Thought I'd have a go at the porous/cracked head modification!

[Frisco]

Also not all GM heads have the grub screws on the dizzy end of the oil galleries

[CortraGTE]

If you look at the sectioned head pic, the two virticle(sp?) channels at either end of the highlighted bit are the head bolt holes.
You can look down them when the head is off and see when to stop.

A pin punch is made for hitting things into holes

Nice one cheers mate!

2 more questions, the bearing lock stuff, once you put it on the pipe does it not get everywhere inside the oil way cause if the pipe is tight does it not just smeer off?

What length did you cut the pipe too?
[Edit] I can't read 87mm

[Frisco]

Yes some/most of the thread lock stuff comes off when the bar is pushed in but i didnt put mountains of it on and any that did rub off ended up in the head bolt hole so i just pushed a rag through that with a screwdriver to clean it out.

Its easy enough with the head off the car. Much better than bining the head anyway!

[Add_Gee]

Once it was inside the head what did you use to tap it in further? A stick?

lmao lmao very technical

[Jack]

lmao lmao very technical

lmao lmao

I can just imagine someone poking a bit of twig in the hole. Genius! lmao

[CortraGTE]

Yes some/most of the thread lock stuff comes off when the bar is pushed in but i didnt put mountains of it on and any that did rub off ended up in the head bolt hole so i just pushed a rag through that with a screwdriver to clean it out.

Its easy enough with the head off the car. Much better than bining the head anyway!

Ah yeah I see, forgot they were gonna be there. (Right after being told too! )

lmao lmao very technical

lmao Yup thats me.

[cambridge]

a metal stick...

[CortraGTE]

I'd hate to be the person that cuts down the tree it came from.......

[Lee H]

It is also worth renforcing the oil gallery before the head cracks.
Not all GM/KS heads have an oil gallery plug on the inlet side, so a suitalbe hole may need to be drilled tapped and cleaned.

Steve

How would you go about drilling and tapping this extra hole? I assume you need a hole at each side in case you push the tube in too far so you can move it back the other way?

[Scoobler]

If there is only one grub screw you can see the tube down the head bolt hole and watch that it doesn't go too far in, you could also put something down the head bolt hole to stop the tube.

ah so its a U like shape?

Benn this pic/explanation may help, its more of a H shape if you looked at the head from above.

• The two head bolt holes A, one of which is used to supply oil (when the head bolt is in palce it will cap off the hole, hence no oil leaks out)
• The two water paths B, these run the length of the head, but it is this section where the oil passes into the water. You can see the missformation where the weakness occurs (all will become clear).
• The centre oil gallery C, this runs from the front of the head to the back, it is connected to the cam oil galleries(D) and the headbolt (A) hole to supply oil rising from block to the cam's. The front of this gallery (on the right in the picture) is blocked off by a grub scrw found on the front of the engine, between the two centre exhaust ports.
• The cam oil galleries D, these run from one end of the head to the other, there is one for each cam. These get oil by it rising up the headbolt, passing into the centre oil gallery, and passing upto them (the paths that leed upto them are caped with crub screws, these can be found under the cam cover).

[Lee H]

Done this myself today, had loads of problems finding something to hammer the tube in with but got it to go in eventually. I used steel tube instead of alloy, is this likely to cause a problem?

[Jack]

Shouldn't be a problem at all. The oil will stop any rust.

[AussieKid]

should be fine

i also did this to my head so i would never have the problem, my tube went right way through, then you just drill down for the cam feed holes and same for the headbolt holes and away ya go

[bbuk]

if the head was off would it be a good idea to insert a bolt on the head then insert the sleeve so u know its gone as far as it's meant to.

[Sinpb98]

And, what kind of material did you get into the head? Alluminium alloy, stainless steel,... i have a porous head and i´d like to solve the problem. As i see this, i´ll have two mean problems: find a great material and the exact diameter of it. May i be able to get in with one hand or must it go into more stronger?

When you refer alloy tube, what kind? Aluminium?
Thanks a lot.

[Jack]

It will have to be an interference fit, and I'd imagine you'd need some gentle taps with a hammer to get it in properly if it's a good fit. Any more and you risk damaging something. Any less and you'll get oil seeping around the tube.

[Sinpb98]

It will have to be an interference fit, and I'd imagine you'd need some gentle taps with a hammer to get it in properly if it's a good fit. Any more and you risk damaging something. Any less and you'll get oil seeping around the tube.

Yes, that´s what i thought.
And about the tube, i suppose that alumiun alloy is better, becouse the head is made of it. But i´d like to read the opinion of those who have done it and are more experienced.

[Astra Dan]

So at what point does the head go 'porous' and mix with the oil?

[alistairolsen]

it doesnt go porous, it cracks beteen the oil and waterways below the tube afaik

[Astra Dan]

Yeah I know, hence the quotes around porous. That's a thick bit of ally to crack!

[curson24]

i was thinking about this mod to the heads and couldn't doing this cause oil starvation to the cam? because using a tube will reduce the internal bore of that oil channel!
i thought about this because i have this mod on my head but the oil is completely blocked off and bypassed outside the head (solid bar mod) and when the car is cold it rattles up top, or even once its been run about and warmed if left to idle it starts to get noisey again like there isn't quiet enough oil getting up.
i presume the oil channels that feed the cams also feed the lifters?

[Nova_Mike]

hi mate quick question between what two cylinders is this gallery? e.g. 2 an 3?
bit worried as far as i know you can only acces the gallery from the exhaust side as the diagram shows only one grub screw

[Nobbie]

Some heads only have one grub screw, as mentioned above.

[Nova_Mike]

oh right yes i see jus checking only scanned fru thread must of missed it dopey

[Sinpb98]

Does anyone know what kind of material should be used?