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Discussion Starter #1
Hey everybody. I just did a rebuild on my 350. 30 over, flat top pistons, new crank/rods/bearings/flexplate etc.

Anyway.. compression is now .75 higher than before (10.25:1) and the motor is definitely harder to turn over with the fresh hone and rings. I got the engine in the car and got ready to fire it up today, and decided I'd check the starter after I primed it to listen for odd noises... sure enough I found an odd noise. The starter engages the flexplate and it cranks over fine.. slightly slower than before, but, it still turns over. I noticed a sort of noise, best described as maybe a clunk or maybe a click. It's not crazy loud or hard, but you can hear it over the starter. At first I thought it was an issue with the flexplate/torque converter so I pulled the bolts and made sure the torque converter was seated in the front pump, then pulled it out a bit and shimmed it up and torqued it down. Then I thought maybe it was a rod knock. Pulled the pan, checked torques and clearances again then cranked it over... noise went away. There's no signs or evidence of contact on the oil pan, and the new crank and rods are stock dimensions. I'm pretty lost here. Any ideas??

Yes I did check PTV clearance and set cold lash.
 

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Discussion Starter #3
I thought you wanted the converter to sit out of the front pump a little, but not too far out of it? I just have a 1/16th thick washer between the converter and flexplate on all 3 bolts.
 

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If the distance between the fully seated converter and the flexplate are too great, it is perfectly acceptable to shim the converter to flexplate bolts...done on racing stuff all the time.....it is not a big deal.

You just don't want it so tight it binds the pump, and not so great that it pulls the pump drive out of the pump gear.

You also don't want so much shim that it pulls the converter nose out of the pilot hole in the end of the crankshaft.
 

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There are cases where some brands of converters have longer snouts, and wont allow the converter to sit against the flexplate. In those types of converters a shim is always used to make up the difference, and not distort the flexplate. My high stall converter came with 3/16" shims in the kit, and needs them to clear the long snout.
 

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Discussion Starter #10
That makes sense. I just have a Hughes gm25, it didn't come with shims. I'm thinking I need to remove the shims so the pilot sits in the crank better.
 

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That makes sense. I just have a Hughes gm25, it didn't come with shims. I'm thinking I need to remove the shims so the pilot sits in the crank better.
Yes, if it will sit against the flexplate with no effort, then I would eliminate the shims. Mine wouldn't get close enough to not distort the flexplate without using shims.
 

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Discussion Starter #12
Yes, if it will sit against the flexplate with no effort, then I would eliminate the shims. Mine wouldn't get close enough to not distort the flexplate without using shims.
I like your thinking. My only question is, what is the furthest you can pull a converter out of the front pump to mate it to the flexplate before you need to shim it?
 

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I like your thinking. My only question is, what is the furthest you can pull a converter out of the front pump to mate it to the flexplate before you need to shim it?
Not certain, but I've pulled them out close to 1/2" and not had an issue. But I'd be concerned more about pulling it out too far, than shims between the flexplate and the converter!
I think the norm would be more like 1/4" of play between flexplate and converter, and I'd shim it to keep it seated into the pump.
 

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Discussion Starter #16
Just measured it. The distance is 1/4. I added a 1/16 washer to put it at 3/16. Here in a bit I'm gonna crank it with the plugs out and see how it sounds.
 

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Sounds like it could just bolt up, and not need shims. If you look at the converter before it's put on the trans, you can see how deep the notches are that engage the pump. They're over 1/2" deep, so pulling it out that 1/4" to bolt up wont disengage the pump notches.
 

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Discussion Starter #18
Sounds like it could just bolt up, and not need shims. If you look at the converter before it's put on the trans, you can see how deep the notches are that engage the pump. They're over 1/2" deep, so pulling it out that 1/4" to bolt up wont disengage the pump notches.
True. You have a valid point. I got it all slapped together and found the problem upon cranking it, I made a rookie mistake and assumed the starter was shimmed properly. It was nkt. The gear was tighter than s**t in the ring gear causing it to pop and bind due to it being too tight. I'm just glad it wasn't anything big. It's always something small lol.
 

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True. You have a valid point. I got it all slapped together and found the problem upon cranking it, I made a rookie mistake and assumed the starter was shimmed properly. It was nkt. The gear was tighter than s**t in the ring gear causing it to pop and bind due to it being too tight. I'm just glad it wasn't anything big. It's always something small lol.
Glad you found it! I usually try to install a new or rebuilt starter with the solenoid removed. Then I grab the plunger and manually pull the starter in so I can feel and see how it engages. Most the time they fit perfect, but when they don't they're easy to find this way. Takes more time, but it's worth it in the long run.
 

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Discussion Starter #20
Yeah... not gonna lie I was going to do that... but when it was on the stand I got excites to get it in the car and skipped that step to drop it in. *smacks myself in the head*

Looks like I know what step I'm not skipping next time lol.
 
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