Engine fasteners

[bash]

I am in the process of rebuilding my engine and I am finally getting close to putting all of the nice shiny bits back together. I am trying to work out what fasteners to use, and I am confused. Searching (here and the whole internet) leaves me even more confused. Some advocate reusing old bolts, others say only ARP will do. So, I am hoping that people will be kind enough to let me know what they used, particularly for the Fidanza flywheel and the main/big-end bearing caps.

I just had a look and found that the original flywheel bolts don't really fit into the Fidanza flywheel holes - that can't be right, can it? If I buy ARP flywheel bolts, won't I just find myself with expensive botls that don't fit?

Richard Good has upgraded main and rod bolts on his website, and they are considerably cheaper than ARP. I spoke to him this morning and he reckoned that the original main cap bolts are grade 5 but the rod bolts are more specialised.

I have ARP head studs - found a place online where the ARP set was cheaper than buying regular studs from TRF (about $90 delivered from https://www.nolimitsmotorsport.com when I bought them last year). All of the other fasteners I have basically bought new from Fastenal/McMaster Carr/Bolt Depot - pretty much all Grade 8, even though I know this is huge overkill for things like the timing cover! Somehow I have been caught up in the fascination with grade 8 bolts that seems to be common in LBC circles, in America at least.

Well, that's enough of the rambling. Any thoughts or advice would be appreciated. By the way, if it matters, the engine is from a 1975 TR6 and I am "warming it up a bit" while I rebuild with a slightly increased compression (around (9:1)), GP2 cam etc. Not looking for huge power, just a few tweaks while it is apart.

Thanks in advance
Alistair

 

[PeterK]

Try these folks. On their home page click upper left where it says Click for APT parts, then select Triumph. They sell ARP fasteners and also sell aluminum flywheels so they should have your answer. https://www.aptfast.com/index.htm

I am also caught in the Grade 8 frenzy but offer that mostly what came on the engine is OK to reuse.

Better (or just new) head studs would be a good thing.

Main cap and rod bolts I would use original, unless they are stretch bolts, otherwise a new quality such as ARP.

Aircraft Spruce has aircraft quality and ... well, this can become a frenzy too so get off the bus anytime.

 

[Brosky]

I just ordered a Fidanza flywheel and I'd also like to know exactly what size bolts it will need.

 

[bash]

Peter - thanks for the reply. I actually spoke to the very nice people at APT this afternoon and I ordered a set of ARP flywheel bolts. I took Richard Good's advice on the Mains and Big ends - he suggested using new Main bolts (I ordered the ones he supplies) and using the stock big end bolts unless you are intending to seriously increase power. If I had any supercharger ambitions I would certainly go with ARP rod bolts.

The stock flywheel bolts have a little bit of a shoulder which means that they don't fit through the holes in the Fidanza flywheel. APT suggested heating the flywheel before installation to allow the bolts to fit or reaming the holes slightly, but I am not sure I like either of those. I suppose reaming would be better, but I would then have to give my shiny new flywheel to a machine shop and hope they are good at what they do! I suppose I handed my cylinder head over... I ordered the ARP bolt kit with washers as sold by APT (total about $20 + shipping) and I am hoping that they don't have the shoulder. I'll post an update when I get them.

Cheers
Alistair

 

[DNK]

Don't remember that my flywheel bolts had shoulders,but that was a few years ago.

 

[bash]

Don't remember that my flywheel bolts had shoulders,but that was a few years ago.

Don

It isn't a big shoulder at all - not noticeable just by looking (unless you look really closely) but the threaded part goes through the hole and the unthreaded part doesn't. When I finally get my crankshaft back into the block I might try a test fit to see if a little torque will pull the bolt through.

Alistair

 

[DNK]

I thought they where threaded all the way,boy it has been a long time. Is yours a stock flywheel?Another thing too. ARP sell direct for less.

 

[Guest]

Pretty sure Ted Schumacher supplied new bolts to go along with the Fidanza aluminum flywheel. Or perhaps I asked that he supply them. I dunno. I forget a lot.

 

[DrEntropy]

Just an FYI, these guys are having an ARP fastener sale thru 02-07-08:

https://www.northernautoparts.com/index.cfm

No affiliation, got it thru an e-mail from a friend.

 

[Dave Russell]

Don't remember that my flywheel bolts had shoulders,but that was a few years ago.

Don

It isn't a big shoulder at all - not noticeable just by looking (unless you look really closely) but the threaded part goes through the hole and the unthreaded part doesn't. When I finally get my crankshaft back into the block I might try a test fit to see if a little torque will pull the bolt through.
Alistair

The ARP flywheel bolts have a short unthreaded shank about 0.160" long that measures 0.375" D. The threaded portion measures 0.370" D. It's important that the shank be a snug fit in the flywheel.

ARP recommends torquing new bolts to spec & releasing three times Before final tightening.
D

 

[PeterK]

And don't forget to use special ARP lubricant on the threads for proper torque.

 

[TR3driver]

The ARP flywheel bolts have a short unthreaded shank about 0.160" long that measures 0.375" D. The threaded portion measures 0.370" D. It's important that the shank be a snug fit in the flywheel.

Right. Not a shoulder at all, but a full diameter shank. Too bad it's not longer, or we could use them for the 'dowel bolts' between the gearbox & engine too.

The alloy flywheel should also be a very snug fit on the end of the crank; so warming it in the oven first is probably a good idea.

 

[DNK]

The alloy flywheel should also be a very snug fit on the end of the crank; so warming it in the oven first is probably a good idea.

A few years to late for that little nugget.