Need some flywheel help FJ40 ‘78 (1 Viewer)

Joined
Sep 12, 2018
Messages
2
Location
CT, USA
Have a 78FJ40. Year ago put in brand new rebuilt 2F and mated a FJ60 new 5spd trans - completed by my local shop. Engine has been vibrating and pinging and rattling since. Mechanics now seem stumped but think the clutch burnt out due to me shifting 2-3K miles on the new trans. They want to replace the clutch before looking into other diagnostics for the vibration. This truck has been through a $55,000 war after buying it “restored” - a lot of that’s on me for not doing my research and first having a full inspection done firstly. Love the truck - can’t afford to sell it now anyway! My mechanics are telling me that only a new flywheel will do. Which we know doesn’t it exist. They don’t seem willing to machine a decent shapes flywheel which has me confused - that without a flywheel the shifting / clutch is somehow better? I guess I’m looking to be educated on the conflicting views on new or machined flywheel or NO flywheel. I think I’m right to say “new” isn’t an option but I don’t have the background to know if my mechanic would have any reason in leading me one way or the other. Thanks and sorry for the long note.
 
Solution
We need more info about exactly what noises it's making, and when. A video of it running , and making the racket would help tremendously.

Oh yea, delete that shops from your contact list!

Krondor

SILVER Star
Joined
Mar 26, 2017
Messages
854
Location
Greenville, SC
If the engine is pinging, It leads me to believe something else is messed up besides the flywheel. It sounds like from what you are describing, the timing is way off which would cause the vibration and pinging. If you can, post up a video of the engine running. At minimum, I would take it to another mechanic for a second opinion.
 
Joined
Feb 23, 2017
Messages
565
Location
Texas
might search the term "clutch chatter"

its the situation of the worn out clutch or irregular flywheel grabbing and releasing on startup from a stop.

very different than engine vibrating/pinging.

machining a new flywheel takes like an hour (at most) at your local old school good auto parts store.


id get a new mechanic
 
Joined
Oct 7, 2011
Messages
1,037
Location
Austin TX
You are probably already aware, but just in case you aren't, these flywheels can't just be surfaced like most other flywheels. If you resurface them, the machinist must turn down the outside area adjacent to the face of the flywheel the same amount, or it won't clamp with sufficient force to prevent clutch chatter and wear. The reason for this is that the flywheel was designed to have the clutch rub on a raised area of the flywheel, and the pressure plate was bolted to a slightly lowered area of the flywheel, presumably to increase the clamping force. If you just surface the entire face of the flywheel, you are going to have a very weak slipping clutch. Also, when installing a new tranny and clutch setup, ( if the bell housing is changed as well) best practice is to use a dial indicator to verify that the bell housing is centered on the crankshaft, otherwise more vibration and wear will result.
 
Joined
Sep 12, 2018
Messages
2
Location
CT, USA
Thanks for all of the help. I just don’t understand my mechanic. New flywheel no where to be found, feels machined is inferior but I’ve read that no flywheel is not something I should want? am I right to assume no shops will have OEM but some may have really well machined flys?
 

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