TR2/3/3A Moss [ARP] Flywheel Bolts

[RedTR3]

It looks like I am going to be replacing clutch components...Now, in looking for parts, I noticed that the only flywheel bolts available are the ARP from Moss. I remember reading that there were issues in the past with these bolts being too long. Is that still a problem? Do these bolts come sith theri own washers or do you use the tab washers? Thanks!

 

[TR3driver]

Based on advice from Kas Kastner, I don't use washers at all. Medium strength, oil resistant Loctite.

Can't help with length of the ARP bolts, I'm still running the originals. Mine were fine even without the tabs.

But it might depend on which flywheel you have. I'm also using a Fidanza flywheel that might be a bit thicker than stock.

 

[ShawnC_at_Moss]

Not to try and out-do Kas, our tech department has talked with ARP regarding the use of these bolts for the Triumphs.
ARPs recommendation:
On Triumph TR2 through 4A, the ARP bolts should be used with the locktabs. A drop of 322-815 ARP Ultra-Torque Assembly Lube must be placed between the locktab and the flat surface under the head of the bolt. This prevents the locktabs from being damaged when the ARP bolts are tightened.

These are new bolts with the correct length. Here is a link to the product on our site with a link to the instructions which goes into more detail
https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=111560

Happy Motoring,

Shawn

 

[DornTRoriginal]

I bought these from Moss and have installed them on my car. No experience yet with their performance but I think it's a better option since my old ones were fine except the locking tabs were in poor condition. These seem much lighter, balanced and high quality. Only problem I had was I did not have the right socket head to use.... I corrected that problem quite easily however duh

 

[RedTR3]

Thanks Shawn, that is very good information. Now, just to clarify...the literature states that the tab washer is not used with the TR4 self-locking bolts. Does that mean that no washer of any type is used with those?

 

[JerryVV]

I considered the ARP Bolts but when I looked at them compared to the OE Bolts the washer face seemed smaller so I went with new OE from TRF. Maybe that's why ARP suggests their bolts be used with the locking tabs. I know the racers use the ARP but they often add more tapped holes on the crank too. Just my thoughts on the subject.

 

[ShawnC_at_Moss]

Thanks Shawn, that is very good information. Now, just to clarify...the literature states that the tab washer is not used with the TR4 self-locking bolts. Does that mean that no washer of any type is used with those?

If you are using the factory flywheel bolts for the late TR4-4A (our number 320-770) then those bolts don't require any washer. If you are using the ARP bolts then they need the locktab even if using on a late TR4-4A that didn't originally need any type of washer.

 

[AHS]

I have to respectfully disagree with the advice from Moss to use a lock tab. These are critical fasteners which must maintain proper clamping force indefinitely, and the last thing you need is a piece of soft metal like a lock tab under the bolt head that has a possibility of flowing outward and reducing the clamping pressure, resulting in loosening & then disaster. Yes, all British cars were built this way back then and it worked. Are you sure those new bolts and lock tabs you're buying are exactly the same hardness & tensile strength available 50 years ago, and are you sure you're using exactly the same torque the factory used? Probably not. You will need a very hard washer and a drop of quality lubricant between the ARP bolt head & washer. I have used the ARP A-series bolts, I even still have a set of new ones in a sealed bag and they were supplied with matching washers. I have also seen a disaster from stock flywheel bolts (used with a lock tab) that sheared off. I have no idea why such an excellent product as ARP flywheel bolts would be supplied without appropriate washers. The bolts have a generous radius between the head & shank (which increases strength) and may require an inner bevel on the hardened washer. These washers are available from good fastener & industrial supply vendors. Don't trust hardware store stuff for this critical job. That's my 2 cents, take it or leave it, but I don't want to see someone have flywheel bolts fail after a little running without having been warned about soft lock tabs.

 

[JerryVV]

Mine did not come with matching washers, if they had I may have used them. The ARP Bolts are spec'd for the BMC "A" Engines but just happen to also fit our wet liner TR engines. Length may be an issue too but I am not certain of that. Good quality original bolts are available and unless you are building a performance engine and adding additional bolt holes in the crank, I'd go with the new OE style bolts. AHS above has a convincing argument. Again the issue that I had was the washer face on the back side of the bolt head is too small when compared to the OE Bolts. A proper washer may fix that issue, mine did not come with a washer.

 

[ShawnC_at_Moss]

AHS,
You're explanation was perfect. Yesterday afternoon we got on the phone with ARP and asked them again about these bolts for the TR2-4A. Their answer was to install without the locktab and use loc-tite on the threads with their lubricant under the head to get proper torque. There was no need for the lock tab, not sure why we thought that, as it can only introduce potential problems. They did suggest that a superior quality wave washer could be added but was by no means required. We have removed the erroneous instructions from the product.

Shawn

 

[DornTRoriginal]

Dang it! I am going to pull out the transmission this weekend and re do the bolts on the fly wheel, I did not use loc-tite and I thought the ultra Torque was to be used on the threads... (dummy me) so based on all this information I will clean the thread holes well with brake cleaner, use some loc-tite on the threads and lubricate UNDER THE HEAD this time. Is there anything else I should be concerned with at this point? Is there a problem with undoing the bolts and then re- installing them? Do I need new bolts? Also, I ordered some lock tabs yesterday too, if anyone needs them let me know...

 

[TR3driver]

Ok, that makes a whole lot more sense. Thanks for following up, Shawn.

 

[TR3driver]

Dang it! I am going to pull out the transmission this weekend and re do the bolts on the fly wheel, I did not use loc-tite and I thought the ultra Torque was to be used on the threads... (dummy me) so based on all this information I will clean the thread holes well with brake cleaner, use some loc-tite on the threads and lubricate UNDER THE HEAD this time. Is there anything else I should be concerned with at this point? Is there a problem with undoing the bolts and then re- installing them? Do I need new bolts? Also, I ordered some lock tabs yesterday too, if anyone needs them let me know...

My opinion, if you torqued them to spec and are not planning to run over 5000 rpm for more than a few seconds, you should be fine. The problems start showing up when you go racing (sustained high rpm operation).

Should be no problem doing the bolt R&R, new bolts not needed unless the old ones are damaged (rust, over-torque, rounded, etc).

 

[Hap Waldrop]

I do the same thing, loctite, torque while it's still wet.

 

[CJD]

Wow. I'd never get anything done if I got this involved in every bolt!

Anyway, here's something to think about. The torques used on these British flywheels are much less than the torques used on the American counterparts I have dealt with. That means they see less stretch, which is what normally keeps a non-lock tab bolt tight. So, is it possible the Standard folks of old studied this stuff in a lot more detail than we know? If we do not plan to use the lock tabs they chose, should we increase the bolt torques to compensate?

ARP makes quality products...but I don't hink they have spent much time racing Triumphs.

 

[TR3driver]

ARP makes quality products...but I don't hink they have spent much time racing Triumphs.

Which is why I prefer to rely on Kas Kastner's advice. He has spent a lot of time racing Triumphs.

 

[Hap Waldrop]

ARP makes quality products...but I don't think they have spent much time racing Triumphs.

But their bolts have The bolt used for both MGBs and the Triumph is 7/16"-fine- 1" long , same as SBC, and SBF, ignore the ARP torque specs on these, and torque to factory specs.