Gear Case Leaking... should I do a cam too?

[Yo Hoot]

I've come to the conclusion after having the front timing cover resealed and a new front main, that the gear case itself is leaking.

I have two choices. Tear more stuff off the front and clean and RTV it OR do the job right and replace the gasket. Big job.

First question is why does that gear case gasket fail in the first place? It's a simple flat interface. No complex geometry. Mine leaks pretty bad even after snugging up all of the bolts. I lose about a quart every two thousand miles.

So... with the mods I have... . basically what most would call a stage one... . bigger turbo, stage one injectors, head studs, Smarty, TST... . 540hp/1000tq, what benefit will an aftermarket cam do for me?

If I do a cam, should I just get a new set of lifters and just chuck the old ones? Are they that much money? I always thought you should always put new lifters in with a new cam.

Is there a writeup for a 3rd gen cam or gear case gasket replacement with pics somewhere?

Thanks,

Mike

 

[blacksheepdiesel]

If you are going that far then a cam change is really no more work. Go for it. To me it would be worth it simply to get rid of some or most of the soot.

Godspeed,
Trent

 

[NIsaacs]

One thing I have noticed over the years of running all types of on and off road equipment, is that too much blowby will cause all sorts of gaskets, seals and orifices to leak. The only fix is a rebuild, just a thought.....



Nick

 

[Mobius1]

If you think about it there is really no more work that needs to be done. I'd say go for it

 

[Yo Hoot]

I don't think it needs a rebuild. Just turned 100,000 miles. I take good care of it and don't thrash it. I have heard though that the power adders like turbos and injectors seem to reduce the life of the engine seals.

Any recommendation on a cam to go with that compliments my mods? I'm not so concerned with brand or vendor but mor with the specs of the cam I should be looking at. Afterwords I'll decide which and where to purchase from.

 

[ENafziger]

I'm not so concerned with brand or vendor but mor with the specs of the cam

It's not quite like the gasser world... you'll be kinda hard pressed to find "specs" on diesel cams from most vendors.

I installed a F1 Helix 2 cam in my truck about 2 years ago. I also did alot of other mods at the same time, so it's hard for me to comment on increased performance. However, I didn't notice cleaner oil or better fuel economy that some people see... or claim to see.

While the Helix 2 may be a good cam, the lobes are significantly narrower than the stock cam lobes. This isn't exactly what I was hoping to see, but I guess many people are running these cams with good success. I've pulled with mine once with the 4,000 rpm TNT-R tune, and it sounded great at that rpm with this cam.

I'd do as much reading as you can stand here and on CompD concerning cams before purchasing one. Whoever you go with, make SURE that you use ALOT of assembly lube, and that you use ZDDP+ or similar additive for at least the first few oil change intervals.

As far as the tappets, if you have less than 100,000 on them, and cam lobe surfaces look good, you should be alright.

--Eric

 

[Yo Hoot]

Good info. I was just so used to seeing on the gas side of things where when you do a cam they always recommend a new set of lifters. Why would these be different? The tappets wear into the cam. Wouldn't you want a new set wear into the new cam instead of an old set that has taken the life of the old cam? I believe the tappets rotate on the cam lobes. Maybe these tappets hardly wear... . the cam gets more wear than the tappets?

 

[ENafziger]

Why would these be different? The tappets wear into the cam. Wouldn't you want a new set wear into the new cam instead of an old set that has taken the life of the old cam? I believe the tappets rotate on the cam lobes. Maybe these tappets hardly wear... . the cam gets more wear than the tappets?<!-- google_ad_section_end -->

I think there's a couple reasons... first, the load bearing surface is very wide, and the cummins engine is designed to go 300,000 miles easily before rebuild; thus, with 100,000 miles or less, they should still be in very good condition. The second reason, is it's somewhat labor intensive, as you have to use a pvc half-cut pipe and "fish" them up into position.

Sure, it'd be better to go new tappets, and that's what some companies will insist on; however, I think you'll find that most people re-use low mileage tappets without problem.

Yes, the tappets do ride directly on the cam lobes. In stock form, this is usually fine for many trouble free miles. The accelerated wear comes into play when you use an aftermarket cam with narrower than stock lobes, higher pressure valve springs, and higher rpm. That coupled with the new CJ4+ oil lends itself toward accelerated wear if zinc and phosphorous additives are not used.

If you can stand a little extra down time, and have the patience and funds, there's no downside of replacing the tappets though!

--Eric

 

[Yo Hoot]

So today I took the fan mount off the front of the engine to see what's going on up there. Looks like a piece of the "gear case to block gasket" is missing. How in the heck can that be? Did it happen during assembly?

Fortunately it's up high and I think it's only oil splash from the gears spinning, slinging the oil through that gap. No pressure.

To clean it up, I sprayed it with brake cleaner. It looked like brake cleaner was going down into the gap where the gasket is missing.

Anyway... job is done. Sure hope it works as this leak has been haunting me for years.


Here is what I saw as soon as I removed the fan mount. Fresh oil.
#ad


#ad



Here is the missing gasket in plain site.
#ad


#ad



Gunked up with Permatex. .
#ad


Strange how the previous attempt I made I could only get the RTV just to where the fan mount was. The missing gasket piece started exactly at the fan mount edge and went up behind it from there.

 

[Prairie Dog]

I wonder if excess crank case pressure could blow the gasket out?

 

[Yo Hoot]

There is that large vent tube that drops down the side of the engine. I don't see how pressure could build but I might be missing something.

 

[rscurtis]

Why would you want to change the cam in a "305" engine?

 

[cerberusiam]

I have been running for almost 2 years with that same spot RTV'ed, still no more leaks from it. That place and one on the driver side behind the CP-3 are th emost common places to leak. I think the gasket makes a jog there and is not as wide as the case so it moves. Typical problem with a cast block vs aluminum case, different expansion rates walk the gaskets and break them.

Is a cam change on a 305 worth it, your choice. Perfromance would be the over riding reason as that cam should have a decent profile sans a lot of the later emissions changes. It is more work if you replace the tappets but not a lot.

 

[AH64ID]

The current part number for the 03-04 cam is the same as the 04. 5+. There are those that say they have been the same sine 2003, and other that say there was a change. I have never seen them to compare, but have had multiple cam companies tell me that the cam has been the same since 2003. If there was a different cam in 03-04 (shield up), then I have never seen specs for it. Since the part number is the same who knows when the change, if there was one, was made. .


So anyways. I run a Colt Stage 1 and like it. It's a very mild cam, so not a HUGE change. It does spool easier, and has more/smoother power down low.

The cam did nothing for soot in the oil.

 

[Shadrach]

I installed a Stage 2 Colt cam when I rebuilt my engine. I never ran it before so I can't do a direct comparison but I do like it. My buddy just installed a stage 3 in his 1st gen and did notice a difference in spool up as well as EGTs, however he also installed a Steed Speed exhaust manifold at the same time. Here are the specs of the different cams: http://www.peakdieselperformance.com/camshafts.html Always use new lifters with a new cam. Shad

 

[Yo Hoot]

The only reason I mentioned a cam is if I needed to tear the front end of the motor apart to fix the leak. If I knew more about what the cams do I might consider one but as it stands there doesn't seem to be much tech info about the cams. If the leak is in fact fixed, i probably won't bother.

Always use new lifters with a new cam. Shad

That's what I've always heard. Apparently these lifters are a bit different. Most say reuse.

 

[Yo Hoot]

Just posting back... . leak is still fixed. Love it.

 

[rashwor]

I have a leak on the front on my engine like Yo Hoot describes. For the time being, it is messy, but not amounting to any volume of oil. I guess I will have to look at this in the future, but for now I am putting it off. I am missing a competent mechanic locally; usually end up with same / more problems after they work on something so I am not in a hurry to let anyone work on it.