Adding a oil drain to big port head?

[ATAl]

Is it possible to add the external oil drain to the 4age big port head?

I'm thinking of copying the setup on the small port head - drill a hole in the corner and thread it to take the oil drain pipe adapter, will this work or are any oil / water galleries going to be in the way?

I want to do this mainly for the sake of reliabilty and oil use as the engine I plan to put this on will be fairly high revving and I've heard that the stock big port heads push lots of oil thru the breather pipe - not good

The head will be on a 7 rib block so I've already got the rest of the oil drain setup.

[kingcorolla]

if your worryed about oily air, just install a catch can.

fuk fuking around with drilling and tapping a feed. Why not just switch to smallport head? or is your current head worked? cams/ ports etc?

[matt dunn]

Dont know how you'd go there,

Have to make sure there are no oil or water galleries that you may drill through.

Matt

[ATAl]

I'm rebuilding an engine from scratch and it's going to be turbo so I may as well use a big port head for the extra flow.

Anyone have a rubbish head (warped, screwed bearings) they want to give to me? I'll drill a hole in it or cut it in half and see if this will work.

[ATAl]

OK here's some pics of the smallport heads oil drain hole, can anyone get pics of a bigport head in the same place?

Sorry about the crap quality

From the combustion chamber side


From the inside (it's the bottom right hole, kind of hard to see)

[Mr Revhead]

hehe iv fitted a catch can to my car.... now it permatly smells like hot oil!

the problem he's reffering to though, is the tendancy for the head to fill with oil at highrevs.... i think iv got the fittings u need somewhere....

and i sem to recall that you can just drill it in the same place... but check that

[ezy10s]

Im having a head built at the moment and i wish i had started with the small port one instead of my big port as we are now back filling the inlet ports as the are simply way too big (i am going for maximum hp figures on this).
Save your self the hassle man- go small port and be done with it.

[ATAl]

It's going to be on a turbo setup engine so I want the biggest ports possible, Also I'm probably going to make the exhaust ports bigger and put bigger valves in, so I have no use for a smallport head - which is unfortunate because I just rebuilt my one

[QikStarlie]

think you wiil find ezy10s is talking about a turbo engine... having the biggest ports possible will be a good way too loose power, velocity and correct port shape along with the flow is what you want. yes it does matter if its turbo

[ATAl]

Ok, I thought that turbo head design just required them to let the most gas possible in, hence the idea for using a bigport head.

Using the old straw analogy:
If you have a small straw and the gas at the inlet is pressurised to say 11psi less gets thru this straw than thru a bigger straw also pressurised at the inlet to 11psi.

I can see how this would make less power if the turbo couldn't supply enough volume, but the turbo on my car should have no problems supplying enough. So while the boost pressure on the small port and big port heads would read the same the big port would let a lot more volume into the cylinders, hence more power.
Whereas the small port would require more psi to get the same amount of gas into the cylinder, and more pressure = more heat = less power.

Anyway thats just how I see it, correct me if I'm wrong.

[Mr Revhead]

theres more to it than size, the thing is while big ports are good, the tvis style are TOO big.... as esy10s has said, hes going for max hp and is filling them in.....

[CAMB01]

U cannot really drill an oil drain hole in a big port head as the ports a bigger there is no room to drill it, where as the small ports, there is more room due to well small ports.
If you are going to be playing around with valve sizes and ports i would get it flow bench tested coz u might make less power if you go too big.

[craigt]

Im building a serious 4AGTE to go into a KP60.
I used to operate a flow bench as part of my job and I still
have access to it. Ive had both heads on the bench and played
round with the velocity probe in both ports.
Im going to be running a smallport head with standard sized valves.
You can actually remove the valves and the flow figures dont increase,
indicating valve size is not an issue.
This ported head fitted with quad throttles is going to be awesome!
I press out the guides, do the porting,
then press the guides back in. This is because a lot of work is required
in the guide boss area, it makes everything so much easier.

[ATAl]

Great thanks for the info.

Do you reckon that quad throttle will be a benefit over standard manifold on a turbocharged smallport?

Would enlarging the exhaust ports help the turbo spool earlier? Or are there simply no gains in bigger exhaust ports?

Also I'm not looking for peak power but a wide power band from 4-8k rpm.

What kind of porting is required for a turbo smallport - just a cleanup and getting rid of that lip in the port just above the valve, or something more serious?

[RedMist]

Craig, you may wish to come and have a look at my big made tiny port. Developed by an ex TWR engineer the ports have been reduced radically to considerably smaller than that of the smallport.

[ATAl]

With everyone saying smaller ports are bigger, I'm starting to think I should get a 20v head.

Is this going to flow better than a smallport head?

Black or silver top flow better for turbo?

It could be easier to use a 20v head because they can already handle 8000rpm without upgrades and quadthrottles attach without any adapters.

[craigt]

Interesting stuff that head of yours RedMist. That would be one serious head. The standard smallport head still has more valve and port area
than most worked V8s and is actually still overkill for a 1600.
Not so much flow-wise but area-wise.
The smallest area without sacrificing flow will always get the better results!
Bet that head of yours is a work of art