4.3lx Broken starter bolt hole

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Well I have figured out the starter problem.

The PO broke the starter mount hole and welded it.

I don't think it has the strength to keep the starter tight.

I am going to try a bolt that is 4.45 and a little thicker.

I did see a post were someone fixed this same problem. I would love to find this post as it explains how he fixed it.

Like him the motor is pushing 150+ on compression and don't want to trash motor.

Please don't respond with you need a new Block.. That's last choice, I don't need the forum to tell me that...

Thanks..
 

81 Checkmate

Lieutenant
Joined
Jul 20, 2010
Messages
1,360
Re: 4.3lx Broken starter bolt hole

Got picture of the hole?

Does it have a flat surface where it's been welded?
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

I checked the bottom with a mirror and its flat. Top side is a little rough but i can grind it flat.
 

81 Checkmate

Lieutenant
Joined
Jul 20, 2010
Messages
1,360
Re: 4.3lx Broken starter bolt hole

So the mating surface is flat...Starter to mounting surface.

Some thoughts.
Posible to oversize and re - tap the hole?
Posible a right angle drill
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

Yes surface is flat.

Going to try a little larger diameter bolt. The metric bolt is a little bit thicker.

Not holding my breathe but i need to try anything and everything.

The next step if the bolt doesn't work i will need to make some kind of bracket.

I did find a Mercruiser starter support bracket but not sure if will work on my starter.

Thanks, and keep the ideas coming
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 4.3lx Broken starter bolt hole

Yes surface is flat.

Going to try a little larger diameter bolt. The metric bolt is a little bit thicker.

Not holding my breathe but i need to try anything and everything.

The next step if the bolt doesn't work i will need to make some kind of bracket.

I did find a Mercruiser starter support bracket but not sure if will work on my starter.

Thanks, and keep the ideas coming

Ayuh,.... Ya need factory standard starter bolts on a Chevy motor,...

The starter Indexes on the bolts for proper ring gear alignment....
That's what the knurlin' is for,..
The newest Merc bolts have rebated heads, 'n that alone is worth New bolts...

Pull yer motor,... On the floor, it might be fixable,...
you've got No access in the hull, 'n No chance of success...

Is it the inboard, or outboard bolt,..??
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

Good advice on the bolts. I used starter bolts that came with it. I guess I need to go to mercruiser dealer and compare the bolts.

Well tonight I mounted the starter with the bolt on the inside and smoked it down then installed the out board bolt with the repaired weld.

When I bumped my remote starter switch I was able to watch the starter and it looks like the torque is causing the starter to drop down.

The bottom line there is a lot of downward movement on the outboard side of the starter. Like it is allowing the starter to move away from the flywheel.

I think from the weld there is not enough strength to hold the starter under load. I am thinking about drilling out the threads and running a bolt through and then using a washer and nut to provide some strength.

Any Ideas or thoughts?
 

Lyle29464

Lieutenant
Joined
Mar 10, 2009
Messages
1,261
Re: 4.3lx Broken starter bolt hole

The bolt hole is too big and or the surface is not flat?
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

Thanks,

I do agree bolt hole to big, the surface is flat. I used a angle square and it checked good.

Now I am checking while motor is in boat so I could be off I will check again.

So any ideas on a fix i.e Larger bolt, Drill out threads and run a bolt with a lock nut and washers all the way through????

I was thinking bolt all the way through for the reason that maybe the weld is not strong enough for the torque..

This would allow for the bolt to provide strength instead of the threads on the weld???

Thoughts?????
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

I was thinking i have enough room to drop the starter out the bottom.

If I used JB weld on a stud and then screwed it up into the mount hole if that will provide a stronger connection??

Thoughts??
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 4.3lx Broken starter bolt hole

I was thinking i have enough room to drop the starter out the bottom.

If I used JB weld on a stud and then screwed it up into the mount hole if that will provide a stronger connection??

Thoughts??

Nope,.... Won't work.... Gotta be bolts. 'cause of the way the starter goes in, 'n out...
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 4.3lx Broken starter bolt hole

There is just too much pressure caused by the starter. A very good weld "MIGHT" work, but in reality, you need a new block.
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

That's what iam trying to avoid but I think it's going to be the case new block.

I have never notice before because I have never had to mess with the starter so much. But does the starter go flush against bell housing or is there a small gap? You need to put your head way back in a really look for it.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 4.3lx Broken starter bolt hole

That's what iam trying to avoid but I think it's going to be the case new block.

I have never notice before because I have never had to mess with the starter so much. But does the starter go flush against bell housing or is there a small gap? You need to put your head way back in a really look for it.

There is a small gap, they only make contact on the block above the starter.

And yes, everyone is trying to avoid pulling the engine and replacing the block. Happens in all of the threads with this problem.
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

Thanks again everyone. I have wasted enough of everyone's time along with mine trying to avoid the obvious.

Well I have a friend with a 4.3lx Vortec that has a scored cylinder wall going by today to look and see if i can rebuild.

The one quick question and then i will start a new thread with new question.

I have a 95 Vortec with a 12 bolt intake can i use my heads and intake from my vortec on this other one?

The heads on the other motor have the 8 bolt intake.

I think i know the answer just wondering if i am correct.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 4.3lx Broken starter bolt hole

Thanks again everyone. I have wasted enough of everyone's time along with mine trying to avoid the obvious.

Well I have a friend with a 4.3lx Vortec that has a scored cylinder wall going by today to look and see if i can rebuild.

The one quick question and then i will start a new thread with new question.

I have a 95 Vortec with a 12 bolt intake can i use my heads and intake from my vortec on this other one?

The heads on the other motor have the 8 bolt intake.


I think i know the answer just wondering if i am correct.

Ayuh,.... You Could do that, but it's steppin' Backwards,...

The True Vortec Heads are worth buyin' another intake for....

Yer '95 is Vortec, in name only....
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

Great point... I have two intake manifolds I will go with those heads...

Thanks again...
 

Idlespeedonly

Senior Chief Petty Officer
Joined
Jun 30, 2011
Messages
779
Re: 4.3lx Broken starter bolt hole

I had the same problem as you are having. I made a bracket that bolts to the two bellhousing bolts. I am a tool and die maker by trade so it was fairly easy to make. But it can be done with great results.
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: 4.3lx Broken starter bolt hole

Does the 4.3 block not have a provision for a bracket on the end of the starter (the forward end)? I know the small blocks do. I had the same exact problem in an old pick up truck. The outboard bolt hole had broken out and allowed the starter to flex more than it should. I installed the bracket on the end of the starter and the problem went away.
 

Aquatron

Petty Officer 3rd Class
Joined
Apr 17, 2011
Messages
76
Re: 4.3lx Broken starter bolt hole

Thanks, no place to mount a bracket.

If you have a picture or a drawing on the bracket that would be great.

But right now moving on to new block...


Thanks again...
 
Top