Having my engine overhauled, anything special i should have shop do?

[Shawn MacAnanny]

Well I've been using him for a long time, 10+ years, if something he suggested was wrong and it broke I honestly wouldn't even be mad because everything he's done for me before has been perfect. I think he misunderstood my dropping the engine off and saying there was no rush and to disassemble it first before I order any studs or clutch etc and see what needs to be done as "budget rebuild". I'll have it balanced. But I want first dibs on those pistons Russ! Haha

 

[MTKirk]

Balance it. Plastikote engine enamel. King bearings. Or clevite 77. Use original oil pump.

If we use new pistons of the same weight as originals, and all other parts are the same, wouldn't the factory balance be maintained?

 

[IDIoit]

If we use new pistons of the same weight as originals, and all other parts are the same, wouldn't the factory balance be maintained?

there are tolerances on weight along with dimensions.
when new parts are introduced, the balance changes.
nothing beats a proper balance.
if you go to a shop, and the machinist says "nah you dont need to ballance your engine"
FIND ANOTHER SHOP.
sure, these engines dont spin at high RPM. but the entire point of balancing is to have proper weight displacement, a smoother engine..
BUT... the real reason i balance EVERYTHING, is for bearing longevity.
a balanced engine will last alot longer due to less strain being put on everything.

 

[MTKirk]

there are tolerances on weight along with dimensions.
when new parts are introduced, the balance changes.
nothing beats a proper balance.
if you go to a shop, and the machinist says "nah you dont need to ballance your engine"
FIND ANOTHER SHOP.
sure, these engines dont spin at high RPM. but the entire point of balancing is to have proper weight displacement, a smoother engine..
BUT... the real reason i balance EVERYTHING, is for bearing longevity.
a balanced engine will last alot longer due to less strain being put on everything.

Unfortunately there isn't a shop any where near me that will balance the entire rotating mass of my engine. I will get my new piston, pin, ring assemblies as close to original weight as possible. And getting them all within 1/2 a gram of each other should be doable (same with the rods I'm reusing). Other than that I don't see what more I can do that doesn't involve shipping my engine somewhere. At a minimum that should have it running as smoothly as it did before?

 

[IDIoit]

do what you gotta do and hope for the best.

 

[riotwarrior]

Unfortunately there isn't a shop any where near me that will balance the entire rotating mass of my engine. I will get my new piston, pin, ring assemblies as close to original weight as possible. And getting them all within 1/2 a gram of each other should be doable (same with the rods I'm reusing). Other than that I don't see what more I can do that doesn't involve shipping my engine somewhere. At a minimum that should have it running as smoothly as it did before?

So you yourself are going to machine pistons to balance pistons pins and rings as an assembly then...??

What are you using as a scale and how accurate is it?

And rods? How do you plan on going about that...there is a procedure for doing rods and probably...no there are some special jigs...you could make them regardless...it is knowing what to do were to remove material and order to do said balancing.

I suppose if uou had your reciprocating assembly self balanced and could accurately do it you might be able to send crank dampner and flywjeel to get balanced but why not semd whole rotating and reciprocating assembly out...build a box send the parts and voila..

Bobs yer uncle.

JM7.3CW

 

[MTKirk]

So you yourself are going to machine pistons to balance pistons pins and rings as an assembly then...??

What are you using as a scale and how accurate is it?

And rods? How do you plan on going about that...there is a procedure for doing rods and probably...no there are some special jigs...you could make them regardless...it is knowing what to do were to remove material and order to do said balancing.

I suppose if uou had your reciprocating assembly self balanced and could accurately do it you might be able to send crank dampner and flywjeel to get balanced but why not semd whole rotating and reciprocating assembly out...build a box send the parts and voila..

Bobs yer uncle.

JM7.3CW

I've got a digital scale accurate to tenths of a gram, & I can remove material from pistons (and pins if absolutely necessary). My goal would to be to maintain original balance, which seemed fine to me AND the truck went 190,000 miles on the main bearings. Hopefully the old pistons are close in weight to the new ones, as well as each other, that way I can just put in the new pistons and be back where it was originally. I will just put the rods back exactly where they were, I don't believe I will even be changing wrist pin bushings. I will weigh the rods to see how close in weight they are to each other, but I'm reluctant to mess with them at all.

I'm hoping I can turn up a lead to get the thing balanced somehow locally, maybe the local heavy truck shops can get it done. I don't see myself shipping parts out to get it done.

 

[Shawn MacAnanny]

He's definitely going to balance the engine he says. He got the heads off today, he says the pistons look fine, i forgot to get more pictures of it the carbon ring where he scraped it off, its just a ring he says its not worn in at all, or a ridge, or some technical term i forget. The cylinders looked like maybe they had some rust or something on them or maybe it's normal? The truck has sat a few months but i did get it running and brought it up to temp weekly for the past couple months. He didnt seem to concerned about it, he thinks it can probably just be honed and reuse the pistons.

 

[MTKirk]

He's definitely going to balance the engine he says. He got the heads off today, he says the pistons look fine, i forgot to get more pictures of it the carbon ring where he scraped it off, its just a ring he says its not worn in at all, or a ridge, or some technical term i forget. The cylinders looked like maybe they had some rust or something on them or maybe it's normal? The truck has sat a few months but i did get it running and brought it up to temp weekly for the past couple months. He didnt seem to concerned about it, he thinks it can probably just be honed and reuse the pistons.

We're havin' fun now! I'm going .020 over on mine. Cylinders were pretty worn from running on dusty Montana prairies with a poorly fitting air filter, so my machinist was able to just hone it to size. Found a guy with a machine to balance mine as well, normally only does work for the semi repair shops, but I talked$$ him in to it. Here's hoping we both turn out OK!

 

[Hydro-idi]

He's definitely going to balance the engine he says. He got the heads off today, he says the pistons look fine, i forgot to get more pictures of it the carbon ring where he scraped it off, its just a ring he says its not worn in at all, or a ridge, or some technical term i forget. The cylinders looked like maybe they had some rust or something on them or maybe it's normal? The truck has sat a few months but i did get it running and brought it up to temp weekly for the past couple months. He didnt seem to concerned about it, he thinks it can probably just be honed and reuse the pistons.

I'm sure he will, but ask if he plans on measuring bore taper. I bet it's out of spec. IMO, always a good idea to get cylinders bored to "true" them up nicely. Especially on an old worn out Idi. Some say that .020 over on a 7.3 & .030 over on a 6.9 is safe to do.
These engines have a very high compression ratio. Any taper in cylinders will cause engine blowby & power loss.

 

[Shawn MacAnanny]

Is 168K considered "worn out" on an idi though? Hopefully the bore taper isnt too messed up. I'm sure he's going to measure everything

 

[MTKirk]

Is 168K considered "worn out" on an idi though? Hopefully the bore taper isnt too messed up. I'm sure he's going to measure everything

If it was run in dust, or with a bad air filter, things can go bad very fast. You have to measure it! With your finger feel for waves at the top of the cylinders (right where the rings would be at ignition) if you feel ripples you are going to need an overbore.

 

[Shawn MacAnanny]

Here are some pics i got when i was there today dropping off the new clutch and flywheel to be balanced, a couple scuffs on the pistons, a scratch on the cylinder wall, he wasnt too worried about either of them, he said the crank journal looked good. I put a borescope in the coolant ports, the cylinder surfaces looked good, on cylinder 6 i found possible oygen pitting starting but it was just at the surface, could also be flash rusting in just that area. The block hasnt been washed yet or anything.

 

[Shawn MacAnanny]

Some coolant surface internal pics

 

[riotwarrior]

I dunno...bores look nasty to me...but wait for better pics

Crank has some scoring going on minor...how do bearings look?

Pistons scuff looks eww..but crown looks saweet.

Again reserving thoughts till bores are cleaned and same with the rest.....

JM7.3CW