Guess the issue!?

[Derek@Vision Diesel]

Checked protrusion on the drivers side this morning once everything was reinstalled.

The back #8 cylidner was .004. You couldnt even feel it coming above deck height.
The #7 is our other bad one at .010.


They were definitely not paying close attention to the surfacing. I dont believe we have ANY pistons coming up to factory spec though, as far as protrusion. So it isnt that they took TOO much off, its just clearly not flat.

 

[SteveBricks]

Have you measured the length of the rods?

 

[Mdub707]

There's no use in measuring piston protrusion since the block clearly isn't flat... can't get a good reading without a good base to measure from. Even if the pistons sat at the same height, they'd still all have different readings. I would measure the rods like SteveBricks is suggesting. That will tell us if you have bent rods for sure.

 

[kevin]

I would put a straight edge on the deck

 

[Derek@Vision Diesel]

There's no use in measuring piston protrusion since the block clearly isn't flat... can't get a good reading without a good base to measure from. Even if the pistons sat at the same height, they'd still all have different readings. I would measure the rods like SteveBricks is suggesting. That will tell us if you have bent rods for sure.

I measured 3 rods and they were all identical.

Valves had to of been the compression issue.
The BO gasket along with the heads being machined incorrectly accounted for the piston/valve contact. And that is most likely the noise it was making also.

This might be a dumb question, and I have my own theory. If the deck of the block is 100% flat from front to back but it was setup up like 1* off in the decking machine, you basically just loose a little compression as you go back. There aren't any other consequences of the block being flat but not level is there?

I would put a straight edge on the deck

The block is straight, it was just set in the machine wrong when they decked it.

 

[SteveBricks]

I measured 3 rods and they were all identical.

There are 5 more

How did you make the measurements? I'm not making any claim of being an engine builder, but it seems to me that the measurement that matters here is c/l to c/l, small end to big end. Is that what you checked? With the protrusion differences you posted, and with the deck surfaces being flat, I don't see how that's possible unless some of those rods are shorter than others.

If the deck of the block is 100% flat from front to back but it was setup up like 1* off in the decking machine, you basically just loose a little compression as you go back. There aren't any other consequences of the block being flat but not level is there?

The c/l of the crankshaft and the deck surfaces should be parallel, obviously. If the deck wasn't parallel with the crankshaft c/l, I think your piston protrusion measurements would have shown that by gradually gaining or losing from front to back (for example .030, .026, .022, .019) rather than being random as you noted. Again, I'm no engine builder, but that seems to make sense to me.

How did you determine TDC when you were making the protrusion measurements? Did you use a degree wheel? Dial indicator?

 

[Mdub707]

I measured 3 rods and they were all identical.
This might be a dumb question, and I have my own theory. If the deck of the block is 100% flat from front to back but it was setup up like 1* off in the decking machine, you basically just loose a little compression as you go back. There aren't any other consequences of the block being flat but not level is there?


The block is straight, it was just set in the machine wrong when they decked it.

Well I guess flat is a relative term then eh? I guess you could consider it "flat" but it's certainly not parallel.

What about the other 5 rods???

There are 5 more

How did you make the measurements? I'm not making any claim of being an engine builder, but it seems to me that the measurement that matters here is c/l to c/l, small end to big end. Is that what you checked? With the protrusion differences you posted, and with the deck surfaces being flat, I don't see how that's possible unless some of those rods are shorter than others.





The c/l of the crankshaft and the deck surfaces should be parallel, obviously. If the deck wasn't parallel with the crankshaft c/l, I think your piston protrusion measurements would have shown that by gradually gaining or losing from front to back (for example .030, .026, .022, .019) rather than being random as you noted. Again, I'm no engine builder, but that seems to make sense to me.

How did you determine TDC when you were making the protrusion measurements? Did you use a degree wheel? Dial indicator?

Yeah what he said.

 

[Jarrod B]

So let me get this straight...



You are taking a customer's money because you told him YOU could fix his truck. But in reality you have absolutely no idea how to fix it or whats even wrong. So you offer up a free t-shirt to have the internet forum community help you figure out what it is??????

Sounds like bad business to me.


If I was a good paying customer that took something to a shop to have "fixed" and then found out they were pimping clothing on the internet in exchange for help cause they had no clue as to what was wrong with my pickup or how to fix it, I'D BE P*SSED!!!!!!!

so you tell me that all mechanics know exactly whats wrong with every engine 100% of the time? bs

 

[Strokersace]

so you tell me that all mechanics know exactly whats wrong with every engine 100% of the time? bs

There a difference between having no idea at all and knowing EXACTLY what is wrong. I never said what you interpreted nor was I implying it.

So you're telling me that if you took your truck to a mechanic and gave him the symptoms to which he said "Huh, I have absolutely no clue what the hell could be wrong. But hey, I'll give her hell!" You'd still say go ahead and have at it??

Same concept of interpreting as you initially did with my post, just opposite side of the argument.


What I was saying is that it appeared that way from what info Derek had given us up to that point. Only after I posted that did he clarify and give more detail about the situation.

 

[Derek@Vision Diesel]

enough with the small talk, no one is going to hurt my feelings over the matter. I just enjoy showing what we are doing here, the progress being made, and getting advice from those smarter than I.

It seems as though I might be a little bit too picky as far as things being perfect. The customer is 100% ready to slap new heads on it and see how it runs with OEM gaskets, but I want to get to the bottom of all these measurements being different first.

 

[Mdub707]

What's the tolerance on the .030" piston protrusion?

I don't understand how they're supposed to be .030" above the deck at TDC, yet material was removed from the block and now some are sitting LOWER in the block, but none of the rods are bent?

 

[Derek@Vision Diesel]

What's the tolerance on the .030" piston protrusion?

I don't understand how they're supposed to be .030" above the deck at TDC, yet material was removed from the block and now some are sitting LOWER in the block, but none of the rods are bent?

All cylinders that were under .020 were removed and measured/inspected for signs of being bent. Nothing was found.

We dont have a single cylinder that is within factory spec of .027-.030.

These pistons could have been shaved down, but there are no signs on them of machine work and the same is still clearly visible.

 

[Mdub707]

I'm not questioning your measurements, just thinking out loud and trying to wrap my head around it. Doesn't seem to make any sense. Or do they originally sit lower and the .030" piston protrusion is a MAX clearance thing? I'm guessing that's what it is...

 

[Derek@Vision Diesel]

I'm not questioning your measurements, just thinking out loud and trying to wrap my head around it. Doesn't seem to make any sense. Or do they originally sit lower and the .030" piston protrusion is a MAX clearance thing? I'm guessing that's what it is...

Well when it says .027-.030 is your factory SPECIFICATION, to me that means that its going to land in that area from the factory.

Doesnt make any sense to me either, quite honestly I have questioned my measurements multiple times and find myself re measuring.... So now that i have re measured multiple times I know they are correct

 

[tensixniner]

What tool are you using to measure piston protrusion?

How did you determine the rods you removed were straight?

 

[Derek@Vision Diesel]

A dial indicator with magnetic base for protrusion.

And i took a micrometer to them and they were all identical length no matter where i measured from

Sent from my DROID4 using Tapatalk 2

 

[golfer]

are you measuring the pistons L&R at the center of the bore in line with the LENGTH of the block? and not side to side towards the valley and/or toward the edge of the block where the exh manifold would be?

basically, you need to measure the piston(s) inline with (and directly "over") the piston pin...since the piston can rock in the bore slightly, on the pin.


the PTV contact, annnnd the lack of compression could have been from the (excessive?) decking of the head(s) which would have allowed the PUSHRODS to effectively cantilever the rocker/bridge to hold the valve(s) open. Not 100% of the time with hydr. lifters...but it is possible.

 

[Derek@Vision Diesel]

are you measuring the pistons L&R at the center of the bore in line with the LENGTH of the block? and not side to side towards the valley and/or toward the edge of the block where the exh manifold would be?

basically, you need to measure the piston(s) inline with (and directly "over") the piston pin...since the piston can rock in the bore slightly, on the pin.


the PTV contact, annnnd the lack of compression could have been from the (excessive?) decking of the head(s) which would have allowed the PUSHRODS to effectively cantilever the rocker/bridge to hold the valve(s) open. Not 100% of the time with hydr. lifters...but it is possible.

the valve job on the heads was awful, 90% of them had signs of not sealing...
The issue we cant exactly figure out is why valves were touching pistons though, none of the measurements seem to give an answer.

And yes we are measuring with the length of the blots right above the pin

 

[golfer]

what is the measured valve recess(es) on the heads?

 

[Derek@Vision Diesel]

what is the measured valve recess(es) on the heads?

They were recessed TOO much from what I have learned. I believe they were about .020. Isnt factory just a hair over .012?? Maybe my mind isnt serving my correctly and I am sure the number is somewhere in this thread, but they were definitely recessed more than enough to meet stock spec.