Well, I almost became the next victim of the dreaded cam pin failure. We had to pound off the cam gear because with the pin starting to bend and shear and it rolled a bugger up on the cam making an interference to the gear. The gear was rotated almost half the width of the pin off original location which is a little less than 10 degrees. I have been having some low boost issues recently and maybe this was one of the reasons? Just to note, the truck started and ran perfectly with no smoking issues at the time of disassembly.

We also checked the distance from the top of the pistons to the deck surface on the block. Helms list piston projection at for a:
grade A gasket at .0088-.0108 with gasket thickness of .0354-.0394
grade B gasket at .0108-.0128 with gasket thickness of .0374-.0413
grade C gasket at .0128-.0148 with gasket thickness of .0394-.0433

I don't know how to determine which grade gaskets came stock (helms says something about grade holes???) but, the cylinders as follows from the top of the piston to the block surface:
cylinder #1 +.001
cylinder #2 -.018
cylinder #3 -.005
cylinder #4 +.005
cylinder #5 -.011
cylinder #6 +.004
cylinder #7 -.008
cylinder #8 +.001

By these numbers I would assume every rod it short, am I correct?

Good find Jon. Check the crank pins as well, they will typically not show the same extent of damage, but will still have some slop usually.

To identify the gaskets, look at the gasket in the corner where the R and L is. Under that, there is an oval cut out in the top layer of gasket, in the main layer there is no holes, one hole or two. A, B, C grade respectively.

Left side is a grade B, right side it a grade C. Is this common to have different grades on each side? Crank pin is in good shape.

Yes, common to see that.

FWIW, we will always install Grade C's for simplicity sake. Has been absolutely no issue doing this.

Wow!:eek:

I am glad you found that before it caused you real trouble. Wonder what my stocker will look like?

you were driving it until you tore it down?

you were driving it until you tore it down?

Yes.

Shaun's truck next??:grd:

Shaun's truck next??:grd:

After he saw the cam pin, it made him a little leary about doing any racing this year.

Does that happen to LLY's too?

Shaun's truck next??:grd:
I will do mine next winter after were done camping like john said I'm not sure if I will race it after seeing his cam.

if your worried about the cam pin, not racing will do nothing to prolong. You should quit driving it all together. Just drive it and enjoy it.

Come on Shawn, you have to race to win. You win, you get cash. Take the cash and build your motor. Simple! :bigglasse

Hey John, I'm into a spare motor for my truck and the doggone thing has the exact same thing as you have.

Supposely the motor has 100k on it, but I was a bit surprised to see this on a motor without the telltale spray pattern on the pistons associated with power adders.

Things that make ya go Hmmm.....

Now you have an excuse to buy a cam. ;)

What about his piston clearances????????

Got her all fixed up tonight! I don't think I'll have this issue again. Next project is cutting the pistons before Friday.

Mat, my motor has 48k miles on her and been running one programmer or another since 20k.

damn john ans 01 with 48k i thought i was bad with a 03 with 39k, nice job on the cam pin fix, i wish i had your fabricating skills

So the rods were all bent with only 48k on the motor??? :eek:

So the rods were all bent with only 48k on the motor??? :eek:

As far as I can tell. If the piston protrusion is supposed to be .009-.014, I'd say yes, every rod was short.

How many pulls with the dual fuelers?

How many pulls with the dual fuelers?

Two pulls and a few trips down the 1/4 mile, otherwise all street driving.

Finally got the pistons all figured out. The finally compression ratio will be 16:1 using the stock LB7 pistons. I will post pics and numbers of what I ended up doing, as soon as I actually cut them tomorrow.

Like I said, here is a pic of one of the modified pistons. What I was shooting for was 16:1. Since I am only running the stock cam, I wanted to leave as much on the top of the piston as possible, and take as much out of the bowl as I felt comfortable with. What I ended up doing is draw the stock piston in solidworks (with help from 1 of the engineers at work) and model it as close as I could measure it and using Guy's compression calculator to give us the proper stock bowl volume.

From there we started chopping away on the computer until all the volumes were exactly where I wanted them. What I ended up with was facing .027" off the top of the piston, then cutting the entire lip off the bowl to a diameter of 2.5", lastly then machining a .1875 radius on the corner.

Will this work??:confuzeld we will shortly find out. I am more than willing to hear any and all comments good or bad on this mod. Since everybody seems to keep there mods to themselves I didn't have much to base the route I took.

Looks good! Why did you lower the cr? Are you still going to run the A5K?

Looks good! Why did you lower the cr? Are you still going to run the A5K?

Yes I still plan on running the 5000. Lowering the cr can't hurt any, and with all the cracked pistons lately I figured it was a good idea.

Looks good to me. The .1875 radius from the bowl to the crown should really help prevent hot spotting. That is what I have planed but with vavle releifs as I am running a large cam.:)

Great job. Thanks for the info! Glad you didn't turn it up with the twin CP3's now?

Great job. Thanks for the info! Glad you didn't turn it up with the twin CP3's now?

I was hoping to see a bent rod when we pulled it apart:)

Thanks Jon for posting your progress. This is a great thread. Nice work too! :thumb:

Got the pistons, rods, and cam all in today, everything went well. As far as measuring the rod bolt stretch, we had to torque every bolt to a maximum of 75 ft/lbs in order to get the bolt to stretch between .005" and .006".

It was much more difficult to get the cam gear on now that the key fits tight as hell compared to what was left of my pin. Should hopefully get the rest of the motor back together this weekend. I know it's going as fast as some people have done a build, but i'm taking my time and checking everything.

I will post pictures tomorrow of the build in progress.

That piston looks exactly the same as the ones Merchant and Touch turned out. Unless the Mahle guy shows up with something different, maybe thats the proper way to decompress the engine.

Looks good Jon.

That piston looks exactly the same as the ones Merchant and Touch turned out. Unless the Mahle guy shows up with something different, maybe thats the proper way to decompress the engine.


Great minds think alike.:D

Got a few more pics for you guys. R&R rods installed, modified pistons installed, ARP head studs and head on and torqued.

I also broke the damn cam position sensor trying to remove it to clean the front cover. :nutkick: :duh:

Looks good John, no time on Saturday. I'll have to swing by when you got' er all tuned in and back together so you can give me a RIDE in that beast!

I'll be in Brookfield next week! I'll call ya, John.

John what were the [cam pin] symptoms you talked about? You said something about lower boost?

John what were the [cam pin] symptoms you talked about? You said something about lower boost?

I don't know for sure if the cam pin was related, but I wasn't achieving the boost levels that some appear to be getting. My max with the 5000 was only 48 psi in 5th gear locked. I gave Bob a ride a while back and he too said I should be running higher that I was. I can't say for sure it was the problem, and it will be hard to do a fair comparison once I get it running again because of the lower compression and oversize injectors.

I never had a problem with the truck whats so ever, that made me believe something was wrong.
The way I figured it, my valve timing was off more than 7 degrees, but less than 10 degrees. I don't have the faintest clue as to how much valve timing can be off before it starts screwing things up?

how bad were the stock rods?

how bad were the stock rods?

Worst one was .027" short, best was .004" short.

Someone asked about why you drop the CR on the engine, it helps lower the Cylinder pressures. Common on high performance diesels, some production diesels are in the neighborhood of 14.5 to 1.

still on the wall of this. i understand clearancing for valves, but if you take cylinder pressure away, isnt that where the power comes from. so now you have to add that much more air to be were you were before

You make it up with boost. Sort of!:D
It takes pressure to make power. More specifically torque. It is more efficient to make pressure with added boost and lower compression ratio then it is to do it with less boost and stock comp. ratio. Now move that torque up the power band and you can make more horsepower with less torque. That means it takes lower cylinder pressures to make 600hp @ 4000 rpm than it does to make 600hp @ 3000 rpm. Lower the comp ratio and raising the rpm could very well be the ticket to high HP and durability. But it will take a complete package to do it. Comp. ratio, cam, valve train, turbo, etc.

Truck is officially up and running and on the road. We put in about 11 hours on Saturday, and about 2 this morning. Starts and runs great with a tow tune I am running. I plan on taking it easy for the 1st few hundred miles just to make sure everything pans out, then afterwards, giver the beans!

congrats, glad to hear she running again

Nice

sweet... Whens it goin on the dyno? the first few hundred go fast.

Never been a real big dyno fan, but it'll show what she can do on the pulling track.

Glad to hear it Jon!

great news, can wait to see it roar!

Never been a real big dyno fan, but it'll show what she can do on the pulling track.

It is going on the dyno no matter what you say!:cool:

Congrats John!

sweet.

It is going on the dyno no matter what you say!:cool:

I'm sure it will end up on a dyno some day or another, but I'm not in a big hurry.

It hasn't been too cold here in the morning lately, yesterday it was around 45 degrees and the truck started no problem and idle smooth upon start up. I only get a puff of smoke right at startup, but other than that it's clear.

I did notice when running the exact same tune as before the motor build, the black smoke really starts to pour out when rolling on the throttle lightly. I don't know if this is attributed to the oversize injectors, or the lower compression, I'm sure it's a combination. Once I get some miles on her, I'll see if the A5K can still clean up all the smoke.