Bad noises from gearbox? - need advice.

[Nero]

What about using some unbrako's, low profile socket head bolts?

[BigMuz]

Generally still thicker than the equivalent hex. Also when you strip the inhex what do you do?

Muz

Carroll Smith used to recommend steam bolts, with a kind of spring built in. See "Engineer to win"

[Datman]

I have a couple of spare sets of flywheel bolts, I have no idea how I have accumulated them! So even if I change them each time I remove the flywheel, I should be good for a while.

Bigmuz, is your recomendation based on a strength/breaking issue, or because the heads will be stuffed once they have been on and off once?

[BigMuz]

A bit from column a and a bit from column b- On multi plate setups we used to have to remove circa half the head- then you root them every time removing them.
Plus they are cheap enough to throw away. It's your legs after all...

Just get a couple sets machined when you get them done and chuck em in a box for later.

Muz

[Nero]

well the unbrako's are a 12.9 grade bolt and even with a thinned head version that I have ground down I have not had an issue. I would prefer them to an unknown grade FW bolt, FWIW have you tried some of the specialist fastner Co's to see if there is a 10.9 or 12.9 low profile 12 point bolt that is suitable?.

[BigMuz]

That is the best answer nero- hard to find the right combination of lengths though-If the shank of the bolt is used as a dowel (as most flywheels do), then try and find bolts that are full diameter. The less thread in this area the better. And metric fine is common and (I have found) hard to get in reduced 12 points..

But yeah, 12.9s are pretty damn hard- my socket allen keys are probably too tired for this to work for me!!

Muz

[Nero]

I too have stuffed a cheap socket allen key in an unbreako, still it is cheaper to do this than the reverse. The full unbreako catalog is pretty extensive and some of the stuff is only available overseas, however that does not make it unaffordable. For such a stressed high mass/energy part I would urge a very good quality bolt and I have some reservations on thinning an unknown quality std bolt in a comp engine. May be worth trying ARP too if you know the full bolt dimensions, they are usually very helpful if you have all of the data.

[Datman]

Thansk guys for the advice.....I will certainly look into different bolts in the future.

I spoke to Stewart Wilkins about this, and he says he has done this quite a lot and never had a problem. Considering I was on a tight time frame I have used the standard (machined down) bolts this time. Next time though, I will certainly look into some stronger, low profile replacements.

Incidentally....the car is now all back together...and for the first time I was able to drive the car....even if it was only about 10m to get it into the garage. No problems though....so that's one bug fixed!

[Nero]

Well if someone has done it and not had a problem it can be confirming of choices made. Naturally enough you always weigh up the risks. Still such a part is a service part that gets replaced each season or so, so maybe it is OK. I often think that manufacturers put in reasonable quality parts, BUT we always take the components past their design parameters and thus service life etc is always going to be shortened.
Are there any dowels as well as bolts?

[Datman]

No Dowels here....just the bolts. Next time it's out....I'll replace them.

[Nero]

I have had dowels added in the past...but different engine and there was space. Always try IAP on 0246474097. Never used them myself as I usually go online. I have seen a FW come off at high RPM...it would make a real mess if it got into the cabin!
By mentioning this I am NOT trying to scare you etc...it just scares the crap out of me!

[Datman]

Latest Pic

For those who care Here's the latest pic...... Loaded up and on the way to the Panel beater to massage the guards to help clear the 15" rims...and bucket loads of Castor.

[Nero]

it looks good and I wish it were mine!

[Guido]

Looking very, very nice!!

[Datman]

Thanks guys....Can't wait to hit the track and see what she will do.