1R34SON Posted December 4, 2008 Share Posted December 4, 2008 Lookin to buy a car and had a compression test done by performance place and just wondering if anyone can give me some advice. ill update the exact results for each cylinder later but on average no higher than 170 and no lower than 150, i think was somethin like 170, 170, 150, 160, 155, 150 like i said ill update bit later, but thats basically what i remember? was told its ok, then told its not any help please???? Thankyou!! Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/ Share on other sites More sharing options...
Pattygtst Posted December 4, 2008 Share Posted December 4, 2008 You get different readings depending on the battery and a few other components. I believe 150 is standard but the higher the better they say. Of course they must be consistent with each other. If there not identical to each other move on to another car until you find one that is. You want it to be spot on Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4299867 Share on other sites More sharing options...
Pattygtst Posted December 4, 2008 Share Posted December 4, 2008 the other thing is you really need a leak down test also. When i had my 100km service the compression was 170 170 170 170 60 65, since the car is pulling max power for the mods i was like wtf Turns out i just had a heap of carbon build up in the intake. Test after was 170 170 170 170 170 170 Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4299872 Share on other sites More sharing options...
VB- Posted December 4, 2008 Share Posted December 4, 2008 numbers dont mean much, its how consistent they are. as a general rule, no more than 10% difference, which your outside of, but i wouldnt be too stressed about it. keep thrashing it Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4299993 Share on other sites More sharing options...
Pattygtst Posted December 4, 2008 Share Posted December 4, 2008 ^ this is on a car he is LOOKING TO BUY, he does not currently own it Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4300002 Share on other sites More sharing options...
mystery_kid Posted December 4, 2008 Share Posted December 4, 2008 go easy, he is a VL driver Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4300030 Share on other sites More sharing options...
1R34SON Posted December 4, 2008 Author Share Posted December 4, 2008 (edited) Ok results were As follows: CYLINDER 1- 170PSI CYLINDER 2- 170PSI CYLINDER 3- 160PSI CYLINDER 4- 150PSI CYLINDER 5- 155PSI CYLINDER 6- 160PSI Guy from the workshop said car runs smooth as a babys behind. and really seems like the guy doesnt thrash it, middle aged and very particular owner and mechanic said car is very well looked after. then again u never kno what happens in japan. Im gona ask for a leak down test I think to be sure. what u think? Edited December 4, 2008 by 1R34SON Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4300036 Share on other sites More sharing options...
Pattygtst Posted December 4, 2008 Share Posted December 4, 2008 have it dynod too. I would be inclining to say that it does not have great compression and you should look for another one. It is not consistent enough in my books Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4300040 Share on other sites More sharing options...
turbo_brian Posted December 4, 2008 Share Posted December 4, 2008 When I bought my car, I had a clause on there, which was I can return the car if my mechanics testing showed the engine was not in good condition. Did a dry compression test: 1 - 176, 2 - 175, 3 - 177, 4 - 176 , 5 - 177, 6 - 176 Did a wet compression test: 1 - 177, 2 - 177, 3 - 176, 4 - 177, 5 - 178, 6 - 178 The minimal difference in figures means that it was great compression to start with, and after using some oil to further seal the rings, the figures where almost the same (there is a variance in or 3 - 5 psi in the gauge I used). Considering the figures where almost identical, it means there is no pressure loss on the rings, meaning any pressure loss is in the valves. a Leak-down test revealed the pistons hold very good pressure, meaning the valves are not loosing pressure, and the engine is in good condition. Did a radiator pressure test as well, revealed no issues, did an intake pressure test, no boost leaks or other leaks,so I rang the previous owner and told him to go nuts with the money, I wasn't disappointed with the tests at all. I later found out from a relative of the previous owner that the engine had blown, and was completely rebuilt from the ground up, forged pistons, rods, balanced crank, all the oil mods to the head, sump baffles, N1 turbochargers, etc. The works has been put into that engine to make it bullet-proof (as bullet proof as an RB26 will get), but then he had to sell for family reasons. If you get a good RB engine, and you let them warm up before revving them and thrashing them, keep good oil to them, and dont rev them over 7,000rpm (unopened), the engine should be good for a lengthy life. It's the other bits you need to worry about, gearbox, diff, suspension, rust through the body, but someone who knows cars will be able to pick if they have been in an accident, or if they are riddled with car-cancer. My only advise: Dont fall in love with a car while looking, treat them all as damaged stock until you find the perfect one, and once you have purchased it, you can fall in love. (I fell in love with a 180sx yrs ago, wanted it no matter what so I wasn't maticulous in checking it out. Later found a 1 inch rust spot, took the screwdriver to it to brake all the rust out before welding a plate to the car, and the hole was 1 inch, but the rust through the panel was 1 foot 2 inches, it was HUGE!!!). B. Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4300869 Share on other sites More sharing options...
R31Nismoid Posted December 4, 2008 Share Posted December 4, 2008 Again - as stated earlier... its the % difference not the actual numbers more than anything. Obviously if it goes 160 150 155 160 150 80 Then you have a problem, but if they are all near enough to the same number, its fine and a good result. If you want a much better TEST - Leak Down test is the one your after Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4300943 Share on other sites More sharing options...
1R34SON Posted December 5, 2008 Author Share Posted December 5, 2008 Again - as stated earlier... its the % difference not the actual numbers more than anything.Obviously if it goes 160 150 155 160 150 80 Then you have a problem, but if they are all near enough to the same number, its fine and a good result. If you want a much better TEST - Leak Down test is the one your after spoke to a guy from a turbo engine tuning workshop and told me this same thing ^ he said that numbers will usually vary. and as long one isnt out by heaps or under 150 its fine. cheers all! Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4301522 Share on other sites More sharing options...
R31Nismoid Posted December 5, 2008 Share Posted December 5, 2008 Under 150 is perfectly fine. If say a motor had all 120 etc, then it just means its a little tired, but still in good condition Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4301612 Share on other sites More sharing options...
2rismo Posted December 5, 2008 Share Posted December 5, 2008 When I popped my stocker, it went: Cyl 1/ 0 Cyl 2/ 75 Cyl 3/ 150 Cyl 4/ 150 Cyl 5/ 150 Cyl 6/ 150 See if you can guess which piston had a broken ringland and which had lost ring tension. Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4301675 Share on other sites More sharing options...
joeyjoejoejuniorshabadoo Posted December 5, 2008 Share Posted December 5, 2008 was it 6? it was 6 wasn't it... Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4301833 Share on other sites More sharing options...
VB- Posted December 5, 2008 Share Posted December 5, 2008 ^ this is on a car he is LOOKING TO BUY, he does not currently own it still... keep thrashing it go easy, he is a VL driver Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4302404 Share on other sites More sharing options...
Kinks Posted December 6, 2008 Share Posted December 6, 2008 When I popped my stocker, it went:Cyl 1/ 0 Cyl 2/ 75 Cyl 3/ 150 Cyl 4/ 150 Cyl 5/ 150 Cyl 6/ 150 See if you can guess which piston had a broken ringland and which had lost ring tension. I'm guessing Cyl 2 had a broken ring land and your ring lost tension when you realised the motor needed a rebuild Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4303332 Share on other sites More sharing options...
1R34SON Posted December 6, 2008 Author Share Posted December 6, 2008 was it 6? it was 6 wasn't it... LOL Link to comment https://www.sau.com.au/forums/topic/247656-compression-results-on-34gtt/#findComment-4303690 Share on other sites More sharing options...
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