jerry598
08-16-2009, 22:45
This is lengthy and somewhat verbose but documents some of the problems I've run into doing a rebuild on my beloved 6.5.
I'm a self-taught novice mechanic - always have tried to do my own work to save $$$ since I was a teenager over 40 years ago.
Heres the story:
1. My K3500 6.5 TD was running great, then the cooling system started to pressurize and burp coolant right after startup. Would burp out the overflow on short trips (tried over and over again to get all air expelled through the screw - no luck. Hoses were hard almost immediately after startup and coolant burped on the shortest of trips - even on idling after startup. In other threads, I found that Jim said it was a classic head gasket failure symptom and sure enough after removing the heads found the LH gasket had a crack in the 3:00 oclock position between the #7cylinder.
2. I also found minor cracks between valves in the #4 and #8 cylinders on the heads but my local machinist did not want to attempt a repair. Should have found someone else to sleeve those passages and might have saved a couple hundred bucks, but have now ordered new heads from Clearwater Florida ($650).
3. Considering the oil smudges that I found on the cylinder walls after removing the heads (apparently due to stuck rings - it consumed 1 qt oil every 400 miles), noticeable ring ridges at the tops of 2 cylinders, and concern about crack issues in the bottom end I opted to pull the engine and rebuild whatever needed it. One minor crack was discovered along one outer bolt hole in the #4 main (completely repairable with one L&S insert ($40). So......took it to a machine shop 150 miles away that could do L&S inserts. Based on Robyn's feedback I had them do inserts in all six outer holes in the 3 inner webs (they were reluctant to do any inserts because they had only installed one of them in all their years of having the kit on hand - they suggested I find another uncracked block instead). I told them to install all six bolt hole inserts anyway (didn't want more hassle with finding another block) and I have faith that these inserts will probably give me an even stronger block than one that is uncracked or stud girdled.
4. I let them talk me into boring all cylinders (probably didn't need to do it and it just incurred extra cost, that and they went all the way to .040 oversize - isn't that the limit?). Also polished the crank (there was virtually no serious wear on main bearings, rod bearings or camshaft bearings and no scoring on journals). I let them sell me new oversize pistons, rings and bearings. They supplied standard bearings which after doing the plastigauge proceedure at only half the torque value, and with dry threads, the oil clearance seems to be too high .004-.005 (see separate thread). I'm going to recheck the clearance once more with oiled bolt threads and full torque values. Don't know about the rod bearing clearance yet, I figured I have to install the crank first (or do I?).
5. Everything was returned to me from the shop unassembled (good) except that they did install the new pistons on the rods and the new rings on the pistons, but I have my doubts that they checked the ring gap or even miked the pistons. Didn't get a box for the rings so don't have a size listing for them.
6. If the bearings still check out with toooo.... much clearance, I will call the shop about exchanging the standard main bearings for undersize ones. I'd have to get .050mm undersize bearings (as listed in the catalog) to tighten the clearance to .002-.003. I was considerable confused about bearing size terminology because even the experts seem to interchange these terms. Seems that undersize bearings (inside diameter less than standard) decrease clearance between the two surfaces, while oversize bearings (larger ID than standard) increase clearance. Most bearings listed in the online catalogs I've checked list undersize bearings in several sizes but almost no oversize bearings.
7. But am I safe relying on just plastiguage? If I go to .025mm undersize bearings that would equal about .001 closer clearance than the .004-.005" on my first check (assuming those numbers are validated on the next check). I'd like to make it right and go to .050mm undersize bearings to get the .0018-.0033 clearance listed in my Hayne's manual, but am I safe to do that by just relying on plastiguage?
7. When I first checked the clearance, I only torqued to half the specified value of 100 and 110 with dry bolts. I will oil the bolts and torque them to full value to ensure that the plastigauge is smashed well enough on the second check tomorrow.
8. Next, I suppose I should have the cylinder bores miked and the pistons miked to make sure they match, right?
9. In addition, should I remove the new rings and fit them into the cylinders myself to check ring gap? I doubt the machine shop did this.
10. I would also like to inspect/replace the oil cooler and oil filter bypass valves in the block. I see no evidence that the shop took them out or replaced them, but I'm not sure yet how to go about that.
10. The shop charged me $1800 for the above work and parts, which of course included the 6 L&S inserts ($240). Now I'm looking at a total rebuild cost of about $3K with the heads, bolts and all other misc. parts, $3.5k after I purchase a new fluid damper. (And no warranty except for yours truly).
I'm thinking I would have been better off to buy a new/rebuilt long block which would have "only" cost about $5500 (from one source) with freight and exchange, and including the fluid damper. Then I would have had a professionally balanced rotating assembly, stud girdle, and ceramic coatings, but no L&S inserts. I'm hoping that L&S inserts are a better way to strengthen the block than even a stud girdle.
If I had gone for someone else's rebuilt long block from a reputable source, I would not have had to do any of this internal work myself and would have had a 1 year/unlimited mileage warranty. The truck would also be back in service by now but it would have cost me at least $2k more than doing it myself.
If it wasn't that the truck body is in such great shape (K3500 ext. cab, black new paint) and the fact that I've already sprung for a rebuilt NV4500 and so many other small repairs and upgrades, I might have long ago given up on this project - But I love my truck, like all of us do.
That's where I am now, checking bearings, waiting on new heads and other parts (timing chain, new oil pressure switch, newer '98 higher pressure oil pump and other stuff.
There are alot of questions here and I look forward to seeing any and all feedback from those of you who aren't laughing to hard right now. Also hope this might help others decide if they want to take on this kind of a job themselves.
I especially want to thank Robyn and the other moderators that have provided so much guidance here on the diesel page - its a great and valuable resource!
I'm a self-taught novice mechanic - always have tried to do my own work to save $$$ since I was a teenager over 40 years ago.
Heres the story:
1. My K3500 6.5 TD was running great, then the cooling system started to pressurize and burp coolant right after startup. Would burp out the overflow on short trips (tried over and over again to get all air expelled through the screw - no luck. Hoses were hard almost immediately after startup and coolant burped on the shortest of trips - even on idling after startup. In other threads, I found that Jim said it was a classic head gasket failure symptom and sure enough after removing the heads found the LH gasket had a crack in the 3:00 oclock position between the #7cylinder.
2. I also found minor cracks between valves in the #4 and #8 cylinders on the heads but my local machinist did not want to attempt a repair. Should have found someone else to sleeve those passages and might have saved a couple hundred bucks, but have now ordered new heads from Clearwater Florida ($650).
3. Considering the oil smudges that I found on the cylinder walls after removing the heads (apparently due to stuck rings - it consumed 1 qt oil every 400 miles), noticeable ring ridges at the tops of 2 cylinders, and concern about crack issues in the bottom end I opted to pull the engine and rebuild whatever needed it. One minor crack was discovered along one outer bolt hole in the #4 main (completely repairable with one L&S insert ($40). So......took it to a machine shop 150 miles away that could do L&S inserts. Based on Robyn's feedback I had them do inserts in all six outer holes in the 3 inner webs (they were reluctant to do any inserts because they had only installed one of them in all their years of having the kit on hand - they suggested I find another uncracked block instead). I told them to install all six bolt hole inserts anyway (didn't want more hassle with finding another block) and I have faith that these inserts will probably give me an even stronger block than one that is uncracked or stud girdled.
4. I let them talk me into boring all cylinders (probably didn't need to do it and it just incurred extra cost, that and they went all the way to .040 oversize - isn't that the limit?). Also polished the crank (there was virtually no serious wear on main bearings, rod bearings or camshaft bearings and no scoring on journals). I let them sell me new oversize pistons, rings and bearings. They supplied standard bearings which after doing the plastigauge proceedure at only half the torque value, and with dry threads, the oil clearance seems to be too high .004-.005 (see separate thread). I'm going to recheck the clearance once more with oiled bolt threads and full torque values. Don't know about the rod bearing clearance yet, I figured I have to install the crank first (or do I?).
5. Everything was returned to me from the shop unassembled (good) except that they did install the new pistons on the rods and the new rings on the pistons, but I have my doubts that they checked the ring gap or even miked the pistons. Didn't get a box for the rings so don't have a size listing for them.
6. If the bearings still check out with toooo.... much clearance, I will call the shop about exchanging the standard main bearings for undersize ones. I'd have to get .050mm undersize bearings (as listed in the catalog) to tighten the clearance to .002-.003. I was considerable confused about bearing size terminology because even the experts seem to interchange these terms. Seems that undersize bearings (inside diameter less than standard) decrease clearance between the two surfaces, while oversize bearings (larger ID than standard) increase clearance. Most bearings listed in the online catalogs I've checked list undersize bearings in several sizes but almost no oversize bearings.
7. But am I safe relying on just plastiguage? If I go to .025mm undersize bearings that would equal about .001 closer clearance than the .004-.005" on my first check (assuming those numbers are validated on the next check). I'd like to make it right and go to .050mm undersize bearings to get the .0018-.0033 clearance listed in my Hayne's manual, but am I safe to do that by just relying on plastiguage?
7. When I first checked the clearance, I only torqued to half the specified value of 100 and 110 with dry bolts. I will oil the bolts and torque them to full value to ensure that the plastigauge is smashed well enough on the second check tomorrow.
8. Next, I suppose I should have the cylinder bores miked and the pistons miked to make sure they match, right?
9. In addition, should I remove the new rings and fit them into the cylinders myself to check ring gap? I doubt the machine shop did this.
10. I would also like to inspect/replace the oil cooler and oil filter bypass valves in the block. I see no evidence that the shop took them out or replaced them, but I'm not sure yet how to go about that.
10. The shop charged me $1800 for the above work and parts, which of course included the 6 L&S inserts ($240). Now I'm looking at a total rebuild cost of about $3K with the heads, bolts and all other misc. parts, $3.5k after I purchase a new fluid damper. (And no warranty except for yours truly).
I'm thinking I would have been better off to buy a new/rebuilt long block which would have "only" cost about $5500 (from one source) with freight and exchange, and including the fluid damper. Then I would have had a professionally balanced rotating assembly, stud girdle, and ceramic coatings, but no L&S inserts. I'm hoping that L&S inserts are a better way to strengthen the block than even a stud girdle.
If I had gone for someone else's rebuilt long block from a reputable source, I would not have had to do any of this internal work myself and would have had a 1 year/unlimited mileage warranty. The truck would also be back in service by now but it would have cost me at least $2k more than doing it myself.
If it wasn't that the truck body is in such great shape (K3500 ext. cab, black new paint) and the fact that I've already sprung for a rebuilt NV4500 and so many other small repairs and upgrades, I might have long ago given up on this project - But I love my truck, like all of us do.
That's where I am now, checking bearings, waiting on new heads and other parts (timing chain, new oil pressure switch, newer '98 higher pressure oil pump and other stuff.
There are alot of questions here and I look forward to seeing any and all feedback from those of you who aren't laughing to hard right now. Also hope this might help others decide if they want to take on this kind of a job themselves.
I especially want to thank Robyn and the other moderators that have provided so much guidance here on the diesel page - its a great and valuable resource!