Changine out valve seal and rear main Q?
 

I gotta change out my rear main and a exhaust valve seal on the number 1 cyl on my cummins. I was just wondering if anyone's got any tips a suggestions for me on how to do it and what to be careful about so i dont mess something up. Also what kind of a spring compressor do i need to get the valve spring off so i can get to the valve seal. Thanks for any help .

The main tip for the rear main is to make sure the crank is completely clean and free any burs these will mess up the new teflon seal. As for the valve seal you should be able to get an overhead valve spring compressor from a local parts store, the trick is getting a fitting to go in the injector hole so you can hook up an air hose to hold the valve up.

Just what mnwild said. Also on the rear main leave the oil seal house on the engine. they are hard to reseal with the oil pan on, and if you do have to remove the housing take a razer blade and work the oil pan gasket off the housing. Valve seals can be replaced if the piston is at the top of the cylinder. be 100% it's at the top or your pulling the head. remove injector to be sure its up.

We used one of these to pull the seal when we did the rear main on my buddys '93, IIRC ~$18 from Advance in the body repair stuff
http://i1025.photobucket.com/albums/...pullerpart.jpg

Changine out valve seal and rear main Q?
 

Fully compress the spring, before you break the retainer loose push down, if you get resistance before the spring makes contact with the head then you're TDC, much easier than pulling the injector. Rear main seal sits in the transmission adapter plate, no need to remove the oil pan. Two self tappers and a slide hammer works to pull the seal. The new seal will come with a plastic sleeve and metal ring to seat the seal properly. Should cost you around 70-80 bucks. That's what I paid directly from cummins.


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ya to get it to TDC i was thinking of rotating the engine until the pin engages to make it top dead center. im pretty sure the number one cylinder is all the way up at that point which is the one that i have to change out. im really nervous about doin the rear main since ive never seen it done before. since i already have the engine out of the truck would it make my life easier to just take the adapter plate off? will i know right away what the oil seal housing looks like so i know to leave it on it? also anyone know of a sticky or something that has some pictures of what things will look like and such. thanks for all the help. :tu:

Changine out valve seal and rear main Q?
 

I'd leave the plate on, take the plate off and that means you have another point for leakage. Since the seal is installed in the adapter plate there has to be another gasket between the plate and block. Given the fact ive never removed the rear plate... I couldn't say for sure but logically I'm correct. take number 1 and number 6 valve covers off. Rotate the engine clockwise, watch your valves. First rocker arm; intake. Second rocker arm; exhaust. Cylinder number 1: intake rocker goes down-piston moving down on intake stroke. Intake valve comes up, approaching BDC. On the compression stroke you Should get about 180* of rotation where the rocker arms sit still, this is where you need to watch cylinder #6. at the point number 1 is moving up on it's compression stroke number 6 (it's paired cylinder) is moving upward on it's exhaust stroke. Exhaust rocker will be down, as you approach TDC exhaust stroke on #6 the exhaust valve will be closing, the last few degrees of rotation the valves on 6 will go in "overlap" the intake valve will open slightly while the exhaust valve is shutting. Soon as you see the intake rocker move stop engine rotation. #6 is in overlap and #1 will be TDC compression stroke. After that you'll be safe to break the valve free and it'll only drop afew millimeters until it makes contact with the piston. Follow me or did I lose you? You can always verify with the pin.


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The rear main Doesn't not sit in the transmission adapter plate. you remove the adapter plate and there is a rear main oil seal housing that the seal is in. had to replace mine already when the flexplate broke and damaged the trans adapter plate and oil seal housing

Changine out valve seal and rear main Q?
 

Well it's been awhile since I did mine, didn't pay much attention. My mistake then. Mine was actually spinning with the crank, leaked like a 5 gallon bucket full of holes lol.


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You said the engine is out? It should be a breeze. The crank journal might have a groove in it from the old seal. If so, cummins sells a kit that puts a sleeve on the journal and an oversized seal. You might want to consider putting 60# valve springs in while eng is out, at least the exh. valves for exh. brake, they're pretty cheap, I just bought 6 valve springs for $55. The rear main is nothin to be afraid of. :c:

hmm alright. is it an issue that i didnt get my seal directly from Cummins. its what you can get from napa. ya i got the 60# valve springs installed a year ago when my head gasket went. im kinda pissed how the valve seal already crapped out when it had all new ones put in.

Changine out valve seal and rear main Q?
 

Nah, no issue. Cummins seals can fail just like a napa seal, just probably not as likely to fail is all.


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its to bad you just got a head gasket from me when the head was off you should have it machined for top hat seals ($80) and then you would have been set

I did not read the thread just this post

valve seal but just get #1 TCD then use a spring compressor or a homemade one cut out a piece of cardboard or rag and cover as much as you can under the valve cover the reason behind is when you drop a keeper down the push rod hole you will kick ur self in the ass I would replace #1 intake and exhaust seals since ur there, if you dont already have them I got some

rear main there alot of fun just make sure you use GENUINE Cummins also use no silicone or other sealants clean the crank to like new if you use abrasives be careful
use the provided seal driver and a SMALL ball pein hammer and tap once this side once that side with light hits till the driver bottoms out it should take you at least 3-5 minuts to drive that in go slow if it looks twisted lightly tap it straight there about 40 bucks so get it right the first time

Brice

ya i didnt really know anything about the tophats at the time. the next time the head gasket pops i will have it done along with other stuff. thanks for the tips. im hoping it will go well. i really dont wanna have to take everything apart again to fix it if it leaks.

anyone know if i should put the valve seals in wet with oil on them or something or dry just the way they are?

i did my rear main seal tonight. i think it went fairly well. i hope it never leaks again on me. the old one was hanging out in there for the ride and pretty much flopped out. someone recomended i put some rtv on it where the gasket and oil seal housing meet. you think this is a good idea?

genuine cummins gasket no
aftermarket gasket yes


also did you install the seal with the seal plate bolted in place? if so dont take it off now if not then be dam careful that the seal dose not roll when sliding on the crank and MAKE SURE THE CRANK IS CLEAN

ya its not cummins. its a felpro gasket from napa. i had already got it a long time ago so i didnt feel like getting the one from cummins. i didnt take the seal plate off. i didnt know that i should have. i made sure everything was really clean and dry since thats what the seal called for. it took me a long time to get the seal on and in place. i did alot of light tapping to ensure it didnt go crooked. ill put some rtv on it and call it good.

if the motor is out you better do a pan gasket and do all the valve seals not just 1 if 1 leaked the others are on there way again if the motors out i would put a cam seal in also just my 2 cents

im not happy with the valve seals i got from napa. theyre not right. ill send you a pm about the ones you got.