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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 4403
Experience:  Owner at DJ Wilson
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Cat 6nz had block redone deck been machined new cat liners

Customer Question

cat 6nz had block redone deck been machined new cat liners new cat deck plate but all 6 liners below deck plate block cut and new sleeves put in top for seal ring then machined my only thoughts is liner flanges to thin if block true and new plate and gasket yet all 6 below deck plte
JA: We'll do all we can to help. Is there anything else important you think the Heavy Equipment Mechanic should know?
Customer: 26,000 on rebuild fire ring on 2 cyl split and the 3k thinner plate will still leave liners less than cat specs i know liner flanges can vary but not all 6 all messure within 2k off each other on height with out gasket and deck plate on block checked 4 spots around each liner
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Heavy Equipment Mechanic about your situation and then connect you two.
Submitted: 6 months ago.
Category: Medium and Heavy Trucks
Expert:  William Herren replied 6 months ago.
Hello my name is ***** ***** I will be assisting you.
Expert:  William Herren replied 6 months ago.
Can you please provide engine serial number
Customer: replied 6 months ago.
6nz29632
Customer: replied 6 months ago.
aint answered anything yet so why ok the 41 dollar charge when only response is for eng sn
Expert:  William Herren replied 6 months ago.
I'm pulling up a spec sheet to send to you that will give you a variation of ways to reach your spec. If that fails we will have to go another route. I apologize for the wait.
Expert:  William Herren replied 6 months ago.
I am having trouble uploading it to this site. Do you have an e-mail that I can send it to?
Expert:  William Herren replied 6 months ago.
https://www.dropbox.com/s/mfoob6zxqg7047z/cylinder%20liner%20projection.pdf?dl=0
Expert:  William Herren replied 6 months ago.
Please copy and paste into your browser
Customer: replied 6 months ago.
i know about shims for liners but my ? is how is it possible for all 6 to b below deck plate block is true and machined flat new plate same thickness as original all 6 liners are new so with that it should be right on specs my only thoughts is liner flange is to thin maybe even wrong liners
Expert:  William Herren replied 6 months ago.
Have you verified liner part #, have I compared old liner to new liner?
Expert:  William Herren replied 6 months ago.
What part number do u have for your liners?
Customer: replied 6 months ago.
you have to exchange old liners and pistons for core charge so no way to mic the two and yes the gold kit i got from peterbilt part numbers match for 6nz00001 and up 435hp to 550hp
Expert:  William Herren replied 6 months ago.
Before you had it machined did u notice any numbers stamped around each cylinder?
Customer: replied 6 months ago.
gold kit number is *****
Customer: replied 6 months ago.
no i rebuilt it put 137,000 on it head was cracked which the first time i used only block rods and crank used pia parts started pushing water out of radiator so this time i pulled engine did a complete out of frame with cat parts only didnt like oil pressure on first rebuild now all is good except for this problem like i said put liners in block messured flange height no plate all with in 2k of each other but fire ring flange is below plate again on all 6 liners the original liners where cat parts have not pulled these liners back out yet but i can see they are not dropped no chaffing on fire ring surface or flange
Customer: replied 6 months ago.
also no shims on origanal liners nor dropped to liner seal surface had some pits so i had block rebuilt did check with straight edge before put liners in block
Customer: replied 6 months ago.
parts list from peterbilt
Expert:  William Herren replied 6 months ago.
im not able to verify any of the machining that has been done, therefore I believe another expert would be better served. I will opt out and allow another expert to answer your question.
Customer: replied 6 months ago.
ok thanks so what happens now
Expert:  William Herren replied 6 months ago.
Your question will be posted for another expert to accept.
Expert:  Daniel Wilson replied 6 months ago.

Hi Aaron, My name is***** will be glad to help. Cat offers a thinner spacer plate. Do you know the part number and thickness of the current spacer plate you have? Let me know

Customer: replied 6 months ago.
its the thick plate i know the thinner plate is 3k thinner but wont be enough to bring liners into specs liner flange are is 6 to 7 below all 6
Customer: replied 6 months ago.
parts list
Expert:  Daniel Wilson replied 6 months ago.

Something is not adding up here. Was the deck planed or counter-bored and shimmed? If planed there is no reason why a new liner should be showing low. How are you measuring your liner protrusion?

Customer: replied 6 months ago.
thats my problem block redone at machine shop had some pitting on upper liner seal surface so had all 6 cut put sleeves in then deck machined flat checked with straight edge set liners in no seals on liners used dial indicator messured all for height difference then put put gasket new plate then used 3 inch 3/4 bolts with flat and rubber washers on each bolt torqued to 70 lbs and liner flange still below plate make no logical since deck flat and true new plate and liners all should be dead on or with in specs
Expert:  Daniel Wilson replied 6 months ago.

Double check the liner part numbers to see if maybe they gave you the wrong liners or spacer plate...

Customer: replied 6 months ago.
do you have part number for thinner plate mine is 6i4421 .0338
Expert:  Daniel Wilson replied 6 months ago.

The thinner spacer plate is(###) ###-####this plate is .003" thinner than the standard plate at. The only way you can use this plate is if all the liners are within .002" adjacent to each other and the overall measurements from one end of the block to the other end, the projection is less than .003" with the standard plate. If you have one cylinder at .0035 and the two cylinders adjacent are .0025 when you install the thinner plate the measurements would raise the liner projection to .0065 with the two adjacent cylinders being .0055. You'd be taking a risk of cracking the liner flange on the .0065 cylinder at a later time even though it's within the .002" spec of the liners next to it.

Use the thinner plate only if the liner is above the max of .006". A high liner projection means that the head is exerting more downward pressure on the flange/liner which can result in cracked or bro***** *****ner flanges.

Customer: replied 6 months ago.
Ok cat has me so confused they saying l have to cut and counter bore and I explained to them block deck is true snd level new gasket and plate should b good I messed liner flanges with caliper and as much as 4k difference between some of mine which still doesn't explain why I'm low they say say shop may cut deck to much but if so still would not have this problem but the piston would contact head bug not the case
Expert:  Daniel Wilson replied 6 months ago.

It is true that counterboring and shimming is required to bring the tolerances into specs. I am assuming you have the bulletin with head gasket procedure for this?

Customer: replied 6 months ago.
No I do not but I did go to cat the liner flange they pulled off shelf is ,355 all of mine flange thickness is .349 so there is my problem now to get them to warranty them
Expert:  Daniel Wilson replied 6 months ago.

Thanks for the update. Click this link for the full procedure for all 3400 series engines. It also covers the liner flange thicknesses.

Repair procedure

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