What Size Grub Screw

[Alf]

For those who have grub screwed the VVT oil gallery in a 33 25det head, what size did you use?

[DVS JEZ]

what ever size you do use just be carefull if you grub screw it, my mates brand spanka engine was mixing oil/coolant, pulled the head back off and the machinist said the grub screw is leaking, yet they cant even get it back out, its got heaps of loctite/sealant on it, there going to weld it and machine it flat

[Alf]

I had the exact same prob except mine was welded (not by myself) and leaked.

I'm going to fit several grub screws as high as possible then weld over the top.

[Adriano]

M8 x 1.25. Ireally cant see a tapped hole with a grubscrew and sealant leaking

[DVS JEZ]

well thats 2 people that have seen it so far

[VB-]

M8 x 1.25. Ireally cant see a tapped hole with a grubscrew and sealant leaking

i wouldnt think so either, only thing i can think is the alu expanding at a different rate to the grub screw with heat, and maybe just pulling away enough to break the sealent. obvious solution here would be to use a 'softer' sealent that has a bit of flex rather than something that sets hard... cant think of anything else.

grub screw needs to be whatever size you tap the head at...

[Alf]

I've used 3 alloy M8 x 1.25 grub screws + sealant so the expansion rate shouldnt be a problem nor should it leak.

Edited April 17, 2010 by Alf

[Thelen]

What is a grub screw? Pics of it?

[Adriano]

Im thinking the people with the leak problem maybe they didnt tap the thread, just wound an m6 grub screw in, then i could see it leaking. On the neo 25/30 i built, we tapped and locktited the m8 grub screw and then epoxy'd it in