bad rotor seal.

I'vve generally found the best way to verify bad valve seals is to remove a manifold, intake or exhaust, and look at the valve stems and tops of the valve heads. Reasonably clean, OK, covered in baked on oil and covering the valve, bad, time to do something. I've seen motors with the intake valves covered in baked oil to the diameter of the valve head, all the way up the stem to the end of the guide. Of course the factory seals on an older Chevy v8 are pretty simple and many did not have seals on the exhaust side.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mohudsolo &raquo;</TD></TR><TR><TD CLASS="quote">But the valve seals do not hold in the pressure in the cylinder, the valves against the seats do. The valve seals never see pressure during the test, so you cannot identify a problem with them using a test that pressurizes the cylinder. Yes the valves open and close during a compression test, as when the engine is running. With bad valve seals, a running engine's vacuum pulls oil past the seals into the intake port and mixes is with the fuel and air. Enough oil and you will see smoke. Small amounts of oil will not show in the exhaust.

When doing a compression test, the pressure will rise on each compression stroke until it hit peak. The compression is being retained in the guage, not the cylinder. The guage has a built-in one-way valve to retain pressure. An interesting thing is that a rotary engine can be checked by taking the valve out of a standard guage and watching the needle bounce. Same bounce for each chamber and OK, one high and two low=bad rotor seal.

I'vve generally found the best way to verify bad valve seals is to remove a manifold, intake or exhaust, and look at the valve stems and tops of the valve heads. Reasonably clean, OK, covered in baked on oil and covering the valve, bad, time to do something. I've seen motors with the intake valves covered in baked oil to the diameter of the valve head, all the way up the stem to the end of the guide. Of course the factory seals on an older Chevy v8 are pretty simple and many did not have seals on the exhaust side.</TD></TR></TABLE>

speaks the truth... an early hint that you may have bad seals is when you start your car in the morning and you've got a little white smoke in the exhaust that eventually clears up.

 

My car in college was a 76 Chebbie Malibu Classic wagon with about 110k on it. By the time it got retired it could hide the entire car in the cloud if it sat for more than 3 or 4 days. That's a 19' long green and woodgrain car to hide. Except for the cloud it ran great. We eventually pulled the heads and cleaned up everything and put in real seals then dropped it into a van, the car was too dissolved to keep.

I've seen a fair number of JDM B16 swaps using early motors with a noticable blue haze to the exhaust. Did those motors have valve seal issues or is it just that they have been around a while and probably spent a fair amount of time sitting in a junkyard waiting for engine swaps to become all the rage?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mohudsolo &raquo;</TD></TR><TR><TD CLASS="quote">... early motors with a noticable blue haze to the exhaust. Did those motors have valve seal issues or is it just that they have been around a while and/or probably spent a fair amount of time sitting in a junkyard waiting for engine swaps to become all the rage?</TD></TR></TABLE>

yes

 

I know a lot of seals tend to dry out and not work well when they sit unused. I had wondered if this was what was happening to the B16a's that I have seen smoking. Do the other seals also tend to leak a bit after sitting? I was thinking cam, crank, and waterpump seals.

 

Hello fellow mohud member Andy . My friend got a first gen B16a. We took the valve cover off and noticed deposits and other signs that the engine had been sitting for some time. The head got hot tanked and fresh valve seals. the bottom end got some ctr pistons. After running it we found the LMA's bad as well. The old motors need some attention. Back on subject, what kind of compression gauge do you have? I had a MAC one that turned out to be junk . 150 is to low.

 

so what should be the compression reading for a bone stock 99-00 Si? i know different motor will have different reading and what's important is the compression variation between cylinders should not be more than 28psi, but what's the average or the usual compression reading for the bone stock 99 Si? thanks.

 

230

 

OK i tested it again with a new gauge. Throttle open, injectors unplugged. 150 across. I called up my buddy who has a turbo Si, he said his was about 145 ish.


Is this low for Si's or normal? My buddies GSR read over 200, and B16 should have higher or equal compression to that (even though we don't have welded chambers)

 

When I had blown ring lands in 2 cylinders my readings were 180, 140, 180, 140. When my car was stock it read 200 across the board. I would say those numbers are low.

 

i think it's low man...it should be around 180-200 depending on the number of miles on the stock motor.....but the main thing is all 4 cylinders should be within +/- 10....