8 replies to this topic

[tommc92]

Hi there.

Just wondering, do I need those lock washers that you bend up against a flat face of the bolt head on my main caps?

One of my engines has them on every bolt, another of my engines has none. Are they necessary?

Cheers, Tom

[crock]

No! Use hardened washers in this application. If the nut backs off enough to need a lock washer you were screwed before you started. I have never seen a car come from a factory using a lock washer in this application. The A series certainly never did.

[tommc92]

okay hmmm can't see any signs of this engine ever being taken apart before, they look like they were specially made for the caps as they have the same shape

[Sprocket]

No! Use hardened washers in this application. If the nut backs off enough to need a lock washer you were screwed before you started. I have never seen a car come from a factory using a lock washer in this application. The A series certainly never did.

Early A series engine DID have main cap and big end cap lock tabs fitted from the factory.

I would personally replace the bolts with later A+ items and do away with the lock washers, as they are a special type of bolt that have a self locking type of head on them. The factory did away with the lock tabs on the A series engines, but I don't know when, and I don't know what type of bolt was used in either application, but these early bolts, while a decent grade, don't have the self locking feature that the A+ bolts do.

Hardened washers are un necessary.

Edited by Sprocket, 26 November 2011 - 11:48 PM.

[tommc92]

I have a set of A+ bolts, but I can't see any self locking features on them. The underneath of the head (where i'm guessing the locking bit would be?) looks exactly the same

[Sprocket]

I have a set of A+ bolts, but I can't see any self locking features on them. The underneath of the head (where i'm guessing the locking bit would be?) looks exactly the same

The locking feature is the head itself. The bolt head has an under cut (recess) and six grooves in the top of the head. When the bolt is tightened down, this special shape of the head alows it to deform slightly, and prevents the bolt from loosening.

[tommc92]

I was just looking at the bolts and thought that must be what it is!
Thank you

[Sprocket]

Next time you take an A+ engine apart, you'll understand, since you need to use a great deal of force to 'break' the bolts loose, and they usually do so with a 'crack'

[tommc92]

Next time you take an A+ engine apart, you'll understand, since you need to use a great deal of force to 'break' the bolts loose, and they usually do so with a 'crack'

Yeah I just took some out of another engine for the one I'm building now, needed a nice large breaker bar on the socket