Compression Test

[SCR34M3R]

Got a R34 GTT thought i would do a compression test this morning

i did 2 tests, first one is

1 = 180 4 = 154

2 = 170 5 = 182

3 = 180 6 = 179

did a second test to make sure as i got a supercheap compression tester

1 = 190 4 = 140

2 = 185 5 = 182

3 = 184 6 = 185

Number 4 is lower then all the others, it is to low or is this still ok?

Cheers

Justin

[Al]

Time to start saving for a rebuild, or at least a major freshen up

After a track day i had a feeling that i had done some damage to my engine, the compression test confirmed it.

1=150

2=153

3=87

4=150

5=148

6=150

[RB30-POWER]

around 14psi is the max suggested difference between cylinders

[typevu]

Ouch!

Edited July 8, 2007 by vietorious

[RB30-POWER]

electronic power balance tests aren't worth squat in my books, unless the cylinder is gone completely you see minimal variation in rpm anyway.

compression check, followed by a leak down test if needed for further diagnosis.

[blind_elk]

#4 is becoming a bit sad. Add a LITTLE BIT of engine oil into #4 cylinder and re-test. No change in compression suggests a valve problem, increase in compression suggests rings are going.

[cowie165]

#4 is becoming a bit sad. Add a LITTLE BIT of engine oil into #4 cylinder and re-test. No change in compression suggests a valve problem, increase in compression suggests rings are going.

If you're new to DIY maintenance, that single post above is the best info you'll read all week.

[wrxhoon]

You have a problem with number 4 cyl. A leakdown test will pinpoint your problem better than anything else . blind_elk 's suggestion is next best option, don't forget adding oil in any cyl will increase compression to some extent because the combustion chamber will be somewhat smaller...

[Fujiwara]

anyone know where i can get a compression test done?

and roughly how much it would cost me?

[cowie165]

Just about any mechanic has a compression gauge. A while back I paid $100 for a compression test and leak down test, so it'll be cheaper than that.

You can buy a compression gauge from eBay for around $60 and DIY too. You could do a spark plug change at the same time and save quite a few dollars.