Stripped Distributor Gear

[DaboatnutinWA]

I have a 21ft Sea Ray with the Mercruiser 4.3L Chevy V6. Runs really good but last summer it died suddenly after getting up on plane. After checking fuel and spark determined that the rotor wasn't rotating. Pulled the distributor and found the gear on the bottom was chewed. Every tooth has been worn down to almost a point. Except fpr 3-4 that were flat as you see in the attached pic.
Long story short, I replaced the gear with a new one, put it back together and its running great. But what I'm dying to know is how did this happen? When I took it to my local marina the mechanics all scratched their heads and said "Ive seen that happen on Ford engines" I dont know how many hours are on the engine (no hour meter yet) and I changed the oil after I got it running again. I used a straight 30W per the owners manual.(Used an OMC brand) Then noticed that the oil pressure was upwards of 80psi where before it was running about 65psi. Maybe I should use a multi weight oil?

 

[alldodge]

I have a 21ft Sea Ray with the Mercruiser 4.3L Chevy V6. Runs really good but last summer it died suddenly after getting up on plane. After checking fuel and spark determined that the rotor wasn't rotating. Pulled the distributor and found the gear on the bottom was chewed. Every tooth has been worn down to almost a point. Except fpr 3-4 that were flat as you see in the attached pic.
Long story short, I replaced the gear with a new one, put it back together and its running great. But what I'm dying to know is how did this happen? When I took it to my local marina the mechanics all scratched their heads and said "Ive seen that happen on Ford engines" I dont know how many hours are on the engine (no hour meter yet) and I changed the oil after I got it running again. I used a straight 30W per the owners manual.(Used an OMC brand) Then noticed that the oil pressure was upwards of 80psi where before it was running about 65psi. Maybe I should use a multi weight oil?

Have found several discussions on the issue, and most indicate that the gear was made from to soft a material. The fix is to get a steel gear.
http://www.summitracing.com/search/d...tOrder=Default

and :welcome: to iboats

Also the engine needs a good cleaning to get the metal stuff out of it

 

[Scott Danforth]

^ +1

its not an oil thing, it is a cheap a$$ distributor gear thing.

 

[keith2k455]

Ditto the gear material...but if one of the distributor gears is going to strip, THIS is the one you want to go!

 

[DaboatnutinWA]

Thank you all for your replies and to AllDodge for the link. I will be getting a steel gear to eliminate this problem.
Yes Keith I totally agree its better for the dizzy gear to get chewed and not the cam. It would suck bilge water to have to replace a cam. The new dizzy gear only cost me 30 bucks.....and a couple hours of time so all in all it was a cheap fix.

 

[gm280]

I actually had one strip like that years ago in my hot rodding days, but on a Chevy 350 engine. It was a brass gear and went quickly. Make sure that there is some endplay because if there is zero, you are loading the distributor gear hard against the cam gear. And that isn't a good thing. So having just a small amount of endplays lets you know they are not force together. I'm sure there is a spec for it...just make sure it is within that spec. JMHO

 

[Alumarine]

Would the pieces be in the bottom of the oil pan now?

 

[DaboatnutinWA]

I actually had one strip like that years ago in my hot rodding days, but on a Chevy 350 engine. It was a brass gear and went quickly. Make sure that there is some endplay because if there is zero, you are loading the distributor gear hard against the cam gear. And that isn't a good thing. So having just a small amount of endplays lets you know they are not force together. I'm sure there is a spec for it...just make sure it is within that spec. JMHO

Thanks for the info. Yes, when i replaced the gear I checked the endplay and there was some. Didnt measure it but it had some play.

 

[DaboatnutinWA]

Would the pieces be in the bottom of the oil pan now?

That's a possibility but the gear didn't disintegrate. Judging by the wear pattern I think it wore down over time. No clue how much time since I bought the boat last spring and there's no hourmeter on the dash...yet. When I changed the oil I pulled the drain plug to be sure I got all the dirty oil out and no chunks fell out so Im thinking it wore down and the metal tuned to powder/dust and the oil soaked it up.

 

[DaboatnutinWA]

I ordered a new steel gear from Summit Racing.

 

[gm280]

Do you have a magnetic oil drain plug? If you do, the particle, if there were any, would be stuck to that drain plug. If there were no large particles then the drain plug would have had some fuzzy looking junk on it... Kind of like those magnetic games we use to play with to put beards and mustaches on the face with the little magnet pencils back it the days... If everything works out correct and you have good oil pressure, then I'd forget about it and boat on...

 

[fishrdan]

What's your oil pressure now that the engine is back up and running again, PSI at idle and at high RPM? You mentioned 65PSI and now 80PSI, is that idle or high RPM?

The oil pump is driven by the distributor's gear, off the cam gear,,, so if for some reason the oil pressure is very high it can put undue stress on the distributor gear.

Does this engine look like it's been removed - rebuilt before?

 

[DaboatnutinWA]

What's your oil pressure now that the engine is back up and running again, PSI at idle and at high RPM? You mentioned 65PSI and now 80PSI, is that idle or high RPM?

The oil pump is driven by the distributor's gear, off the cam gear,,, so if for some reason the oil pressure is very high it can put undue stress on the distributor gear.

Does this engine look like it's been removed - rebuilt before?

Those observations on oil pressure was at idle and 1000-1200RPM. Was running it on the trailer with earmuffs. At the time (last Oct) I wasn't able to take it out on the water for a test ride..
Was told by P.O that engine has been replaced but I have no info on when. I'm guessing 10 years ago. Also, no hour meter so again, have no way of knowing. But it does run very good, starts right up. I pulled the valve covers and looked at the valvetrain and it looked very clean. Some surface rust on the engine (external) but not too much. Has a sticker on the valve cover that says Dealers Marine which 'Ive traced to an outfit in Minnesota.
Besides the distributor issue, haven't had any major problems other than some crappy/old gas from sitting too long and I compounded the issue by putting ethanol blended gas in it but that's because I learned about using ethanol free gas a little too late. Now I know not to use that crap. I'm buying the good stuff at the dock. Since doing that it runs so much better. Also helps to replace the fuel/water filter. (Done that twice)