Alternator Conversion - Bolt Falls Out

[davemoore]

So I finally gave in and converted my 1983 Merc 470 to an alternator.

The installation was a snap, and I have since revised the mounting arm from what is shown in the photo to provide for full adjustment.

However - I have one huge problem: the main mounting bolt (3/8") continuously falls out while out on the lake. After the last time, I removed it and installed a lock washer under the head, but it fell out again.

Is the solution as simple as some Loc-Tite thread lock? Or am I fighting a losing battle?

I know the block/head get hot while motoring, and there is a lot of vibration, so I'm not sure if just Loc-Tite will solve this. Do I need a different type of bolt (some other metal)?

Thanks in advance for the help.

 

[Bondo]

Re: Alternator Conversion - Bolt Falls Out

Ayuh,... Ya talkin' 'bout the big bolt on the portside of the alternator, to the head, through a little piece of 1/2" pipe,..??
If so,....
I'd go with a thicker, stouter, tight fittin' spacer block than the 1/2" pipe,...
Along with a good gr.8 bolt, 'n lock washer,..
I'd elbow torque it to 'bout 40ft.lbs., with lock-tite...

Have ya got anymore supports from the backside,..??
That'll help knock down the Vibrations....

 

[Eric 3.7LX Alpha 1]

Re: Alternator Conversion - Bolt Falls Out

I have a somewhat similar setup except I have an additional bracket on that port side bolt, that goes to the top 2- front cover bolts that you can see in the photo.

I made my own brackets from one I seen on ebay. Here is a pic of the one I copied, you can see the extra bracket off the front cover.

 

[Don S]

Re: Alternator Conversion - Bolt Falls Out

That extra bracket in Erics photo and the extra holding power is the difference between the good (expensive) kits, and the cheap (inexpensive) kits.
Even if you replace that pipe with a perfectly machined spacer, and locktite the bolt, the bolt will break next.
The conversion kits are all about solidly supporting the alternator to keep it from vibrating different from the engine.
The kits that hold up to the vibration cost money.

 

[fmalott]

Re: Alternator Conversion - Bolt Falls Out

i agree i think there is not enough support on the alternator i did the conversion with the hunn-finn version and there was alot of more support

 

[davemoore]

Re: Alternator Conversion - Bolt Falls Out

UPDATE: Don, you're a psychic. I tore into it today, only to discover that the bolt had indeed sheared off. Fortunately, I was able to get a grip on the piece in the head and remove it.

I fabricated some brackets and now have it supported on the front and back of the alternator housing from the two bolts in the front cover in addition to the connection to the head. I also used a grade 5 bolt instead of el-cheapo. It's as solid as a rock now! No movement at all. When I try to shake it, the entire motor moves. Thanks for all the help everyone.

Headed out to the lake tomorrow to give it a test run. I'll let you know if anything changes. ;-)

Dave