Need some help here guys:
Story so far - My sons '76 with 302 and 3 speed standard. Skirt on a piston broke then it let go of connecting rod which knocked a hole in cylinder #7 before it got shutdown.
Pulled motor and replaced with a 5.0 out of a '96 explorer. Swapped over intake, carb, new dizzy with steel gear, exhaust manifolds - kept the serpentine setup. Bought a cheap diaphram clutch kit off rockauto and a 11" flywheel for a late model f150 - sachs NFW1128 - shows to be the correct 50 oz. Swapped everthing over, new flywheel bolts, torqued and blue loctite, used the correct shouldered pressure plate bolts. Compared new flywheel to old one to make sure it was same diameter/tooth count.
I might have flipped it over and compared the weights between the old 28 oz and new 50 oz - but I can't remember.
Put it all back together - back in truck - fires up, fix a couple vacuum leaks, timed at 8 BTDC, runs good, pulls hard good idle - ~ 20 in vacuum at idle with some needle bounce < 0.5 inch. Super smooth at idle
Now here is the SOB about it - revs fine to (I'm estimating RPM) to around 3500-4000 rpm and then the engine vibration starts to come on - gets worse with increasing RPM - very consistent vibration - its not missing. Doesn't matter if its clutch in/out - rolling/still - on the gas or coasting.
Feels like a washing maching when it spinning at full speed and just slightly out of balance. Its not severe, but its significant - something is out of balance in motor. If I drive and shift normal I never notice it.
Removed serpentine belt - no change.
Pulled harmonic balancer as that was pretty easy and replaced with a new one - no change.
Now I'm thinking 3 options:
1. Clutch pressure plate was poorly balance/not balanced.
2. Flywheel is poorly balanced or possibly a 28 oz (rockauto hasn't been great at getting me the right part) - could have not been drilled correctly and pressure plate is not centered.
3. Crank is bent?
So my question - has anyone accidentally put a 28 oz on a 5.0 and was the vibration severe or "moderate". I'd like to rule out wrong flywheel. I'm thinking we will pull transfer case/tranny and remove pressure plate - then reinstall bellhousing so I can start engine and rule out clutch.
Story so far - My sons '76 with 302 and 3 speed standard. Skirt on a piston broke then it let go of connecting rod which knocked a hole in cylinder #7 before it got shutdown.
Pulled motor and replaced with a 5.0 out of a '96 explorer. Swapped over intake, carb, new dizzy with steel gear, exhaust manifolds - kept the serpentine setup. Bought a cheap diaphram clutch kit off rockauto and a 11" flywheel for a late model f150 - sachs NFW1128 - shows to be the correct 50 oz. Swapped everthing over, new flywheel bolts, torqued and blue loctite, used the correct shouldered pressure plate bolts. Compared new flywheel to old one to make sure it was same diameter/tooth count.
I might have flipped it over and compared the weights between the old 28 oz and new 50 oz - but I can't remember.
Put it all back together - back in truck - fires up, fix a couple vacuum leaks, timed at 8 BTDC, runs good, pulls hard good idle - ~ 20 in vacuum at idle with some needle bounce < 0.5 inch. Super smooth at idle
Now here is the SOB about it - revs fine to (I'm estimating RPM) to around 3500-4000 rpm and then the engine vibration starts to come on - gets worse with increasing RPM - very consistent vibration - its not missing. Doesn't matter if its clutch in/out - rolling/still - on the gas or coasting.
Feels like a washing maching when it spinning at full speed and just slightly out of balance. Its not severe, but its significant - something is out of balance in motor. If I drive and shift normal I never notice it.
Removed serpentine belt - no change.
Pulled harmonic balancer as that was pretty easy and replaced with a new one - no change.
Now I'm thinking 3 options:
1. Clutch pressure plate was poorly balance/not balanced.
2. Flywheel is poorly balanced or possibly a 28 oz (rockauto hasn't been great at getting me the right part) - could have not been drilled correctly and pressure plate is not centered.
3. Crank is bent?
So my question - has anyone accidentally put a 28 oz on a 5.0 and was the vibration severe or "moderate". I'd like to rule out wrong flywheel. I'm thinking we will pull transfer case/tranny and remove pressure plate - then reinstall bellhousing so I can start engine and rule out clutch.