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Ricardo · 06-06-2026, **(Subject: x-15 liner shims )**

ive searched around a bit but havent seen anything specific to what im trying to understand so if theres already a post on this i apologize.

x15 started putting compression in coolant so i tore it all down and found fire ring on head gasket busted out on cyl 3 cleaned everything up and had from .009 to .003 liner height pulled liners and measured the block and had readings from 4.7260 to 4.7275 (monaco height block zeroed for 4.7240 and a reading of -.002 to -.0035) this seems like a lot less variance in height to me does the captive shim take most of the wear?

per a previous post on here seems to be ideal block depth of 4.740 giving a finished height of .015?

regardless .009 is too low so ill be cutting it for .020 shims to a depth of 4.740 i believe is correct

My question is the captive or factory installed shim thats installed on the new liners is that to be used plus the additional .020 shim to achieve this height?

From cummins bulletin TSB120249
"NOTE: It is acceptable to install a factory shimmed cylinder liner assembly, on
top of a service shim, on engines that have had the cylinder block counterbores
machined."

Stainless shims over brass shims?

first isx rebuild for me can rebuild a yellow one with my eyes closed but this is all new to me so any input is appreciated

Rawze · 06-07-2026, **(Subject: x-15 liner shims )**

== First and foremost, if the head gasket let go on the engine it means that the block needs to be counter-bored and the cylinder head is no good. - ISX's do not crush fire rings or blow head gackets unless a liner was dancing in the block.

== NEXT: Is that someone needs to find out WHY it did this. There are several reasons, and all of them point to engine abuse of some sort ... which is VERY common with ISX's. Abuses such as...

== Bad delete programming (#1 cause), as more than 90%+ of all delete programming is absolutely harmful to the engine without even adding any power yet.

== lugging the engine below 1500 RPM for most of its life. Most of these newer trucks are geared waay too tall, and the ISX's best longevity is in the 1600-1700 range, with it in the 1500 - 1900 range during heavy operating loads. It has short connecting rods and light weight pistons, very different than those yellow beasts of yester-year.

========================
as far as the inframe...

The shimms that come default on the new liners are to be used. Also an additional 0.020" shimms are also needed when counter-boring the block. - The block MUST BE COUNTER-BORED and liners raised in height above factory spec or the engine will not last, and you will be doing it all over again in short order. Also, everything has to be VERY PRECISE and torques absolutely correctly!.

Correct heights are as follows...
https://rawze.com/forums/showthread.php?...9#pid28349

ALSO here is the tings needed to build it right. Any compromise and your just wasting your moneys... here is info that is NOT in the manuals...
info: https://rawze.com/forums/showthread.php?...6#pid70606

One mistake, oversight, or shortcut,... and its wasted time and moneys. - Bad delete programming and its wasted moneys... NOT USING ALL OEM parts... and its wasted time and moneys...- Don't be the next fool on here in 2 years complaining that it did not stay together.

Ricardo

I absolutely agree there’s no question about it I will be cutting the counterbores, actually already started just waiting for shims to arrive before I proceed to final depth to confirm height will be as stated .014-.015

As far as engine abuse goes well I purchased this about 40k miles ago so what the previous owner did is out of my hands, was it lugged? Probably, most everyone does it and don’t understand what that does to an engine. If someone tells you they never lug it they’re lying to you.

100% stock no delete no aftermarket parts no tuning it ran fine the way it was so it’ll stay that way and get proper maintenance until it doesn’t and then we go down that rabbit hole.

As far as oem parts go well you won’t like it and by the sounds of things I’ll probably regret it later but I use {after-market branded } for all my cats and that’s what my machine shop is a dealer for so that’s what it’s going together with (liners pistons rings and gasket) everything else replaced will be oem such as oil pump cooling jets things of that nature. Will it work out for me well maybe maybe not lots of shops local to me use them and I know a few guys pushing 500k since with no issues, I can promise you oem or not this truck will not make it to a million, 10,000 hours maybe but the line of work it does it gets hours not miles.

As far as the head goes what’s the reason behind new? What’s the bad with resurfacing the head maybe only needs .001 and all the liner marks are gone? Not trying to be bullheaded or saying that I’m not open to replacing the head just seems as though we live in a throw it away and get new society these days so I just like to learn the reasoning behind why you do things the way you do

Ricardo

{removed post, incorrect info towards cummins engines.}
Most of that makes sense to me, so now to the next question new head -$8,000 and “recon” head 4,000 so what’s Cummins doing to recon a head testing for cracks and cutting new seats essentially replacing the valves and “cleaning” the deck without actually removing material to not “change” the compression ratio? Not saying that’s the route I’ll be going but definitely something to consider

Rawze

(Yesterday )Ricardo Wrote: {removed post, incorrect info towards cummins engines.}
Most of that makes sense to me, so now to the next question new head -$8,000 and “recon” head 4,000 so what’s Cummins doing to recon a head testing for cracks and cutting new seats essentially replacing the valves and “cleaning” the deck without actually removing material to not “change” the compression ratio? Not saying that’s the route I’ll be going but definitely something to consider

The main issue is that your trying like all h#4ell to apply yellow engine standards to a red engine. -- they are not tolerant to this kind of foolishness.

I give that engine about 2-3 years max and all that moneys will be wasted once again... everyone blaming the engine and their regrets instead of investing in the right way to do everything.

ALL OF THOSE PARTS from that after-garbage place you mentioned may be ok for some other brand of engine,... but NOT FOR AN ISX!!!... PERIOD!!.

DO NOT SAY YOU WERE NOT WARNED!!!. -- THEY DON'T LAST VERY LONG AND IT COSTS WAAAY TOO DAMN$M MUCH MONEYS TO MAKE SUCH HORRIBLE GAMBLE WITH SOMEONE'S $40,000 COMMERCIAL ENGINE WITH! - YOU'RE AT THE WRONG PLACE IF YOU WANT TO ARGUE THIS!!.. IT'S WAAAAY TOO COMMON AROUND HERE, AND PEOPLE FIND OUT ALL THIS THE EXPENSIVE AND HARD WAY IN THE END!.

AND YES... THAT THING SHOULD ABSOLUTELY LAST A MILLION MILES IF IT IS BUILT CORRECTLY AND NOT ABUSED INTO THE GROUND!. - THAT IS THE ENTIRE POINT OF IN FRAMING IT INSTEAD OF REPLACING IT.
YOU'RE DIRECTLY ON THE PATH OF THAT THING NOT LASTING FOR =S$IT!!!.. THAT IS THE PATH YOU'RE ON AND I FEEL SORRY FOR ANYONE WHO END UP IN IN THAT POSITION!!.

== I am muting this person from further shoving their own foot in their mouth.. go make your argument over on social medai where that after-garbage argument nonsense belongs!.

Rawze

I guess this person never read into much of my forum before.. but would like to argue the use of after-garbage and shaving heads and all the other failed crap that is well documented across time on here.

If your truly looking for a debate, and not simply professional advice on this ... my forum is NOT the place for that... here is why...

An inframe is an investment into the future for a trucking business. It is a big investment that takes more than a couple 3 years to recover from for most people. It is "buying another truck" kind of expensive!> and If the engine fails in less than 6 - 8 years of run/use down the road, then it is simply wasted efforts and moneys. - THEREFORE IT BECOMES A COMPLETE GAMBLE to use non-oe parts which have a proven track record around here, especially so on one of the brands/methods you mentioned in your first post, on these red engines to have serious problems either right away, or in short order after such work is done.

A BIG ISSUE is that, as a mechanic, they fail to see that they are on the wrong side of the coin on this one. - The repair shop/mechanic is NOT the one who has to suffer the consequences of such a bad investment as the failures happen again, either right away, or down the road in a relative shortened time frame.

When someone is caught up into, and are pushing this known bad investment of after-garbage internals for the ISX's onto others ... for this, I do not tolerate it on my forum.

Here is a relevant re-quote from: https://rawze.com/forums/showthread.php?...3#pid85603

(12-19-2025 )Rawze Wrote: (related information, not directed towards anyone)...

AN INFRAME is an investment...

When it comes to expensive repairs to your equipment such as a complete rebuild, it should be seen as AN INVESTMENT, into the future. It is very similar to investing in stocks or other things that you do not know the outcome for.

.. And just like investing in stocks on the market,... if you do not invest in the right ones,;.. then it hurts.. IT HURTS BADLY!.

I don't know about anyone else.. but I would only want to invest in something that absolutely will yield a profit instead of something shady or is of lesser certainty.

The same thing goes with an inframe for your truck. - INVEST WISELY.. VERY VERY WISELY, because anything less, and it hurts like all h#ell financially in the end.

With an inframe, your investing in the future longevity of the equipment. - Your investing and making a gamble on 'how long' until the next inframe comes due in the future. I don't know about anyone else,.. but I want to invest in something that I know the answer to.. and do not have to second guess.

THIS IS WHY I always push so hard for people to buy only OEM components on these red engines. Its not because I care about the manufacturer, or want to make their sales go up,.. it is because WE KNOW WITHOUT QUESTION what the expected lifespan is for those components when everything is done correctly. - WE ALREADY KNOW that the engine has a potential to go that next million miles reliably, and without headaches. - This is like investing in IBM instead of Juicero.

The future of the equipment can be well-calculated when a known quality of investment in parts have been made. - The profit margin and longevity can be estimated fairly accurately,. And this allows someone to make wise decisions.

ANYTHING LESS than demanding 100% perfection and quality of the job and its components = LESS TIME until something major fails again, meaning LESS LONG TERM PROFIT, or NO PROFIT AT ALL!.

Most truck O/O’s (owner operators) do well to be able to make back in about 3-4 years at a minimum, or to break even on the $$,$$$ (5 figures) of moneys spent for a rebuild in re-claimed profits. The engine HAS TO LAST THIS LONG OR MORE, otherwise, you only sink further into that endless financial hole of ‘Can’t seem to get ahead’ oblivion. This is not any place to be at all as a truck owner, yet I see it over and over with many trucks.

It is a repeating story that is all too familiar around here, especially with inframes, and it ALWAYS HURTS BADLY!.

This is why I push for people to use only genuine OEM parts. At least that investment IS WELL KNOWN. It is the norm for an engine/truck to last a long time (unless someone tortured or abused it) before its first inframe, and be quite profitable. There is no reason for it not to do the same (or better) the second time around when everything was done right, and all replacement parts were of the same OEM quality.

The next thing on the table is that during an inframe/ major rebuild, this also lends itself to IMPROVING THINGS in a genuine way beyond what the OEM requires if possible. things like mentioned in this post...
info: https://rawze.com/forums/showthread.php?...6#pid70606

On a red engine, things like raising liners to improve strength and using better assembly techniques that are above and beyond the required minimum to help ensure the best longevity possible. This instead of simply ‘doing according to the book’ type of no give-a-damn lazy, speed-gun happy methods like most repair shops do. – this is NOT being wise, and very, VERY few repair shops will even bother, nonetheless get mad at you for even questioning how they do things.

It never fails that the more volume that a big repair shop does, it seems that the more bad habits they acquire and the less in touch with reality and care for longevity they have. Higher popularity and higher volume of what they do seems to ALWAYS drop the quality of outcome. This is the first red flag.

FIND that one repair shop who is willing to listen. Find that place that you can point out the extra steps as mentioned on this forum, and have then read and understand ‘that extra mile’ and are wiling to do so… and you will find someone who truly cares, and not just someone who is only concerned with getting your truck ’in and out’ and argues with you otherwise, or is willing to use or push garbage components or methods onto you otherwise.

Rawze

Rawze

And to address the idea of 'machining, or "shaving' the cylinder head". It should never be done on an ISX.. or red engine for that matter...
https://rawze.com/forums/showthread.php?...0#pid79010
and...
https://rawze.com/forums/showthread.php?...1#pid17421

besides that,.. there is no way for all those valve seats on a used head with a lot of miles on it to last another million miles any ways... and no way to build the materials back up without multi-million dollar deposition and tooling machinery that only an OEM will use.

.. and building them up with chromium, etc. and re-cutting them (I have seen some places to this) only serves to become a stop-gap measure that only lasts a few years, then its failure city all over again. The compression ratio and other characteristics of these engine is just too high for this kind of old-school nonsense.

mikkhh

Around how much is the price of new x15 engine nowadays? Is it sold without injectors fuel pumps etc? If is and is priced less than cost of parts it may make more sense to buy new engine, raise the liner protrusion to 0.014" and throw in new head gasket, head bolts, rod bolts and call it ?