I am currently in the middle of my rebuild of my 99 cummins. 

 

I made one mistake in my disassembly of the block. I forgot to remove the tappets and lay them out in order and with everything else after i removed cam. I spun the block on the stand to work on something else and down fell all 12 tappets onto the garage floor as I am chasing them down before they rolled under bench,  cussing my way as I go. 

 

Now my question to you guys is this, how important is it for the tappets to go where they where.  Everything else is meticulously laid out and my ocd is driving me up the wall about this. Does it matter? I can not see any differance in wear, marks, or with the micrometer between them. 

 

This rebuild is a preventive maintenance rebuild and not because it blew up or something like that. 260k on odometer. No wear, just leaky seals. 

I'd just stick them in personally.    Look at it this way, if you were to buy new tappets you would be in the same situtation you are right now.  The Tappet hole wouldn't be "honed" to fit the tappet in question.

Personally, I would buy new ones and let them wear to the cam properly. While it may look like there is no wear, each one has worn a little different to each cam lobe. 

2 hours ago, TFaoro said:

Personally, I would buy new ones and let them wear to the cam properly. While it may look like there is no wear, each one has worn a little different to each cam lobe. 

I agree with this as well, same thing with valve bridges etc. the "touching" components in the valve train should always go back in the same position/orientation as they were removed due to the specific wear patterns. Some might disagree but this is what I was taught in the Cummins factory training classes I attended as well a what I've been taught over the years building/overhauling heavy Diesel engines.  I would personally replace them, better safe than sorry.

I would buy new ones, I've rebuilt a few motors and freshen a few up,  on rare occasions I've reused lifters,  most of the time I put a new set of lifters even with an old cam. You actually extend the life of the cam by putting new lifters on every so often, may not be true in all cases. If you put a straight edge on the lifter surface it's dome-shaped, as lifter wears it becomes concave shaped. Cam is also grounded a certain way so it zigzag  back and forth and makes lifter spin so it wears even. 

A way to tell if you eating your cam or lifter away, is if you're constantly adjusting your valves. Make sure you run oil with high zddp first 5 hundred to a 1000ml miles to get things broken in.

Edited April 11, 20178 yr by Dieselfuture

I, too, would replace them. 

Replace. The new tappet can take a new wear pattern from the cam. Moving them around tends to promote accelerated wear of the cam and tappet.

Right on, I shall be getting new tappets then. Thanks for all the advice and reasons why you answered the way you did. 

Some painting pics. Waiting on block to get done at machine shop.....

Nice! I like the red and black! Looks great

Looks good in Cummins Red. I'd love to be able to do that soon. 

The color I used was dupli-color engine enamel in Chrysler Industrial Red from Orielly's.  I couldn't find a cheap source of cummins paint locally. 

I had never used enamel paint before.  There is definitely a learning curve to it. Pull any tape seams whike the paint is wet or  you will wind up with sloppy lines as the tape will tear instead of releasing. The valve cover came out horrible.  On a brighter note, I now have a reason to buy a sandblaster....

On 5/11/2017 at 10:24 PM, Mariocand said:

 

Looks good!! Make sure to take some videos while you're at it.

Just a quick video. I owe you guys a full write up on the build and will in the future. 

 

This video is of me running at 60mph and about 10% throttle. I went to about 50% throttle for a couple seconds amd then let off. Still keeping it easy on motor....only 130 miles on it so far. The exhaust is so loud because I only have the downpipe on as of yet. 

20170516_104927.mp4

Watch "First full throttle test.  Tuner on level 1. 650 miles on motor" on YouTube

I let off when it hit 30 psi. I was stoked about how little the lag is just to get up to 20 psi.

 

 

And since I haven't done the write up of build or created my signature I'll add a brief description of what it has.....

 

Rv275 injectors.

103# springs.

Stock turbo hx35 with wicked wheel.

Banks big head wastegate.

Banks 4" monter exhaust turbo back.

Afe intake, dry filter. 

Edge juice with attitude and cs2 monitor. 

Pusher intake horn.

Grid heater deleter by xdp

Mishimoto radiator. 

 

New pistons, bearings, and seals from mahle. All standard size. 

 

 

My reason for the rebuild...

Edited May 29, 20177 yr by Mariocand