Last night I started tearing down the lower end. Got the pan off, removed oil suction tube, it has a brace that bolts to the block. The part of the brace that mates with the block that the bolt goes thru was cracked in half so will have to TIG that and put another piece on it to stiffen it. Anyway, I got the rods and pistons out and called it a night. The next step was to measure the bores before I loosened the main caps which I planned to do today. The block was in the stand crank up so I made a mental note to remove the tappets this am before flipping it over to mic the bores. So what do I do this morning?, flip it over and watch all the tappets fall out on to the floor. Now what? The book specifically says to mark each tappet so it goes back in its original bore with its original push rod. I had marked the push rods when I took them out. Do I have to buy all new tappets and push rods? What's the risk if I just stick the tappets back in anyway? They're in great shape, I'm thinking if i just check the valve clearance more frequently I may be ok, anyone know? On the plus side, the bores are great, max of .0008 taper on one, the rest .0005 or less. This engine is on its first overbore. The crank is in great shape, never been ground. The rod bearings definitely need replacing, a little bit of base metal showing thru the babbit in spots. mains look good but will replace anyway. The pistons look like new. I'm planning on using a 220 grit ball hone to deglaze, new perfect circle rings along with rod and mains.
Don't do this (long)
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TAKE IT TO A MACHINE SHOP........ let then put it on the honeing machine so it will be trued up and hone all cylinder to same size..... get oversize rings and file fit them ..... install new cam bearing, have em check alignment of crank and do a cleanup of the top of the block deck. install & hone new rod bushings and measure big end. polish crank n rod & mains in crank machine. finally do a complete cleanning. ( i use spray starting fluid ) do it once and do it right. it will be a lifeime engine if you do. these commonly go 500,000 miles.
just my o2
bob
just my o2
bob
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If you try to re-use those lifters you risk wiping your camshaft. The tops of new lifters are slightly domed, you can hardly see it with the naked eye. Using cam/lifter lube at install, the cam wears in the lifters to match its lobes. Each lobe is somewhat different from all the others due to mass production. See that the full surface of cam lobe wears on surface of lifter thereby wearing them into a matched set.
If you try to re-use the lifters the lobes and lifters are no longer matched, and the high spots on lifters wipe out cam lobes. It can happen in 20-30 seconds after startup, or you may get away with as much as a few days. This applies to every engine design I know of where lifters ride directly on cam. Far too high a probability of major damage to risk it far as I'm concerned.
If you try to re-use the lifters the lobes and lifters are no longer matched, and the high spots on lifters wipe out cam lobes. It can happen in 20-30 seconds after startup, or you may get away with as much as a few days. This applies to every engine design I know of where lifters ride directly on cam. Far too high a probability of major damage to risk it far as I'm concerned.
The taper may or may not be severe but most all blocks have some taper. The only time to do the honing is while it's apart, so as long as it's opened up do the machine work regardless of taper.
Oversize rings can make up for any slight oversize from honing process. You don't usually need o'sized pistons unless you had to clean up bad cylinders. It's important to properly hone [grit and diagonals] the cylinder wall surfaces to Cummins spec for good oil control and ring sealing. File fit rings as Bob suggests are the only way to go, so that each ring is custom fit to each individual bore. Careful staggering of ring gaps per specs is critical to long life performance.
Some people think that what Bob posted is high performance stuff: no way! It's the very basics of it on any rebuild or don't even bother opening it up. I would add that it's nice, if you can afford it, to also have the crankshaft and camshaft bores align-honed, then deck the block. There's some free horsepower there, up to 20%!
Oversize rings can make up for any slight oversize from honing process. You don't usually need o'sized pistons unless you had to clean up bad cylinders. It's important to properly hone [grit and diagonals] the cylinder wall surfaces to Cummins spec for good oil control and ring sealing. File fit rings as Bob suggests are the only way to go, so that each ring is custom fit to each individual bore. Careful staggering of ring gaps per specs is critical to long life performance.
Some people think that what Bob posted is high performance stuff: no way! It's the very basics of it on any rebuild or don't even bother opening it up. I would add that it's nice, if you can afford it, to also have the crankshaft and camshaft bores align-honed, then deck the block. There's some free horsepower there, up to 20%!
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Now to keep things in reality, is this your experience speaking where this has happened to you or is this an urban legend being rebroadcast? I have swapped lifters in other engines that became mixed when the engines were dismantled and ran those engines for years without camshaft problems. Some other camshaft companies advise against using new lifters on an old camshaft. So if you mix up your lifters you would then need to replace the cam and lifters? Now if this was a 4BT in an aeronautical application I would be in total agreement.
Bob and JimmieD - I am in total agreement that's what's necessary to make this a perfect engine that will go half a million but hear me out. This is going into a 1990 F150 4x4 that I use as a winter beater and general day to day beater for hauling stone, dirt, old car parts, firewood, etc. I'm getting some weld in panels for the body, will do a paint job along with front end rebuild. If it sees 7,000 miles a year that will be a LOT. I've got a 2004 F350 crew 4X4 Powerstroke that I use for general use, long trips, heavy towing, etc. The taper spec is 1.5 thou max so I am well within that. The book says use a ball hone to deglaze for a re-ring so I'm thinking I do that along with new bearings and I will have a "lifetime" engine. I'm 55, say I keep it for 25 years, at 80 it will have 125- 175K miles on it. I think it will go at least that with a deglaze, new rings and bearings. If i can still screw around with this stuff when I'm 80 then I'll rebuild it again if it needs it! But I will definitely have the shop clean up the deck, maybe I'll have them do the deglaze while its in there. On the lifters, what JimmieD says makes sense. The book led me to believe that the pushrods and lifters were a matched set since it said that if a lifter has to be replaced you have to geta new pushrod for it also. I'm going to see what they say on this at cumminsforum and TDR, I bet I'm not the first guy to do this. I'm liking what Bob is saying, especially since these lifters show no visible one directional wear BUT I'll price new lifters just in case.:idea: Thanks.
Steve
Steve
Well, Bob, I don't have persoanl experience with using old lifters that are mixed up because I heard about this stuff maybe 35 years ago. It's not at all urban legend but simply part of the mechanical relationships part-to-part.
Every single cam grinder and mfgr. out there will tell you this is correct. They all say to NEVER reuse old lifters with a new cam, but you can use new lifters with an old cam. Every pro engine builder I know of [Mopar] will agree. This has been the industry standard in engine rebuilding for as long as anybody can remember. The problem isn't that it's guaranteed to trash the cam every single time. The problem is the Russian roulette: will I trash my cam this time, or get away with it? Spending several grand to assemble an engine properly doesn't matter much when you wipe out the cam a few minutes, yes minutes, later.
I got a free '77 Power Wagon with 440 because the guy that worked on it didn't know about cam/lifter lube and proper cam break-in. Important stuff and real dicey to take a chance. I can't say 'just my opionion' because every builder and mfgr. I know of agrees. That's all I know about it.
Every single cam grinder and mfgr. out there will tell you this is correct. They all say to NEVER reuse old lifters with a new cam, but you can use new lifters with an old cam. Every pro engine builder I know of [Mopar] will agree. This has been the industry standard in engine rebuilding for as long as anybody can remember. The problem isn't that it's guaranteed to trash the cam every single time. The problem is the Russian roulette: will I trash my cam this time, or get away with it? Spending several grand to assemble an engine properly doesn't matter much when you wipe out the cam a few minutes, yes minutes, later.
I got a free '77 Power Wagon with 440 because the guy that worked on it didn't know about cam/lifter lube and proper cam break-in. Important stuff and real dicey to take a chance. I can't say 'just my opionion' because every builder and mfgr. I know of agrees. That's all I know about it.
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never reuse lifters if they show wear or have been mixed up. and dont hone the cam bore as there is no way to install cam bushings except the front one. also you get out of an engine what you do upon a rebuild. cut corners and you get that quality. do it right and get a new engine. guys the parts for these engines to do a major o/h is less than 750.00 , machine work for a good job is aprox 500.00 max. if your on that tight of a budjet leave it alone till you can do it right. you,ll be glad you did in the end. again just my experience. 30 yrs as a diesel mechanic and diesel shop owner . 22 yrs of over the road trucking
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Well I'm not a new kid on the block either. My mechanical experience goes back to the first learning stages that started 42 years ago in 1965. Yes I do put everything back in the same location it comes out of and use the old cardboard box trick. It was always common back then to buy a used cam and unmarked lifters and then install it in another engine that would run for years without a failure. The theory was the cam and lifters were equally hardened for their application and after the initial run in time they would work without any problems. If the cam or lifters showed any signs of wear the cam and lifters would be junked. Of course money available and marketing methods have changed since those days. As I said earlier, I never have had a catastrophic camshaft failure or valve settings that would not remain in tolerance for this reason.
I'm sure it's one of those, "To each his own...' type things, Bob. I personally choose to follow the recommendation of the camshaft mfgrs and engine rebuilders that have said don't do it. If you've had good results with reusing lifters then that's great! I just don't want something to come back and bite me, and it's relatively cheap for lifters.
Just for the hell of it I'm going to chuck up each of the lifters in my lathe, mount a .0001 indicator on the toolpost and drag the indicator across the face of each lifter in the center two times 90 deg apart with the cross slide and see what it says. There is no visible scoring or wear pattern. Any idea what a new set costs?
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