Mackpro Posted April 2, 2008 Share Posted April 2, 2008 We dont work on V-8's hardly anymore but we have this 1985 Magnum RW in the shop with a 1000cid 500hp engine with amiss and fuel smoke. We found the bad/missing cylinder. We had the injector checked, its OK. The valves are adjusted correctly. We did a compression check and the bad cylinder had 200psi lower pressure than the others. We removed head and checked valves, all OK. Got a new piston, liner and rings to install. We got to looking at the connecting rod and to me and the other guys it looks bent. We assume its needs to be straight like E-6 and E-7 rods but we dont really know being a V-8. Need help, Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/ Share on other sites More sharing options...
Barry Posted April 2, 2008 Share Posted April 2, 2008 That rod looks normal to me. I think the meat on the one side of the crank side makes it look bent, but i don't think it is. If it was bent, at least one would have come through the block by now! Quote Barry - Watt's Truck Center Parts Manager and BMT Webmaster...1-888-304-MACK Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18043 Share on other sites More sharing options...
theakerstwo Posted April 3, 2008 Share Posted April 3, 2008 Ever bent rod that i have seen could be detected by looking at the wear on the old rod brgs. because i think which ever way a rod bends it will show more wear on one side of the rod brg. I aways look at the old rod brgs close when i pull them out so you know what is going on. if in dought you better change because it is you not some one else working on it and when the head is back on and it is still smoking you will be mad at your self and no one else. glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18049 Share on other sites More sharing options...
fjh Posted April 3, 2008 Share Posted April 3, 2008 That rod looks normal to me. I think the meat on the one side of the crank side makes it look bent, but i don't think it is. If it was bent, at least one would have come through the block by now!The rod is bent!Which hole did it come from? Looks like 7-8 was the inlet gasket whole or missing a peice Check all the intet manifold gaskets BEFORE you preasure wash this engine!I have seen that happen twice before Caused by water getting in thru a blown out gasket on the inlet manifold!A simple preasure tst of the inlet system will tell the tale if you got any more blow outs. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18052 Share on other sites More sharing options...
Mackpro Posted April 3, 2008 Author Share Posted April 3, 2008 The rod is bent!Which hole did it come from? Looks like 7-8 was the inlet gasket whole or missing a peice Check all the intet manifold gaskets BEFORE you preasure wash this engine!I have seen that happen twice before Caused by water getting in thru a blown out gasket on the inlet manifold!A simple preasure tst of the inlet system will tell the tale if you got any more blow outs. It was #8 cylinder, we are doing more checkes on the engine, thanks for the info. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18055 Share on other sites More sharing options...
Mackpro Posted April 3, 2008 Author Share Posted April 3, 2008 We put piston/rod back in engine and measured piston to block height at maximum travel. We compared reading to cylinder beside this one and found the piston in the bad cylinder was lower( not coming up to the top of the block) so it seems the rod is bent. We are replacing the rod and hopes this fixes problem. Thanks for the help guys. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18061 Share on other sites More sharing options...
fjh Posted April 3, 2008 Share Posted April 3, 2008 We put piston/rod back in engine and measured piston to block height at maximum travel. We compared reading to cylinder beside this one and found the piston in the bad cylinder was lower( not coming up to the top of the block) so it seems the rod is bent. We are replacing the rod and hopes this fixes problem. Thanks for the help guys.Yup i garrenty it will fix it .Don't let that truck leave your shop till you check the rest of the inlet gaskets!It can happen again! Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18068 Share on other sites More sharing options...
ciw65 Posted April 5, 2008 Share Posted April 5, 2008 I gather you have both banks heads off. Check for water stain of the liners. You may have uncovered a problem that might cost the owner dearly down the road. If it has let water in through an inlet gasket, guaranteed it won't be the only cylinder water affected. Whatever happens, the owner is one lucky fella, that bent rod could have been a real disaster. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18094 Share on other sites More sharing options...
Mackpro Posted April 9, 2008 Author Share Posted April 9, 2008 Well we have run into another problem. We order a new rod and compared it to the bent rod and sure enough it was bent. We installed the new piston on rod and put back in engine. We put head back on. Went to adjust valves and when we turn engine and #8 piston goes up to almost full travel engine locks up like piston is hitting head (or something), all valves on #8 are up/closed, no fuel or coolant on top of piston, all parts# are correct, part# on new rod macthes old bent rod and all other rods in engine. It seems what bent old rod is trying to bent new rod. We still have oil pan off. Any idea? Thanks guys Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18178 Share on other sites More sharing options...
theakerstwo Posted April 9, 2008 Share Posted April 9, 2008 When the engine is locked up check and see if you have any valve clearace and if you dont then the piston may be hiting the valve and if it does have clearance with preesure held on the crank then try to mash the valves down and if you can then valves is not hitting the piston. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18182 Share on other sites More sharing options...
Mackpro Posted April 9, 2008 Author Share Posted April 9, 2008 Well we figured it out, seems the tiny nut on the engine brake pass-through somehow fell into the intake manifold the when we were adjusting the valves it made its way on to #8 piston. Had to pull head again, lucky no damage other than need new nut. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18183 Share on other sites More sharing options...
theakerstwo Posted April 9, 2008 Share Posted April 9, 2008 That is the reason about 40 years ago i learned to tape up the opening on a manfold when it is open and dont open it untill it is ready for the hose. I have worked at a dearler for manyyears and will say that i have seen about one hundred engines go thru this same deal and it is that it is mosty from young guys that have not thinking how easy it can happen and yes it has happen to me. I see guys ever day still doing it and if i say any thing about it most will say i have never did it before and i have even got guys a roll of tape and they will throw it back to you any way i am glad you found it. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18184 Share on other sites More sharing options...
fjh Posted April 9, 2008 Share Posted April 9, 2008 Well we figured it out, seems the tiny nut on the engine brake pass-through somehow fell into the intake manifold the when we were adjusting the valves it made its way on to #8 piston. Had to pull head again, lucky no damage other than need new nut.Those make alot of noise when the engine runs!Been there done that one too!The engine will run after too!at least it only cost you a couple of gaskets.You never confirmed was the gasket in one peice? Dosent much mater as somone could have repaired it after the damage was done.chasing this smoke problem.the absolute best thing to do is remove them insulaters till the head is back on its real easy to spin them little devils into thw inlet on install. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18185 Share on other sites More sharing options...
Mackpro Posted April 10, 2008 Author Share Posted April 10, 2008 Those make alot of noise when the engine runs!Been there done that one too!The engine will run after too!at least it only cost you a couple of gaskets.You never confirmed was the gasket in one peice? Dosent much mater as somone could have repaired it after the damage was done.chasing this smoke problem.the absolute best thing to do is remove them insulaters till the head is back on its real easy to spin them little devils into thw inlet on install.The tech tossed the old intake manifold gasket so we didnt get to check for cracks or pieces missing but we did check the others. The guy working on the V-8 has been here almost 30 years and I've been here 21 years and this is the second time something like this has happened since I've been here, you can never be too carefull. But the good news is it's fixed and running better than ever. Just wish I'd got to do the test drive. The last time I worked on that Magnum was about 20 years ago when we bought it from an insurance company. It was pulling a coal dump trailer and was dumping the trailer when the top of the ram broke and fell on top of the sleeper then the trailer bed fell onto the ram and pile-drived the ram through the sleeper down between the front seats. We repaired the truck and sold it to the guy that has it now. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18191 Share on other sites More sharing options...
fjh Posted April 10, 2008 Share Posted April 10, 2008 The tech tossed the old intake manifold gasket so we didnt get to check for cracks or pieces missing but we did check the others. The guy working on the V-8 has been here almost 30 years and I've been here 21 years and this is the second time something like this has happened since I've been here, you can never be too carefull. But the good news is it's fixed and running better than ever. Just wish I'd got to do the test drive. The last time I worked on that Magnum was about 20 years ago when we bought it from an insurance company. It was pulling a coal dump trailer and was dumping the trailer when the top of the ram broke and fell on top of the sleeper then the trailer bed fell onto the ram and pile-drived the ram through the sleeper down between the front seats. We repaired the truck and sold it to the guy that has it now.We sold 2 magnums here one same as that one and one MH both are long since gone Of the dosens of MH COs sold in this neck of the woods I hardly see any on the road now!there is still a few RWs still up and at em but and lots of good ol RDs and CHs Its a shame the MH in my mind was the BEST cabover Ever built by ANYONE.I'm not saying I like Cab overs Or anything about em, Just that It was one of the Best. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18211 Share on other sites More sharing options...
Brian Posted April 11, 2008 Share Posted April 11, 2008 Mackpro68 Where are you located in Western Ky? Block Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18224 Share on other sites More sharing options...
GearheadGrrrl Posted April 11, 2008 Share Posted April 11, 2008 We sold 2 magnums here one same as that one and one MH both are long since gone Of the dosens of MH COs sold in this neck of the woods I hardly see any on the road now!there is still a few RWs still up and at em but and lots of good ol RDs and CHs Its a shame the MH in my mind was the BEST cabover Ever built by ANYONE.I'm not saying I like Cab overs Or anything about em, Just that It was one of the Best.I heartily agree- I drove a few MHs at UPS and they were miles ahead of any other cabover. Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18232 Share on other sites More sharing options...
Mackpro Posted April 11, 2008 Author Share Posted April 11, 2008 Mackpro68 Where are you located in Western Ky? BlockPaducah Quote Link to comment https://www.bigmacktrucks.com/topic/3593-v-8-bent-rod/#findComment-18234 Share on other sites More sharing options...
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