40 replies to this topic

[Guess-Works.com]

and dont forget to make the holes in the gasket bigger

[Ethel]

Probably too late to err a little caution but....

Just because it's beeen drilled and retapped don't assume it is UNF (but chances are it is). I'd try carefully threading a bolt or 2 in to establish what thread has been used mate would be more available, so you never know.

Regarding Stainless, a 5/16" A2 grade stainless fastener will be about as strong as the original 1/4" fastener - but depending on the amount of thread engaged the improved strength of the threading in the block may be main factor.

Last time this came up DK suggested a chromate plate high tensile fastener would be the strongest option. That makes sense to me - a flanged hex head and well greased threads would seem the best way to ensure even torque and that they'll come back out when you want them to.

Squeezing the gearbox to block joint a little harder might help to stop a leak but a careful look at and dressing of the mating faces along with a fresh gasket on a squeeky clean joint would make success more likely - torque it up as you would a head gasket too, from the centre working out.

' mate would be more available' - I typed M 8, sometimes pc's can be too clever for their own good

Another good point from GuessWorks - if you wanted to be really flash a slight countersink might help things sit together nice 'n flush too

[GraemeC]

A countersink on the gasket? Wow that would be impressive.

Sorry, in one of those moods today!

Edited by GraemeC, 05 October 2007 - 09:56 AM.

[Guess-Works.com]

you will have to countersink two of the holes in the gearbox case ( well apart from drill out the holes ) the ones above the diff casing or you'll not get the cap heads in...

[GraemeC]

I don't think countersinking those holes wouldn't make much difference John , counter-boring (if there is sufficient meat) may help though.
However I suggested use of standard bolts, or possibly even studs, in these locations as, even if you get the cap heads in, getting an allen key to them will be tricky!

[mini93]

some one said grease on the bolts to help them come back out, make sure its copper grease normal grease is likly to burn away

[Dog]

Well good news fellas.

The holes are 5/16 UNF Took the block to the nuts n bolts place, and I have 9, 5/16", and 2 that are standard 1/4".

The two that are standard 1/4" are the two above the diff housing. Best of all, I got the lot for nothing I got them in 8.8 HT steel, after a quick session drilling my box to suit the new bolts, all is great for pairing the block and box...

I am going to use paper gaskets, along with blue silicon gasket glue, just the help it stick. I would of got the lot together tonight, but I can't find my "half moon" seal I had a brand new one in the kit I got, and I can't it anywhere So its on hold till I can get one

[JetBLICK]

some one said grease on the bolts to help them come back out, make sure its copper grease normal grease is likly to burn away

phaaaaaa, no need for copper grease there! they'll soon get covered in oil

[mini93]

that is true but will the threaded section?

[Dog]

I can't see why to bother anyways, they never did to standard engines...
I'll be putting some cooper slip onto the gearbox bolts, transfer case, and flywheel housing bolts, just to make it smoother going home, and making it more accurate for torquing up.

And to be honest guys, once the new engine goes in - I am going to be a right tart with it, as I'll be showing it next year, as per "concourse" spec's it needs to be mint. So ANY oil marks, will be soon cleaned up

[Dan]

and making it more accurate for torquing up.

Greased threads will make the torque far less accurate. Torque figures tend to be given for either dry or lightly oiled threads. If you coat them in grease and use the same figure you will massively overstretch the bolt. Having said that using the same figure for an oversize fastener will understetch it so maybe it'll cancel out. Not likely though.

The two you have at original size above the diff housing may need to be studs and nuts as original. Getting any kind of screw in there is tricky. Remember the nut and bolt through the dowel.