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General Forums => The Mess Hall => Topic started by: stan98tj on November 19, 2013, 09:08:37 AM
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Finally took the jeep in to get all the leaks taken care of. Had a rear main and oil pan leak. This would be the 3rd time the oil pan gasket had been changed in 2yrs. Keep in mind the Jeep sits during the 4 months I'm at sea. Other things that have been changed: valve cover gasket, front main (2 times). They also changed the distributor seal as it was leaking as well.
The shop then held on to the Jeep to do a cylinder test and found cylinders 2+3 had "excessive blow by." The figures they gave me were 81 on cyl 1, 51 cyl 2, 55 cyl 3 and 61 cyl 4. They explained to me this was causing excessive crank pressure and would blow out the seals in the engine and to therefor expect it to leak again. They figured this would also contribute to my rough idle/misfire.
What do you guys think? Pistons wore down and not allowing for good compression? This is a rebuilt motor from 2007. Is it on its way out?
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FSM lists 120 psi for new engine - maximum difference between cylinderss 30 psi. Your numbers are low, and you are right at 30 psi difference. You need to have this rechecked, also have them do a "wet" compression check to determine if the leakage is at the rings or valves.
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Those are all really LOW numbers. At minimum you need new rings. Might need a hone to clean things up a little. If it's a lot of wear then you'll need to bore it.
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FSM lists 120 psi for new engine - maximum difference between cylinderss 30 psi. Your numbers are low, and you are right at 30 psi difference. You need to have this rechecked, also have them do a "wet" compression check to determine if the leakage is at the rings or valves.
Wet compression test, is that when you fill oil up in the spark plug port and take a reading? I think I did this waaaay back when I got the jeep. I knew nothing about nothing then and was merely following directions.
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Is this thing going to grenade on me? I feel like this is where it's alllllll headed to. Catastrophic failure like the first engine. Kind of ticks me off, though. It's a completely rebuilt long block and isn't that old and doesn't have that many miles on it. I'm not sure I really wanna tear into it (again) and replace pistons and whatnot. I feel like if it's going to require extensive work, like the head coming off, then I may as well gut it and replace with something better and stronger...TDi or 4.0 at the least-though I really want the TDi.
Perhaps I should take a wet test? Wonder how much longer I have left with this thing....
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Is this thing going to grenade on me? I feel like this is where it's alllllll headed to. Catastrophic failure like the first engine. Kind of ticks me off, though. It's a completely rebuilt long block and isn't that old and doesn't have that many miles on it. I'm not sure I really wanna tear into it (again) and replace pistons and whatnot. I feel like if it's going to require extensive work, like the head coming off, then I may as well gut it and replace with something better and stronger...TDi or 4.0 at the least-though I really want the TDi.
Perhaps I should take a wet test? Wonder how much longer I have left with this thing....
No, it usually leads to burning oil, poor mileage, a lack of power and bad emissions. Not to mention smoke out the tail pipe when you romp on the throttle.
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like others said, the numbers are so low that i am suspect it would even start - i think they might have done a static pressure test rather than a cranking compression test (unless they forgot to open the throttle). on a cranking compression test you should be at about 150 for a decent engine, nowhere below 120.
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You guys think this is what is leading to the misfire/near stall I am experiencing every time I start up. Happens within a min or two of starting, idles fine then goes into a spasm and idles poorly. If I start driving before it does this, the motor begins to stall, experience severe loss of power and then it finally catches itself. If i'm not getting good compression in the cylinders, would that contribute to it?
What sort of test should I do to gain some actual understanding of what is going on?
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Do a compression test then follow it with a wet compression test.
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I take it they did a cylinder leak down test? In essence what that means is you pump 100 psi of air into the cylinder and you measure on the second gauge how much pressure remains in the cylinder which is in your case was 85 psi, 65 psi and so forth in percentage cyl one has 15% leakage which is to much the rest are worse. 10 percent is the acceptable limit. Now this is a test you do with a hot engine with the cranckase ventilation system disconnected. Each cylinder has to be in top dead cneter with both valves closed. Doing one of these tests is a pain in the butt to do right, but will tell you condition of valves, piston ring sealing better than any other test available. If this test got done correctly then your engine is due for a rebuilt
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I take it they did a cylinder leak down test? In essence what that means is you pump 100 psi of air into the cylinder and you measure on the second gauge how much pressure remains in the cylinder which is in your case was 85 psi, 65 psi and so forth in percentage cyl one has 15% leakage which is to much the rest are worse. 10 percent is the acceptable limit. Now this is a test you do with a hot engine with the cranckase ventilation system disconnected. Each cylinder has to be in top dead cneter with both valves closed. Doing one of these tests is a pain in the butt to do right, but will tell you condition of valves, piston ring sealing better than any other test available. If this test got done correctly then your engine is due for a rebuilt
Yikes. Fan-friggin-tastic. Deja vu all over again. Maybe it will hang on for the time being and let me run it into the ground. Now if it's valve related, could it be valves sticking or need a valve train replacement or something more complicated? If it's pistons, then I am wondering how the rings could have worn so quickly. I fear it could be even worse than that and perhaps the cylinder walls are fouled?
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First find out if they did this correctly, they should be able to tell if there was air leakage at the intake or exhaust
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buy a $20 compression tester, warm up the engine, take the plugs out and test each cylinder (remove the fuel pump relay, disconnect the coil and crank it a few times to clear the pressure from the fuel rail, then test each cyl with the throttle fully open).
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Who rebuilt the engine last time? Was the head rebuilt?
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Who rebuilt the engine last time? Was the head rebuilt?
S&S out of Spokane Washington. Bought the long block from them for 1500 in 2008
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If you ignore the fuel supply and ignition systems, an engine is basically an air pump. The pump pulls air through the intake and pushes air out the exhaust. The dry compression test tells you how well the pump is working. As the engine warms up, the pistons expand and the ring seal gets tighter, and that's why you warm the engine first. If one or more cylinders fail the dry compression test, then you have a leak in your pump. Possible leaks include worn rings/cylinder walls, leaking intake valves, leaking exhaust valves, blown head gasket or cracks in the head or block (less common). The wet compression test (oil added into the cylinder) helps the rings seal better and if the compression gets better, then ring blowby is the suspected. If the wet test does not improve compression, then valves or head gasket are suspect. Normally, a blown head gasket will yield other symptoms (bubbles in radiator, white smoke in exhaust, overheating, etc.). The condition of the spark plugs is another good diagnostic - a black, oily plug on the cylinder with low compression indicates worn rings or worn valve guides. The leak down test is useful because you can listen for the leak (leaking intake valves blow into the intake, leaking exhaust valves blow into the exhaust system, worn rings blow into the crank case). The most common valve leak is on the exhaust side because of heat. An exhaust valve that does not close all the way will burn and leak. Another old school diagnostic tool is the vacuum gauge. Valve problems cause the engine's vacuum reading to bounce up and down. There is no one single test that gives you an answer, you must gather all the info you can and then play detective.
If you determine that the rings are not sealing to the cylinder walls, then a tear down is in order. The cylinder bores wear more at the top than the bottom, and the amount of bore taper and overall cylinder wear determine whether you can get by with honing/new rings or a full rebuild (bore the cylinders oversize and get new pistons and rings).
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buy a $20 compression tester, warm up the engine, take the plugs out and test each cylinder (remove the fuel pump relay, disconnect the coil and crank it a few times to clear the pressure from the fuel rail, then test each cyl with the throttle fully open).
A proper leak down test is a much more accurate test to determine engine condition that a simple compression test
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A proper leak down test is a much more accurate test to determine engine condition that a simple compression test
to tell him if those numbers are accurate or not, at 65 on the leak test or whatever that was should be easy to tell if it's a valve or rings with a compression test - i don't think there would be too much trouble to investigate that particular cylinder.
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Talked briefly with the shop today. They estimated cyl 2 and 3 had 35 and 46% blow by. He also said that he expects that the motor has lost power and will blow a seal eventually and leak oil again. Our conversation got cut short but I'll call them tomorrow and see if I can get any more info.
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Got done talking to the shop. Piston rings need to be replaced on #2 and #3 and perhaps cyl walls need to be honed as well. Bottom line, the engine needs to be torn into in order to figure the extend of the repair. Given the possible piston ring issue, I wonder if it's even worth it.
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I don't know about the pricing where you are but a couple of engine supply companies in NC sell remanned short blocks for $650 with your core and longblocks for $850. Just a htought if your on a budget. If you want pm me for more details.
Al
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I would contact the guys you bought it from, shouldn't fail after 1 year of use even if you drove 100 miles every day
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I would contact the guys you bought it from, shouldn't fail after 1 year of use even if you drove 100 miles every day
it's been 5 yrs
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Why not do all the cylinders since you're already doing half of them.
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Why not do all the cylinders since you're already doing half of them.
yeah, no point in doing only 2 cyl since you take it apart - question is what's the wear in the block and did they go with o/s pistons when they did the repair or just std and honed the cylinders (if the latter you'll probably need .020 or .030 pistons and to bore/hone the cylinders) - if you have your old block i would rather start there, get pistons, rings, bearings, timing chain, etc and swap it when it's ready.
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yeah, no point in doing only 2 cyl since you take it apart - question is what's the wear in the block and did they go with o/s pistons when they did the repair or just std and honed the cylinders (if the latter you'll probably need .020 or .030 pistons and to bore/hone the cylinders) - if you have your old block i would rather start there, get pistons, rings, bearings, timing chain, etc and swap it when it's ready.
Don't have my old block. Had to give it to S&S as a core charge. Honestly, i'm having trouble determining if this is even worth pulling apart. I already replaced 2 pistons on the first engine within the first 2 weeks of ownership. Then it blew up completely. I then bought this rebuilt engine and 5yrs later, the piston rings are toast and the cyl walls need to be honed (maybe). I just don't feel it's worth tearing into. This is pushing me to really do the TDi swap or any swap other than another 4cyl. Could be a series of bad luck, but I feel like if I'm going to basically rebuild an engine I should just swap a different one in...and if i'm going to do that, then I feel I should look for something better than a 4banger.
The unfortunate thing is that I can't sell this engine. Unless I find a 4banger fanatic who wants the block to build up.
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Don't have my old block. Had to give it to S&S as a core charge. Honestly, i'm having trouble determining if this is even worth pulling apart. I already replaced 2 pistons on the first engine within the first 2 weeks of ownership. Then it blew up completely. I then bought this rebuilt engine and 5yrs later, the piston rings are toast and the cyl walls need to be honed (maybe). I just don't feel it's worth tearing into. This is pushing me to really do the TDi swap or any swap other than another 4cyl. Could be a series of bad luck, but I feel like if I'm going to basically rebuild an engine I should just swap a different one in...and if i'm going to do that, then I feel I should look for something better than a 4banger.
The unfortunate thing is that I can't sell this engine. Unless I find a 4banger fanatic who wants the block to build up.
So when the first engine blew up was it the same ones that you repaired or one of the other ones? This is why an engine builder would never do just a partial rebuild by choice.
It might be easier to get a 2.5L from a salvage then to rebuild your existing engine.
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how many miles since you put in the replacement engine?
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So when the first engine blew up was it the same ones that you repaired or one of the other ones? This is why an engine builder would never do just a partial rebuild by choice.
It might be easier to get a 2.5L from a salvage then to rebuild your existing engine.
The first engine burned a hole in the #1 piston. Replaced that and #2 piston (I think the rings were worn on it). Then when the motor detonated, pistons 3 and 4 were grenade with nothing left (if I remember correctly). I had replaced the head and sent it back to Clearwater Cyl as the final detonation was catastrophic. The entire motor was replaced at that point with a motor from S&S in Washington.
So to answer your question, this is motor #2 and motor #1 was sent to them as a core charge. 2 totally separate motors.
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how many miles since you put in the replacement engine?
Not quite 50k
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The first engine burned a hole in the #1 piston. Replaced that and #2 piston (I think the rings were worn on it). Then when the motor detonated, pistons 3 and 4 were grenade with nothing left (if I remember correctly). I had replaced the head and sent it back to Clearwater Cyl as the final detonation was catastrophic. The entire motor was replaced at that point with a motor from S&S in Washington.
So to answer your question, this is motor #2 and motor #1 was sent to them as a core charge. 2 totally separate motors.
Actually, what I was getting as was shortcuts were taken. You had problems with #1 and #2 then when that was fixed #3 and #4 went. When one or two cylinders need work, it's always best (and cheaper in the long run) to do all of them at the same time.
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Actually, what I was getting as was shortcuts were taken. You had problems with #1 and #2 then when that was fixed #3 and #4 went. When one or two cylinders need work, it's always best (and cheaper in the long run) to do all of them at the same time.
Indeed, the first time it happened I was still in college and had forked over $5500 to an asshole who selling me a Jeep with a blown head. I didn't know it of course. So when we replaced the head and opened it up and saw the burned piston I replaced what I could afford to. From that point, there were no shortcuts taken because the motor blew completely and was replaced with a rebuilt motor.
Essentially what occurred the first time was the head was cracked, fuel was dumping in there cause it wouldn't start. I had hotter spark plugs and ended up with a detonation which damaged piston #1 and possibly #2. Head and psitons were replaced but, coolant somehow traveled to the oil pump, killed it and detonated the motor which took pistons 3 and 4. At least, that's what we think occurred. It was back in 2008.
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Not quite 50k
that's very low, i would still call the people you bought it from regardless of how long its been - my guess they did a patchup job and not a full rebuild or who knows what parts they used (although rings and pistons are fairly cheap so i don't know what they would have saved on those).
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that's very low, i would still call the people you bought it from regardless of how long its been - my guess they did a patchup job and not a full rebuild or who knows what parts they used (although rings and pistons are fairly cheap so i don't know what they would have saved on those).
Most rebuilds have a mileage as well as a time limit on the warranty though. I'm sure they'll say they can't do anything.
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Most rebuilds have a mileage as well as a time limit on the warranty though. I'm sure they'll say they can't do anything.
it doesn't hurt to ask, you never know.
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7yr 70k is the warranty. I have to check into it as when I bought the motor, I didn't have much money left and didn't buy the extended warranty. At any rate, even if they would honor it, I would rather get money back than put another 4 cyl in there seeing as the last two 4cyl ended up failing on me, the first at 89k and this one now is on its way out at barely 50k. It just seems like a waste to put the effort into swapping another one in or even rebuilding. The shop I just got it back from advised I not put any more money into the engine. On the downside, they aren't going to warranty any of the seal/gasket work they did because according to them it will leak regardless due to excessive crank case pressure.
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Man bad luck ,, I rebuilt my engine at 125K (It had a BAAAD weekend.. ) and 80K later still going strong.
Mine is stock rotating parts with Hesco cam, springs, timing chain. Engine B&B with basic head work.
Good Luck!
Dave