Cab off repair and lift installed on my 6.4

sootie · Mar 27, 2020

I've never seen any six four, with a regrind or replacement cam, not have valve impressions on the pistons after some use with a race tune. Way more valve float on these things than people account for. Couple that with more rigid pushrods and low tolerance and you have a game of whack a mole

FourEyed · Mar 29, 2020

Spoke to the machine shop.

He didn't recall piston protrusion exactly, but said it was high teens .16-.18. Said specs called for max of .32 and it was under that.

Valve recession was set at .19.

All he really did was assemble the short block, and bolt on the heads. I installed the rest of the valvetrain and fuel lines. I would really rather not rip it all apart again at this point, but if you guys are really thinking it will be an issue I don't think I have a choice but to clay it and check p/v clearance.

Zeb · Mar 29, 2020

FourEyed said:
Spoke to the machine shop.

He didn't recall piston protrusion exactly, but said it was high teens .16-.18. Said specs called for max of .32 and it was under that.

Valve recession was set at .19.

All he really did was assemble the short block, and bolt on the heads. I installed the rest of the valvetrain and fuel lines. I would really rather not rip it all apart again at this point, but if you guys are really thinking it will be an issue I don't think I have a choice but to clay it and check p/v clearance.

Piston protrusion sounds good. Valve recession is toward the shallow end for a Stage 2 cam.

I’d be a bit leary to just take his word for it. You’re a days work and some gaskets away from knowing EXACTLY what you have. I’d be checking it. It’s cheaper to do it now and know, than have to fix it later.

FourEyed · Mar 30, 2020

Unfortunately I agree with you... There is just too much $ on the line to take any chances.

This sucks. I even asked RCD when I bought everything if I should just go ahead with valve reliefs and they told me it wasn't needed. If I don't have enough clearance I'll have to see if they would be willing to take these pistons back so I'm not out $$ and can just pay the upcharge for the correct pistons.

Zeb · Mar 30, 2020

FourEyed said:
Unfortunately I agree with you... There is just too much $ on the line to take any chances.

This sucks. I even asked RCD when I bought everything if I should just go ahead with valve reliefs and they told me it wasn't needed. If I don't have enough clearance I'll have to see if they would be willing to take these pistons back so I'm not out $$ and can just pay the upcharge for the correct pistons.

You shouldn’t have to exchange pistons.

I would check your clearances with a set of solid lifters and adjustable pushrods to see what p to v clearance you actually have. Once you have those numbers post up what you find and we can go from there.

If your piston protrusion is actually 0.016”-0.018” I would recommend leaving the pistons alone and getting the valves set to the deep end of factory spec and you’ll most likely be good at that point.

Gotta have actual number first tho.

sootie · Mar 30, 2020

ya-my experience also. All the cam resellers say "drop in". unfortunately real life says different. Just machine the pistons you have.

FourEyed · Apr 1, 2020

These pistons are coated..otherwise that would be a good option.

Tomorrow I will have some help, and we will be checking the p/v clearance. What is the minimum clearance I would need for this setup? If it's too tight, I will have to swap pistons to ones with fly cut's..

Zeb · Apr 1, 2020

FourEyed said:
These pistons are coated..otherwise that would be a good option.

Tomorrow I will have some help, and we will be checking the p/v clearance. What is the minimum clearance I would need for this setup? If it's too tight, I will have to swap pistons to ones with fly cut's..

0.035” clearance is considered the minimum.

I’d cut the pistons you have and/or set valve recession deeper before spending for fly cut pistons. The coating is gonna disappear after a few minutes of run time anyway.

Shafer171 · Apr 2, 2020

What Zeb said the coating will be gone before you do the first oil change.

FourEyed · Apr 2, 2020

Checked a couple cylinders. was a pita, and took some time, but tightest clearance we could come up with was .036 on the intake and .052 on the exhaust.

I'm going to run it. feels a lot better now knowing for sure what I have though.

Thanks to those that gave me the heads up to look into it.

Zeb · Apr 3, 2020

FourEyed said:
Checked a couple cylinders. was a pita, and took some time, but tightest clearance we could come up with was .036 on the intake and .052 on the exhaust.

I'm going to run it. feels a lot better now knowing for sure what I have though.

Thanks to those that gave me the heads up to look into it.

Did you use solid lifters and adjustable pushrods to do the checking?

FourEyed · Apr 3, 2020

I'm not the expert.. it was more of a watch and learn venture for me.

But he did bring his own lifters that he uses for checking, and put in lighter test springs and different pushrods. Everything had to come apart it was a pain. Tested it before at and after tdc for each. Checked it at #1 and #6. Those were the closest tolerances we could find.

Zeb · Apr 3, 2020

FourEyed said:
I'm not the expert.. it was more of a watch and learn venture for me.

But he did bring his own lifters that he uses for checking, and put in lighter test springs and different pushrods. Everything had to come apart it was a pain. Tested it before at and after tdc for each. Checked it at #1 and #6. Those were the closest tolerances we could find.

Sounds like it was measured correctly. :clapping::clapping:

webb06 · Apr 4, 2020

Shafer171 said:
What Zeb said the coating will be gone before you do the first oil change.

What makes you think the coating comes off? I just had a 6.4 apart that had coated pistons installed 20k miles ago and they all looked fine, except for the cracked one.

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Zeb · Apr 4, 2020

webb06 said:
What makes you think the coating comes off? I just had a 6.4 apart that had coated pistons installed 20k miles ago and they all looked fine, except for the cracked one.

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First one I’ve seen that had run time and you could tell that the pistons were coated.

I’m surprised a Maxxforce piston cracked.

webb06 · Apr 5, 2020

Zeb said:
First one I’ve seen that had run time and you could tell that the pistons were coated.

I’m surprised a Maxxforce piston cracked.

Agreed. First time I’ve seen one cracked.

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FourEyed · Apr 5, 2020

Yeah that's surprising to see one crack. Any idea what caused it?

I've had good luck with coated pistons in the past. I've ran them in my turbo motor in the mustang and they held up great last time I had it apart.

webb06 · Apr 6, 2020

FourEyed said:
Yeah that's surprising to see one crack. Any idea what caused it?

I've had good luck with coated pistons in the past. I've ran them in my turbo motor in the mustang and they held up great last time I had it apart.

Assuming injector. We had them all tested and several didn’t pass.

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FourEyed · Apr 6, 2020

Got it back together, and in the truck over the weekend.

Holy. Hell... What a pain in the ass to line everything up and get the trans / converter together in the truck. I wish I had a lift for the cab.

[/url]20200404_112501 by Joe malucci, on Flickr[/IMG]

[/url]20200404_112446 by Joe malucci, on Flickr[/IMG]

[/url]20200404_130616 by Joe malucci, on Flickr[/IMG]

Partial cab lift / going back down.

[/url]20200405_131142 by Joe malucci, on Flickr[/IMG]

Most of the hard part is done and back together. Just have some odds and ends to take care of.

[/url]20200405_153637 by Joe malucci, on Flickr[/IMG]

[/url]20200405_172133 by Joe malucci, on Flickr[/IMG]

Couple more nights after work and I should be pretty close.

Also found this.. Can't believe I missed it when I took it apart, but my hot side tube is pretty much rotted through. That's another 20hp right there! Waiting for my new pipes to come in before I get the rad in.

[/url]20200405_154348 by Joe malucci, on Flickr[/IMG]

FourEyed · Apr 15, 2020

Well finally got it fired up last weekend. Bled the fuel system and it fired right off.

For the first time doing this I'd say everything went better than expected. I'm no pro mechanic, just not afraid to jump into things. Took my time, torqued everything and it came out great. Took it for a ride yesterday, and all seems well. I hope I never have to do this again...

I did go through the codes on the mini maxx and found a stored old code of P0284 Cyl 8 contribution / balance. I assume this was probably a hanging injector that caused the cracked piston.

What is the general guideline for breaking these in? How many miles of "normal" driving should I do before hooking it to a trailer?

https://www.youtube.com/watch?v=fs1ZQ53ENn4