stevieturbo

These engines use only 6 bolts and no dowel. Although every crank and flywheel Ive seen does have a drilling for what looks to be a large dowel.

Has anyone bothered to install one ? Certainly cant do any harm ? Although cant say Ive had a problem despite the lack of fixings

lizeec

iTrader: (57)

That extra hole is to index the flywheel to the crankshaft, and yes putting a dowel pin there can do harm, it will mess with the balance of the flywheel and the engine and you will have vibration that might or might not be noticeable, but in the long run it will ruin the main bearings and crank, unless you install the dowel and then get the crank and flywheel balanced together.

NVR_SPDS

iTrader: (39)

I wouldnt even worry about it. the flywheel-crank bolts align the flywheel to the crank, and every car ive done a clutch on never had a dowel, without issue.

stevieturbo

Many engines do not. But virtually every other engine I work on either has more bolts, better spec bolts, or both of those and a dowel.

The fact an LS has only 6 bolts, and not even proper high tensile is quite surprising. Especially given the abuse they can take.

I cant actually think of any other engine Ive seen with the same number or less bolts. Usually there are at least 8 bolts

lizeec

iTrader: (57)

Well think of the massive rear slick on a top fuel dragster and that wheel is held on by 5 studs and 5 nuts and the rotational forces put on those studs by that engine and those slicks, and if that is strong enough to stay put I am pretty sure that flywheel aint going nowhere due to bolt failure.

stevieturbo

Interesting comparison.

But even my crappy old diesel Volvo uses 9 high tensile bolts and makes no power whatsoever.

Sierra Cosworth 2 litre turbo high tensile 10 bolts.

Subaru uses 8 high tensile bolts.

It just seems odd that a large V8 uses so few, and of relatively low quality.