Couple quick questions
 

I'm going to have a number of dumbass questions over the next 90 days so bear with me. Trying to get the bottom end assembled this weekend so......

1 - I ordered my new rear main and it also came with a little o-ring that's about 3/4 an inch. What the hell does that go to?

2 - anything special I need to know about installing the rear main? Not much online about installing a 1 piece rear. It appears it is just held in via the rear cap?

3 - should I use permatex on the corners of the rear main cap? The book I'm following is for a gen IV unfortunately so I just wanted to make sure

Thanks guys, have some patience with me here. Plenty more amateur engine building questions to come, but trying to get the bottom end together so I can get bob some measurements next week

Oil pump passage on cap mating surface . GOOD LUCK!!!

are you talking about the rear main seal ? and what engine ? guessing 1 piece rear main seal...they just get knocked in with a tool till bottoms out, I use a little RTV around the outer edge

Glad I asked! I'd have ****ed that up for sure

Yes, 1 piece rear main. GenVI 502.

I've seen some people say they just point the new one in with the old one and a blunt punch. Reasonable approach or not?

Does autozone or advance rent one of these tools?

They do make a special tool to install the seal. Some say you must use the tool. I use my brain a block of wood and a hammer. Never had an issue. If I purchased special tools for all the different seals I've installed over the years I'd need another toolbox to put them in and id never be able to afford a boat.

10-4. So bottom line, do final crank install then pound in seal. I assume a thin coat of 30w oil on the cra shaft seal side is appropriate?

I never used anything. Most seals are meant to be installed dry depending on what it's made of.

I usually put a thin coat of rtv(on outside of seal) for insurance and help it slide in too, it should push in pretty easy,but they prob dont recommend it:)


http://www.offshoreonly.com/forums/g...-build-up.html

I would definitely use a coat of oil on the inside ( crank side ) of the new seal . Things that rub are never put together dry .

never install a seal dry unless you plan on it leaking.i have never heard of installing one dry.where did you get info to install without lube?

if you installed the rear main cap without it don,t sweat it as it is really not needed.

Teflon seals go in dry. Pretty much a diesel only thing, though.

2 before you set the crank in oil the seal and the crank where the seal rides,then carefully slide the seal on part way.then set the crank in,then slightly lift the back of the crank and slide the seal all the way in,then install the caps.some people use a little rtv on the outside of the seal but i never do and so far none have leaked.

a friend of mine put the rear main seal in dry on a mark4 engine,2 weeks later he removed the engine and replaced the torn up leaking seal.guess what,he oiled it the 2nd time and it,s all good.i certianly can,t see any harm in oiling a teflon seal.

personally i like my crank lubed up before insertion!

Thanks guys.

Haven't done the final clamp down yet so I'll follow your advice mike.

Interesting. I would never have thought to not oil a seal before install.

Call Jesel ask them why you should install the front seal dry. Many manufacturers recommend dry install.

When these seals start leaking it's not because the sealing lip has worn out. It's because there is a spring inside the lip that losses it's tension. If you are good you can remove the seal take the spring out shorten the spring to get the tension back re-install and good as new. I've done this many times in a pinch. When customers needed to get on the road and a seal wasn't available.

Rtv on the outside of the seal is not a good practice especially on the seals that have the blue sealant around the seal. The rtv has a chemical reaction with it and will not dry properly. In a case where there is a lot of pressure the seal will push out. The best thing is to clean the outside of the seal with lacquer thinner and install.

i stand corrected,thanks for posting the link.

i can not agree,the seal was ripped but the spring was intact.i will say you one thing,you are a brave man for reuseing a used seal.not something i would do.

Just sharing some hard earned knowledge. I replaced a front seal on the same Cummins 3 times before someone informed me I was the one causing the issue. Of course, they waited until I finished my long-winded rant about junk seals.

Learn something everyday. Thinking out loud here....assembling heads without lubing the valve steams properly would be unthinkable. Maybe the assembly lube on the Teflon seal creates a perfect "leak" for the valve stem.

http://www.summitracing.com/parts/cc...12oaAg9z8P8HAQ

Used hundreds of these successfully.

Not something a care to do either but drastic times call for drastic measures. Many many times I've ran into situations where you just couldn't source a seal for days and people need their cars...

I always wipe the inner groove with grease if there is a spring to keep from knocking it out on install and some on the lip...

Well, it's in. Used your method mike of raising the crank slightly but I did install basically dry.

Hoping to get the pistons in this week so I'll be back for more questions shortly. Thanks!