Ok so me and my dad have been rebuilding a 351w for my sister's 80 mustang.


I ended up getting a free 351W complete from top to bottom. We were told by the guy that the engine was rebuilt (verified that) but never ran right so was pulled back out and the truck was taken but not the engine.


Well it had sat outside for quite a while but I figured it was good for at least parts. The engine was seized up by the time I had gotten possession of it so as soon as I got it home I tore it down sure enough to find rust on the cylinder walls.


We had the engine completely checked over by our machine shop and he was able to just hone it.


So fast forward I am using the pistons that were in the engine before (hypertetic stock dish) along with connecting rods and crankshaft as everything looked great as far as that.
I did order new rings.


Now this is where I get to where I am confused:
While at work dad put the rings and pistons in the engine and hooked up the crankshaft. He turned the crankshaft to verify everything turned correctly and he said it was extremely tight almost like a bind then but it turned until so far then was completely locked up going that way but could turn it back and get it all the way to the same position before it locked up again.


So he pulled one bank (not sure which side either 1-4 or 5-8) and turned it. He said it turns over all the way but still feels like it is to tight. Put that bank back in and does the same thing again.
He has been trying to turn it over with our 26" 1/2" drive ratchet
There are no heads on the engine, bearings are what came with the engine since they looked good. The balancer and flexplate aren't on it either.


I am thinking maybe the crank is out of spec somehow, connecting rods are slightly bent, or the piston where the wrist pin goes through is messed up causing a bind.


Dad agrees with the wrist pin theory but none of the others.


Anybody have any ideas of what it could be?
The engine is a 351W EFI from a 87-94 truck I believe it is a 87-89 truck because I also got a BW1354 transfer case with it which are in 87-89 trucks.
Thanks for any help
Trav

 

I'm thinking it's your crankshaft is out spec. Or more likely to me wrong main bearings.

 

After looking a bit it looks like the connecting rods are so tight against each other it is pushing it up against the crank and each other causing a bind. When you take one bank of pistons out it isn't jammed in there and turns fine.


The block is a E9AE and the connecting rods say C9OE?? Are these original connecting rods?


I am wondering if something is the wrong part.


If this engine needs a crankshaft and/or rods I am just going to build a 408 and use the other 351 I have that is in the car now (using for moch up). I don't want a 408 in the stang as it will be to much power for its intended purpose.
Trav

 

I believe those connecting rods are correct for the engine, they stayed the same for many years.

To find out where the binding is coming from you need to take all the connecting rods off of the crank. Then try turning it.

If there is still binding, it is either in the crankshaft itself or the camshaft if that is installed.

Add one rod and piston and try again. Make sure to oil the bearing and piston when installing.

Keep adding one piston/rod combo at a time, and you should discover what is causing the trouble.

Maybe a bearing cap is installed incorrectly.

Edit:
I see in your last post that it is not binding if only one bank of pistons and rods is installed. Possibly the conrods are installed the wrong way.
Regarding the cylinder numbers stamped into the rods, these numbers must be oriented towards their cylinder bank. So numbers 1 to 4 point to the right side of the engine, nos. 5 to 8 to the left.

 

I suggest doing the same thing.


When I build a short block I always spin the crank after each piston install. There is a spec for the amount of resistance you should see on a completed assembly. Anything different and something is wrong.

 

Connecting rods are installed the correct way and the pistons are all put back in in order of how they are numbered from the other rebuilder which matched when I pulled them out and set them in order.


I have put 1-4 in only one at a time and no binding. As soon as I put 5-8 (tried 1 at a time 5 with 1-4, 6 with 1-4, etc) and as soon as I put the second bank on it is so tight together it won't move.


It has to be the connecting rods are expanded or the wrong ones or the crank is shrank and or it is the wrong one.
The 302 in my 88 when I rebuilt it was no where near having the connecting rods pushed up against each other like this.


The crankshaft I can't find any casting numbers on however it does have a 3.5" stroke so it is a 351 crank of some sort just is it Windsor, clevland or such. Are the clevland and M series any different of a crank?


If my machine shop wasn't so busy I would bring it up to him but being beginning of winter he is extremely booked up. Even my buddy whom builds 302 and 351 racing engines is extremely busy right now.
Trav

 

If you put 1 through 4 in, then added 5 through 7, and it was fine, but got tight when #8 was put in, that's where you should start looking for the probem. It might be that cyl, or piston has a problem.

 

no it doesn't matter which one. As soon as I put 2 connecting rods on the same spot of the same spot of the crank it can't turn doesn't matter which ones.
Trav

 

The binding sounds like it's occurring at the crank journal. Perhaps the connecting rods are to wide? Or the ID of the rods are to small and when you tighten them up it binds?
I would take the crank and piston rod assembly to a machine shop and have then checked out if you don't have the tools to measure the clearance.

 

If the rods got install on the pistons backwards the rod bearing will bind. Look closely at the orientation of the bearing, it is offset to one side a little to clear the radius on the crank journal against the throw. If the rod is backwards the edge of the bearing will bind on the radius..

 

What was the endgap in the rings? I see you added new rings old pistons and just honed maybe a tapered cylinder and to tight of a ring gap.

 

Something to check (not being snarky) are you putting things together with the engine upsidedown? Are you putting 1-4 in the right holes and not 5-8s holes? Reason I ask is I did it once myself. Everything was fine on the first four, but the fifth one bolted in and it wouldn't spin. Mic'd the crank T-guaged the rods and it all checked out. Took a break and came back and realized I had the first four on the wrong side and when the fifth was put in, the fillet radius was causing the rods to bind together.

 

Checked it and it is all good. even tried turning it around and same thing.



Ring gap was all speced out and correct. I had a machine shop hone the block and had him pre inspect it like I always have him do.

Tried that even tried putting the pistons on the opposite sides to see if somehow it got put in the wrong spot during tear down but everything is now how I had it pulled because it didn't help.


Dad was saying one of the connecting rods look to be at an angle slightly. What could cause this?
Trav

 

OK, if the rods are on correctly and 1-4 doesn't bind and when you add to the other bank it binds are you sure you aren't putting the rod caps on backwards. If you do the first bank won't bind because the rod will move to the side away from the crank radius fillit. As soon as you add a rod to the other side it will force both rods on that throw together, no side clearance between the rods. The little tang that keeps the bearing from spinning has to be on the same side, rod and cap.

 

checked that out already even tried flipping the rod caps but it still binds.


I think I really need to bring it to my machine shop to check if everything is true.
Trav