454 Timing cover leaking
 

I have a 1990 convincor 25 with 454. It was freshened up about 3 years ago, I notice last year from time to time I would get a little bit of smoke from engine compartment after running for awhile. I could never see where it was coming from until today when I tore the entire back seat out for repair and replace. It appears the timing cover is leaking? Hard to tell for sure but it is right in front on the bottom there was a little drip. What is was doing was getting thrown up toward the alternator and burning off. Anyhow I am mechanically inclined just have never done this job before. I want to replace timing cover gasket and all necessary gaskets/seals to do the job. Can anyone help me out? Do I need specials tools? I know I need a remover for the balancer, do I need a tool to reinstall? or can I get back on without? Is a there a criticial torque spec on the balancer too? any help would be appreciated. thanks

Its a pain in the a$$. The timing covers are actually made to go before the oil pan goes on. Chances are it is leaking right at the corners where the timing cover meets the block and oil pan. If you have never done it before and the leak is small, I would consider leaving it, or trying to clean the area and seal it with some RTV.

In the past, I have done the following.

Loosen about 4-5 oil pan bolts down each side from the front with the very front ones almost all the way out.
Carefully use some screw drivers and wedge the front of the oil pan down a little bit.
When you get the timing cover off, grind off 1/4" of the inside corners of the tabs that hold the timing cover tight to the pan.
Remove the rubber gasket from the bottom of the timing cover and use some Black RTV instead when you reinstall it.

Sounds like your on the right track. Sounds like it must be a small leak. More than likely where the oil pan meets the timing cover. Like you said pull the balancer off and clean everything up good with some carb cleaner especially around the sealing edges. Personally I would maybe consider resealing around the edges although it's difficult to say if your front seal is bad and that is where it's leaking. I rarely use the front bottom rubber gasket on those and just use a decent size beed of silicone however shape in a manner of which it doesn't tend to push inward toward the block. After it sets up go around the whole cover with a little beed just to be certain.

You can get a balancer installer at your local automotive store however you can also just heat the balancer up near the middle but don't get to hot that you melt the rubber seal on your timing cover. You can use an impact to put it back on however once it bottoms you could back it back off and torque it back to specs. Not sure off the top off my head but probably around 85 ft pds. You can look that up. Not a bad idea to mark your timing tab where the back side of your balancer before you pull it so when you reinstall it you know roughly when your on all the way although you should feel it bottom out.

Sounds like Griff has been there before also. I was writtting my post when he posted.

I had a simalar problem and since he said it was slinging oil up onto the exhaust manifolds to burn. I would check the front crank seal first before the cover and pan gaskets. I couldn't see any way for the cover gasket or pan gasket to leak and come anywhere near the crankshaft to get slung off of the balancer. It woould just run and drip into the bilge. Just my own exp. and 2cts.

I've also got a leak coming from the timing cover/harmonic balancer area. I talked to my mechanic about it, and he said to pull of the balancer pulleys, and check to see if I can see some silicone in the balancer key way. He says some engine builders can be dumb and forget to silicone the key way, and oil will come out through it. I've yet to check mine, but will soon. If you see no silicone, pulling the balancer, siliconing the keyway, and reinstalling the balancer would be a good start according to him..........

That's because that cat of yours lays right down flat in those 6 footers. LOL.. You might be right though. But depending on water conditions and how many buds I drink I tend to have a lot of **** go places it normally don't.

I would guess the seal also but who knows. Just seems unlikely the cover would just start leaking.

hmmm. That is actually a good point...

That crank seal takes alot of abuse. It's worth replacing it to see if that fixes the leak before he starts tearing things apart. Check tof a worn spot on the balancer where the seal rides. If it's worn, theres a sleeve for that and good point on sealing the keyway(s) and sleeve if you need one.

Hey John, As for those 6 footers I normally try to keep up on top but all that jumping sloshes alot of oil towards the front of the engine where it doesn't belong. Engines going in next week, can't wait!

It was nice knowing you Bill... Is it to late for me to take out an insurance policy? LOL... Just kidding my man.

Thats what I was going to suggest.^^^

Well my first step is gona be get that balancer out of the way and see what I find. Now I just need to find the damn time to do it!

Oil leaking through the keyway will generally drip onto the inside of the front pulley if the engine sits a while.

As said check the crank seal as well or just replace it.

Well, in my case, the front seal was already done. I only get the leak when running real hard and getting the oil hot. spins off from down there and hits the cooling hose that goes under the motor and drips off the front and off the back.

Can't speak for the other guy, but it was an idea that i was given from my mechanic. I'll be checking the key way first as it is the easiest.

When the oil heats up and thins out it can make it's way to some pretty difficult to find places. Sounds like your on the right track. I'm not sure how long of period your boat sits however that can sometimes be a little harsh on seals, etc. Like I mentioned before it would seem odd for your cover to just start leaking.

Its either the gasket or seal it coming from behind the balancer and its not right in the back side of the balancer so I am thinking its not the seal but the cover gasket or right where it meets oil pan or something, im not real familiar with these so, I will find out tomorow hopefully if I get out of academy early tomorow!

I wonder if you applied a little air pressure through the dipstick tube and spray the entire area with windex or something similar and see if you get any bubbling. Never done this on an engine but why not? Things may change with heat though so it may not be real accurate. Also may want to seal any valve cover holes if you try this.

How about the seawater pump? Fought that on an engine b-4. Thought it was a timing cover but it was the front seal on the seawater pump. Just a thought to check...

My sea pump is way off to the left side of the motor seperate and they oil is no wheres near it so prolly not that. Im goin to go out in a little while and start pulling apart and see what the deal is here. Little sh** annoys me lol!

Well, i got my balancer off today. Took some doin to get that baby off. I did see some oil on the outboard side of the seal lip, but i'm not sure if that is signs of a leak, or if that happened when i pulled the balancer out.......

It's gunna be very hard to differentiate the leak from the seal, or the bottom gasket to mating with the oil pan, seeing how if the seal is leaking, the oil would go down there anyways. The motor hasn't been run since late october, so what ever residual oil is left is few and far between. If i wanted to change that seal, what do I need to do to accomplish that. Does the cover have to come off for that to happen?

My two options, was to just change that seal, or drop the oil pan a bit and pull the cover off and buy the imco polished aluminum one with the seal already in it and put it on. But i wasn't sure how good the pan would seal back up to the cover if i did that............ What do you guys think.

Seems like me and the general are dealing with very similiar leaks.........

Yup sounds like the exact same leak as mine. I finally got my balancer off today too, wow I was scared. Not only at how hard it was to come off, but what I found when looking close at crank threads. Turns out someone has already repaired threads in the crank with a thread repair recoil, yippy just what I did not want to find. Looks like it is 1/2" fine thread now. Anyhow my next issue is I can not get my cover off! I guess I have to do something with the pan? I just dont see how the damn pan is holding that on the bottom, but I don't wana get in a bad predicatment now. I didn't even think I was going to have to mess with the pan on this 454, but its obviously not coming off. It did not appear to be the seal leaking on it, but moreso the area where it meets the oil pan. I wish Id had one of these apart before, but never have. SO, do I have to drain all the brand new oil I put in it before putting away? and do I have to pull the pan then? can I get away without pulling the pan completely off and what am I going to find where the pan and cover come together, im pretty sure I have a one piece oil pan gasket? My last issue when it comes time is going to be getting the balancer back on, I am nervous about pulling on them recoiled threads to get it back on. Why me? lol

If the engine hasn't been run since October and there was residual oil on the seal, I would think the seal is suspect. Oil wouldn't run up from the pan or around to the front from the timing chain cover gasket. Oil runs down inside the cover from the lifter valley and lubes the chain and runs over the crank snout. Crankcase pressure can push it out from the crank seal. Check your balancer for wear at the seal lip. Replace the seal and give it a run. It's some work to put it back together but I think that's the culprit. Alot less work by far than either the cover or pan gaskets which are unlikely to just start leaking. Good Luck!

General, to pull the cover you need to at least loosen the front few pan bolts. Theres a lip that locks the cover to the pan. Doing so however will most likely ruin the pan seal for sure, so be very sure that you think it's the pan gasket leaking or the cover gasket. The most likely is the crank seal as I described. Probly easier to pull the engine and do the pan gasket properly. By the way the threads in the crank snout are supposed to be 1/2" fine machine thread.

Well in my opinion I don't think it is the seal leaking from what I see. But my problem at this point now is that I have broken the gasket seal now on the cover in an attempt to remove, so I guess I am SOL now with no turning back now. I am not pulling the motor out of this boat, I will burn it before I pull a motor lol.

You have to pull more than a front couple of pan bolts. Pull all the bolts you can reach on both sides of the pan, leave a few in the rear. I use plastic wedges (log splitting type) and slowly pry the pan down and use the wedges to hold the pan away from the block. Be super careful removing the front cover so that you do not mess up the gasket were it wraps around the timing cover (tear it and you are pulling the pan). You will see the rear lip of the timing cover and you have to slip the gasket around and off of it to get the cover loose. Check to see the condition of the cover were the lip is spot welded to the cover. The oil will travel in the crack where the two are mated. When going back togather smear that seam with some good sealant (Pro seal or Right Stuff) and carefully reinstall..

Can the seal be replaced with the timing cover still intact? Is there a special seal installer used in the case where the crank snout is sticking out yet?

I think i do have a very small groove where the seal rides on the balancer. What can i do about that?

Try polishing the grove out with some fine emery cloth and see if it will pull out. If not a new dampner would be the best bet. Yes you can install a new seal with the cover on (prefer not) but you can use a piece of pipe the same dimensions as the seal outer surface a big washer and drive it in with the the balancer bolt very slowly and carefully (home made installer).

Yeah, I had already taken some emery paper to it. It took about 50% of the groove out. I can barely catch it with my finger nail now. It should be fine.

I'll be picking up a new seal and give that a wirl. Do you guys grease the seal lip when installing the balancer?

Yes use some assembly lube or light grease. Depends how long it is going to sit b-4 running. If your going to fire it right up, light lube will work.

it will be sitting for another 3 wks at least..........

Either or will work, little on the lip and a little on the dampner. Do not try to pull you dampner on with the mounting bolt. That is a good way to mess the threads up in the crank snout. Worth the money to buy a installation tool. Or pound it on with a soft dead blow, until just about on all the way, then maybe pull it in the rest of the way with the bolt. Good luck hope that does the trick.. Pete

Please don't beat that balancer back on. Just go to an auto parts store , most have loaner tools available . get a balnacer install tool . It makes life easy!!!

yeah, i had went to o'reilly to get the removal tool. I had noticed they had an installer tool as well. Don't know how it works, but i'll find out.

On another note, I havn't changed the seal yet, and am hesitant to do so. Am I running the risk of damaging that cover trying to change the seal with it still bolted to the motor. I don't want a worse leak than when i started..... Lol.

Agreed..........

So I got my cover off finally, but it didn't quite come off like I wanted it to. I broke part of the flange off because im an idiot and forced it. Of course the broken piece went into to oil pan so I had to take out almost every pan bolt to get my hand in there and find the piece. Just great. So I go to order a new cover through local merc dealer at a heart stopping price of $207! I said screw that i went to local GM dealership and have ordered one for a chevy truck with 454 for $60. Should be here tomorow morn and Im hoping it is the same, it looked the same on the computer. The only difference I know it is going to have for sure is the hole in the bottom of the cover for the crank sensor is going to be open, in which mine is closed off as this doesnt have a crank sensor. So I am just going to make a plate to cover the hole and gasket it off. I think that little bit of work is worth the almost 150 bucks in savings. Im starting to think I should have left the small leak alone lol.

Isn't this stuff fun. Just look at it as a good learning experience. We all get them. What is your plan on using the lower rubber seal. Regardless when you done run a beed of RTV around oil pan and timing cover. Use your finger to lightly press it in around those areas and let it do the work for you. The less you fuss with it the better end result in most cases. Sometimes these things can be a real pain however it's the way it goes and when it's done you'll be happy and glad you did it. A little advice though next time is do the RTV thing first. It's easy and effective when done right. Kind of like sealing a shower door. One of my engines is in need for some sealing up front somewhere also. I remember seeing it leak on the dyno however have not gotten to it yet. I'll recall your thread when repairing the leak. LOL...

Also if you ever did have to pull your engine it's really pretty easy. Much easier than it looks. Way less time than a car engine. I even pulled one under an old oak tree behind my house once. Shouldn't take more than two hours at the most. That's even without doing it before.... Doesn't sound like your at that point yet though.

Good luck,

Ha!... Not all of us live out in the boonies where we can commandeer an easy access Oak tree for a few hours. It's a b!tch of a time trying to get an engine out for me... I usually pay one of the hi-lo drivers at my old work $50 bux to work the forks while I get everything out of the way.

The lower rubber seal on mine is part of the oil pan gasket, its all one piece, so Im just going to clean it good, coat it up and make sure it sets in the new cover proper and seal her up. Im just praying the cover is the right one when I pick up tomorow morn.

post from the edge
 

My only experience with a timing cover oil leak is on the generation IV big blocks. Other than the front seal failing the next problem are the corner bolts from the oil pan which are usually stripped by over tourqing. I believe the problem is the bolts are to small in diameter and the alignment of the pan, the pan gasket and timing cover is terrible. I have replaced the sheetmetal cover with an aluminun one and tapped the bottom holes to a larger size amd use a bolt with a pilot end and put them in first. I put a very small amount of RTV at the corner joint of the timing cover gasket, pan and block and locktite the timing cover bolts in. The trick I have yet to master is assembling evenly and carefully enough to not repeat the problem

was the cover plastic, or aluminum, or steel?