ddestruel

I potentially am going to have to pull my 98 12v due to an agrivating oil leak, no its not the KDP and timing cover, its timing cover to block on driverside bottom corner.

so if i pull the engine which Imler and everyone else seems to think i need to, im thinking at the same time im probably going to throw a new set of bottom end bearings in her and re-seal the engine along with doing some other minor performance mods. I dread the thought since she is so tight, has no blow by but since she is out i cant see why not to consider touching a few things up.

I know while she is out i may even consider decking the block and head and then a new gasket and studs to hold the towing (45psi or so) twins she will run next year. (im thinking no Orings cause i dont think they will ever be necessary) If thats the case ........................




potentially a set of pistons is in order. I know changing pistons helps clean up the 370 injectors how much though is yet to be seen. (ive often wondered in an opacity test or smog test of any sorts if 370's with correct 370 pistons and smaller twins would be clean enough to get by?)


I have heard that Piers sells a forged piston that is not Cummins but has the bowl design and is without the teflon and ceramic coatings. Piers also said the compression difference is .75:1 between a stocker in my 215 motor and a 370 piston, so that will be minimal.


How much do 370HP pistons cost, what CPL and serial number will i need to order them how do the forged pistons compare in silicon content over the Cummins pistons. I also hear the rings are down further ont he marine pistons which would increase thier durability but also should aid in longevity also right?






looking to button her up, and hook onto the trailer and not have to wrestle with her again for the next 300k+ miles thats not too much to ask right.

Thoughts & comments welcome, tell me im throwing good money after bad and i'll listen.

currently she has 140k miles on her

RCW

With such low mileage swapping pistons is just opening a can of worms unnecessarily, unless you have internal cylinder or piston wear today.

Before you pull the engine, pull the timing cover and tighten the bolts that fasten the gearcase to the block. They all work loose, and I have yet to see one that will not button back up and stop leaking, unless it is so loose that it is full of dirt from being submerged in a mud bog. If that is the case you will also need to pull your camshaft and replace the front bearing, because it will be scuffed.

As far as the forged aftermarket pistons with the marine combustion chamber design, they will not really clean up the low end smoke from 370 injectors, but they do solve the timing burn issue that creates that ever so slight lag 1,900 rpm and solve some drivability issues at highway speeds IF the correct copper spacers are used to set the injectors to the proper height. Do not expect to just toss the new design pistons in and have it run better, it will not. You will have to adjust the injectors and set the initial fuel pump lead on a bench, and then get the timing reset for your cam and injectors before they will really make much difference for you.

ddestruel

You are probably right.

BTW i do have the right copper rings and i also set the timing up to 16* right now.

I seriously doubt there are any issues internally with this motor bearings ect oil pressure is un-believable warm 45 at 800 rpm 52-55psi at cruise1800-2000. on a mechanical gauge. sometimes someone else has to say it to make you calm down and rethink things. and take the more levelheaded aproach

wannadiesel

Sorta unrelated but I figured it might save you a lot of time and aggravation.

Cummins now says it's OK to pull the cam gear off with a gear puller to remove the timing case without pulling the cam. They say to heat the cam gear to reinstall.

gunracer1

but does anyone have a idea on what puller to use? i tried 3 different ones this weekend on a truck that lost the dowel pin. i am about to drill and tap the gear and use a good steering wheel puller.

wannadiesel

Check with Infidel, I think he posted the info first.

J.R. Adkins

Dang man just pull the cam!!!

J.R.

Smkndzl

we pull the cam gear on every housing job , just remember to hold that cam in place after heating the cam gear or you will knock the cam plug out in the back of the engine. most cam gear pullers that have three fingers, you do need to remove the thrust bearing bolts and let the cam come out enough to stick the puller fingers behind the gear.