Flywheel differences

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Playher

Junior Member
Joined
Oct 1, 2022
Posts
11
Reaction score
17
Location
Buffalo WY
First Name
Patrick
Truck Year
1987
Truck Model
V20
Engine Size
350 TBI
Dale, can you tell me more about the hydraulic clutch/master cylinder install. Thanks
 

Lost adventure

Junior Member
Joined
Aug 28, 2024
Posts
2
Reaction score
2
Location
Pa
First Name
James
Truck Year
85
Truck Model
K30
Engine Size
454
Which clutch/pressure plate did you guys end up going with? I see some posts people said the sm465 to nv4500 could use the sm465 clutch/pressure/pilot but I see other posts said you have to use the 98+ clutch/pressure etc. I've also seen that you have to shorten the clutch pedals rod because it puts to much "pressure" at rest and won't allow the pressure plate to fully release. Im kinda at a standstill with my swap because the clutch isn't fully releasing and not sure where to go from here.

Same boat 85 nv4500 to 454. 98 nv4500 gm diesel trans with internal slave swap done with great pedal and using the sm465 clutch/pressure plate but it's just not releasing. If the 98+ clutch/pressure/pilot is the answer then it's not a huge deal to swap. But if it's the rod length then it's gonna be annoying.

Any insight? :) @Frankenchevy @Dale Downes
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,446
Reaction score
8,682
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Which clutch/pressure plate did you guys end up going with? I see some posts people said the sm465 to nv4500 could use the sm465 clutch/pressure/pilot but I see other posts said you have to use the 98+ clutch/pressure etc. I've also seen that you have to shorten the clutch pedals rod because it puts to much "pressure" at rest and won't allow the pressure plate to fully release. Im kinda at a standstill with my swap because the clutch isn't fully releasing and not sure where to go from here.

Same boat 85 nv4500 to 454. 98 nv4500 gm diesel trans with internal slave swap done with great pedal and using the sm465 clutch/pressure plate but it's just not releasing. If the 98+ clutch/pressure/pilot is the answer then it's not a huge deal to swap. But if it's the rod length then it's gonna be annoying.

Any insight? :) @Frankenchevy @Dale Downes
Isn't there a spot on the bell housing to check TO brg to pressure plate clearance? If so pop the push rod off at the pedal and see if you get your clearance. If not you know the problem is in the to brg and pp. Don't know why shortening the push rod would be a big deal but if so I'd think you could cut a spacer out of a aluminum with a hole saw a drill bit an a Sawzall to space the master away from the pedals. Keep loosening your bolts to determine diamension then measure the gap and buy an piece of aluminum plate that thick.
 
Last edited:

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,082
Reaction score
7,756
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
@Lost adventure , My engine is 1 piece rms and balance is different than an 85, iirc. I’m kind of an idiot though, so I’d listen to just about anyone else when it comes to solutions to your problem.

I had a 96-99 L31-R 350. My nv4500 was a rebuilt later model unit and I used the Advanced Adapters BH. I used a factory hydraulic pedal assembly (1986+ iirc). I think I used 1986 master and external slave, McLeod 12” clutch and centerforce billet flywheel (for the l31-r).

I don’t know what modifications are needed to adapt a mechanical clutch pedal to be used with a hydraulic master, if that is what you have.

Again, I only retain this info long enough to do a project, then it’s gone. I have too much information in my daily life and too little brain power, so I’m the wrong guy to ask. @SquareRoot may remember if he has time between spellchecking the word axil and recommending LS swaps.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,192
Reaction score
8,030
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
I avoided the internal throwout bearing like the plague. If the seal leaks it ruins everything inside the bellhousing. I can only speak to the external slave arrangement.
 

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,082
Reaction score
7,756
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
Doesn’t @bluex have an nv3500 with internal slave?
 

bluex

Full Access Member
Joined
May 9, 2013
Posts
1,971
Reaction score
2,575
Location
Spartanburg SC
First Name
Paul
Truck Year
1978
Truck Model
C15
Engine Size
350
Doesn’t @bluex have an nv3500 with internal slave?

Yes I do. Also have a NV4500 in my 99 dually with an internal slave. They use the same slave, as does a same year range T56.

On the older blocks to use an internal slave the flywheel needs to match the year of engine. The pressure plate needs to match the year of the trans.

I found that out the hard way. @Lost adventure if you used an 85 pressure plate that's your issue. The fingers on a clutch fork style pressure plate are roughly 1/2" taller than one for a internal slave. Buy a pressure plate for a 98 an it should work as intended.
 

Lost adventure

Junior Member
Joined
Aug 28, 2024
Posts
2
Reaction score
2
Location
Pa
First Name
James
Truck Year
85
Truck Model
K30
Engine Size
454
Yes I do. Also have a NV4500 in my 99 dually with an internal slave. They use the same slave, as does a same year range T56.

On the older blocks to use an internal slave the flywheel needs to match the year of engine. The pressure plate needs to match the year of the trans.

I found that out the hard way. @Lost adventure if you used an 85 pressure plate that's your issue. The fingers on a clutch fork style pressure plate are roughly 1/2" taller than one for a internal slave. Buy a pressure plate for a 98 an it should work as intended.
Thanks for the feedback, I ended up separating the bell housing from the block just a lil bit and it seemed to have solved the issue temporarily. So I think the next step is to do that and replace the sm465 clutch to the 98nv4500. I think those fingers was causing the bind up. I tried the pedal deal first and it didn't fix it, so I figured before I cut I just loosen and slide it back. Did you end up using the factory internal slave or was there a specific one. I used the factory one and matched it up to the older one that was on there and they were the same hight at compression and released. Do you think the pilot bearing will have to be replaced as well with the 98s?
 

bluex

Full Access Member
Joined
May 9, 2013
Posts
1,971
Reaction score
2,575
Location
Spartanburg SC
First Name
Paul
Truck Year
1978
Truck Model
C15
Engine Size
350
Thanks for the feedback, I ended up separating the bell housing from the block just a lil bit and it seemed to have solved the issue temporarily. So I think the next step is to do that and replace the sm465 clutch to the 98nv4500. I think those fingers was causing the bind up. I tried the pedal deal first and it didn't fix it, so I figured before I cut I just loosen and slide it back. Did you end up using the factory internal slave or was there a specific one. I used the factory one and matched it up to the older one that was on there and they were the same hight at compression and released. Do you think the pilot bearing will have to be replaced as well with the 98s?

No the pilot should be fine. I put a bushing in my 99 because the bearings will destroy an input shaft quickly if they get damaged.

I used an LUK factory replacement slave and clutch kit for a 97 truck.
 

Latest posts

Forum statistics

Threads
44,157
Posts
950,607
Members
36,273
Latest member
dannyphx
Top