Alright Guys,

My truck has reached a point where it is leaking oil from every orifice and I have to at least replace all of the main gaskets. I pulled the front harmonic balancer tonight and was alarmed that the seal was warn past the lip on the bottom.

What I mean is the crank seal has a lip all the way around the outside. The lip is still intact towards the top, but is non existent towards the bottom. The red arrow indicates where the seal is missing in the first image.


This image shows you where the seal starts to deteriorate.


My question is, does this mean my bearings are going bad, or is this a potential misalignment of the front plate and the casting. The engine does not make any knocking sounds only lifter ticking. It has some ware around 75k (and is about 14 years old) on it and the compression is about 145psi to 150psi on all cylinders except number 6 which is around 140psi.

I know nothing about the internal of engines. I have no problem braking into the engine a little bit, but really wanted to leave the crank shaft and pistons alone. I am thinking of replacing the cam with a comp cam 260 and install new hydraulic lifters and springs while working on the engine.

What do you guys think is this common, or do I need to look at replacing crank bearings as well.

Again I am new at this so what do you think?

Thanks,
Cody

 

If that's the one on the timing cover you can pull the cover and change the seal. They may be press fit I'm not sure.

If you are going to start putting speed parts at all on it I would start thinking about new pistons. Although the ones in 95 and 96 were stronger someone may be able to confirm.

Assuming it's carbed a cam change is probably not worth it until new pistons, and the asthmatic carb, intake, exhaust are upgraded. If you are mechanically inclined and have access to the tools it's not hard to rebuild these engines.

 

jason832,

Thanks for the reply. I watched a youtube video on how to replace the seal, and it does not seem all that hard honestly. I was just questioning the condition of the seal ware. I was just wondering since the seal was warn about 1/16" or so more on the bottom than the top. Can you conclude anything from this such as bad warn bearings, or if the cover might not have been installed centered. As far as the cam, I may just go back with a stock cam. Just thought if I could get any more performance out of the engine while I had it apart I would rather spend the money on speed parts than standard replacement parts.

I am just weighting all my options at this point. I am also considering buying a new PowerTorque Engine Long Block from the parts store for a little less than $1400 and just installing new gaskets and putting that back in the truck.

The problem is I don't have $1,400 lying around, and I don't really know anyone who knows how to rebuild an engine :/

Thanks,
Cody

 

I'm sure if the main bearings were bad you would have a knocking or ticking or something. The seal may be bad from age and milage. The 300 in stock form will last a long time but as soon as you start adding power to it a basic rebuild with new pistons, rings, and bearings are a good idea. I've put a 4 barrel and good exhaust on a low milage stock everything else engine. After 6ish months one cylinder started losing compression and there's scratches in that cylinder wall (I have yet to pull the pistons).

I'd say change the seal and leave it, or do a basic rebuild with a better carb, intake, exhaust and the cam upgrades you mentioned.

 

Well, I took some time tonight to take a set of calipers and take some rough measurements from the crank to the outside of the seal (where the metal portion of the seal meats the cover). I discovered it was pretty close from left to right, but off about 70 thousands vertically. After pulling a few of the bolts out, i discovered the cover was almost bolt bound as high as it would go.

You can see in the image below the threads are toward the bottom of the hole. This would make sense why the seal was warn so much on the bottom. If i had to guess, they may have installed the oil pan first then the timing cover. Since the oil pan is not OEM, it is probably slightly off or the pan was tightened too tight not leaving enough room for proper clearance for the seal in cover. Either way, its something i will pay attention to when i get the engine back together one of these days.

 

No wonder the front of the engine was so covered in grease and oil now that i have uncovered this

 

I've taken them off and not the oil pan many times and not had issues.

Put a new seal in, start the bolts in by hand until they stop them tighten them so its aligned better. I don't know if you should tighten the oil pan bolts or block bolts first for the best results though, I can check my shop manual in the morning if you want.

 

 

The way to this is to install the pan bolts first and snug them just enough so you can install the cover bolts, then snug the cover bolts up just enough so it holds the cover flush to the block.
Then tighten the pan bolts, then the cover bolts.

That front crank seal can be replaced with out pulling the cover. Earlier ones you had to pull the cover. You will need timing gasket set to complete this job if you pull the timing cover.

 

The shop manual agrees pan bolts first then cover bolts.

 

I've had mixed results on various engines pulling the timing cover and splicing in a new section of the oil pan gasket. Some times it worked fine, and other times the spliced area leaked like a sieve. The timing chain throws a lot of oil right at the splice area, so the fit has to be perfect. The age of the old gasket seemed to be a big factor. The older the existing gasket is, the harder it is to seal up well with the new section.

If at all possible, I'd suggest replacing that seal without pulling the timing cover. A seal puller like the Lisle 58430 should be able to do the trick:



If replaced in situ, you also avoid potential problems with seized bolts, etc.

If the crankshaft is scored at the seal land, don't panic. That's very common and can be fixed with a Speedi-Sleeve repair kit.

Remember my personal motto: As little as possible, for as long as it takes...

 

Thanks guys for the reply's. I am actually going to pull the engine and replace all of the seals and freeze plugs while it is out of the truck. The motor is leaking oil from every ware and I would like to get it stopped.

I do have a question thought. Why are there 2 different types of oil seals for the timing cover.

One has a flange

https://shop.advanceautoparts.com/p/...g+cover+gasket

One does not have a flange. I believe this one is similar to mine.
https://shop.advanceautoparts.com/p/national-multi-purpose-seal-2942/3267776-P?searchTerm=timing+cover+gasket

Are they interchangeable, or do you have to get a different type of cover for one with the flange? The reason I ask is because it looks like most of the kits such as fel-pro come with the flanged oil seal.

 

Never ever had an issue doing this , just make sure surfaces are clean and RTV the splice points. If done properly and correctly they will be as leak free as a full pan gasket. Plus the 300 I6 is one of the easiest to do. The 335 Series not so much..