65GGvert

I'm in kind of a bind here, I've got the transmission out of my 60 doing a 4 speed swap on a friend's lift. The flywheel needs to be replaced and some of the vendors show a 153 tooth and some 168 tooth. I read a post from DZAuto from a few years ago that ALL 60 Corvettes had the 168 tooth 14" flywheel. I measured across the outside of mine and it is very close to 14". And the clutch/plate I bought for the car says 10.4" so it is the 10" (10.5) version.Does that mean that is the 168 tooth? It is stock to the car new. I have an opportunity to get a 168 tooth fairly quickly if it will work and I can't get to the car right now. Anyone able to verify what I need?

Frankie the Fink

Can you get the flywheel resurfaced and a new ring gear installed? That's what I did on my 61. I also had a 10.5" cluthch installed that was rated higher than an 11" as part of my 5 speed imstall.

65GGvert

I have to wait till morning to see if the local machine shop is working on Sat Memorial Day weekend. The teeth are fine, the surface of the flywheel is heat crazed. A friend has a 168 tooth 14" flywheel I believe to fit a 65. I don't know yet if it has the bolt pattern for the 10.5 clutch. I'm trying to narrow my options.

Edit: His won't work, I'll need to try the machine shop first.

427390HP

Tom (DZAUTO) is THE expert on C1 drivetrains (among many other things as well). He has responded to numerous posts with highly detailed information on what does and what does not work regarding bellhousing, starter, flywheel, clutch, and transmission combinations. You can do searches for posts by Tom or searches for your specific question and find the answer.

I just did a quick search and here is the link that should answer your question. Look specifically at post #6:

https://www.corvetteforum.com/forums...960-vette.html

Everything I have read when I converted my '60 back to a 4 speed says you will need a 168 tooth flywheel. You can verify that by counting the teeth on your old flywheel.

Terry

DZAUTO

ALLLLLLLLLLLLLLLLLLLLLLLLLL 55-62 Chevrolet V8 engines (265, 283, 327, 348, 409) had a 168 teeth flywheel. PERIOD! And the big bell housing with the starter attached to the bell housing (NOT the bottom of the block). PERIOD!
MOST, but not all, of the early flywheels had a bolt pattern for the 10in clutch (now replaced with a 10.4in clutch). This includes ALLLLLLLLLLLLLLLL 55-62 Corvettes. SOME 55-62 V8 engines, such as HD service (Taxi, police, trucks, etc), hi-perf 348 and 409, had a 168 teeth flywheel with a bolt pattern for an 11in clutch.
In 1963, the smaller 153 teeth flywheel was introduced. Obviously, those flywheels would only have a 10.4in clutch.
ALLLLLLLLLLLLLLLLLLLLLLLLLLL the early 168 teeth flywheels that I've seen with a bolt pattern for the 10in clutch, COULD NOT HAVE HOLES ADDED FOR AN 11in CLUTCH, BECAUSE AT THE OUTER EDGE FOR THE CLUTCH DISC (BELOW), A GROOVE WAS MACHINED INTO THE FLYWHEEL SURFACE, WHICH PRECLUDED ADDING HOLES TO AN EARLY FLYWHEEL SO THAT AN 11in CLUTCH COULD BE USED!
I do not have a clue why GM machined this groove into the flywheel surface!





Therefore, if it is desirable to install an 11in clutch in a 55-62 Corvette, ANY 66-85 168 teeth NEUTRAL balance flywheel with a bolt pattern for an 11in clutch is a pure, 100% swap. Of course, this EXCLUDES using a 454 flywheel because those are EXternal balance flywheels------------------won't work on a neutral balance engine.
You CANNOT use an 86-later flywheel because the crank-to-flywheel bolt pattern changed.

65GGvert

Thanks Tom, I have read all your posts that I could find about this before I asked. My problem is finding a local flywheel on a holiday weekend. A local parts outlet says they have a 168 tooth flywheel that fits all GM (says prior to 57, but also says exc sb 400 and 454). I'm going to go look tomorrow, but just didn't feel knowledgeable enough without asking. They don't list Corvette parts, just old Chevys. Would a 57 chevy SB 168 tooth flywheel be the same? Thanks, Jack


EDIT: I just reread your post which I thought said "all Corvettes 55-62" but I see now it said "all Chevys 55-62" so I'm assuming that it will work whether for Corvette or Chevy, am I correct with this?

65GGvert

Several local parts houses have a 168 tooth 14.14" flywheel that fit a 57 58 69 60 chevy 283, but the compatibility chart says it will not fit a 60 Corvette. They also say for 11" clutch, I have a 10.4", is that a problem for the compatibility. I hate to press on this, but my car is apart and not at my place. Thanks for any help.

MikeM

The flywheel will work in your car if you use the 11" clutch. Some flywheels were drilled for both the 10.4" (10") and the 11" clutch.

A little heat checking won't hurt anything as long as the metal hasn't turned black/blue and the surface is smooth.

65GGvert

Thanks Mike, I found a machine shop open and he's turning it now. He says it will be ok, but there is some serious checking on the surface. We'll see.
Thanks again to those who responded

Frankie the Fink

The right machinist will make it like new...

DZAUTO

Let me just re-emphasize, ALLLLLLLLLLLLLLLLLLLLLLLLLLLL 55-85 V8 crankshafts and flywheels share the SAME bolt pattern. You can bolt a 1955 V8 flywheel onto a 1985 V8 crankshaft, or vice versa. PERIOD. I DO NOT CARE WHICH V8 ENGINE IT IS!
Now, for SB400 and 454 engine/flywheel interchangeability. AGAIN, ANY, ANY, ANY 55-85 V8 flywheel will bolt up to ANY 55-85 V8 crankshaft. A SB400 or a 454 flywheel will bolt up to a 1955 265 crankshaft----------------but it will shake the engine apart, because the SB400 and 454 flywheels are EXternal balanced.
Below is a comparison between a 168 teeth neutral balance and an EXternal balance flywheel, such as for a SB400 or 454. Notice the flywheel on the right has an added weight, that is for an EXternal balance SB400 or 454. Otherwise, they are totally, purely, completely, 100% interchangable.

A later, 168 teeth flywheel with a bolt pattern for an 11in clutch is a 100% bolt-in swap in ANY 55-62 Corvette with a manual tranny. The starter will engage the flywheel and the flywheel/11in clutch WILL FIT in a 55-62 bell housing. It doss NOT MATTER if the bell housing is a 55-59 cast iron version, OR, a 60-62 alum version-------------------EVERYTHING still bolts together and fits just as though Chevy had done it at the assembly plant.

65GGvert

It hasn't been all that smooth. Had the flywheel turned as far as they would turn it. Still had cracks all around. Spent about 3 hours trying to find a flywheel that worked with my 10.5" clutch and pressure plate. Finally bought one for a 11" clutch and an 11" clutch set. The clutch fork spring steel clip that fits against the release bearing was broken, took one off a C2 clutch fork put it on mine. (tig welded the rivet on one side to hold it in place) Put the trans in (not as easy as it sounds) and mounted the linkage (also not easy as it sounds), bolted everything up, speedometer cable about 5 inches short of working. Tried to get the cable and housing out through the firewall grommet, no success yet. Also the shifter hits the side of the hole a little when going to reverse, needs some trimming. Gave up for today, try again tomorrow. Just have to figure out what length speedometer cable and housing I need.

DZAUTO

Parts stores, such as O'Reilly, NAPA, etc, sell universal speedo cables/housings in different lengths. If you get yours pulled out---------------TAKE IT WITH YOU TO THE PARTS STORE-----------show them what you have and that you need a longer one. If the longer cable that they have is longer than what you need, MOST LIKELY you can just sort of re-route the cable so that it fits fine. No big deal.

65GGvert

In case you're still following, here's the latest. I picked up a 63" speedo cable and it fits fine. Mounted everything in the car, adjusted the linkage, filed off the left side of the hole where the shifter was hitting when moving to reverse. Everything together, started car, vibrated badly with any increase in rpm.

When I bought the flywheel, the guy brought out two, one external balanced (for 454) and one neutral balance (for small block). He brought out the 11" clutch kit and we matched up the pressure plate holes on the small block flywheel, then he boxed everything up. I told him the number on the box wasn't the part number I asked for and he said that was the manufacture number and not their number that I got from their catalog. After the vibrating, I looked up the number on the laptop and crossed it, it's the big block external balanced. I did not look at the back side before I bolted it up. I will from now on. Tomorrow I start all over from scratch and hope to get my money back on the flywheel and clutch set. I ordered a flywheel from Jegs that will work with either clutch size and elsewhere found a 10.4 clutch set with the three finger design instead of flat diaphragm because the way the clutch linkage is aligned on the 60, the clutch return spring holds the clutch to the floor when it's pressed and to the top when pulled up with the flat fingered pressure plate. It was designed to assist with the clutch when passing center on the way down. That won't work with the diaphragm style pressure plate and longer release bearing. I could modify the clutch return spring to work but I'm going back to the right size clutch and linkage set
I spent several hours researching and visiting auto parts stores trying to find the clutch I wanted to start with and gave up. It's almost impossible to find a 10.4" clutch with the 3 finger pressure plate setup. None of the flywheels come up as compatible with the 60, every compatibility chart says the 168 tooth 14 1/8" flywheel is not compatible with a 60 corvette, but as DZAuto said, that's what it has. All the big Corvette vendors wanted to sell me the 153 tooth 12 7/8" flywheel.

Just posting in case anyone later searching is looking for issues.

DAN70

Jegs sells a dual pattern , for 10.5" or 11". And, it won't break the bank....

65GGvert

That's the one I ordered yesterday. Thanks

DZAUTO

Are you telling me that AFTER I posted a picture comparing an internal balance flywheel with an EXternal balance flywheel, you didn't bother to take a look at the back side????????????????????????????
I give up!!!!!!!!!!!!!!!!!!!!!!!

65GGvert

I did look at the auto parts store, he brought up one of each. I told him I wanted the NON external balance for a small block and the clutch kit. He took one of the boxes back and I pointed out that the part number on the box he left was different from the catalog #. He said "I double checked it, that's a manufacturer number, we use a stock number, it's the right one". I did not look after I got back to the car, but as I said in the earlier post, I will from now on. I listened very carefully to what you said and knew what I wanted thanks to you. I just didn't get what I wanted.
I went back over this morning and with all cleaned up parts and recent experience, we had the shifter off, driveshaft out, transmission out, flywheel out and boxed up in about an hour and a half. I have ordered a dual pattern flywheel and 10.4 clutch set with the borg and beck fingers like the original that should be here Thursday. I don't know yet if I can get my money back on the wrong stuff, they're closed for the holiday.

Armed with the information you provided, we knew right away what was wrong and cross referenced the manufacturer number to find out for sure that it was wrong before we pulled it back out. The receipt I got from the seller had no numbers at all. It just said, "one flywheel", one clutch set"

Thanks again for your help, I wouldn't even have known why it was wrong without it.

65GGvert

Tom (DZ), I am not an engine builder or master mechanic. What makes the 454 engine require an external balance? What is balanced differently in the engine to require an external balance? I'd like to understand the physics of the balance system.

DZAUTO

ALLLLLLLLLLLLLLLLLL engines have a LOT of rotating and reciprocating weight swinging around the crankshaft. This weight (counter weights on the crank, rods, pistons, piston wrist pins, rod bearings, rings,) must be harmonious as it rotates and the weight of the counter weights on the crank have to offset the weight of the other parts which are in constant motion so that vibrations don't occur while the engine is running.
When an engine's rotating parts are taken to a machine shop for machining and balancing, the machinist weighs each part, grinds metal off of rods and pistons as needed so that all are equal, adds the appropriate bob weights to the rod journals of the crankshaft, places the crankshaft in a machine which spins (sorta kinda like having your tires balanced) the crankshaft and a read out is given to show where weight needs to added (by welding) or removed (by drilling) from the crankshaft counter weights (did you ever notice the big holes which are drilled in some of the counter weights of a crankshaft?). When all the rotating parts of an engine are properly balanced, the engine runs nice and smooth.
A hole can be seen in the front and rear counter weights of this SB400 crank.





NOW, FINALLY an answer to your question.
BOTH the SB400 and the 454 cranks do not have enough weight (because there is not enough clearance inside those blocks for bigger counter weights) to permit balancing the rotating assembly INSIDE the block. THUS, on a SB400 and a 454, there is added weight on BOTH the flywheel and the harmonic balancer. This also includes derivatives of those engines, such as a 383, 406, 420, etc and 468, 496, 502 big blocks. When weight is added OUTSIDE the block (ie, flywheel, balancer), it then becomes an EXternal balanced engine.
I've already posted a picture showing the added weight needed for a SB400 and a 454 flywheel (by the way, this is also applicable for the flexplate used with auto trannys). Below is the harmonic balancers for a SB400 and a 454. By adding weight on the OUTSIDE of the block, the engine then becomes an EXternal balance engine. ALLLLLLLLLLLLLLL engines which have the balancing INSIDE the block are referred to as NEUTRAL balance engines. Their flywheels and harmonic balancers have a NEUTRAL balance.
This is a balancer used on a 454. Notice the added weight on one side of the hub.



This is a SB400 balancer (red) compared to a neutral balance (350) balancer. Notice weight is REMOVED from one side of the outer ring.





With all of this said, there is one last thing pertaining to balancing an engine. An EXternal balance engine, such as a SB400 or 454BB, CAN BE balanced internally. BUUUUUUUUUUUUUT, it's expensive. To have an EXternal balance engine balanced internally, a hole(s) is drilled SIDEWAYS into either or both front/rear counter weights of the crankshaft and then a slug of HEAVY Mallory metal is pressed into the hole. I believe Mallory slugs are about $100ea, and it may require as many as 4 slugs to provide the needed weight to a crankshaft. Sorry, I don't have a picture of any of my cranks which have Mallory slugs added to them (never thought to take a picture when I had it done.).