pistons...

[billmongold]

so it turns out i have shot rings in my car so im prob going to just throw some pistons in there while im at it. i was wondering if any of you are running hyper pistons... or if you know anyone running them. horror and success stories are welcome. i hear dont do it but id like some more info. thanks guys

[scott87star]

Yeah, AGC ran some hypers up to and over 30 pounds of boost before the lands gave out racing a Mercedes around 610 here in Houston. I am planning on running hypers in my current build which will go to 20 lbs boost with E85. Don't let anyone smack talk the hypers, they run much tighter clearances so they don't sound like a diesel at startup. The "advantage" of forged pistons is their ability to take a bit of abuse but if you think like I do any abuse is too much abuse. Tune it right, watch the turbine inlet pressure and GO!

 

Scott

[Indiana]

A glass house is fine until someone throws a rock at it.

 

Stock pistons will take more abuse than those hyperUs can. Nobody has asked him WHY he thinks he needs new pistons. His posts start with wanting to trade a VW for a Conquest, he gets one then he said he rebuilt it but mentions a headgasket and JVEK then he has a high rpm "miss". He says it very rich. What does this tell you? What does this have to do with needing pistons? Someone is giving wrong information or he is making assumptions. The stock pistons are not weak and rings aren't worn out. Blowby from no oil separator will cause all sorts of smoke bombs and he was saying he was removing everything from the ignition system and asking about Ford JY parts. The ignition system no matter what you do still has to fire a spark plug and a distributor or a crank sensor there's NO difference this is only a reference signal to the ignition controller and in our case that's the ignitor. The mechanical ignition advance in combination with the vac. adv and retard unit is the simple way to get the job done. The ECU isn't controlling the timing and unless there's a stand alone ECU to control timing there's not an easy replacement for the ignition system and if there were that Ford system lacks boost retard and knock sensor control for safety so you can't use it anyway. He's asking for pistons and I'll bet its because this motor is smoking and he pulled the separator off a long time ago and someone is saying his rings are worn and so are his pistons and they are just guessing. Its too easy to answer a question but pistons imo aren't going to solve the problem and nobody is bothering to ask.

[billmongold]

ok... ive been a tech for 5 years now and im not an idiot. i have worn rings. i did a super-budget rebuild because this car is my dd and i need it done asap for cheap. i rebuilt it without changing the rings. i may have broken a land or the rings may be shot because there is excessive crankcase pressure, even at idle. the separator was removed by ther previous owner, but its smoking off idle and blowing oil out the nipple on the vc. i didnt remove the line, i got the car like that. its also blowing the dipstick out of the tube, running like s***, and has low compression. i know our ecu doesnt control timing, i know how a distributor works. and what does my previous vehicle have anything to do with this? granted im new to boost, im used to building and modifying cars. i have been working on sbc's for about 10 years now and i built the jetta from stock. ask gary how it runs. please dont try to insult me or question my intelligence, i was simply asking about hyper pistons. i know how they do in n/a applications, just not boosted ones. sorry for the rant, but i dont like being flamed.

[billmongold]

and thank you for telling my hypers are not that great. i kinda had an idea. my buddys motor just grenaded a keith black hypers after 2k miles

[Dad]

I have probably 8-10 k miles on my hypers.

 

Dad

[Caliber308]

I have probably 8-10 k miles on my hypers.

 

Dad

 

That comment by Dad is the best information on Hyper-Us you will get in this entire thread.

 

Bill

[starquestJOE]

IMO the only thing that may need upgrade is the head studs. BUT i dont think they need to be upgraded, but only replcaed. i just took apart a " BUILT " tep motor. well the only aftermarket things in the motor were BEK, ARP headstuds, and a AJUSA headgasket. i have run up too 18psi on the 12A. too 25psi on a 57trim. And finally 20psi on my Holset HX40. I'm still TBI as well. this STOCKISH motor never failed or gave me one problem

[Indiana]

ok... ive been a tech for 5 years now and im not an idiot. i have worn rings. i did a super-budget rebuild because this car is my dd and i need it done asap for cheap. i rebuilt it without changing the rings. i may have broken a land or the rings may be shot because there is excessive crankcase pressure, even at idle. the separator was removed by ther previous owner, but its smoking off idle and blowing oil out the nipple on the vc. i didnt remove the line, i got the car like that. its also blowing the dipstick out of the tube, running like s***, and has low compression. i know our ecu doesnt control timing, i know how a distributor works. and what does my previous vehicle have anything to do with this? granted im new to boost, im used to building and modifying cars. i have been working on sbc's for about 10 years now and i built the jetta from stock. ask gary how it runs. please dont try to insult me or question my intelligence, i was simply asking about hyper pistons. i know how they do in n/a applications, just not boosted ones. sorry for the rant, but i dont like being flamed.

 

If you have a broken ring land you will have an issue, after you sort out the rest, and it will run fine then foul out all the spark plugs in about 5 minutes and do it over and over and over but you didn't break any ring lands or have a broken ring because I've seen that too and I know what the symptoms are. It doesn't matter how much money you spent either and it doen't matter if your a "tech" or not or how long you have done that. It won't matter how old you are or what other car you have had. The people that convert their motor to mpi do their best to copy exactly what the distributor and vac. advance unit do in their ignition maps then fine tune depending on their max boost levels. If you didn't know, the vacuum advance unit when there is boost and this is only on this engine not on any others that I know of, it can also reverse and it retards timing too. The vac. adv. is independent from the mechanical advance. If the vac. adv. unit is bad, and its common for them to be bad when they get old, your car will run like crap under boost and it shows up about 3000-3500rpms. To test that, take the cap off and get a piece of hose and suck on the vac. adv and watch the arm pull in, it should react quickly and return quickly after you release the suction. Now, to see if it leaks, suck on the hose again then cover the tip of the hose with your tonque and that arm better not slowly move back out, if it does its junk and you must replace it and its about $65.00

 

but you just told me what the main problem is. This motor has allot of blowby at idle and it gets worse from there and it has much to do with the way the timing cover is completely open to the crankcase in the front not a couple little holes up through the head and its not assembled like a small block Chevy motor at all is it? It will blow that crankcase pressure out and fling oil out with it that is coming off the rocker assembly if the oil cap is off while running and this is completely normal and every one of these motors does it new or old no matter who put it together its just a fact of this engine. Old rings are just fine providing you did put them in cleaned out ring grooves and preferably in the same place they came from. What does needing pistons have to do with your rings that were reused or anything else? How abouut just rings then? I'm trying to save your money not spend it. You said oil blows out the valve cover and it smokes, yep that's what happens and if you plugged that valve cover port up and drive the motor it sure the hell will blow out the dipstick and half the oil with it and it would on mine and everyone elses too. Now, do you want me to tell you what else is likely wrong?

 

You said it didn't have a separator when you got it, ok that's alright you can deal with that now. There's another thing it must have and that's a PCV valve from the dealer and not one from any parts store of any brand, it can only be OEM. Why you ask? Where does boost enter the engine? It enters into the intake manifold from the throttlebody, from the turbo etc but it gets into the intake and at the base of the intake is a port that is where the PCV valve hose connects to. While you are running off boost or idling or cruising the crankcase pressure, or blowby, flows either/or out through the PCV valve into the intake and is burned or it passes back through the separator and ends up in the turbo inlet so its burned anyway it just takes a different path and it depends on the volume of the blowby and that's related to the engine rpms and remember this is when there is no boost pressure. The problem of the non OEM PCV valve is when there IS boost pressure. This is what is causing your smoking, its burning oil and the dipstick is blowing out right? Since you have the port from the valve cover not letting pressure escape it will build up very quickly and if the PCV valve isn't sealing out the boost from the intake manifold, there's just no way all that boost pressure blowing into the crankcase isn't going to cause problems and all the NON OEM valves SUCK. They are made poorly internally and the piston inside isn't sealing and those all pretty much all made for a carbureted motor and for not letting in pressures from a backfire that comes through the intake manifold. Mitsubishi is still using this same PCV valve and that's a good thing and its about $5. its a dark color metal, almost looks like it was dipped in a black ink the half washed off so unless you see that its not an OEM valve and its time to replace it with a new one. Now, what happens to all that blowby that is generated when the PCV valve isn't letting in boost pressure? Its supposed to go back OUT the separator, filter out the oil that is suspended in the pressure to reclaim that because burniing it is a bad thing plug its messy in the intercooler. When you lift the throttle and there isn't boost the flow through the separator reverses and the PCV valve opens back up and fresh filtered air goes into the crankcase and evacuates all the blowby CRAP you don't want left in the crankcase. That blowby has unburnt fuel in it and what's also in the crankcase that you don't need to add any fuel too? Oil.

 

Next, you say it has "low" compression. How did you check this? Did you pull out all the plugs, hold the throttle fully open and crank over the motor and you got what? At least 100-120psi? 130ish would be nice but "low" is like 80. This isn't a high compression motor say compared to that VW or a DSM that has something like 240psi compression. Next is the rocker assembly, is it mechanical or hydraulic? Does it have jet valves? If it has jet valves those can't be adjusted until the mechanical rockers are set or after the hydraulic lifters are set and that means you have to run the motor first but that may be another issue. The lifters, did you clean them? They have a chamber that might have crap in it from 20+ years who knows and they won't seat or they are pumped up and your valves aren't seating and that makes for poor compression numbers and if you have a dead, dying or dirty non seating lifter your compression numbers in the cylinders will be all over the place and not close to each other and with will suck. I think you can tell from the compression numbers if the lifters are letting the valves seat but you need to check and make sure they are pumping up and to do that you need to pull the valve cover. Get the cam lobe on its base to check the lifter in each rocker and then push on the outer tip of the rocker and if that rocker arm pushes down that lifter is dirty or ruined, you can try and clean them or just replace them. You can have lifters that are not pumping up and have compression numbers like 50-35-60-80 does that look like your numbers or better or worse? This has nothing to do with rings or pistons no does the dipstick and smoke and oil problem. If you replaced the pistons and rings and left everything else the same it would still do the SAME THING its doing now.

 

You can go check that and let us know what's going on. After you deal with these mechanical issues then you can deal with the sensors, checking and setting those up and the ignition system. You can't fix it all at once. One part at a time and this isn't difficult but it has challenged people for 20+ years before you saw one and it still is. Its why these cars are sitting for sale dead or someone can't figure them out and puts in a SBC instead.

 

You can deal with 20+year old dirty injectors and drip or leak and have poor spray patterns and this is effecting the volume of fuel dispensed and its poorly atomized and its not burned properly. The spark plugs if they aren't the correct type they won't work either. If the plug wires are laying on the valve cover and crossed over each other that causes misfires at high rpms under boost. The ignition coil, the stock one is fine but you can use a MSD blaster if you like just make sure you get the one that's for electronic ignition because there are about three different ones.

[billmongold]

thank you guys for your input and esp you, indiana. sorry for accusing you of flaming me i didnt read your post correctly. the nipple on the vc is not plugged, if it were i would expect it to push the dipstick out. as for the blow by at idle, its enough to smoke from the edges of the hood and by the headlights while idling. it also throws a nice blue puff of smoke every time i shift and then touch the gas. the underside of the hood is COVERED in oil as is evertyhing from the dipstick back (manifold, throttle body, firewall.). i had to drive like 80 miles today and had to put a quart and a half of oil in it. im currently running 10-40. i already considered the pcv as a possible issue. at first i thought it might be a head gasket bc im pretty sure my head is warped, but i havent taken it apart and looked, because it is my dd. and if it was good id have to use a new gasket and bolts. i may just do that anyway considering i already have them. i figure its possible (but not likely) that the hg blew between the cylinder and an oil passage, but im not having any cooling issues at all. idk. im just going by what i have seen in the past on other cars (granted, they arent boosted...) and they have all had broken rings or pistons.

[vbrad511]

First things first run a compression check. My 88 (with an 87 motor) only runs between 95 and 100psi and runs and drives fine. It puffs a little smoke between gears if I'm into it, otherwise doesn't go through any notable oil between changes. From there get a separator in place and functional, and a new PCV valve. That'll halt a lot of your underhood mess. Like the guys have said, these bottom ends are pretty solid. I wouldn't tear it down until you've eliminated the smaller, obvious possibilties.

[billmongold]

i ran a compression test with my friends inaccurate tester and it said like 30 psi in 3 cylinders and like 7 in no. 3. i just got my tester from self storage to get an accurate set of numbers im just waiting for my car to cool a bit before i go and burn myself on the turbo. should have numbers up in an hour. and my big issue isnt the lil puff of smoke, i can live with that... its losing so much oil and smoking and running like poo. thanks for the help guys.

[billmongold]

drumroll please...

cylinder 1- 115 psi

cylinder 2- 105 psi

cylinder 3- 60 psi

cylinder 4- 105 psi

 

still could be a blown hg but its not looking too promising.

[vbrad511]

Take the hose off of your compression tester, and pull the schrader valve (tire's valve stem valve) out of the bottom. Thread it into that #3 hole and then hook it to a compressor and give it a little air. Listen/feel for where the air comes through. Blows out the intake, you've got a bad/burned intake valve. Out the exhaut, a bad/burnt exhaust valve. Out the oil cap, past the rings. When you do this, get #1 on TDC, then rotate it a half turn. That'll put #3 at TDC.

[billmongold]

good tip. i already have a hose with the schrader valve removed that i use for doing valve springs with the head on. i may have to look into that.

[starquestJOE]

i had the same problem with a car i redid last year. took the motor apart this year to rebuild the short block for another car, and the ring lands on the #3 piston were broken off

[Indiana]

Does that head have jet valves?

 

Did you see if the lifters in the #3 cylinder are pumped up and tight? You might also bleed them again then crank the motor over until it gets oil pressure then check it again.

 

You can loosen up the rocker assembly and stick in a wire through the hole in the rocker arm tip but imo its just easier to remove the rest of the bolts from the rocker assembly and pull those lifters all back out, bleed them all down so they are squishy and start over. If you want to clean them, do that in a pan with diesel in it and do it while in the fuel, insert the wire to open the valve then squish them over and over and allot of crap will flush out of the chamber then release them the last time in the fuel so it sucks some in then pull the wire out and leave vertical under you put them back in the head. They should still be a little squishy before you crank the motor over. You may have just one lifter that's pumped up too tight and the valve isn't seating or it has something stuck in it and the valve can't close so there is not only a noisy lifter but it causes the valve to open later and close sooner and at cranking rpms of like 150-200rpms that 60psi is all you'll get.

 

Did you put new valve seals in this head as part of your rebuild? If you did, see if any came off and if you didn't poke something through the spring and see if they are still soft or hard as a rock and need replaced, if they are hard they WILL leak oil down the valve stems and cause smoking even without crankcase pressure issues. They will cause the motor to smoke more while idling then when driving. The oil that did leak while driving has a chance to run all the way down while idling at the lower rpms and it looks like a freight train.

 

Unless you did something insane while driving it since you put those pistons back in they shouldn't be broken. Never seen any broken ring lands in any of these motors I've taken apart but I've seen them with broken rings and those eat up cylinder walls and that's what I was describing above when the compression can appear normal but then the motor will foul out all the plugs in a few minutes. You can still drive the car for a short time it just runs ok for a mile or so then it just runs like crap. The plugs will be coated with oil from all the crankcase pressure. If you think that non stock PCV valve is leaking boost, take the hose off the plug both the ports and put a hose off that valve cover port and poke it in a bottle.

 

 

Detailed factory TSB procedure for this: http://www.b2600turbo.com/lash%20cleaning.pdf

http://www.b2600turbo.com/images/valveliftercutaway01.jpg

 

 

 

 

 

 

[billmongold]

no jet valves in the head. the valve guide seals are all new. my big issue right now is the crankcase pressure off boost. obviously boosting its much, much worse, but theres a serious problem. the plugs are fouling pretty quickly. ill let you guys know whether its the rings or the ring lands when i tear it apart in a few days

[billmongold]

tore the engine down tonight... carnage. broken ring landsand broken rings on no. 3, 2 spun rod bearings, and a blown head gasket. in other words i need a new motor or decent pistons and a crank cut.

[Indiana]

Its the hard part of finding out why. Got any ideas? I don't think it was your rebuild, I never did. Busted pistons can cause crankcase pressure that blows oil out that leads to ate up bearings but the reverse is also true. It could have been your ignition system, the timing could have been off or it was lack of fuel. I hate to give up on finding out why things fail, you don't learn anything. When I saw the post the first time I hadn't assumed you had assembly issues but I think that's what I think you thought I was saying. There are common issues with this car for everyone and its the same questions all the time. Those have to be addressed even with your new motor.

 

Sorry, hang in there you will make it better.

[billmongold]

thanks bud. im pretty sure it was just bad rings, then the lands broke, then it burned too much oil (even though i put in like 2 quarts a day... then low oil pressure, and spun bearings. it just sucks because if i didnt have to order the rings, im confident i could have fixed that before there was bearing damage. anybody got a cheap shortblock, lmao. i was just talking to a friend at a machine shop and he said theres a formula for computing actual under boost compression ratio (boost divided by 14.7 [atmospheric pressure] plus 1 x compression ratio) given that at 18psi i was at 15.3:1 on pump gas.i dont know how accurate that is but he's a well-known machinist and engine builder and i trust him.

[Indiana]

Pump gas wasn't the problem, we are all boosting on it and you can use that formula but you are missing some details. The time you sustain that boost is when the temperatures increase and cause the problems and its that you are out of fuel at high rpms. To me 18psi is not high boost but that is related to the turbo you have and for that turbo it just got to where it runs decent with this engine.

 

You've detonated and cracked a ring and this isn't something you can hear or know about until it is contined to run with it cracked. You could drive around for 5000miles at lower boost with a cracked ring until it ate up the cylinder wall and caused the crankcase perssure to blow the oil out. If it happens again and again, that detonation, you can end up breaking more rings but not that one that is already broken its not sealing anyway and the rings slam into the lands then break those unless the detonation was so severe that it all happened at once. Those broken pieces eat up the block and don't seal boost then the oil blows out. When it was that bad you foul plugs and you said all that happened. It all was because of that boost pressure at HIGH RPMS and detonation is hard to hear sometimes and if you never heard it you just ignore it because the motor is still running but the power is off, at higher rpms it sounds like little hammers hitting the block and its only going to take once for it to happen to cause that damage IF you ignore it and keep on letting it happen for more than a second or two. This is what killed the motor and the lack of fuel to run that boost pressure at high rpms. The stock regulator isn't going to do much past 13-14psi boost and you're at 18 so you have +3 blowing against the fuel pressure lowering it even more. Do you remember hearing detonation? How hard and how many times did it run before it didn't seem to pull like it used to? That first time the dipstick blew out is the first time it detonated and that damage was done and likely its after the headgasket blew. Since you had no separator hose on the valve cover and it was not capped the pressure normally couldn't have built up to blow the dipstick out unless it detonated. When it detonated the headgasket blew partially and your one lower cylinder pressure shows that and that made the dipstick blow out.

 

That formula you heard is true but its easier to see in a chart. Look here at it: http://www.kb-silvolite.com/article.php?action=read&A_id=57

[billmongold]

i dont alwasy run the car hard, around town its mostly about half throttle full boost, which is more than enough to get it moving. i know what detonation sounds like and i never heard it but it still obviously could have been an issue. the rings could also just have had gobs of miles on them... the pistons came from an unknown mileage parts car. the car was not driven much after it started running really poorly. i didnt look at the cylinders yet... when i pulled the rod caps i got pissed and pulled the pistons and crank out just to look at the crank then walked away before i flipped out

[Indiana]

Was the block ruined? Might need to have a machine shop look at it so see if any grooves are in it or worn spots in the middle of the bore. How many pistons were busted? You sure they were OEM pistons? If it was ruined, still save the oil squirters. If the crank was OEM and was the hardened one even with no oil they can't still be good if not badly scored and might just need polished. The rods you can't just have reconditioned and that's always good anyway and its inexpensive.

 

These are OEM pistons they have a bumpy surface, is this what yours were?

 

http://www.b2600turbo.com/images/IM000174.JPGhttp://www.b2600turbo.com/images/IM000178.JPGhttp://www.b2600turbo.com/images/IM000219.JPG

 

 

http://www.b2600turbo.com/images/IM000182.JPG

 

 

[psu_Crash]

tore the engine down tonight... carnage. broken ring landsand broken rings on no. 3, 2 spun rod bearings, and a blown head gasket. in other words i need a new motor or decent pistons and a crank cut.

 

Sorry to hear that. I destroyed the engine in mine quickly after I bought it. Simply from lack of knowledge and understanding. Stick with it and like Indiana said, learn from your mistakes.

Best of luck!