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Old 05-26-2014, 01:47 PM   #1
cst350
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Ticking noise under load?

Just got everything together and on the road. Rebuilt engine, new TH400 trans from Summit. When I jump on the gas I get a ticking noise that sounds like it is coming from the trans area.

I read that sometimes the flexplate can rub the starter under load. I have a GM performance mini starter. The clearance between the pinion and flexplate is .04 (which is the smallest the directions call for). Would be cheap to get the shim kit to increase the clearance... anyone think this is the problem?

I get zero noise when in neutral all the way up to 3500 rpm. Same if I put it in gear and hold the brake. It is a standard bore 350 with cast iron Vortec heads and my timing is set at @8 deg.
Really don't think it is exhaust or valves since there is no noise when not driving.
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Old 05-26-2014, 02:48 PM   #2
Ridgeclimber
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Re: Ticking noise under load?

Is it possible you have a cracked flex plate?
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Old 05-26-2014, 03:43 PM   #3
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Re: Ticking noise under load?

It could be an exhaust leak at one port.
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Old 05-26-2014, 04:54 PM   #4
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Re: Ticking noise under load?

Bent speedometer cable?
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Old 05-26-2014, 05:38 PM   #5
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Re: Ticking noise under load?

It could be detonation from low quality/low octane gas or ignition timing/advance, too. The engine tries to "pre-ignite" the fuel charge due to elevated temperatures in the cylinder. Maybe the spark plug tip remains hot enough to cause this condition?

I would check out your spark plugs and see if they have the appearance of the "OVERHEATED" spark plug in the photo attached.

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Old 05-26-2014, 05:42 PM   #6
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Re: Ticking noise under load?

Could be your distributor. Don't know what kind you have but some you can adjust the vacuum canister with an Allen wrench in the end of the canister. Or the weights inside the dist might be off but you can get springs and weights to fix that. Had similar probs recently.
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Old 05-26-2014, 05:51 PM   #7
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Re: Ticking noise under load?

Thanks for all the help.

Just got done checking the flex plate. Removed the TC bolts and slid it back to look with a flashlight. No cracks that I could see. When I turned the flexplate to look at all the bolts I notices the flexplate closes the gap on the starter pinion to almost zero in one spot. This means the flexplate is not entirely flat (.045 to 0 at the pinion)

Does that mean I need a new one? ($$$)

Will go look at the plugs now. Still gonna try all the cheap fixes before breaking out the credit card

I remember a friend who had a bad speedo cable, it made that noise when pushing it out the driveway... mine doesnt make any noise when pushing it around.
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Old 05-27-2014, 05:06 PM   #8
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Re: Ticking noise under load?

New flexplate might be in order. You could cerainly use a shim at your starter anyways. .01 is about where you want to be anyways. May just start there as it could at least get rid of the sound you mention. The stresses under load may cause the 0 clearance pportion to touch.
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Old 05-28-2014, 07:34 PM   #9
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Re: Ticking noise under load?

Problem solved! Thanks for all the replies.

The shim kit did the trick. I would have never thought about the starter hitting the flexplate but as usual spending late nights on this site payed off again.

How did us amateurs get anything done before the World Wide Interweb?
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Old 09-06-2017, 04:53 PM   #10
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Re: Ticking noise under load?

Quote:
Originally Posted by cst350 View Post
Problem solved! Thanks for all the replies.

The shim kit did the trick. I would have never thought about the starter hitting the flexplate but as usual spending late nights on this site payed off again.

How did us amateurs get anything done before the World Wide Interweb?
Same problem took 700 miles and a $5 shim kit.
I checked everything but....... runs great crate 290hp, 72 Blazer.
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Old 09-06-2017, 04:58 PM   #11
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Re: Ticking noise under load?

Quote:
Originally Posted by Wrenchbender Ret View Post
It could be an exhaust leak at one port.
Always check that one first!
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Old 09-06-2017, 05:17 PM   #12
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Re: Ticking noise under load?

Glad you fixed the issue...but ....

Make sure the starter motor has the additional support bracket on the end of the motor that goes back to the engine block...

I dont know how many blocks I have had to repair because of this $ 5 piece of steel...

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Old 09-06-2017, 08:12 PM   #13
toolboxchev
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Re: Ticking noise under load?

Quote:
Originally Posted by AussieinNC View Post
Glad you fixed the issue...but ....

Make sure the starter motor has the additional support bracket on the end of the motor that goes back to the engine block...

I dont know how many blocks I have had to repair because of this $ 5 piece of steel...


Never looked for one of those, Is it common at the Auto parts stores? GMC Paul's I would bet.
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Old 09-06-2017, 08:17 PM   #14
AussieinNC
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Re: Ticking noise under load?

http://sdparts.com/i-19887150-gm-fac...IaAiX6EALw_wcB

$ 10...

plus the bolt...its a 3/8 UNC x 5/8" long

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Old 09-06-2017, 08:18 PM   #15
toolboxchev
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Re: Ticking noise under load?

Quote:
Originally Posted by AussieinNC View Post
http://sdparts.com/i-19887150-gm-fac...IaAiX6EALw_wcB

$ 10...

plus the bolt...its a 3/8 UNC x 5/8" long

Dig it, Thanks!
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