Mercruiser 470 - Help Please!

[BlueNote2]

I am installing an Alternator Conversion Kit to a 1986 470.

I overtightened one of the bolts that goes through the Water Pump Housing and broke the threads. The threads came out with the bolt. Now coolant is leaking from it and I cannot tighten Bolt.

Thank you in advance for your suggestions.

 

[GA_Boater]

Welcome aboard, Blue.

Look at installing a Helicoil. You can get a kit at your local auto parts store. Maybe 30 bucks and the tool is reusable for size different coils.

 

[BlueNote2]

Thanks GA_Boater, will check it out.
Point taken. I have edited my post to show appreciation.

 

[GA_Boater]

Edited mine too, Blue. It shouldn't be a hard fix. Just watch over torquing bolts in aluminum. Never any fun. Good luck.

 

[wrestling coach]

Once your repair is complete the threads of ALL the bolts you removed for your kit should have Permatex Aviation Sealer applied. You can get it at NAPA.

 

[BlueNote2]

@Coach,
Bought some Permatex Aviation Sealant today when I picked-up the HeliCoils. Great suggestion!



Follow up questions:

The box for Helicoil is 5/16-18...is that the correct size for a 470? They matched it to size at Auto Parts store, but the salesperson has never installed one before.

Does anyone happen to know what size drill bit I need; The box does not say anything about bit-size? I would hate to screw-up twice in a row (no pun intended).



Thank you.

 

[Bondo]

@Coach,
Bought some Permatex Aviation Sealant today when I picked-up the HeliCoils. Great suggestion!



Follow up questions:

The box for Helicoil is 5/16-18...is that the correct size for a 470? They matched it to size at Auto Parts store, but the salesperson has never installed one before.

Does anyone happen to know what size drill bit I need; The box does not say anything about bit-size? I would hate to screw-up twice in a row (no pun intended).



Thank you.

Ayuh,.... The drill size needed is most usually stamped into the tap ya use to cut the threads for the heli-coil,...

 

[BlueNote2]

Bondo,

Yeah, there it is... "Use drill size 21/64" " just like you said.

Just wondering, do you hail from Maine/New England or is "Ayuh" pretty common on this forum.

 

[Bt Doctur]

If you managed to destroy your cover, pm me if needed

 

[BlueNote2]

Glad to keep you in mind Bt Doctur, could you be more specific.

 

[Bt Doctur]

I have the main cover and the small 3 bolt cover

 

[Bt Doctur]

http://www.breezeworks.net/cgi-bin/...ads.asp?ForumID=1&TopicID=2305&PagePosition=1

 

[Bondo]

Bondo,

Yeah, there it is... "Use drill size 21/64" " just like you said.

Just wondering, do you hail from Maine/New England or is "Ayuh" pretty common on this forum.

Ayuh,.... I was brought up on the western fringe of Downeast Maine,....
Eastern Penobscot county,....

I've been a Maineiac in exile for nearly 40 years now, but everybody still tells me I talk funny,....

 

[wrestling coach]

Here is a helpful video.
https://www.youtube.com/watch?v=79IYC4L68LU

 

[stonyloam]

Yeah a good torque wrench is a real help when working on the front covers. Real easy to crack the bolt flanges if you are not careful. I managed to crack one even WITH the torque wrench.

 

[BlueNote2]

Do I need to remove water pump housing before drilling, or can I just drill-out the original hole as-is?
Will it leak coolant if I make the hole slightly larger on coolant housing?

 

[achris]

As the tap for the heli-coil will be bigger than the hole in the housing, best remove it.

 

[BlueNote2]

Just an Update:



I had a brainstorm after I started making preparations to take apart water pump housing and tap new heli-coil.

I tried a longer bolt of same thread size, and was elated to find that there were still threads and room at the back (because of the depth of the alternator bracket that was added).

I added the Aviation Sealer to Threads and completed the job today!!!

WOOOHOOOOO!!!!!!!! YES.


Big Thanks to posters who took a few minutes to answer this post before.

 

[Bondo]

Just an Update:



I had a brainstorm after I started making preparations to take apart water pump housing and tap new heli-coil.

I tried a longer bolt of same thread size, and was elated to find that there were still threads and room at the back (because of the depth of the alternator bracket that was added).

I added the Aviation Sealer to Threads and completed the job today!!!

WOOOHOOOOO!!!!!!!! YES.


Big Thanks to posters who took a few minutes to answer this post before.

Coool,.... Glad to hear it worked out Soo well,....

 

[GA_Boater]

Good Blue. Just keep in mind that while the longer bolt holds now, there may just a few threads left. Keep an eye on it. But still :thumb: