Samsupra Posted July 14, 2009 Share Posted July 14, 2009 Hi guys Sorry for another compression test question but im still unsure after searching through threads i couldnt find my answer. So.. i am currently in the middle of single conversion after my hybrids blowing , to keep it brief i asked JPS to do a compression test to see how the engine was after the hybrids going and i got the figures 1:170 2:150 3:170 4:155 5:170 6:170 Is this compression safe to run with my new single build(T61)? Go easy as i dont really know much about internals and these types of testing JPS said if i left it and just bolted all the car back together he suggested not to run it above 1bar? i would like to have atleast 1.2 with this new kit ? BUT this was a cold test which i thought is inaccurate?(JPS said the difference would be minimal around 5% if was warm) They have done a leakdown test but i forgot to get the figures will ask tomorrow and post. Now my question is or advise please would be where do i go next ? I was told by JPS that the low compression on 2 + 4 is due to the rings he thinks. So from this test (done yesterday) should i tell them to take it apart and put new rings in and see how she is inside which is very exspenisve and could never end ? or like i said ealier get her back together and mapped to 1bar and leave it? Sorry for the long questions but i would much appreciate any advise Cheers guys Sam Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 14, 2009 Share Posted July 14, 2009 Its not so much low figures, its the %difference between them, also the leak down will be more indicative of the true state of the bores/rings. Cold to hot won't make a vast difference, but they should have used a bit of oil down the bores to determine if the lower figures are due to rings or valve seal. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 15, 2009 Author Share Posted July 15, 2009 Thanks for your advise ricky i will ask them today if they can do that oil test on the bores. What does that difference indicate to you? Im still very unsure what to do next guys so any more advise would be great Thanks Sam Quote Link to comment Share on other sites More sharing options...
Kranz Posted July 15, 2009 Share Posted July 15, 2009 The figures for the leakdown test (which should really be done hot) would be useful to determine if this is indeed the rings not sealing properly. The difference in compression from 170 to 150 is 13%. The most I would say is acceptable before an engine (in a standard road car) needs a rebuild is 20%. Ideally it needs to be 5% and no more then 10% in a performance motor. Engine out and partial rebuild with new rings and re-seating the valves would be a good idea if you could do it yourself as it would be relatively cheap and a lot of the annoying jobs could be done suvh as valve stem seals, valve clearances, cam belt etc. The thing is that it is still a big job and to have a garage do it will still cost £££££. Wait to see what the result of the oil in cylinder compression test is, plus post up the leakdown results. There *may* be something gained from those results. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 15, 2009 Author Share Posted July 15, 2009 Thank you Kranz for your advise much appreciated. I have just rang JPS they will ring me back and give me the leakdown figures very soon and will post then, also i have aksed for them to do test with th oil over the bores. Unfortunately I not a very good with my spanner so doing it myself i think is out the question. Its just i bought my car for 14.5k and for the hybrids to blow a week after purchase and the car since has been at a garage getting fixed for month now its driving me mad! im just so unsure what to do as ive poured alot of money into her after purchase. Will apdate as soon as i get more info Cheers Guys Sam Quote Link to comment Share on other sites More sharing options...
Guest Supra2 Posted July 15, 2009 Share Posted July 15, 2009 sounds like jps wants to have your pants down. Quote Link to comment Share on other sites More sharing options...
Tom Posted July 15, 2009 Share Posted July 15, 2009 (edited) 14.5k is a lot for a supra!, where did you buy it from? i'd probably single it anyway, I bet there are tons of supra's out there running fairly well with much lower compression between the cylinders than yours, just budget for a rebuild in the future in fact i've driven 3 single turbos supra's running fairly good power and all were very low on compression I even had an old 200sx which although a little smokey had 110 70 110 50 and still pulled well and took a serious amount of abuse! Edited July 15, 2009 by Tom (see edit history) Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 15, 2009 Author Share Posted July 15, 2009 Hi Tom I bought the supra from a private seller and he didnt use any forums really so the car is slightly unknown. It was stunning when i bought it never smoked looked a very gd example until a 2 weeks later when i got the confidence to turn the boost to 1.4 and it goes bang Do you think i am worring about this compression test too much? it was done COLD which i thought was inaccurate. I wont be tracking the car it will just be a toy at the weekend use and sunny days and may once or twice take a trip to Nburg ring but thats it so i wont thrashing it about. Thanks for your advise Keep it coming Sam Quote Link to comment Share on other sites More sharing options...
Tom Posted July 15, 2009 Share Posted July 15, 2009 the mechanic i've used has always done compression test's for me from cold, and I trust his opinion on testing this way although it would probably bug me that the engine isnt 100% (i'm a little OCD with things like that , even if it they were all 170 apart from one that was 169 that would bug me too ) I don't think it's that bad, i'm no expert but I would go for it and as said just set aside some cash for when it does start losing power/getting smokey or not making as much power as you want it too I think at this point you might be throwing money away just edited my post above Quote Link to comment Share on other sites More sharing options...
Tom Posted July 15, 2009 Share Posted July 15, 2009 also I think if you take JPS's advice and only run 1bar I think you'll find that's rather quick Quote Link to comment Share on other sites More sharing options...
SteveC Posted July 15, 2009 Share Posted July 15, 2009 Looks to me like those figures have been rounded up or down to the nearest '5', so in actual fact they could, in reality, be a little closer than they appear. Those figures may not be ideal, but they're not that bad. I'd go with Tom's advice and just run the car for now and bear in mind that you may need some work done in the future. Just keep an eye on the compressions every few months and see how it goes. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 15, 2009 Author Share Posted July 15, 2009 Thanks guys, thats the same advise my father and my girlfriends dad is giving me which sounds like the route i am swaying towards at the moment. The single i will be running is T61PHR kit (.68) and would of liked to run atleast 1.2bar which this brand new kit Im sure this will be alot quicker then the hybrids but i was able to change boost from 1.1,1.2,1.3,1.4, and only having 1 bar boost now i feel like im a limiting myself after doing all this work to the car...( since it been in the garages it had full service, cambelt change filters, oils, RLTC fitted, allignment, engine oil cooler, trans oil cooler, bigger injectors few other bits cant remember off the top of my head ) Its just a little annoying to get this work done and not to be where you want even after putting alot of money into her Quote Link to comment Share on other sites More sharing options...
wkdtime Posted July 15, 2009 Share Posted July 15, 2009 Thanks guys, thats the same advise my father and my girlfriends dad is giving me which sounds like the route i am swaying towards at the moment. The single i will be running is T61PHR kit (.68) and would of liked to run atleast 1.2bar which this brand new kit Im sure this will be alot quicker then the hybrids but i was able to change boost from 1.1,1.2,1.3,1.4, and only having 1 bar boost now i feel like im a limiting myself after doing all this work to the car...( since it been in the garages it had full service, cambelt change filters, oils, RLTC fitted, allignment, engine oil cooler, trans oil cooler, bigger injectors few other bits cant remember off the top of my head ) Its just a little annoying to get this work done and not to be where you want even after putting alot of money into her Im sure if all the guys that are running single were to have a compression test, I would think that quite a few of them will probably see a some fluctuation in the percentages as you do too. I wouldn't worry about it, just go with the single. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 15, 2009 Author Share Posted July 15, 2009 Cheers Wkdtime im sure your right i could be stressing over this more then i should or need too, i will update with leakdown figures and the oil test this afternoon once i get a chance to speak to JPS then i can see more specifically where the problem is. So you guys think i would be ok just to leave and go single but keep an eye on the compression every month? Sam Quote Link to comment Share on other sites More sharing options...
Tom Posted July 15, 2009 Share Posted July 15, 2009 yep just wind up the boost and worry about the rest later , as long as you can afford a rebuild later on then you'll be fine Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 15, 2009 Share Posted July 15, 2009 Don't panic too much its not looking that terrible, and its all dependant on the tests being done right in the first place;) Shame you didn't have a look on here first, as there are several well sorted singles for sale around the price you paid, including mine. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 15, 2009 Author Share Posted July 15, 2009 (edited) Thanks for advise guys does help me alot thanks. Tom-If i was to wind the boost up i think i would only go to 1.2 Max(Will that be safe if i only use it occassionanly and not for long ?), still might just leave it at 1 bar. Tricky-Ricky - well thats puts me at ease at litle bit but i wasnt able to ring jps to get the results of the leakdown test but will definately post tomorrow. I did look on this forum when i was looking and none really tempted me till i found mine not on here though. She looks stunning from outside but i think the previouis owner didnt care for as much as i will, she needs a bit of TLC and i think she be running smoothly if i get her out and put some of that system cleaner to clean engine to clear some of the carbon build up? which is best to buy ? Sorry forgot to ask which would be more costly to say if my engine did go, rebuild or buy a gd used TT engine? Cheers guys Sam Edited July 15, 2009 by Samsupra Forgot to ask a question (see edit history) Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 16, 2009 Author Share Posted July 16, 2009 (edited) Hey guys Got some more bad news:( Rang JPS this morning and my figures for the Leakdown test : L/D test OIL on bore test 1-15 2% 2-25 5% 3-15 2.5% 4-50 25% 5-10 0 6-25 0 The leak down test was done dry, and done twice and came back with the same figures. Now JPS have said this is worse then he expected and really suggests now that i have partial rebuild , they also said he could hear air leaking from the exhaust and inlet. change the rings, home the bores, gaskest and bearings if needed. Now sorry to ask the smae question again.. but from these results what should i do! ? Help please as i really dont know Any advise will be much appreciated Cheers Sam Edited July 16, 2009 by Samsupra bad punctuation (see edit history) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 16, 2009 Share Posted July 16, 2009 First off looking at those figures i'm a little confused, i must presume that the figure shown is that actual leakage figure in PSI, in which case the leakage figure and the % figure don't match up! Also i have never seen a cylinder with 0% leakage. Plus i would expect to see in the region of 10 to 20% as normal on a good condition road engine, so to me either their equipment is not accurate or they are not conducting the test right, sorry! what do others think? Chris? Quote Link to comment Share on other sites More sharing options...
SteveC Posted July 16, 2009 Share Posted July 16, 2009 I too was a bit confused by those figures. I guessed that the first figure is the psi improvement with some oil down the bores, and the second figure is percentage of leakage. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 16, 2009 Author Share Posted July 16, 2009 Thanks Tricky-Ricky been very helpful through this thread. Right ill re post all of the tests clearly Compression test ( done COLD) 1 - 170 2 - 155 3 - 170 4 - 155 5 - 170 6 - 170 LeakDown test ( done DRY - what does this mean? ) 1 - 15 2 - 25 3 - 15 4 - 50 5 - 10 6 - 25 Im unsure what these results mean so if they could be explained and where to go from here or your advise and opinions all welcome:) Lastly the Oil on bore test 1 - 2% 2 - 5% 3 - 2.5% 4 - 25 5 - 0 6 - 0 Hopefull thats made if clearer for you to read guys and yes i notied the 0% on 5 and 6 and i thought that is near impossible? Am i getting done over by this garage? So confused Help! Cheers Sam Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 16, 2009 Share Posted July 16, 2009 I will try and clarify this a bit, the figures you have been given are still a Little confusing. Cold compression figures are OK and make sense, However the leak down test figures need to be clarified, are they the PSI leakage? or are they the % leakage? the result is useless unless you are provided with the reference pressure. (Explanation of how a leak down test is carried out, a spark plug adaptor is screwed into the cylinder to be tested which MUST be at TDC on the firing stroke, this will be attached to two gauges in line, a reference pressure is applied to the cylinder, usually 200PSI the second gauge the one closest to the cylinder is read and will indicate the amount of pressure that is leaking past rings or valves, this is read initially as pressure, but interpreted into %, so reference pressure 200PSI and the second gauge shows only say 150PSI which equates to 25%) The third test which is the most confusing, shows the results in % which would normally apply to leak down not compression test, but although oil is commonly used in a compression test, if it is used in a leak down test (don't see the point as a constant pressure is applied so any oil is forced from the rings anyway!) Consequently the third test result is also useless. I hope this make sense to you, but i'm afraid you are either getting the results confused, or the garage don't know what there about. Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 16, 2009 Author Share Posted July 16, 2009 Cheers Ricky does help Sorry for the confusion i have just spoken to JPS again and on the leakdown test is it the % of leakeage. The third test, the oil on bore test he said he cranked 35psi through it to get these readings and said this is the % lost through the rings i believe from what i undertsand. He strongly recommended that quite is bad on cyclinder 4 and that really should change rings and probably the vavles. If i was not to do this and leave it and mapp to safe 1bar theres is still a change of blowing the crank seal shafts again plus he could hear air leaking rom inlet and exhuast whilst cranking 4 cyclinder Hope this helps, if not i will try and get more info if needs be If anyone else has experience with this stuff or expert advise it would be greatly appreciated, as my car is sitting in the garage awaiting my decision on what to do, really need help guys Thanks Sam Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 16, 2009 Share Posted July 16, 2009 Sorry but going by the info you have been given, i would say take it somewhere els that know what there doing. "The third test, the oil on bore test he said he cranked 35psi through it to get these readings and said this is the % lost through the rings " Quote Link to comment Share on other sites More sharing options...
Samsupra Posted July 16, 2009 Author Share Posted July 16, 2009 Does this not make no sense to you then ricky? Maybe im relaying the info wrong but if you was in my boots what would you do? Quote Link to comment Share on other sites More sharing options...
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