rumpy Posted October 15, 2006 Report Share Posted October 15, 2006 First let me start off by saying I am in big trouble... financially and my technical knowledge is lacking to say the least. With that said.. the problem. I was driving and noticed a hard, fairly consistant knock coming from my engine. I consulted some guys from work. We pulled my engine and found a heavily worn piston. Now, a little about my truck. I have dished Diamond Forged Pistons, total seal rings, new rod bearings, head work by alaska drag bike, new injectors, electric fan, and a STS turbo currently running 8 lbs boost. All the engine upgrades where installed after the turbo, due to my wastegate freezing(alaska.. go figure) and overboosting my engine destroying some piston rings. So, i thought i would make the engine 'bullet proof' to avoid future repairs all while enjoying a fast truck. So i asked around and upgraded all items mentioned above. So now i have these destroyed pistons/rings, and i'm not really sure what to do. To make matters worse, my transmission is failing. It won't shift into 2nd or 3rd unless i'm barely giving it any gas at all. Which is an entirely different issue. I need some advice on how to correct my piston problem.... any help will be greatly appreciated. Please keep in mind I'm in the airforce(I'm on a strict budget). Oh yah, I took my pistons to ALaska Drag bike(the only good machine shop in town I know about) and the guy looked at them for two seconds and set they are too small, and that i need to bore and hone my engine. That is the only advice i've been given, and can't really afford his prices to have the work done, then buy the additional engine parts. However... if this is my only avenue, i will obviously have ot make this happen. Specs from Diamond Piston: Bore= 4.000 Comp Height= 1.336 Stroke= 3.622 Rod Length= 6.098 Effective Volume= -13.7cc Weight 452 grams - T here are some pictures... the first piston is easily the worst..... Link to comment Share on other sites More sharing options...
cadowns Posted October 15, 2006 Report Share Posted October 15, 2006 What cylinder # is that worst piston? What does the top look like? CD Link to comment Share on other sites More sharing options...
Bowtie70SS Posted October 15, 2006 Report Share Posted October 15, 2006 Who put the engine together? You need to use a dial bore gauge and measure the bores in the block. Then take a micrometer and measure piston skirt diameter. Subtract the diameter from the bore size and that is your skirt clearence. Looks like one of two things, either you had it way too tight or way too loose. The problem here is a lot of machine shops have their own idea of how tight a piston should fit...you should go strictly by the piston manufacturer not by Jim bob at the machine shop. I had a very similar thing happen to me, my engine was assembled way too loose. That's the last time I ever let anyone else build me an engine. I don't know what to tell you other than if you do the work yourself it should "only" cost around 12-1500. Maybe this was caused by detonation if the clearences are ok. Good luck Dave Link to comment Share on other sites More sharing options...
rumpy Posted October 15, 2006 Author Report Share Posted October 15, 2006 Unfortunately, I don't know what the correct piston number is. I did however, make my own map of the engine and numbered the pistons so i wouldn't mix them up. My truck isn't at my apartment complex though, so I can't tell yah which one. I should be able to post that tomorrow. I think maybe part of the problem is my STS turbo system is remote mounted near the back rear tire, bringing in unwanted dirt/dust. STS has recently made a shield that i have yet to install. SOO, do you suggest I take my block to AK drag bike and have them provide me with the measurements(or can I measure it accurately?)? What if they are all different? Pictures: The farthest right piston is the worst worn piston.... Link to comment Share on other sites More sharing options...
Bowtie70SS Posted October 15, 2006 Report Share Posted October 15, 2006 Typically the machine shop will finish hone the engine bore to the desired skirt clearence...that's why you need the pistons before you do any machine work. I would have them check the block for tapered bores to see what your options are. Were the bores scuffed or just the pistons? Typically there are 2 kinds of pistons for a 6.0...one that is a drop in replacement for a used std bore engine and one that is for a true 4 inch bore on a new engine block. Mahle makes some like this. You can buy those pistons thru Thunder racing for around 5 bills if I remember right, add $400 for a bore and hone, hot tank and new cam bearings plus 3-400 for rings and bearings and you should be up and running. Believe me I feel your pain...I F'd mine up twice with a catalytic converter that I didn't realize was clogged. Good luck Dave Link to comment Share on other sites More sharing options...
rumpy Posted October 15, 2006 Author Report Share Posted October 15, 2006 Typically the machine shop will finish hone the engine bore to the desired skirt clearence...that's why you need the pistons before you do any machine work. I would have them check the block for tapered bores to see what your options are. Were the bores scuffed or just the pistons? Typically there are 2 kinds of pistons for a 6.0...one that is a drop in replacement for a used std bore engine and one that is for a true 4 inch bore on a new engine block. Mahle makes some like this. You can buy those pistons thru Thunder racing for around 5 bills if I remember right, add $400 for a bore and hone, hot tank and new cam bearings plus 3-400 for rings and bearings and you should be up and running. Believe me I feel your pain...I F'd mine up twice with a catalytic converter that I didn't realize was clogged. Good luck Dave <{POST_SNAPBACK}> Thanks for your input, it is greatly appreciated. I will call AK drag monday and get some estimates for some of the work you mentioned above, i will post what he says. Thx again - T Link to comment Share on other sites More sharing options...
misterp Posted October 15, 2006 Report Share Posted October 15, 2006 I agree with everything Bowtie says, and see a couple other things. If you look at the first photo ALL the left-hand four pistons are worn *bad*, the right-hand four actually look alright, I'd clean them up and reuse them if they measure-out ok. But that evidence would lead me to believe the left-hand four came from the same engine bank - it just looks a too fishy. It is obvious from your close-up photos that these pistons have not had much life on them - exactly how many miles since they were installed? The scratches in the closeup do not look like dirt or engine oil contamination; looks like scuffing to me. Another thing - for such low life those pistons have a TON OF CRAP on them; in your last pic there's only one piston crown that looks even halfway clean (farthest right) and even it is more like what I would expect out of a mid-life teardown. Those other seven look absolutely horrid, I've pulled better looking slugs out of demolition derby car engines that had 150-200K miles. What do the back of the valves look like? Are the valve seals leaking a ton of oil down into the combustion chambers? That stuff looks so thick I could probably pick it off with my fingernail; it's almost guaranteed to be causing increased risk of detonation. It *might* be possible that one bank ran leaner than the other, enough to cause those four pistons to get hotter and expand more than the other four. What's the back-story on your engine tuning? AFA what to do from here - new pistons and rings are a must. Since you ran 4.000 pistons last time I can guarantee you a .030-over bore/hone is going to be needed. This time buy the pistons first, and on the side of the box will be labeled the exact cold clearance, and make sure that each of the eight bores is honed to exactly match it's intended piston as none of the eight will be exactly 4.030 in diameter (each varies 1 or 2 thousandths, this is normal). Gapless rings are nice but the performance difference is actually small and you can save $100 in getting a more traditional ring package. Also, since there appears to be no dirt contamination in your oil and the bearings are fairly low mileage - IF they are scratch-free I would not at all hesitate to reuse them provided you reuse the shells in the exact same journals/positions and they measure out ok, that will save you more $$$. Bearings are meant to be reused, just make sure you keep them in exactly the same position and absolutely clean and scuff/scratch free while the engine is apart. Find out and fix whatever is causing all that combustion chamber buildup. Last thing - as long as you are running an air cleaner on the STS you should be fine. To evaluate if your air cleaner is working well enough, look for scratches in the piston skirts *above* the top ring land. From the two piston skirts you show it looks fine. Mr. P. Link to comment Share on other sites More sharing options...
nixsupersport Posted October 15, 2006 Report Share Posted October 15, 2006 **** IT, drive that bmw in the first pic nixsupersport Link to comment Share on other sites More sharing options...
rumpy Posted October 16, 2006 Author Report Share Posted October 16, 2006 The pistons have about 5k miles. When i lined up the pistons for the photo, they are in no particular order. Some are just worn more than others, dunno why. However, the pistons that have the reddish color on them are all from the driver side, the plugs were reddish too. Dont' know what that is from. My truck is tuned by Nelson tuning, the company who tunes STS trucks. As far as the tune went, the truck ran well, but wasn't as fast as i expected. I took it to a local track and my fastest time was 14.6, which was a little bit of a let down. (Although i did take second in the Northern Diesel Performance Power truck series race!) All i did was tell the STS guy up here what was inside my truck, he contacted Nelson tuning, and a computer arrived a couple days later. Question: If i do get a .030 overbore/hone, will this require new crank and rods? Sorry, as i wrote above, i'm not very mechanically inclined. My bearings are worn aswell, and i definately require new rod bearings, probaly new main bearings, i'm going to check those this week. Also, I don't really know how this was happening, but somehow(maybe that really bad piston?) oil was getting into my intake, and oil is either making its way down towards my turbo... or up the turbo to my intake.... don't really know. I do know the "L" tube connecting my intake pipe to my intake was soaked of oil when i took it apart.... so kinda clueless as to how that happened?.... Also, bad news about when this occured. I was outside of Willow Alaska, which is about 40 miles in the middle of nowhere, so i was forced to drive my truck an additional 40 miles after it started making noise. So I imagine that made everything worse. So once again, i'm still lost in this mess and don't really know what I need to do to get everything sound. The sad part is, i've considered buying a 6.0 from the local junk yard, install that beast, turn my turbo down to 5psi, and sell the truck.(which i'm keeping in the back of my head as a last ditch option) This is turning into a huge mess that I can't afford. Your advice is greatly appreciated. Link to comment Share on other sites More sharing options...
misterp Posted October 16, 2006 Report Share Posted October 16, 2006 That info helps - it is obvious you have two possibly three issues. 1) short block - it's still going to be overall better to fix your engine, you'll be a lot happier and achieve your goals assuming you can get the machine work done right. Bowtie got it right earlier - you'll need new pistons, rings, bearings, plus bore/hone/assembly. Use your existing rotating assembly, it's much stronger than you think. If you did not add ARP rod bolts last time get them now (mandatory not optional). Remember to also budget for new gaskets. This is assuming that the heads/valves are not damaged, they need to be inspected because if you put leaking valves on top of new bottom-end you'll be going through all this again at a later date. 2) oiling problem: bet you $1 that you have a defective seal in your turbo; the center section (the part lubricated with pressurized oil) is more than likely leaking/spraying oil into the intake side of the turbo - you can verify this by disconnecting the boost pipe off the turbo and using your finger see if the turbo outlet is coated in oil. If indeed the center section of the turbo leaks you will have to contact STS about the problem and what their warranty will cover (if anything). There is no way that the engine can leak oil into the elbow adapter, the exhaust feeding the turbo is never allowed to mix with the fresh intake air (think about it...) meaning that *if* the engine were spewing oil out the exhaust manifolds there is no way it could have gone into your intake. 3) after you get the truck running again you are going to have to get the tune dialed in right. You've got two choices on this, you can take it to a proven professional tuner -or- you can buy software to record/log the engine as it is running and email that info to Nelson and he can tweak your tune to match your truck. Mr. P. ps - it might help if you take pics of the pistons arranged as they were pulled from the block as well as the bearings. I'm also going to go out on a limb and say that given the evidence on the pistons and oil in the intake your poor performance was due in part to the excessive oiling, you probably had that issue since day #1. With 8-lbs boost I would expect the truck to at least be in the upper 12s, all things being equal... Link to comment Share on other sites More sharing options...
rumpy Posted October 17, 2006 Author Report Share Posted October 17, 2006 Thanks for your input, i really do appreciate it. I contacted AK drag bike, they are going to build my bottom end completely. I'm ordering new Diamond pistons, total seal rings, new main/rod bearings(any suggestions), and already have ARP bolts. Bore/hone .030 over and install all of the above. They are gonna pull apart my heads, inspect/clean/reseal, and put everything back together like it should've been the first time. All of this for $1050(i supply parts). These guys are well known in alaska for being the best machine shop and they back all their work. I'm pretty excited about it, now just wanna have it done. As for the turbo, i contacted STS, I told them what was going on, we have pretty much narrowed it down to a bad check valve on my oil line feeding my turbo. That is a $15 dollar part. I'm not 100% sure that will solve the problem, but it looks like the most likely cause - more to come when i get access to my truck(thursday). The tuning. I'm going to borrow a friends laptop that already has all the software i need, the connection wire, and i think i only need to buy a wideband O2 Sensor. Then i will be in touch with nelson's and work with them until my truck is right. Question: I am pretty sure these pistons will suffice for my application, any input: Part # 126-11515 Diamond Pistons LS1 Forged Dished Piston set w/ -15.0cc Dish, 4.030" BORE / 3.622" Stroke / 6.098" Rods / 1.340" Comp Height / .945 x 2.950 Wrist Pins Included $600.00. Well, other than that, i think all i need is time. If you have any additional input, don't hesitate to share it. Thanks 2 everyone who has guided me. - Trav Link to comment Share on other sites More sharing options...
misterp Posted October 17, 2006 Report Share Posted October 17, 2006 I think you're back on the right track. I ran the numbers and a 15cc dish with stock heads only gives 9.0:1 compression, that's kinda low but it does leave a whole lot more room for boost. Do you have any HP or torque goal figures? Because you might benefit from raising the CR to 9.5 or 9.75 to 1, you'll get a bit snappier performance off boost. Or you can get heads with smaller combustion chambers or have your heads shaved Discuss CR with both your tuner and machinist before ordering pistons. Mr. P. Link to comment Share on other sites More sharing options...
rumpy Posted October 17, 2006 Author Report Share Posted October 17, 2006 I think you're back on the right track. I ran the numbers and a 15cc dish with stock heads only gives 9.0:1 compression, that's kinda low but it does leave a whole lot more room for boost. Do you have any HP or torque goal figures? Because you might benefit from raising the CR to 9.5 or 9.75 to 1, you'll get a bit snappier performance off boost. Or you can get heads with smaller combustion chambers or have your heads shaved Discuss CR with both your tuner and machinist before ordering pistons. Mr. P. <{POST_SNAPBACK}> What size dish would i need to achieve around 9.75 to 1? Where can i find a set? Thx - Trav Link to comment Share on other sites More sharing options...
Bowtie70SS Posted October 18, 2006 Report Share Posted October 18, 2006 You're close enough with those pistons that you have a couple of options first you can have the heads milled the proper amount to obtain your compression ratio. Second you can use a combination of different head gaskets and block decking. Consult with your machine shop as they should be able to do a little math for you to get you the number you are looking for. Good luck Dave Link to comment Share on other sites More sharing options...
rumpy Posted October 18, 2006 Author Report Share Posted October 18, 2006 You're close enough with those pistons that you have a couple of options first you can have the heads milled the proper amount to obtain your compression ratio. Second you can use a combination of different head gaskets and block decking. Consult with your machine shop as they should be able to do a little math for you to get you the number you are looking for. Good luck Dave <{POST_SNAPBACK}> Thanks man. Link to comment Share on other sites More sharing options...
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