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Old 08-30-2021, 12:29 AM   #1
Ziegelsteinfaust
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LT1 350 timing issue.

Today was a great day. I got my stepside running again, and the line at in-n-out was short for lunch. If Maria Sharapova would of called it would of been a trifecta.

The LT1 350 does not have factory timing marks, and I did not remove the cylinder heads to get a good position to make some.

Right now I have a good approximate mark by taking all the plugs out, and bringing #1 to TDC. Then rocking it back, and forth to get my mark. As if feel I could sense the piston changing direction.

So as I tune it anyone been in a similar situation, and how did you go about it?

Pointers? Thoughts?
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Old 08-30-2021, 11:23 AM   #2
Warrens69GMC
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Re: LT1 350 timing issue.

Lt1 in 1970 or 1990's?

A digital timing light should work with either-

https://www.amazon.com/INNOVA-3568-D.../dp/B000EVYGV4
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Old 08-30-2021, 01:54 PM   #3
Ziegelsteinfaust
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Re: LT1 350 timing issue.

1990's

I converted my reverse cooled LT1 to a carb, and distributor. So I can watch it move as I play with timing.

My big problem.is figuring out true TDC with out tearing the engine apart. Which I do not want to do. Or atleast the only way I know.
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Old 08-30-2021, 02:44 PM   #4
MySons68C20
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Re: LT1 350 timing issue.

Piston stop in #1 cylinder. Rotate engine both ways making sure you are on the firing stroke which you can establish by looking at the rotor position on #1 cylinder/dist cap firing. Just have to be sure you are on the firing stroke not 180 deg off. Split the difference between the 2 and that'll be tdc for #1. A timing tape is necessary unless your dampener already has marks on it.
There is a way to do it with a timing light but I've never done it that way. You will need to figure out a pointer bolted to the block somewhere to mark tdc on your timing tape once you have that established.
Hope this helps!

Last edited by MySons68C20; 08-30-2021 at 02:48 PM. Reason: added info
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Old 09-09-2021, 02:56 PM   #5
mattfranklin
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Re: LT1 350 timing issue.

Agree.

Do you have a place to attach an old fashioned timing pointer, like on the timing cover, so it will be reasonably close to the front dampener without hitting it?

They have piston stops that screw into the sparkplug hole. Put a piece of masking tape all the way around dampener. Rotate both ways until you hit the stop and make a mark on the tape next to the pointer when it stops from each direction. Then split the difference between the parks and call it TDC. I think they also sell thin metal timing tapes for common size dampeners. Just line up zero at your TDC mark and attach the tape.

You could also use the 40rpm drop rule. Adjust timing for max idle rpm and then retard it until the rpm drops by 40.

If your exhaust is quiet and your ears are really good, then you can advance it until you her a little light pinging and then back it off a little. Then see how it feels. But your exhaust better be quiet and your ears better be pretty good for you to do this. ;-)

Let us know if you have further questions.


Quote:
Originally Posted by MySons68C20 View Post
Piston stop in #1 cylinder. Rotate engine both ways making sure you are on the firing stroke which you can establish by looking at the rotor position on #1 cylinder/dist cap firing. Just have to be sure you are on the firing stroke not 180 deg off. Split the difference between the 2 and that'll be tdc for #1. A timing tape is necessary unless your dampener already has marks on it.
There is a way to do it with a timing light but I've never done it that way. You will need to figure out a pointer bolted to the block somewhere to mark tdc on your timing tape once you have that established.
Hope this helps!
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Old 09-09-2021, 03:47 PM   #6
Ziegelsteinfaust
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Re: LT1 350 timing issue.

I did put a timer pointer on it, but the crank is not keyed like a typical sbc.

Right now it is about 90% timed, and was running good. Till my front seal failed, and I am about to start it up after lunch.

When I rebuild one for either my Camaro which I stole the engine from or a replacement for my truck. I will use a keyed crank so I can use a pointer
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