u need to mic the piston, then u need to get a dial bore gauge and measure the bore. u have to measure the piston in the specified location (see helms manual). then u gotta check the cylinder bores for taper and out of round. after all that is figured and whether u can still use the oem piston or not. once u got the piston, u get the rings… install the rings onto the piston, measure with a feeler gauge into the ring lands with the rings in them. can’t have too much space. once u got that… then u install the pistons with a ring compressor into the block. then from there u find the gap of the single ring on top… and measure how much space is there. there is a spec. make sure its in spec and if it is then u are good to go and proceed farther. its all mentioned in the manuals.
[QUOTE=rc51ed;2041907]if all they replaced was the rings on the piston then you should get your head checked. the valves has a rubber o-ring before the vavle retainers that keeps the valves lubed to a minimum. if it gets worn or broken off, oil leaks into the the compression chamber thru the valves. depending on how long it took to get the engine work done. the o-rings could have dried up and be needed to change. its the most easiest part of the head that is overlooked at when rebuilding and engine.
ed
2-cents[/QUOTE]
basically he’s saying that the valve guides could be an issue. to figure this out for sure a leak down test must be performed.
Did a compression test today, and got 160 psi across the board. The psi seems kind of low to me for a RS Machines 12.5:1 piston, but they are all the same, and it was a cheapy autozone compression tester that I used. When I did the test, it was WOT with the ecu unplugged and all the plugs out. Cranked it over exactly 5 times on every test, and tested each cylinder 3 times. Do these numbers seem low to anyone else?
Edit: In case elevation and weather matter, I’m at around 500 feet above sea level, the weather today was a scorching 103 degrees with 33% humidity and a barometric pressure of 29.89 inches.
Edit 2: The engine was cold. Hadn’t started it for about 2 hours… That might be why it was so low.
160psi is no ttelling you your pistons are working or not working. that number is telling you how well each cyl is holding pressure in it.
normally i would say if the numbers are all the same you’re ok, but being that you just built the thing. you should have numbers in the 200 range or higher. put a little oil on top of the pistons and do the test again.
[QUOTE=icemanGSR;2042219]160psi is no ttelling you your pistons are working or not working. that number is telling you how well each cyl is holding pressure in it.
normally i would say if the numbers are all the same you’re ok, but being that you just built the thing. you should have numbers in the 200 range or higher. put a little oil on top of the pistons and do the test again.[/QUOTE]
yea. i agree with iceman. u should have higher numbers than that. i hope those pistons are legit tho.
do the test hot then come back to us
I’m gonna try to get to it tonight when it cools down. It’s 105 degrees here today. Went to the pick and pull for some interior pieces and thought I was gonna fall out… hah
[QUOTE=rc51ed;2041907]if all they replaced was the rings on the piston then you should get your head checked. the valves has a rubber o-ring before the vavle retainers that keeps the valves lubed to a minimum. if it gets worn or broken off, oil leaks into the the compression chamber thru the valves. depending on how long it took to get the engine work done. the o-rings could have dried up and be needed to change. its the most easiest part of the head that is overlooked at when rebuilding and engine.
ed
2-cents[/QUOTE]My stock engine smoked badly until I installed new valve guide seals. It didnt smoke real bad just going down the road, but if I sat at a light or drive through it would let out a big cloud when I went to take off. The problem is the oil leaking past the guide seal, down the valve stem and then puddling on the back of the valve when u are sitting at idle. Then when u go to accelerate, a large volume of air goes across the valve and brings the oil into the engine to burn. The valve guide seals are different between the intake and exhaust valves and u can tell them apart by the color of the spring. Also, the smoke might just be from fuel. Make sure u watch your oil consumption.
if it was my valves wuldnt i see oil leaking from my head rite out the exhaust manifold becuase i needed valve seals on my old motor and it leaked …i have a weird feeling my turbo is blown…my car smokes like CRAZY wen its sitting at a red light or wen im let go of the gas pedal on the highway …thats wen the smoke is at its worst…
im gna do a compression test tomrow wat should i be hoping for? with the low compression pistons?
wats up guys i did the compression test today and i got 150 rite across the board…if i was leaking oil in every cyclinder wouldnt my oil light come on for sign of loosing oil pressure? im hoping its the turbo but theres no signs of the turbo leaking oil.
I found the problem!!!
i found out wat it is its the turbo… i pulled off the oil line today and let the car run with no oil runing to the turbo and the smoke dissappeared . hooked it back and then big cloud of smoke …i have a t-61 turbo and a cheap ebay oil line …u guys think i can save the turbo if i get a resistor on that oil line ???
what size feed line is it?
-3 one not needed
-4 one is needed
if its a ebay turbo then yes one is needed no matter if its a -3 or -4 line
yea i had a -4 on there i just bought a -2 but i think its to late i already blown the seals …i think its from all the metal shaving too…that deffinitely had something to do wit it blowing…
-2 is to small
my turbo blew this exact way. fresh build, i guess metal got in the turbo and i had no inline filter. a not so old gt28 destroyed. it sucks.
i put the car back to stock everything and it still smokes a lil and it smokes alot under a heavy load… should i be concerned?? motor has now 375 miles on it
The oil expander ring, that corrugated flexible ring, should not be gapped but put in as is. If there was any metal removed from the expander ring, you will be burning oil. I learned the hard way. I pulled the pistons out bought a new set of rings, gapped each ring per the specs of the ring manufacturer and left the oil expander as is. Now I have a beautiful engine.
Same thing im going through. except mine was burning oil real fast, about a quart every 2 weeks. Just pulled the head off and measure new ring gap and it was exceeding maximum on new rings. Luckily i have a spare block and the gaps are perfect on that one.
The machine shop must have bored it out to its threshhold. End gap of the NEW oil control rings were at .036in when max is .028in. so, the new block is going in now.
might sound like a newb on this one…im not to good with the specs on the ring gap i just bought a stock motor but i wna keep my built one in there im gna have the head off tomorow i was gna pull everything out last week but been working lately …can anyone break it down to me in a retard version like by steps …
wen i pull off the head will i be able to tell that theres a gap by eye? how to i measure the rings to the bore? just to let everyone i have 81 mm pistons…
[QUOTE=acuralover;2058291]might sound like a newb on this one…im not to good with the specs on the ring gap i just bought a stock motor but i wna keep my built one in there im gna have the head off tomorow i was gna pull everything out last week but been working lately …can anyone break it down to me in a retard version like by steps …
wen i pull off the head will i be able to tell that theres a gap by eye? how to i measure the rings to the bore? just to let everyone i have 81 mm pistons…[/QUOTE]
you’ll need to take the pistons out and remove the rings off the piston to measure the ring gap if that’s what you want to do. then you put one of your rings in the cylinder and push it with the piston so that it sits straight and with a feeler gauge you check the gap.