1725cc flywheel vs 1592 flywheel

[mamoose124]

A few months ago I was inquiring about fixing the gear ring on my 1725cc flywheel so I can use it when I remove the 1592cc engine from my Series II. One of you SAOCA member suggested, “I would use an earlier flywheel as the clutch parts are more available.†(I searched for this original thread but could not find it) At his suggestion, I decided to use the flywheel from my 1592 cc engine on my rebuilt 1725 cc engine when the time comes. However, now that I have found a good gear ring for the 1725cc flywheel, I am back to thinking about using the original flywheel thus saving the effort of removing the flywheel from the 1592cc engine. But, because of the above comment that clutch parts are more available for the older flywheel, I am curious to know why that is so. Logically, it should be the other way round. Secondly, I’m now thinking that the 1725cc flywheel will not match up with my current clutch.

Can anyone answer these two questions: 1. Why should clutch parts be more available for the old flywheel? 2. Will a 1725cc flywheel connect up to my current clutch without a problem?

 

[RootesRacer]

A few months ago I was inquiring about fixing the gear ring on my 1725cc flywheel so I can use it when I remove the 1592cc engine from my Series II. One of you SAOCA member suggested, “I would use an earlier flywheel as the clutch parts are more available.” (I searched for this original thread but could not find it) At his suggestion, I decided to use the flywheel from my 1592 cc engine on my rebuilt 1725 cc engine when the time comes. However, now that I have found a good gear ring for the 1725cc flywheel, I am back to thinking about using the original flywheel thus saving the effort of removing the flywheel from the 1592cc engine. But, because of the above comment that clutch parts are more available for the older flywheel, I am curious to know why that is so. Logically, it should be the other way round. Secondly, I’m now thinking that the 1725cc flywheel will not match up with my current clutch.

Can anyone answer these two questions: 1. Why should clutch parts be more available for the old flywheel? 2. Will a 1725cc flywheel connect up to my current clutch without a problem?

1) For some reason the 7.5" clutch has been hard to source of late, perhaps becuase there are few if any other apps that use that particular pressure plate but the 8/8.5 PP is used on other relatively common vehicles so its available.

2) Clutches go with flywheels. PPs have different bolt patterns so an early clutch wont mount on a late flywheel and vice-versa. In fact, you will want to make sure that the flywheel, clutch PP, TO bearing and clutch pedestal are all used as they essentially form a "matched" set for the clutch system.

 

[alpine_64]

All per what jarrid has posted. Also using the early series flywheel allows upgrading the clutch to a volvo unit, you van slso adapt to mgb pressure plate and throw out

 

[mamoose124]

1) For some reason the 7.5" clutch has been hard to source of late, perhaps becuase there are few if any other apps that use that particular pressure plate but the 8/8.5 PP is used on other relatively common vehicles so its available.

2) Clutches go with flywheels. PPs have different bolt patterns so an early clutch wont mount on a late flywheel and vice-versa. In fact, you will want to make sure that the flywheel, clutch PP, TO bearing and clutch pedestal are all used as they essentially form a "matched" set for the clutch system.

Thanks for the explanation, RootesRacer. If I understand point 2 correctly, If I attached my 1592cc flywheel to my rebuilt 1724cc engine, it should connect to my existing clutch without any problem. I'm not making any changes to my clutch PP, bearing or clutch pedestal.

 

[mamoose124]

1725cc flywheel vs 1595cc flywheel

All per what jarrid has posted. Also using the early series flywheel allows upgrading the clutch to a volvo unit, you van slso adapt to mgb pressure plate and throw out

Thanks for the information, Michael, on the Volvo clutch and MGB PP and throughout bearing. I will include this information with my compatible parts list for my Series II.

 

[RootesRacer]

Thanks for the explanation, RootesRacer. If I understand point 2 correctly, If I attached my 1592cc flywheel to my rebuilt 1724cc engine, it should connect to my existing clutch without any problem. I'm not making any changes to my clutch PP, bearing or clutch pedestal.

So long as the flywheel, PP, Fork+TO and pedestal are all matched for the specific PP on the flywheel.

Also keep in mind that there are both diaphragm spring (Late SIII?/SIV) and coil spring type (SI/SII/SIII) 8 inch PPs which have different thrust heights and require different pedestals.

The coil spring type will accept an 8.5 inch disc for more torque, IIRC you have to change the diaphragm type PP to another application to run an 8.5 inch disc for the later 8 inch PP.
I like the early clutches, they are bulletproof (but heavy).

 

[mamoose124]

OK, I may be dense but let me go through this one more time to be certain that I have it correct. I am building a 1725cc engine. I will remove my 1592cc engine which has a complete new clutch assembly (mabe1500 miles on it). I will remove the flywheel and new clutch assembly from my 1592cc engine and bolt it to the rebuilt 1725cc engine. Am I correct in thinking that this will slip right into the transmission spline without any problem?

 

[RootesRacer]

OK, I may be dense but let me go through this one more time to be certain that I have it correct. I am building a 1725cc engine. I will remove my 1592cc engine which has a complete new clutch assembly (mabe1500 miles on it). I will remove the flywheel and new clutch assembly from my 1592cc engine and bolt it to the rebuilt 1725cc engine. Am I correct in thinking that this will slip right into the transmission spline without any problem?

You are correct, provided as I assume the trans unit and flywheel worked as a unit with your 1592.

 

[mamoose124]

1725cc vs 1592cc flywheel/clutch

You are correct, provided as I assume the trans unit and flywheel worked as a unit with your 1592.

Yes, my everything works smoothly. Just building a new engine.

 

[mamoose124]

1) For some reason the 7.5" clutch has been hard to source of late, perhaps becuase there are few if any other apps that use that particular pressure plate but the 8/8.5 PP is used on other relatively common vehicles so its available.

2) Clutches go with flywheels. PPs have different bolt patterns so an early clutch wont mount on a late flywheel and vice-versa. In fact, you will want to make sure that the flywheel, clutch PP, TO bearing and clutch pedestal are all used as they essentially form a "matched" set for the clutch system.

RootsRacer,

I found a new ring gear for a 1725cc flywheel but because I have a new clutch mounted to my 1592cc flywheel, I have decided to use it when rebuilding my 1725cc engine. The ring gear on my 1592cc flywheel is also badly scared up so I would like to replace it with the new ring gear. I have laid up the new ring gear over the 1592cc ring gear on the flywheel and they look to match up perfectly even though I haven't counted the number of teeth on each ring gear. Can you tell me if these ring gear are identical and, therefore, appropriate to have it mounted on my 1552cc flywheel?

Thanks,

Mike

 

[George Coleman]

Ring gears are all the same!

 

[mamoose124]

Thanks, George, for the confirmation. I was pretty sure that they were but wanted to have some confirmation.