Damaged Dist Gear

[FreeBeeTony]

Got towed in today!
After some T/S found a bad dist gear (see pics)
Just rebuilt the engine over the winter and installed the CompCams XM270HR Cam.
Just got off the phone w/ CompCams and was told I did not need to replace the dist gear for this Cam. They said maybe the dist gear was previously worn or the bushings in the dist were bad.
I intend on rechecking the dist shaft bushings and see if I can see the cam gear from the dist hole.
Now for the real question.......
What are the chances I can replace the dist gear and re-install?.....if I can see the cam gear.

 

[Bondo]

Ayuh,..... You should be able to see the cam gear, if yer hull will allow a straight down view,......

If the cam gear looks Ok, 'n the bushin's are Ok, I'd just change the distributor gear, 'n see what happens,.....

 

[SkiGuy1980]

I lost the distributer gear on my 4.3 merc a few years ago. The cam shaft was clean so we rebuilt the distributer with a new gear and had no problems. Good luck!

 

[alldodge]

Looks like the gear was not checked for correct depth and was down to low. Probably need to shim it up some. Install and put some grease on the gear. clamp it down and rotate a couple times, then check wear pattern

Do you have a regular oil pump or other type?

 

[Scott Danforth]

check cam gear, if good, go with a bronze dizzy gear.

 

[Bondo]

Looks like the gear was not checked for correct depth and was down to low. Probably need to shim it up some. Install and put some grease on the gear. clamp it down and rotate a couple times, then check wear pattern

Do you have a regular oil pump or other type?

Hmmmmm,...... Was the gasket installed,..??

 

[FreeBeeTony]

FYI......
I was running ~3500RPM when the failure occurred.
Engine backfired through the carb and engine died......would not start.
When checking the timing it seemed pretty far off.....so I pulled the distributor and found the damaged gear.
I'm guessing the dist, jumped and the timing changed.
Didn't have a chance to get back down to the boat.
Is that dist gear something I could pick up at a auto parts store?

 

[scoflaw]

If the cam gear looks good , un scathed by this , then the Rockwell hardness number between the 2 gears is different. An alignment issue would show wear on both gears if of equal material

 

[GA_Boater]

Was it your motor that the cam gear was too far back on the camshaft and you pinned the gear? Might be another member.

 

[FreeBeeTony]

Does this seem like a possibility?
Need to measure the shaft tomorrow.

 

[Scott Danforth]

Measure your shaft first.

https://www.summitracing.com/search?keyword=COMP Cams Bronze Distributor Gears

 

[FreeBeeTony]

Think I found my problem..........see pics.
Measured the shaft ~0.48.........probably need the 0.491 gear.
Shaft seems a bit worn. Going to see if I can find the gear and bushing and try to use for the rest of the season!
Can I use the shaft to get the bushings out?

 

[scoflaw]

Go with Comp Cams gear recommendation. The last thing you want is a diz gear that's harder than your cam gear. Unless you have a billet cam you don't want a fast wearing bronze gear. I think the bushing and shaft damage was caused by the 2 gears being incompatible and not visa versa, shafts and bushings can last a very long time

 

[FreeBeeTony]

I think the bushing and shaft damage was caused by the 2 gears being incompatible and not visa versa, shafts and bushings can last a very long time

The engine only had 60hrs w/ the new cam........I'm thinking that the bushing caused the gear to fail.
Any suggestions on where to purchase the bushings and gear?

 

[alldodge]

Need to make sure I know what your working on, I'm old and don't remember the mix.
Is this a 1984 350 block and distributor?

 

[FreeBeeTony]

No, the engine s/n was 0DXXXXX.......350MAG, Roller Cam, TBIV ignition, Weber Carb.

 

[alldodge]

No, the engine s/n was 0DXXXXX.......350MAG, Roller Cam, TBIV ignition, Weber Carb.

Your making it harder (at least for me) but 0D (had to find it) puts it in the 1987 to 1995 model.

In that case the distributor gear bushing is 23-90915 (item 10)
https://www.mercruiserparts.com/bam/subassembly/31780/1014/110

 

[achris]

No, the engine s/n was 0DXXXXX.......350MAG, Roller Cam, TBIV ignition, Weber Carb.

When posting serial numbers, please post the whole number. Partial numbers are as useful as no number at all.

Chris.......

 

[FreeBeeTony]

Looks like the dist gear has 2 sets of holes for the pin to position the gear on the shaft........they're about 0.020 apart in height, Looks like mine was installed using the upper hole making it higher......and the gasket was installed on the dist.

 

[FreeBeeTony]

Received bushings yesterday and should get the gear today. plan is to install gear on dist later w/ grease and install w/ gasket, then spin the engine to check wear pattern. will post pics when available. Probably going to run for at least the rest of the season unless it looks really bad. Any other thoughts?