HEI new gear or Replace with Old gear - JeepForum.com
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post #1 of 5 Old 05-09-2021, 01:14 AM Thread Starter
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1968 CJ5 
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HEI new gear or Replace with Old gear

I just installed a new HEI distributor with the new drive gear. I was reading in another jeep forum, and they recommend installing the old gear because the new one wears. Also, instead of 5 degrees, what about 7 to 8? I guess if I get pre-ignition at full throttle, back it off. It's spotless inside. It only has 37000 miles on it.

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post #2 of 5 Old 05-09-2021, 08:19 AM
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The new ones can be hardened and chew up the other gear. It seems to be more prevalant on V8s.

I like to advance timing to the point of detonation and back off two degrees. Using a specific number isn't always applicable. At the altitude I live at we can need 10-12 degrees of initial advance.
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post #3 of 5 Old 05-09-2021, 09:01 AM
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I bought a cheaper HEI unit from CRT performance for my 258 and I installed it with the gear that was already on it. No issues thus far. At some point many years ago, these HEI kits were sent out with hardened drive gears for "strength" but they ultimately proved to be money wasted as they tore up the softer cam gear. I don't believe it's an issue in modern day so I would install it as is. As far as timing, every engine will be slighlty different, i.e. altitude and engine modifcations. At my altitude here in central Florida, my timing is set at 8 BTDC and it runs smooth.
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post #4 of 5 Old 05-09-2021, 09:01 AM
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I've always read that the gear issue was a v8 issue and have yet to read about any problems on an inline 6. I admit I have zero experience on the issue with multiple engines, but I put one in my wifes 258 2 years ago and one in my 258 a year ago and have seen no issues to this point. However I haven't pulled either to actually look at them.
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post #5 of 5 Old 05-10-2021, 03:57 AM
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If in doubt try to drill the gear. If you can, it is fine for material hardness.

The timing marks and manual can be a bit misleading. You are dealing with modern fuels, worn timing chains, worn distributors and possibly harmonic balancers that have moved.

There are three methods I have used, the set by timing light and marks as per manual, the manifold vacuum method and the pinging method. The last two are particularly useful on my 1951 L134 as I cannot see the timing marks on the flywheel that well as it is under the starter. My guru when i was a kid was an older guy with 20 years of working on performance cars (Jags, Alfas, Astons, Ferraris) and the pinging method was his favorite.
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1984 CJ7 258ci - Puthijeep
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1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
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