Distributor gear broke off!!!!!!

[lilb]

First off i have a Cobia 225 esc with a 5.7 and a alpha1 gen2.

The last time I took the boat out it ran great on the way to the beach, but on the way back it seemed like it was working really hard. For a motor with 320hp it shouldnt't have been struggling that hard to get up to 40 mph with a 21 pitch prop.Then all of a sudden a loug bang and it just died. So i hade to be towed in. Well I finally got a chance to look at it last nite and no spark. So i pulled the distributor cap and cranked it over and what do ya know the rotor wasn't turning. So i pulled the distributor and found that half the teeth on the gear were worn down and the other half were gone

I was wondering how this would happen? Why would the gears just break off like that? Would i have any thing to do withthe motor struggling so bad to get up to speed?

Also the motor has mabye only 2 hrs on it and now im stuck with the decision of pulling it out to find the missing teeth or run it till it blows up and send it in for warranty. What would have caused this?

 

[lilb]

Re: Distributor gear broke off!!!!!!

Thanks for the info bubba. Ya kinda upset about the fact it only has 2 hrs on it. I looked at the gears on the cam while a friend bumped the engine over and they all look good, still looks like new.

I know that there are teeth in there from the dist gear but i have had problems with the engine builder from the time i got the engine, so I think I am just gonna run it till it blows up and send it back to warranty it. It has a 2 yr warranty on it so I mught as well.

 

[zbnutcase]

Re: Distributor gear broke off!!!!!!

Thanks for the info bubba. Ya kinda upset about the fact it only has 2 hrs on it. I looked at the gears on the cam while a friend bumped the engine over and they all look good, still looks like new.

I know that there are teeth in there from the dist gear but i have had problems with the engine builder from the time i got the engine, so I think I am just gonna run it till it blows up and send it back to warranty it. It has a 2 yr warranty on it so I mught as well.

Don't bother as it won't be covered, because by posting here, there is now record of your issue, which needs to be dealt with NOW

 

[jtmarten]

Re: Distributor gear broke off!!!!!!

By chance is it a roller cam, and not using the proper dist gear? Or not a roller and using a roller dist gear??
Should have 10+ hrs on it before you start hammering it. Could just be that things were still tight with only 2hrs run time.

 

[lilb]

Re: Distributor gear broke off!!!!!!

Ya nutcase your probally rite as if I ran it again and it did blow up iI would be more upset at the fact that i was stuck in the middle of the bay wit no power only paddles. Are there ant thoughts as to why this would have happened?

I mean it ran fine for the ride out to the beach(about 3.5 mi) then sat for a few hrs and it was really hard to start back up and when i got it running it didnt go to far and was laboring really, really hard, then bang it was done.

 

[zbnutcase]

Re: Distributor gear broke off!!!!!!

Was the heads and/ or block surfaced? In a nutshell, if they were, and the intake manifold as well (needed to maintain alignment with heads) it lowers the dist mounting in relation to the cam, throwing gear alignment off. Just a thought

 

[lilb]

Re: Distributor gear broke off!!!!!!

It is a non roller cam im guessin cuz i was told by engine builder that it was not, nor does it have roller lifter in it. Good call on the heads beind shave and the block decked I didnt think of that.

When it get torn apart to find the problem iI will be putting a bronze gear on the dist just to make sure this doesnt happen again.

 

[John_S]

Re: Distributor gear broke off!!!!!!

It is a non roller cam im guessin cuz i was told by engine builder that it was not, nor does it have roller lifter in it. Good call on the heads beind shave and the block decked I didnt think of that.

When it get torn apart to find the problem iI will be putting a bronze gear on the dist just to make sure this doesnt happen again.

The bronze gear is for a roller cam, not for the standard cast ones. Even if it was a steel roller with steel gear, and you didn't have the bronze gear, I doubt it would be tore-up like that in such few hours. The bronze gear is to sacrifice itself, for the cam. If it was a bronze gear on a standard cast cam, again should last much longer than a few hours.

What distributer was in the engine? GM or aftermarket? Any late model GM will have a melonized gear for use on either cam type.

IMHO: something else caused this issue. When you pulled the distributer was it locked down tight or was it loose? Are you able to turn the oil pump?

 

[lilb]

Re: Distributor gear broke off!!!!!!

John S. Yes the stock distributor that came with the boat in 91' is in the motor. The oil pump spins freely with a flat head screwdriver as it should, and yes the distributor was locked down tight when this happened. Also the timing was set at 8 deg before tdc as the manual states. I didn't get the cam card with the motor so that is why i set it to the merc manual. The cam card was supposed to have been mailed out on the first of the month but i haven't seen it yet.

As far as the bronze gear goes I know it sacrafices it's self for the cam that's why I thought it wouldn't hurt to put one on when I renstall it. Does anybody knows would this be a recipe for disaster?

 

[Kainon]

Re: Distributor gear broke off!!!!!!

with the heads & intake shaved, the dist would sit lower, and tightened, could be the oil pump was jamming and causing excessive drag on the dist gear. I think the gear hight would be OK.. but I would take some measurements to the bottom of the slot, and measure to the roll pin on the dist gear.

 

[John_S]

Re: Distributor gear broke off!!!!!!

Did you do the recommended flat based cam break-in procedure? Also, pull both valve covers and rotate the engine over a dozen times or so. Make sure each valve is going up and down and the lift seems right and mechanical fuel pump is working.

A remote possibility is that a roller cam was installed with flat based lifters and no front retainer.

Outside of what zbnutcase suggests, and absense of any other corrective action, this will just be a repeat exercise, or worse.

As far as your warantee, it might be void by putting the hammer down with less than 2 hours on the motor. You might already own the problem, and not want to compound it by risking further damage like a rod through the block.

 

[lilb]

Re: Distributor gear broke off!!!!!!

There is another problem with the engine builder i forgot to mention THE BLOCK HE SENT DOESNT HAVE THE FUEL PUMP EXCENTRIC ON IT. So i had to switch to an electric fuel pump. What a nice guy huh? I made sure the pump i put on was for carberated engines and also put a in line fuel pressure gauge to make sure it doesnt get to much pressure. It put out a steady 6 lbs of pressure at idle and the same at 3800 rpm in the water. I never got the motor past 4000 with it in the water and i only went there for a second then backed it off because i wasnt payin attention to the tach.

When i first started the new motor I set the timing, tuned the carb idle screws, Then ran it up to temp, And ran it at 2500 rpm for 5 to 10 mins for the cam to break in, Finally shut it down. Yes i did this on the muffs i know it's not a good idea to do so but i kept a eagle eye on all the gauges when i did so. The temp never got above 175. Droped the oil and filter and added new.

I then took it to the bay and went puttin' around at verious rpm's for about an hr not to exceed 4000 rpm. So i thought i did a good job with inital break in.( I was alot nice to this motor than the last new motor i built over 10 yrs ago and it still runs like a raped ape to this day but that was for my truck) Thats why i took it easy on this motor because a boat is alittle different than a vehicle.

 

[John_S]

Re: Distributor gear broke off!!!!!!

Do the valvetrain initial check to make sure you haven't lost a lobe. I'd follow it with a vacuum gauge on the first start-up. If that is the way you go vs a teardown.

Are you able to see any of the cam lobes from the distributer mounting hole? ie id if it is a roller vs flat based cam. I suspect not. Intake would probably have to come off.

 

[lilb]

Re: Distributor gear broke off!!!!!!

Well it looks like im off the where i keep the boat to check to see if all the valves are moving as they should and also to see if its a roller cam of flat tappet. Thanks for the info i will keep ya posted with what i find out.

 

[lilb]

Re: Distributor gear broke off!!!!!!

Well I finally got a chance to take a look at the motro to see if everything else was ok. What i found was all the valves opperate as they should. I cant tell if it is a roller cam or not yet im gonna have to take the intake off the motor to find that out. But i did take some pics of the distributor gear they didn't come outto clear but you can tell what happened

 

[John_S]

Re: Distributor gear broke off!!!!!!

When you have the intake off, take a very good look at the cam distributer drive gear. Its hard to believe it didn't get messed up. The view through the distributer hole might have prevented a good enough inspection.

 

[lilb]

Re: Distributor gear broke off!!!!!!

Well I finally hot time to lift the motor out of the boat and tear it down to find the missind teeth from the gear. I couldn't find any? any where. I also had the cam shaft out still looks like new. So I reasembled the motor and put it back in, so now I have to get a new gear and put it in and try this again. Hopefully it doesnt do the same thing.

When i had the motor apart I put in a different oil pump some one told me it might have been the pump that was putting stress on that gear, since i had 60 psi of oil pressure when it was warm at idle. Well Hopefully this fixes what ever problem I had. Off to get the new gear and get it running

 

[John_S]

Re: Distributor gear broke off!!!!!!

I assume the cam was a standard flat hydraulic and not a roller then, correct?

 

[lilb]

Re: Distributor gear broke off!!!!!!

Oh ya I forgot that part yes it is a flat tapet. Sorry.

 

[sethjon]

Re: Distributor gear broke off!!!!!!

Bring it back sooner rather than later. He might tell you that you've been abusing it. If hes reputable he should take it in and do the fix right away without any hassle.