Clunking noise when starting

[Green79k10]

Hey guys.. I have a 79 k10 with a 350.. I’ve owned her for about a year and a half.. when I first bought her I replaced the carb and had a buddy of mine adjust the timing.. and she ran fine.. no problems starting up or anything.. about 6 months ago my starter went out.. so I replaced it.. truck fired up just fine (no shims were on the old starter so I didn’t add any on new starter).. then maybe a few weeks later I started her up and she made some awful clunking noise.. but once the motor fired up it stopped.. I shut the truck off and crawled underneath.. the fly wheel teeth look fine from what I can tell.. this never happened with the old starter.. only thing I’ve figured out so far is that it only seems to do the clunking when the truck is warmed up.. when she has sat for a week or so.. I can go out and she cranks right up no problem.. then if I shut it off and go to start it back up.. about 50% of the time she will clunk..

anyone have any thoughts to what the hell is going on? Just a bad remanned starter? I didn’t think trying to shim it would work because it doesn’t do it every time.. I’m no gear head when it comes to working on motors so be easy on me

 

[Frankenchevy]

Have you looked at the tolerance with the starter pinion engaged into the fp/fw?

 

[Green79k10]

No I haven’t.. what exactly should I be looking for?

 

[80BrownK10]

Sure the solenoid is kicking the Bendix out every time all the way and not bouncing it around? Don't know I'm just throwing ideas out

 

[shiftpro]

Mine does that too, and I changed starters with no difference. The ring gear looks fine, like really nice but it clunks just like a missing tooth. I got missing teeth alright, but they're in my mouth.
??

 

[Frankenchevy]

If I remember correctly, you want about 1/8” between the smooth part of the armature and the fp/fw unengaged. If you have that, check the armature when engaged with the fw/fp. I’ve personally haven’t had to shim a mini-starter, which is what I run.

 

[Green79k10]

Sure the solenoid is kicking the Bendix out every time all the way and not bouncing it around? Don't know I'm just throwing ideas out

It’s possible.. especially with it being a reman.. but what I don’t get is why it only seems to do it when the truck is warmed up.. unless it’s just by chance that it’s never done it when the truck has been sitting

 

[Green79k10]

If I remember correctly, you want about 1/8” between the smooth part of the armature and the fp/fw unengaged. If you have that, check the armature when engaged with the fw/fp. I’ve personally haven’t had to shim a mini-starter, which is what I run.

I will take a look tomorrow.. thanks!

 

[80BrownK10]

It’s possible.. especially with it being a reman.. but what I don’t get is why it only seems to do it when the truck is warmed up.. unless it’s just by chance that it’s never done it when the truck has been sitting

Cause the heat soak...it has time to warm and soak into the solenoid. Heat shows weak electricals. Things expand and connections expand and maybe don't make connections bas well or it just shows the weak electricals. This is usually where weak electronics show themselves, when they get hot.

 

[Green79k10]

Mine does that too, and I changed starters with no difference. The ring gear looks fine, like really nice but it clunks just like a missing tooth. I got missing teeth alright, but they're in my mouth.
??

Did yours just randomly start doing it one day? Or has it since you’ve owned it?

 

[shiftpro]

Did yours just randomly start doing it one day? Or has it since you’ve owned it?

As soon as I paid for the truck...