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Crankshaft / damper / flexplate question


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Hey, guys!

 

The Jeg's catalog lists some dampers as being specifically for 1984-1995 small blocks, and others just list the application as "SB Chevy". Does it make a difference? And which application do I ask for that utilizes a 7 1/4" damper? Parts guys these days need to know what a 7 1/4" damper oringinally went in before they can pull it off the shelf. Apparently the days of looking in a paper catalog are long gone. They found one that was 6 3/4" diameter, but it was almost twice as much as an 8" one! For that money, I could almost afford a Fluidamper.

 

Also, I don't know whether to get a 153 tooth or a 168 tooth flexplate, and I'm so ignorant I don't even know what qustions to ask. What necessitates the use of which flexplate? I'm using a 700R4 tranny, and I'm using the full sized starter out of a Chevy Camaro, one that seems to be on the JTR "approved" list. So which flexplate would you recommend?

 

I'm just weeks away from pulling the inline 6 engine out of my car, but I've got these few niggling questions to be answered before I dive in. I've gathered most of my parts, but the flexplate/damper issue has me stumped. I've not worked much on American engines before, and the education process is PAINFUL! :mad:

 

Here's the information Mortec had on my block:

 

14093638...350...87-95...2 or 4...Roller or flat tappet cam

one-piece rear seal

 

Engine casting F3093, indicating a production date of July 30, 1989

 

Thanks,

 

Scott Ferguson

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Over the years, Chevy changed the timing tab location a couple of times. That would be my guess on yours. I don't know of anything that used the 7 1/4' balancer, but there were some 6 1/4, 6 3/4, and at least 2 8" balancers (one 1.25" wide and one 1.50" wide)Generally, if they list a special part for an application, it probably is. Check out these guys for an SFI approved balancer for less than $100. http://www.catpep.com/Products.htm

 

They also have SFI approved flexplates. Flexplate and starter application is dictated by the choice of one or the other. The straight across starter (the Camaro one should be) uses the 153 tooth 'wheel. It is 12.5" across. The 168 tooth 'wheel is 14" across and uses the starter with the staggard bolt pattern.

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Mike,

 

Thanks for the reply. Do you think it would be worth my while to swap out starters for a staggered-bolt unit so I could go with a larger diameter flexplate? I'm wondering if I should take advantage of the greater mechanical advantage afforded by the 14" diameter plate?

The motor is a low compression rebuild, so it shouldn't present a difficult load for the starter to turn.

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No. The 168 tooth flywheel will not work using the JTR setback mounts since it relocates the starter outboard. The increased leverage comes at the expense of RPM as well, making for a harder starting engine. I wouldn't worry about it at all as the 12.5" flywheel is plenty sufficient.

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