The Return of Rusty

[Gary Lewis]

Yes, you can certainly replace both the engine and transmission with reman'd units.  But don't give that engine away as it is pretty strong.

And, fyi, if you are going reman'd you should consider going with a 400 instead of a 351M.  From the outside you can't tell the difference.  The only differences are the crankshaft, which has 1/2" more throw on the 400 than the 351M, and the pistons.  Other than that every nut and bolt is the same.  So it will bolt right in where that engine is.

[ArdWrknTrk]

Truck IS good and strong, but if Clay is going to toss it for reman, he more than likely's going to trade it for core.

[ClayJ]

Ok guys, reading this morning and I came across this site https://www.diyford.com/install-ford-c4-c6-transmissions-step-step/

It referenced this part

This looks like the spacer the guys at my FiL's shop were talking about. I know it doesn't show up in the parts diagram but could there be something to this?

[ArdWrknTrk]

A) You don't have a smallblock (Windsor) OR a 300 I-6.

I've never seen one of those in ANY truck I had apart, and I'd never put one in if it was mine or a customer's.

But that's just one shade tree mechanics experience, and opinion.

[Gary Lewis]

I've never seen anything like that on any of the Ford's I've worked on.  But in this case with the breaks we've seen being at the point where the flat portion turns into a curve, you are limited in the size of reinforcement you can put on as it has to sit on the flat.  But all that does is ensure any flex is at the transition point, and that doesn't seem very good.

[ClayJ]

Gary, do you remember what the condition of the motor mounts were when you reinstalled Rusty's engine? I'm wondering if one may be broken allowing the flexplate to be strained and cracked.

[FuzzFace2]

ClayJ wrote

Gary, do you remember what the condition of the motor mounts were when you reinstalled Rusty's engine? I'm wondering if one may be broken allowing the flexplate to be strained and cracked.

Even if a motor mount was broken I cant see that a cause for the plate to strained as the locating dowels and bell housing bolts should keep the motor & transmission as 1 unit.

Missing or dowels that don't fit tight can be an issue.
Dave ----

[Gary Lewis]

Clay - I didn't replace the mounts, but did inspect them and they appeared to be fine.  However, I agree with Dave - the engine and tranny are locked into a unit and whatever happens to the engine also happens to the tranny's case.  So bad engine mounts could cause the engine/tranny combo to torque over, but they wouldn't cause internal damage.

I can only think of three things that would cause cracking/breaking of a flexplate, and they are all internal:

1. An incorrect flexplate

2. A mismatch in the angle of the tranny mounting to the engine, causing the flexplate to bend on each rotation

3. Bent component: Something like the crank or the input shaft to the tranny could be bent, causing runout that causes the flexplate to bend

But supposedly they've been using the correct flexplate - after the incorrect one was used initially.  So if the tranny is matching up to the engine correctly, and if the correct flexplate is now being used, something is wrong with some component.

I can't imagine an engine's crankshaft being bent with the wrong flexplate being installed.  But I can imagine something being bent or damaged in the transmission.  I still think something was hurt when the wrong flexplate was used.

[ClayJ]

Ok guys, so Rusty is in the shop awaiting surgery. In order to make Rusty dependable (not break flex-plates) I've decided to replace the long block with a re-manufactured Ford 400. So not only will I gain power, but should pick up some additional economy as well. I know Gary is partial to Rusty's engine so I offered it to him first as a courtesy but he has since declined so if anyone is interested in a 351m w/ RV cam and .060" over forged pistons feel free to let me know.Engine will probably run a Manual tranny just fine but I'll default to Gary to help explain that one. Fortunately the company that I'm ordering the long block from has plenty of cores and does not require a charge or the core itself to be returned. This definitely hurts the wallet but after deep thought, I feel it's better to bite the bullet now and have a dependable truck I can work. I will be pulling the valve covers, oil pan, carb, distributor, intake/exhaust manifolds, etc. to use on the new block. Cylinder heads will stay with the 351m block. While the engine is out we'll replace engine mounts and anything else that's worn/deteriorated.

Well now that the unpleasantness is out of the way I can talk about the long block I did order. Had several people suggest Jegs, Summit, Blueprint, Jasper as possible engine sources. These places have great engines with long warranty but the $ is up there. After some searching I compared a company called Powertrain Products Inc. and a Texas shop named Mabbco Motors in Tyler. The Powertrain Products 400 long block would be a straight OEM non smog replacement with no options for upgrades.The sales rep even told me any changes i.e. upgraded cam would void the provided warranty. The Mabbco block however, gave options for some goodies at a better price than the Powertrain block so I went with the Mabbco. Only Mabbco downside is a 4 week lead time. I will however be able to save the $200 in shipping by doing a local pickup so there's that.

Upgrades I went with:
-Steel Intermediate shaft
-Set of 16 HP Valve Springs
-New Fuel Pump Eccentric
-Ford Oil Filter Adapter
-New RV Camshaft
-True double Roller Timing Set
-Intake Manifold Valley Pan gasket set
-High volume oil pump
-Moly piston rings

I would have loved to go with some Tim Meyer pistons in this build but I'm just about tapped out on this project. LED Headlights and upgraded bumpers will have to wait a year.

[ArdWrknTrk]

So what are you going to use for a transmission?  :ear s

[ClayJ]

The C6 that's already in. The guys at the transmission shop and my FiL's shop both say there's absolutely nothing wrong with the transmission.

[ArdWrknTrk]

Fingers crossed!

[Gary Lewis]

Yes, finger's crossed!

Clay has a really nice engine spec'd out, so I'm confident Rusty is going to be very strong.  

[ArdWrknTrk]

I know I'd have a DTI on that crank flange, and if it IS out be looking to make it a 400.

While I don't have motor mounts or an exhaust to work with that engine maybe it would be great for someone like Chris, who's truck could use a heart transplant.

[ClayJ]

What aftermarket flexplate would you guys recommend when the new long block is ready? I've seen several different variations from the stock steel replacements, heavy duty forged, as well as billet one piece. Also just making sure I'm tracking the correct specs to match D1AZ 6375-A. 164 tooth count, 28oz imbalance, Flexplate Diameter:14.240 in, do these sound correct?

[ArdWrknTrk]

Are you running the 1/4 in under 10 seconds???

Dennis Carpenter has it for $75.
I don't hear bad things about their products

[ClayJ]

Hahahaha no way. Just want to absolutely ensure a quality, correct flexplate goes in. If I have another break I will probably cry and boy howdy would that be ugly.

[ArdWrknTrk]

I don't see any reason to fit one that doesn't fit your intended use.
There's absolutely no reason for an *SFI flexplate in a farm truck (unless it's THAT farm truck)

I've had engines with titanium valves, retainers, collets, pushrods and valve springs.
Yeah, if you're going there, you need to go there.

But you need a flexplate that isn't damaged by "whatever"
Like I said, I would have a DTI on the crank flange and if it wasn't right I'd put a straight 400 crank in it.

(Oh autocorrect, I love you so)

[ClayJ]

Not trying to be "That" farm truck. Just looking to have this thing bullet proof.

[ArdWrknTrk]

And you still don't need a 12,000 RPM flexplate in a 5,000 RPM farm truck...

But hey, it's your money!  😉