I'm gathering up misc parts for my swap of a M5OD-R2 behind 1979 351W. (please, no flak on my tranny choice. It will work well for what I need)
Anyway I was looking at flywheels. I need 164 tooth 28.2 oz. I happened to notice the fine print on one said "for one piece rear main seal engines". None of the others I looked at have mentioned rear main seal. Mine is a two piece (I recently replaced it). Anyone have any idea why what rear main seal it has makes a difference for the flywheel??

 

That I have no idea! I would compare what was originally on the 351 to you're looking at buying and see, but I suspect that it will be OK. I've never seen the rear main type used as a spec for flywheels and flexplates. Do any other places advertise that part that way? My suspicion is that it will work fine, but don't go on that...

I'm almost 100% certain that it makes no difference on a 302/5.0, I mean after all, how many guys with an '82 or '83 5.0 Mustang ended up putting in a newer one-piece-seal 5.0 engine, and reusing their old flywheel? Probably a few. You could compare the '82 and '84 5.0 flywheels, but I think they're the same engineering number. I think '84 is the first one-piece seal, and '85 was the first year for the larger clutch and somewhat different flywheel.
But who knows, the 351W could be different...
And another source for that flywheel would be 302s from before 1980 or so, when the 302/5.0 went to 50 ounce imbalance. 351Ws stayed with the 28 oz throughout their entire run.

 

What year and vehicle did the 351W come from, since it's not original to your truck?

One piece 351W rear main seal introduced in 1983 Passenger Cars; F150/350; Bronco & Econoline from production date 7/11/1983.

Parts catalog makes no mention of a specific flywheel used with a one piece rear main seal.

 

I mentioned 79. From an LTD but LTD's were just automatics. I have been scanning some parts listings. Looks like 79 Econolines came with 351W and standard trans. Old and new come together with the 79 Flywheel and the 90 11" clutch.
An ATP Z288 (EOTZ 6375A) fits 79 351w and says it accepts an 11" clutch.

 

1975/76 is one type, 1977 is another, 1978 is different again, as is 1979/80. 1981/97 is the same. All have a 164T ring gear.

351W introduced in 1975 Econoline.

 

They're all 28 oz and 164 tooth. I wonder if the difference is clutch size bolts holes?

 

It could be the location of the holes or just the bolt spacing. I ran into this when we put a Centerforce clutch in my dad's '75. It was a 302 but still 28 oz. and 164 tooth with a 3 speed.

 

Just for curiosity I checked 77 thru 79 351w and they all take the same crank part # and all have 2pc rear main seals.

 

They must be trying to differentiate the two to reference 28vs 50 maybe. Not any reason I can think of otherwise.

 

I certainly don't claim to be an expert on flywheels but I have done the M5R2 swap in my 77 F100 w/ 302. I went from a T18 to the M5R2 without changing the flywheel. I also had good clutch material as well and didn't change the clutch.

So do you currently have a manual trans in the truck? If you do could you just re-surface the current flywheel and use that?

When I was doing some of the research I think most of these flywheels would take a 10" or 11" clutch. Hope that helps.

I've got some notes on bleeding the hydraulic clutch. Just search my name.

Also, I had the shift forks go out on me just a few months after the install. The replacement forks I had to grind down slightly to get them pass by one another.

Overall I'm really pleased with my swap. Running thru all the gears is fun. Really made the truck fun to drive. My son even enjoys driving it.

I'd like to hear about your truck and how you plan to use it.

Good luck.

 

My truck is a 68 short box. The original 360 and 3 on the tree was replaced with a 79 351w + C4. The motor is stock with a mild cam, 4 barrel and headers. The automatic is kind of boring. Around town it'll be more fun to hear the motor as you rev it up through the gears. With the automatic you pull away from the lights and it's in 3rd gear before you know it unless you're tromping on the gas and you easily end up over the speed limit. I've ordered a flywheel that's from a 79 351w Econoline standard trans and the notes said it accepts an 11" clutch. I'm using the 90 stock 11" clutch. Biggest challenge will be setting up the pedal geometry for the throw of the clutch master. I have a 90 parts truck that I can use for measurements. I was also able to buy the 90 lever that attaches to the clutch pedal assembly to push the master so that will help.

 

https://www.ford-trucks.com/forums/1...l#post15011633

Take a look at this link for some ideas about how to create the link to push the clutch master. I did have to create my own push rod that was a bit longer than what was provided by the manufacturer.

 

So I've got my M5OD installed and clutch bled. I still have to finish the tunnel mod and get carpet and seat back in and finish wiring up the bare column with no shifter. I let the truck down on the floor and started it and backed it out of the garage and let it idle a bit. I noticed the motor was rough ? shaking? Pulled it back in and shut it down. Very first thing I thought was oh cripes the flywheel has the wrong balance. Now I somehow have to trouble shoot this thing to figure out what's wrong. Everything went together pretty well. The flywheel was tight on the crank and needed the bolts tightened to suck it on. Torqued to spec. Pilot bearing came with the clutch kit. It went in tight and all the way in. Tranny took a lot of wiggling to get it lined up and on but went up against the engine by hand eventually and I didn't use the bolts to force it on.


Flywheel - ATP Z-288 I spec'd it for a 79 351W. I counted 164 teeth. No where did it say the imbalance but all 351W take 28oz regardless of year.


Clutch kit - LUK 07057 11". Spec'd for a 90 F150 with 302 and M5OD. It came with a needle pilot bushing. There were lots of bolt hole choices on the flywheel and the clutch bolted on easily. There were no dowels to mount it, just the bolt holes.


I'm not sure how to trouble shoot this shaking. I'm thinking I'll have to pull the trans but not sure what to even look for. Buy another flywheel? I warmed the truck up 4-5 minutes. It was running smooth prior to the swap. I only slipped the clutch as I pulled it out and in and with the tunnel still open I could hear the clutch engaging smoothly against the flywheel. The shake was really noticeable as I brought the idle up but I didn't really rev it up.

 

I'm not 100% certain but I think you have to have dowel pins to locate the pressure plate.

 

Yup I think I messed up not using dowel pins. Never knew there was such a thing. (not a std trans guy). But the question is, is this causing the engine shake??