Cat 943 with 3204 piston question

[petemoss]

I'm restoring a cat 943 track loader and hoping someone can answer this question. It's a 1981 versión serial number 31y01018 engine 3204 dt... serial number 10x01169, arrangement number 4n8376, non turbo...

It has the 2 ring pistons and I was told by another mechanic to upgrade to the 3 ring versión... I found a good price on an aftermarket kit at fridays parts and they have 3 piston options...but.... I gave my serial number and over email I was told that only the 2 ring piston option would work in this engine.... there seems to be a language barrier so I'm not sure if I'm getting the accurate feedback for my engine.

So, to sum up... can anyone verify if my early model 3204 non turbo engine can be upgrade to a 3 ring piston? And if so are there different 3 ring pistons over the years that only work with some 3204s and how would I distiguish which is which?

Thanks!!

 

[HarleyHappy]

I have had no issues with Friday Parts. I would call back and explain to them you want 3 ring pistons for that engine prefix and they should probably be able to tell you.

 

[excavator]

FYI a 3204 is a half of a 3208 so 3208 pistons would also be the same.

 

[petemoss]

Thanks... I know these engines were in production for many years and some changes were made so having trouble getting to the bottom of the question whether the upgraded 3 ring piston will work with the original connecting rods. Friday parts told me I had to go back with 2 ring piston but I'm wondering if they were just playing it safe based on my pictures I Sent of original 2 ring pistons...

 

[petemoss]

I have had no issues with Friday Parts. I would call back and explain to them you want 3 ring pistons for that engine prefix and they should probably be able to tell you.

Thanks, but I can't get anyone on the phone with any expertise... only through email and theyve been really slow to respond... days pass... and they finally told me I had to go back with 2 ring pistons based on pics I sent of my old 2 ring pistons.. I don't know if they are just playing it safe or if that's the only option because another cat guy said I should definitely go back with 3 rings. Ill keep calling around I guess.

 

[Nige]

What Part Number is marked on your connecting rods.?

 

[cat951b]

Hi petemoss,
try here at IPD. I rebuilt one of these last year with IPD parts and it turned out very well.

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www.ipdparts.com

 

[petemoss]

What Part Number is marked on your connecting rods.?

6n8011

 

[petemoss]

What Part Number is marked on your connecting rods.?

Well... I'll get back to you for sure on that when I verify what is actually stamped in the original rod...I have them at machine shop right now so I can't put eyes on it myself... to be clear i had to order 1 rod and that part number is 6n8011... originally I don't recall if I used a number off the old or not... but when it got to the shop the guy said it was the same rod so that number should be right

 

[Nige]

Well 6N8011 services to 8N3753.
To the best of my knowledge either of those rod Part Numbers will accept a 3-ring piston. There have been a number of members on this forum who have rebuilt their 3204 machine engines using 3-ring IPD pistons.

 

[petemoss]

Thanks! I contacted Ipd and waiting for a call back. My machine shop guy didn't get back to me on that rod number but pretty sure that's it or equivalent

 

[Welder Dave]

Can vouch for IPD 3 ring pistons. Engine has a little more power and starts instantly.

 

[Dave Neubert]

I always put them back with 3 ring should be no problem

 

[petemoss]

Thanks... I'm gonna post my piston pics and a link to fridays parts engine kit

https://www.fridayparts.com/overhaul-rebuild-kit-for-caterpillar-cat-3204-engine

From this link you can scroll to the pic showing the 3 piston types that are available with this kit...

Fridays told me I couldn't go back with anything but the 2 ring but I'm not sure why other than them basing it on my original pistons

also waiting to hear back from IDP and maxiforce on what they offer.... nothing yet...

 

[Tyler d4c]

We just got 3 ringed pistons for a d4c from interstate mcbee I i think from maxiforce.

 

[petemoss]

Thanks everyone... just to close this for now... 3 ring piston from fridays parts I was told wouldn't work so I Sent with interstate mcbee... may have more questions as this project unravels!

 

[cat951b]

Try IPD, you won't be disappointed.