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Determine engine rotation

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=50247
Printed Date: April-29-2024 at 3:11am


Topic: Determine engine rotation
Posted By: PA 79
Subject: Determine engine rotation
Date Posted: September-22-2021 at 9:42pm
Bought a project 79 sn with a 351. The starter is missing. Like to get a starter n see if she’ll fire b4 I pull engine n start the rebuild. But I’m not 100% sure what the rotation.
Prop is right hand. Has velvet 1:1 trans. What are some other ways to know without turning over



Replies:
Posted By: KENO
Date Posted: September-22-2021 at 10:01pm
If you don't mind  pulling the distributor, you'll know for sure

If the gear is slanted like this   \\\\\\\\  it's reverse rotation

If the gear is slanted like this   ////////  it's normal rotation

RH prop and 1 to 1 B/W would make you think it should be reverse rotation, but the distributor gear will tell for sureWink

If you don't want to pull the distributor, take off the distributor cap and turn the engine with a 15/16ths socket on the front crankshaft bolt while you watch the rotor in the distributor.

It's gonna turn counterclockwise if you're turning the engine the correct way. If you go the wrong way the rotor will go clockwise

Whether you have a RR or normal rotation engine it will turn counterclockwise due to the cut of the drive gear teeth on the camshaft and distributor.

So in your case, I'd start by rotating the engine counterclockwise when viewed from the front and the rotor should turn counterclockwise if it's a reverse rotation engine.


Posted By: PA 79
Date Posted: September-22-2021 at 10:45pm
Perfect. The distributor spun CCW when I turned the crank to the left.
Thanks! I’ll have to order a starter n see if she’ll fire. Will the order be 18456273?


Posted By: Gary S
Date Posted: September-22-2021 at 11:16pm
Yes-






  

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http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS
95 Nautique Super Sport


Posted By: KENO
Date Posted: September-23-2021 at 7:18am
If you haven't ordered the starter yet, here's a link to a reverse rotation starter from Arco marine (Part number 70201)

http://marinepartssource.com/starter-arco-70201?gclid=CjwKCAjwy7CKBhBMEiwA0Eb7ah-JnogGi7rP3zGp8pVtk4iyCnn4TCGnvHMO4F4LnjzP72Ja1Q7gdRoC5hgQAvD_BwE" rel="nofollow - link

It's the newer more modern PMGR type starter that Ford started using back in the early 90's.

It's smaller, lighter, turns the engine over faster, and draws a lot less starting current.

It takes a small easy wiring change that's explained in the instructions that come with it or you can find the change discussed here on CCF.

Lots of places sell the starter with quite a wide range of prices, but the link above has a decent price. Wink




Posted By: PA 79
Date Posted: September-23-2021 at 8:25am
Thanks KENO! Just to confirm, when turning cam ccw and distributor is also ccw. That looking at the front of engine?
I plan to pull engine and rebuild it. U have any service manual suggestions?
Also noticed engine mount bolts have been epoxied. So while it’s out, I plan to replace stringers. So watching a few YouTube videos. I seen a guy peel the top of the fiberglass off the stringers, dig and shop back the rotted wood, then use the fiberglass as a form to pour an epoxy/resen. Any thoughts on that


Posted By: KENO
Date Posted: September-23-2021 at 8:38am
Originally posted by PA 79 PA 79 wrote:

Thanks KENO! Just to confirm, when turning cam ccw and distributor is also ccw. That looking at the front of engine?

Yep, 

If you're in the front turning the wrench to the left so the pulleys and belts are going to the left and the rotor is going counterclockwise, it's a reverse rotation engine.

If you were sitting in front of the gas tank looking forward while somebody else rotated the engine, it would be rotating to the right from that viewpoint 

The marine industry looks at rotation from the rear and for lack of better words, it can be real confusing when dealing with reverse rotation engines


Posted By: KENO
Date Posted: September-23-2021 at 8:50am
Here's a link to a pretty good manual from Ford. It's also in the CCF reference section

It's from 1979 and was written before the PMGR starter was available, so any starter stuff is the old positive engagement type.

http://www.correctcraftfan.com/downloads/Ford_302-351_Service_Manual.pdf" rel="nofollow - link

You'll have to keep in mind that your engine is reverse rotating when buying certain parts.

Ask questions here on CCF first if you're confused on the RR parts.

It's easier  than asking later Wink


Posted By: KENO
Date Posted: September-23-2021 at 8:51am
Stringers.............we'll let that some others talk about that Wink


Posted By: PA 79
Date Posted: September-23-2021 at 9:51am
Appreciate all your info. I’ll check the link.
   I’m new to the forum. Still have to figure out how to post pics n whatnot. But I’m gonna get motor out n rebuild b4 I get into stringers.
   Hopes to be pulling skiers by 4th of july


Posted By: KENO
Date Posted: September-23-2021 at 10:19am
Here's a link to a pretty new thread about a 75 SN from another new guy

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=50219" rel="nofollow - link

Might be some good reading, along with a disagreement or two Wink




Posted By: PA 79
Date Posted: September-23-2021 at 10:57am
That’s sweet! Can’t wait to get home this evening with all my new info.


Posted By: KENO
Date Posted: September-23-2021 at 1:14pm
Originally posted by PA 79 PA 79 wrote:

That’s sweet! Can’t wait to get home this evening with all my new info.

Ya think that's sweet, here's a link that'll keep you reading till Thanksgiving day or so  Wink

Multiple pages of threads in the link

http://www.google.com/search?q=correctcraftfan+stringers&oq=correctcraftfan+stringers&aqs=chrome..69i57j69i60l2.14594j0j4&sourceid=chrome&ie=UTF-8" rel="nofollow - link


Posted By: MrMcD
Date Posted: September-23-2021 at 2:15pm
I had a Malibu for 20 years, at about 5 years old I found my engine mount bolts on one side were loose, I could not tighten them, wood rot was in the stringer.  I pulled that mount off, opened up one of the mount holes to about 1 1/4” in size, worked around inside the hole breaking up the rot till I could vacuum it out and hit good wood in all directions.  Treated the interior with a product that kills wood rot.  Stinky stuff available at Home Depot.  Let that sit for a week or so to sink in deep.   Scraped the interior and Vacuumed it out again and then filled it with a construction epoxy that is supposed to be very strong.   Looked a lot like JB Weld but came in large 2 part application tubes.  After that cured I installed the motor mount, drilled my pilot holes for the mount bolts and re installed them.   Those bolts were still in place and tight when I sold the boat 15 years after the repair.   The key here I think is that my rot did not extend much past my mount bolts.   If it had the entire stringer would need replacement, this boat was only 5 years old, yours is a bit older and your rot may be extensive.

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