I have a horrible repetitive knocking noise coming from the bottom front of the engine block. The knocking has increased after an engine flush and driving about 300 miles. The gas engine is a 392 CID 6.4L V392LPG IH V8. I suspect a rod bearing is failing. I'm planning on dropping the oil pan and going in from this area. Are there any tricky problems I may encounter? I've ordered a set of standard size rod bearings, the shop service manual is on order, I'll have the torgue wrench, etc. From what I've been reading the bearings snap in and out. Should I be able to tell which piston rod has the bad bearing once the pan is removed? Any comments are appreciated.
Probably won't be able to tell until you drop the rod bearings out.
I wouldn't guarantee it's a bearing, if you've driven it 300 miles with the knock. I would take a look at the timing gears too. On edit: How's your oil pressure? does the knock get faster and slower with RPMs?
The knocking increases with a corresponding increase in rpms. Oil pressure seems to be very low at idle but increases with rpms. The oil pressure does not stay consistent.
If you drop the bearings make sure to check the crank.Most of the time when rod bearings start knocking the crank will be damaged.
This will be interesting... All of my repairs and learning experiences are being done outside on the forest ground about 200 miles from where I normally live. It's on a small mountain home lot where the truck can live for the winter although there may be 10 feet of snow on top of it before Spring. I removed the exhaust pipes and pulled the oil pan. There was almost a teaspoon of metallic debris in the bottom, some pieces were magnetic that looked like small chunks of a casting with smooth flat surfaces and some were aluminum that looked like a coke can had been shredded into small irregular pieces. I was able to easily remove every rod bottom cap, push the piston assembly up away from the journal and remove all top and bottom bearing for all 8 cylinders. I was surprised just how easy this was! All of the bearings were in good shape but I replaced them with the new ones anyway. No sign of the problem causing the knock. I was able to visually inspect with a flashlight laying on the ground, all of the wrist pins, the cylinder walls, the bottoms of the hydraulic lifters, the lobes on the camshaft, everything I could see in this area. I rotated the crankshaft and everything else that it drives while watching the movements. Everything was easily and smoothly rotated and nothing unusual was apparent when moving everything by hand. I then started thinking I should pull a valve cover and see what's under there. I just pulled the one that looked as if it had been pulled before (liquid gasket stuff squeezed out onto the block). I have no idea why or when it had been pulled off before. There was nothing unusual when visually inspecting this area. Before wrapping up for the day, I took one last look from under the block. Since the knocking was coming from the bottom front of the engine, I concentrated my attention in those spaces. I examined what I could see of the timing set (two gears) and rotated them while watching the gear teeth turning. I discovered an area where the teeth had broken off on the smaller (upper) gear. I now believe that these are the magnetic metallic pieces that looked like castings that were in the oil pan. Using the shop service manual for pictures and explanations I came to the conclusion that the aluminum pieces were from a camshaft thrust flange that is attached to the front of the timing gear that is attached to the camshaft (this was a guess not having taken the front cover off). It appears I've found some of the damage but not the cause of the damage. In calling and talking to people about parts (by the way, the IH dealership wants $330 for a timing set while the set is available other places for $100 or less), a helpful guy told me exactly what had happened in the engine. He is 100% positive... I'm now 100% disappointed... One of the five cam bearings has disintegrated and that's what the aluminum pieces were from. Once the cam bearing was shot, this led to the teeth on the timing set breaking. The knock comes from the out of balance camshaft and/or the broken teeth area on the gears or something related to this. I'm now learning/reading/researching on how to rebuild this section of the engine. Unfortunately it looks like the engine will have to be pulled from the truck since new bearings, and camshaft will have to be installed. Very inconvenient given where the truck is sitting... but it could always be worse. Why did the event occur that caused the problem? The explanation is that this is just a 25 year old vehicle that has been known to do exactly this. He also mentioned that it is not uncommon for the number one and two pistons to become a bit noisy due to an advanced or enhanced cooling system (I don't know what that means... yet). I have the beginning of many questions for everybody: I guess this is called a long block. Are all the different displacement engines from IH long blocks and are all long blocks the same size? Can one long block be substituted for another long block. Why is it called a long block vs a short block? Are there differences in the V392 engine if they are from different years. This engine and truck are from 1984. Can I put a 392 from the 70's into this truck? Will the flywheels be the same and will the manual transmissions mate with the engine in the same way? What could I expect to pay on Craigslist for a used 392? I've seen one for $400 supposedly that ran "good". I know it's always "Buyer Beware". Are these engines common? I'm thinking of taking one apart just for practice or rebuilding one before I pull the one in the truck. I'm a total newbie in this area but I'm not afraid to get my hands dirty and buy a Lisle cam bearing tool and a few other tools I'd need! Thanks for all of your comments and help. Gary
hi Gary, I just bought an 86 international s1700, but i barely know anything about dump trucks. at this point can you please tell me what brands of motor and transmission oil is used for this truck and how much oil goes in it. And i will also appreciate it if you can give me hint on how to get the book manual for this truck. Thank you. karayes.