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engine question

Nebraska, I just changed my rear seal and pan gaskets today. Took my time, its too stinking hot!!!! Looks like I'm good to go to Salt springs to meet some of the boys that are going there on July 30. Believe it or not. The guy who did the motor before I got it must have put the rear pan gasket in backwards! That is why I had the leak I beleive. Any way, it was not a bad job. At least the things in the open, didn't even remove the basket. LATER, WADE.
 
Wade,

Are there any tricks or tips you can give for changing the rear mail seal? I plan to start tonight and hopefully finish.

The new seal I got is a rubber seal (2) Piece? Can I just push the old one out and slip the new one around the crank? I also has someone tell me that I don't want to make it flush with the block????? do you need to push it not as far or farther around the crank so the flange part of the seal doesn't fall on the cap joint surface??? he really confused me when he told me this.

Thanks,

Dan
 
No problem, Your seals will be two halfs. The ones I took out were flush with the block. The ones I put in are flush with the block. Mine were felpro and the instructions stated to set them flush with the block. Dropped the pan, pulled off the main bearing cap. Try tapping the seal out. If no luck, undo the next bearing cap to relieve some of the pressure on the seal. Your oil pickup tube might be attached to that one. If its still hard to hit the seal out, losen the next one also. Just losen them don't take them off. I used a small torx head screw driver and tapped the end till it moved about a 1/2 in. Then I was able to take it out with my fingers. You can use pliers to pull it out. Put the seal in with the open end toward the front of the motor. The numbers on the seal should face the fly wheel. oil the new seal, slide it in. Dry the oil off the ends of both after install. tighten your cap back at 90 ft. lbs. torque. Don't tighten it down in one shot. Alternate tightning until you reach 90 on the caps you losen also. Don't forget about them. Make sure all are tight. Scrape the old gasket material off the block and pan. Then put new seals on the pan. Used a tack sealer on my pan gaskets, just a touch though, don't want to get the excess in the motor. Had to hit my holes on the pan with a hammer because someone tightend them too tight and distorted them. Just tighten the pan bolts enough to get a little squish out of the gasket. Hope I got to you in time before you get started.
 
I didn't get to read you reply till I gave up on it for the night. I'm having trouble getting the old seal out. I have loosened all the caps and still not moving. I'm not sure what to do now. I got frustrated and figured it better to get some sleep and try again tomorrow. I did notice that the timing chain is pretty sloppy on the sproket though... hope it makes it thru the rest of the season. Also there was something plastic that was broken up and sitting in the bottom of my oil pan.... any ideas as what that could be? Any more suggestions on getting a stuck seal out? I'm trying to do this without taking the engine off the boat. Not much room to work but hopefully it will come out.

Thanks,

Dan
 
95% chance the plastic is teeth off of your cam gear. G.M. used plastic teeth on allot of their cam gears. Timing chains are always an issue with direct drive airboatmotors. When you let of the gas the prop dereving will load a chain in the opposite direction. That’s the same reason why a manual transmission car will wear out a timing chain in half the time an automatics will.
 
Nebraska: Is it that much trouble to replace the timing gear now instead of next time? I was a aircraft mechanic in the airforce and maybe that is what ruined me on these kinda things .. but when I am out in the swamp I will do whatever and patch it up anyway I can to get it home without being pulled in. However when I am at home I won't leave to go out on my boat when I think I have a problem.

We had manuals in the airforce that told us when to do things based on either calendar time or engine time. We don't have a peridodic schedule for airboats so when something is noticed I feel it should be noted and fixed.

Maybe where you run getting help back to the dock is no big deal but where I run if someone has to pull you across miles of mud or dry ground it is dangerous and hard on their boat as well as your boat. I have been pulled and done the pulling and when you pull someone in and then they comment that they saw the problem before they went out it really sets your teeth on edge. I breakdown alot but they are minor things and considering the places I run they are to be expected however no one will ever hear me say I left home with a potential major problem. Most of us do this for fun so going out is not a matter of life or death or even our job on the line so why take chances. You are very lucky to have found the sloppy chain and have been told that your cam gear may be failing it seems to me waiting till next season is not a good plan you already have it tore down now. Just my thoughts on it
 
hardest thing on cad's is removing the hub if you can get to it with a puller (There press fit no retaining bolt unless you put one in with a correct washer)you should not have to remove the engine.actualy since you have the oil pan off allready it should be a snap.
 
ps I use a stanard 3 leg puller ,harmonic balancer pullers don't usualy work that well for me, depending on the condition of the old cad engine you might have to load the puller and apply a little heat to get the hub to let go.
 
Nebraska, I really don't know why that seal is so stubborn. Might have been overheated at one time or two. Try some PB Blaster. I used a torx head screw driver and had to strike it pretty hard. Maybe get one that is real close to the diameter of the seal end but don't gore the seal grove. Once she moves it should come out. Must have some crud on it getting it stuck. Didn't have any plastic in mine but I believe that it my have been rebuilt prior to me buying it. The pistons from the inside were pristine along with the timing chain. No obvious metal in the pan just a little dust.
 
I have an engine question for you guys using HEI ignitions. I have a 4 pin control module that I recently replaced. Do these go bad often? If so is there a type or brand I can buy that is better than another. I want to have a spare cap, rotor , coil and module just in case. Any thoughts on this will be appreciated. WADE
 
I actually have an entire HEI distributor under my deck for my boat. I have had caps go bad, rotors shatter, pickups go bad. Its easy to fix if you have everything in your hand, and it's not alot of extra weight.

Larry
 
I'll add the pick up to the list for sure. Mines on a caddy and I'm going to find a whole one soon. thanks for the reply larry. Are you going to the springs!
 
Nebraska, maybe use a punch so you can get a solid strike on the seal. The screw driver my be to forgiving on a stuck seal.
 
Got it changed last night. Took about an hour of tapping with a punch, allen wrench, and a small phillips screw drive but it finally came out. I think maybe the additive that I let the parts store talk me into swelled the seal. It was split in the center of it though so it made it fee worth it to change it. I'll be back in the river tonight or tomorrow night though. Thanks for the help.

Dan
 
Not to insult anybody but make sure you get the lip of the seal aiming in the right direction allot of people screw that up and also be sure to oil the seal with oil or a thin coat of molly lube.
 
I got it in the right direction. I had to look at it about 3 times to convince myself especially with my dad standing behind me saying... make sure you put it in in the right direction. I soaked the new seals in motor oil for a while before I put them in. That isn't a bad thing to ask (the direction) I replaced a seal in a 350 chevy I had before and it didn't last long because I put it in backwards. Have they made a gear drive for big block cadillac engines yet?

Thanks,

Dan
 
Waterthunder":1ulfzlf6 said:
When you let of the gas the prop dereving will load a chain in the opposite direction
Click to expand...

Never thought of that, do you recommend a gear drive timing set?
 
I run a gear drive on every conventional SBC and BBC airboat engine I build. That way you will never have a problem . If you run a chain always advance it 2 degrees more than you want because within 20 hours you will loose 2 degrees due to chain stretch.
 
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