Compression tester question for VE and maybe VGs
08-20-2002, 04:22 PM
#1
Compression tester question for VE and maybe VGs
I bought an used tester that is your standard guage w/ the rubber hose and threaded connection(to the plug hole) But as you know on the ve, it has a deep socket to access the plug. There is no way I can tighten the threaded end to get a good seal. Do you guys know of a place to buy solid tube "extension" that I can thread into the plug hole and then attach the tester into that?
And are all spark plug thread sizes common? ie.. I don't have to buy some type of adaptor to fit into the Nissan VE sparkplug hole?
The usual Home Depot and run of the mill auto stores came up nada. I'll try to call a few tool places today. If I find something, I'll post up for others.
And are all spark plug thread sizes common? ie.. I don't have to buy some type of adaptor to fit into the Nissan VE sparkplug hole?
The usual Home Depot and run of the mill auto stores came up nada. I'll try to call a few tool places today. If I find something, I'll post up for others.
08-20-2002, 06:55 PM
#2
Senior Member
Join Date: Feb 2002
Posts: 365
Re: Compression tester question for VE and maybe VGs
Originally posted by Jeff92se
I bought an used tester that is your standard guage w/ the rubber hose and threaded connection(to the plug hole) But as you know on the ve, it has a deep socket to access the plug. There is no way I can tighten the threaded end to get a good seal. Do you guys know of a place to buy solid tube "extension" that I can thread into the plug hole and then attach the tester into that?
And are all spark plug thread sizes common? ie.. I don't have to buy some type of adaptor to fit into the Nissan VE sparkplug hole?
The usual Home Depot and run of the mill auto stores came up nada. I'll try to call a few tool places today. If I find something, I'll post up for others.
I bought an used tester that is your standard guage w/ the rubber hose and threaded connection(to the plug hole) But as you know on the ve, it has a deep socket to access the plug. There is no way I can tighten the threaded end to get a good seal. Do you guys know of a place to buy solid tube "extension" that I can thread into the plug hole and then attach the tester into that?
And are all spark plug thread sizes common? ie.. I don't have to buy some type of adaptor to fit into the Nissan VE sparkplug hole?
The usual Home Depot and run of the mill auto stores came up nada. I'll try to call a few tool places today. If I find something, I'll post up for others.
they have EVERYTHING. good luck. let me know how it turns out.
08-20-2002, 10:35 PM
#3
check the threading on a plug (just buy an $0.89 ceapo Delco plug or something) and see what the thread on it is.. it's probably a 1/4" straight thread... same as a 1/4" npt, but straight cut instead of tapered.
which probably means you can have a 6,8,10,xxx" piece of 1/4 metal pipe threaded and it'll screw right into the hole.
Then again, I just got the rubber hose as tight as I could by hand with mine. that will be good enough to get a test on, as the cylinder raises pressure fast enough that a small leak around the threads won't mess up readings too much.
(Also be sure to do the measurements with the throttle wide open. it makes more difference in the readings than anything else.)
which probably means you can have a 6,8,10,xxx" piece of 1/4 metal pipe threaded and it'll screw right into the hole.
Then again, I just got the rubber hose as tight as I could by hand with mine. that will be good enough to get a test on, as the cylinder raises pressure fast enough that a small leak around the threads won't mess up readings too much.
(Also be sure to do the measurements with the throttle wide open. it makes more difference in the readings than anything else.)
09-22-2002, 09:11 PM
#4
Just did the test w/ the tester I bought used. Fronts were 190ish psi all across and the rears were about 190-200ish all across. I didn't crack the throttle at all. Engine was cold. So looks like the compression is okay.
09-23-2002, 08:14 AM
#5
Hmmm... That's interesting, Jeff. I did a compression test on my cylinders just before tearing my car apart to put in a new fuel rail [all I can say about THAT little job is... 
] and I had 175-180 psi on all six of mine (it's a VE, btw).
] and I had 175-180 psi on all six of mine (it's a VE, btw).
09-23-2002, 10:24 AM
#6
Member
Join Date: Aug 2002
Posts: 81
Originally posted by Jeff92se
Just did the test w/ the tester I bought used. Fronts were 190ish psi all across and the rears were about 190-200ish all across. I didn't crack the throttle at all. Engine was cold. So looks like the compression is okay.
Just did the test w/ the tester I bought used. Fronts were 190ish psi all across and the rears were about 190-200ish all across. I didn't crack the throttle at all. Engine was cold. So looks like the compression is okay.
Not necessarily...
http://www.weekendmechanicsclub.com/...e-Mityvac2.htm
"1. Make sure the engine has been warmed up before beginning the test, to insure that the oil has been warmed up. A cold engine will not test correctly.
...stuff deleted...
4. Hold the throttle to full open position to ensure the engine gets adequate air intake.
...stuff deleted...
When the compression is found to be too high in one or more cylinders, this would be an indication of excessive carbon build up in the engine. This can only be corrected by performing a chemical de-carbonizing process on the engine (specialized service), or by removing the cylinder head(s) and physically removing the carbon that is attached to the cylinder portion of the head(s) and the tops of the pistons..."
--SAM
09-23-2002, 10:28 AM
#7
Hmm. I did the same test on my buddy's 4-gen warm and it came up with similar results but it's pretty easy to do the test again when warm. Thanks for the info. I was considering doing the water mist in the intake thing to clean out the carbon.
09-23-2002, 12:05 PM
#8
Senior Member
Join Date: Mar 2002
Location: Ontario, Canada
Posts: 1,114
Jeff92se:
Keep in mind that your readings will be lower after extending the gauge pipe 'cause it encreased the volume of the cylinder. Not a great deal lower but still different from what you would have received from the stock gauge.
Keep in mind that your readings will be lower after extending the gauge pipe 'cause it encreased the volume of the cylinder. Not a great deal lower but still different from what you would have received from the stock gauge.
09-23-2002, 12:14 PM
#9
Na. I didn't use an extender. Just screwed in the stock hose as best I could. Hand tight was plenty good. Plus even with the extra volume, you can just keep cranking the engine until the compression tops off.
Originally posted by Tarzan
Jeff92se:
Keep in mind that your readings will be lower after extending the gauge pipe 'cause it encreased the volume of the cylinder. Not a great deal lower but still different from what you would have received from the stock gauge.
Jeff92se:
Keep in mind that your readings will be lower after extending the gauge pipe 'cause it encreased the volume of the cylinder. Not a great deal lower but still different from what you would have received from the stock gauge.
09-23-2002, 12:43 PM
#10
Member
Join Date: Aug 2002
Posts: 81
One other important variable I'll mention is the actual calibration of the pressure gauge.
I not unusual to find low-end gauges that are off by 20 pounds or more. What you can do with an un-calibrated gauge is compare cylinder pressure differences but unless you know what the correction factor is, it can be difficult to conclude whether your engine is over- or under-pressure from factory spec.
There are several ways to check your gauge, I prefer cross checking it with a friend's high-end gauge. Another would be to find a friend with a brand new BMW or Porsche and offer to measure their compression and then compare your readings with the factory specs. However, don't forget to warm up their car before making the measurements. :-)
--SAM
I not unusual to find low-end gauges that are off by 20 pounds or more. What you can do with an un-calibrated gauge is compare cylinder pressure differences but unless you know what the correction factor is, it can be difficult to conclude whether your engine is over- or under-pressure from factory spec.
There are several ways to check your gauge, I prefer cross checking it with a friend's high-end gauge. Another would be to find a friend with a brand new BMW or Porsche and offer to measure their compression and then compare your readings with the factory specs. However, don't forget to warm up their car before making the measurements. :-)
--SAM
09-23-2002, 12:46 PM
#11
I bought a new one from a parts store (cheapie one for like $40) But I tested some of the cylinders with both guages and they both read almost identical. So I think the guage is okay. Plus even if the guage was off, as long as it was consistently off, I could still be able to determine if one or more of the cylinders was doing something funny.
09-25-2002, 08:46 AM
#13
Well the reason for this test was try to determine where my coolant is disappearing to. So naturally I was thinking HG. There's not that many ways a little bit of coolant can get into the oil. If you have any ideas, I'm all ears. I'm sorta stumped
Originally posted by Tarzan
...which is unlikely to happen to Maxima. My mechanic's car is 92GXE and he put 550K on it. It drives and feels same as my own 93GXE with 90K.
...which is unlikely to happen to Maxima. My mechanic's car is 92GXE and he put 550K on it. It drives and feels same as my own 93GXE with 90K.
09-25-2002, 11:51 AM
#14
Originally posted by Jeff92se
Well the reason for this test was try to determine where my coolant is disappearing to. So naturally I was thinking HG. There's not that many ways a little bit of coolant can get into the oil. If you have any ideas, I'm all ears. I'm sorta stumped
Well the reason for this test was try to determine where my coolant is disappearing to. So naturally I was thinking HG. There's not that many ways a little bit of coolant can get into the oil. If you have any ideas, I'm all ears. I'm sorta stumped
09-25-2002, 11:53 AM
#15
I've had the lower one off but I used two new gaskets($$!). I tried to make VERY sure to put those on correctly. You never know though. I don't think coolant runs though it anyway. I know for 100% no oil runs though it.
Originally posted by eric93SE
Have you ever had the lower intake manifold gasket off? and maybe reused the original gasket?
Have you ever had the lower intake manifold gasket off? and maybe reused the original gasket?
09-25-2002, 11:57 AM
#16
Originally posted by Jeff92se
I've had the lower one off but I used two new gaskets($$!). I tried to make VERY sure to put those on correctly. You never know though. I don't think coolant runs though it anyway. I know for 100% no oil runs though it.
I've had the lower one off but I used two new gaskets($$!). I tried to make VERY sure to put those on correctly. You never know though. I don't think coolant runs though it anyway. I know for 100% no oil runs though it.
------------
Have you seen the setup that the FSM uses for doing a compression test? They have a long extension pipe that has a tapered rubber end that fits into the spark plug socket. It looks like its something that can be made on ones own, and then connected to a compression guage.
09-25-2002, 12:00 PM
#17
The one I used screwed in and it was fine. Probably better than the hold down type so you only need one person to do the tests.
How did the oil pump tests go??
How did the oil pump tests go??
Originally posted by eric93SE
Thats right I forgot.
------------
Have you seen the setup that the FSM uses for doing a compression test? They have a long extension pipe that has a tapered rubber end that fits into the spark plug socket. It looks like its something that can be made on ones own, and then connected to a compression guage.
Thats right I forgot.
------------
Have you seen the setup that the FSM uses for doing a compression test? They have a long extension pipe that has a tapered rubber end that fits into the spark plug socket. It looks like its something that can be made on ones own, and then connected to a compression guage.
09-25-2002, 12:05 PM
#18
Originally posted by Jeff92se
The one I used screwed in and it was fine. Probably better than the hold down type so you only need one person to do the tests.
How did the oil pump tests go??
The one I used screwed in and it was fine. Probably better than the hold down type so you only need one person to do the tests.
How did the oil pump tests go??
09-25-2002, 02:00 PM
#19
Senior Member
Join Date: Jan 2002
Posts: 554
hey, i'm losing coolant too and its not drippin from tha radiator...all i know is when i check at the end of the month, the lil ater container on the left side of tha radiator will be completely dry....but i don't have leak anywhere...
hopefully tha oil pressure test will prove your ideal correctly as to what happens to tha VTCs....can't wait for tha reuslts!!
hopefully tha oil pressure test will prove your ideal correctly as to what happens to tha VTCs....can't wait for tha reuslts!!
Thread
Thread Starter
Forum
Replies
Last Post
Unclejunebug
5th Generation Maxima (2000-2003)
10
04-02-2016 05:42 AM