OMC 3.8L engine and Distributor

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Craig S

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I have a 1986 Avanti with an OMC 800 stringer mount powered by a 3.8L (229) GM engine.I still have points and condenser in a prestolite distributor. (IBM 7021). I was told that I should have an IBM 7014 and that using the 7021 could ruin my engine. Well, I've run this engine for years with this distributor and it runs great when all is adjusted correctly. (points etc.)
My not so good manual only shows a kaiser V6 with the distributor in the front. My engine has the distributor in the back center. I believe its a chevy engine. I used the rear block casting number to look it up. I still don't know how to decode the number stamped into a block tab on the front of the block on the starboard side. Theres a lot i don't yet understand about the chopped off V8 and 60 degrees vs 90 degrees or the semi cross firing. I'll have more to learn and would appreciate any input or direction to other links/sites. Soooo does anyone else out there have a 3.8 chevy using the 7021 distributor?
And how can my engine run so good if it's the wrong distributor?
 
Howard Sterndrive

Howard Sterndrive

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Re: OMC 3.8L engine and Distributor

You might just have a 7021 housing with a 7014 guts (the point cam for the 229 is unique)
You can pull your rotor off and look at the shape - 7014 has this uneven hexagon
notice 3 of the lobes are sharp, and the other 3 are rounded
img203.gif

7021 has an even hexagon

Your engine will run ok short term with the even fire pattern, but 3 of your cylinders will be firing 12 degrees early, and 3 will fire 12 degrees late.

OR, depending on how it was timed, 3 cylinders might be bang on, and 3 would be 24 degrees out of time.

The best explanation of this is in the Mercruiser manual for the 229 and 4.3.
It is manual #7
The OMC manuals make no mention of how to time #1 on a 229 and that may be why someone replaced your distributor.... it is a brain teaser for sure... if you don't understand, it won't run....
 
Howard Sterndrive

Howard Sterndrive

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Re: OMC 3.8L engine and Distributor

better pic- see how the cam looks like someone did a bad moulding job out of clay....
229uneven.jpg
 
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Craig S

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Re: OMC 3.8L engine and Distributor

Thank God for the Pros!
This makes so much more sense to me now. I can't go look at it for a couple of hours but I think I have the evenly spaced lobes. Here's another interesting thing: I've been playing around with the timing. The setting is supposed to be 10 before TDC. Well when I advance the timing off the plate, I'll guess about !5 to 16 before TDC, I get an extra 5 MPH top speed. I'd guess with the uneven lobes, I might get even better performance.
Thanks again
 
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Craig S

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Re: OMC 3.8L engine and Distributor

hmmmm The second pic didn't come through for me.
 
Howard Sterndrive

Howard Sterndrive

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Re: OMC 3.8L engine and Distributor

Craig S said:
, I'll guess about !5 to 16 before TDC, I get an extra 5 MPH top speed. I'd guess with the uneven lobes, I might get even better performance.
Click to expand...

that's probably where you get the closest to having all sparks near the right place.

Forget performance.... get the right distributor so 3 of your pistons won't beat the nonsense out of the rod bearings from the detonation

And your water skier won't have to plug their nose from the stink of improperly burned gas

the 7014 is a bit of a rare bird... too bad I just tossed one.
 
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Craig S

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Re: OMC 3.8L engine and Distributor

Yes, it's a shame you pitched it. Anyway I'm now convinced I have the semi even fire 3.8. I did some measurements of the balancer with some pistons at TDC. I heard they make a timing tape but I just used regular tape. I could go into more detail if anyone cares. Anyway, I've started looking for a 7014 and feel like I'm snipe hunting. I think Mallory can make me one, but I don't even want to ask for how much. So does anyone out there have a Prestolite 7014? Can you recommend a place to find a used replacement?
 
swaycleveland

swaycleveland

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Re: OMC 3.8L engine and Distributor

if im not mistaken that motor was put in the the 1980 to 84 chevy malibu, monte, caprice, and elcamino. ya might start there
 
swaycleveland

swaycleveland

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Re: OMC 3.8L engine and Distributor

howard do you have the page from the mer manual i cant seem to find a good link
also i want to have a spare cap am i correct that i i need a 7014 cap

i have a 1985 4winns with a 3.8l 229 omc 800 stringer
just looking to get a spare everything cap rotor points condensor just to keep around seeing as how omcs arent around any more
 
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