Standard rotation dist in Rev rotation 454
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=48526
Printed Date: October-06-2024 at 2:35am
Topic: Standard rotation dist in Rev rotation 454
Posted By: ShyDookie
Subject: Standard rotation dist in Rev rotation 454
Date Posted: April-09-2020 at 3:28pm
| I’m replacing the distributor on my ‘85 Southwind due to the weights on the original Mallory (with electronic conversion) being seized. I’ve been having some popping, surging, and cutting out entirely above 3,000 RPMs, so with the seized up weights, i figured a new electronic distributor wouldn’t hurt. When I pulled out the original to install the new one, I found that the original has standard rotation gears (/////) instead of (\\\\\). How is this possible? The pulleys turn CCW and prop CW and the engine tag shows 1-2-7-5-6-3-4-8, which is how the wires are attached. |
Replies:
Posted By: KENO
Date Posted: April-09-2020 at 3:39pm
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You're doing too much thinking/reading about reverse rotation Fords Chevy handles reverse rotation differently and for a Reverse Rotation PCM Chevy and most other RR Chevy's the same distributor is used in both with the same gear because the cam still rotates in the same direction in both engines. There's more to the story, but the short answer is that the same gear is used on both  |
Posted By: KENO
Date Posted: April-09-2020 at 3:45pm
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The slightly longer version is that Chevy uses a 2 gear setup instead of a timing chain to drive the cam on a Reverse Rotation engine, so the cam is turning the same way in both engines. The gear setup makes the cam turn backwards as compared to the crankshaft rotation so it's turning the same way as the standard rotation cam. The cams aren't interchangeable from Normal to Reverse Rotation because they're ground with different firing orders It's confused many people so don't feel like the Lone Ranger
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Posted By: KENO
Date Posted: April-09-2020 at 4:05pm
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Here are a couple of pictures First one is a normal rotation Chevy cam drive setup, the crank and cam turn the same direction  Second one is Reverse rotation cam drive setup, the cam turns the opposite direction from the crank 
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Posted By: ShyDookie
Date Posted: April-09-2020 at 4:17pm
| Extremely helpful. I just ordered a standard rotation gear to swap out. Thanks! |
Posted By: KENO
Date Posted: April-09-2020 at 4:28pm
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It's not really that easy, the direction of the thrust on the distributor shaft would have been in the opposite direction on the RR distributor you just bought You should return the whole distributor and get the correct version This is also hard to explain Was this a DUI HEI by any chance? Here's somebody else's experience with this issue in the link http://www.correctcraftfan.com/forum/forum_posts.asp?TID=38867&title=454-pro-tec-swap-to-dui" rel="nofollow - link I'd call DUI or whatever brand you bought and explain your situation |
Posted By: ShyDookie
Date Posted: April-09-2020 at 5:54pm
| It is a DUI. I spoke to them earlier today. They suggested the gear swap. I had one in my 78 Nautique that was reverse Rotation but that was a commander 351, and the swap is quite easy. Thanks for all the help. Too bad I didn't see that thread before ordering this one! |
Posted By: KENO
Date Posted: April-09-2020 at 7:26pm
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Hope it all works out Just remember...............it's a lot easier to ask first, buy after that
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