Austarion

hi guys, just a few questions if you dont mind.

i've got my evo head on, but i didnt drill the two extra coolant holes in the block at the front... now im not planning on running huge power, am i going to have to rip the head off and drill them or can i get away without?

i asked redzone and he said "its a good idea if youre running a rear water outlet"

i dont quite understand this, what other outlet is there to use? and why am i seeing pictures of people welding spouts onto the water pump, facing towards the firewall? is that just another option for a bypass pipe or what? help!

Hey.

There are two options to run.

1) is via the rear (normal) thermostat housing. You don't NEED to drill those two holes but it does help flow.
See image here (I am not embedding it as its quite big)
http://projectzerog.com/images/4g37waterNeck.jpg

2) Is via the front where you close off the rear, and weld on a new pipe from the front water hole. You NEED the front holes drilled for this method.
See image here
http://projectzerog.com/images/cleanEng ... Corner.jpg

Hope that helps.

ah awesome mate! thanks for the help. yeah im running the rear outlet with an old toyota thermostat. ive got my manifolds on now and most of the way through the wiring, really didnt want to rip everything off again. cheers

Take it all off. The 2 holes at the front (for the rear outlet version) allows the water to flow the right direction without hotspots.

With the evo head did you enlarge the clearance for the oil feed to the head given the increase in head bolt size? If you didn't do this the head will have to come off and you can correct the coolant flow direction at the same time.

With the Starion head the coolant path is such that the dominate flow is from the rear of the head to the front while with the dohc head the dominate flow is from the front to the rear. The flow direction is controlled by the size of the holes or lack of holes in the block, head and the head gasket.

dwlee wrote:With the evo head did you enlarge the clearance for the oil feed to the head given the increase in head bolt size? If you didn't do this the head will have to come off and you can correct the coolant flow direction at the same time.

no i didnt, please explain whats required here. first i've heard of it. obviously the bolt holes have been enlarged to 12mm for the head bolts, but thats the extent of it.

Using the larger head bolts with an evo head can restrict oil flow into the head due to the reduction in the clearance between the rear exhaust side head bolt. The oil flows around the head bolt into an oil gallery part way up the hole. If the correct clearance is not maintained you run the risk of not getting enough oil to the head.

See
http://www.orldsm.com/archive/index.php/t-14025.html
and
http://www.dsmtuners.com/forums/cylinde ... 4g63t.html

Edit: changed inlet to exhaust

ok so i'm running a 1/2" bit up as far as the oil gallery on the bolt hole closest to the CAS. i'm using an ARP stud set too so going by the same logic that allows for a 35 thou clearance. should be heaps

any preferable size for the water holes in the block? same size as the gasket holes i guess.... how deep is the steel in the block there?

This is avandull's block in other thread:

Not that big holes... 6mm?

The holes in a dohc block I have in the shed are 6mm. Also, note the oil inlet is on the exhaust side.

dwlee wrote:The holes in a dohc block I have in the shed are 6mm. Also, note the oil inlet is on the exhaust side.

Sounds right. I just drilled them the same size as the gasket.

I did not drill out the head stud hole that carries the oil supply.

However my turbo oil feed is coming from the back of the oil filter housing, not the head. So this might explain why I have not had any problems.

The cam shafts have no signs of wear and I have been using the same head and cams since 2009

avandull wrote:I did not drill out the head stud hole that carries the oil supply.

However my turbo oil feed is coming from the back of the oil filter housing, not the head. So this might explain why I have not had any problems.

The cam shafts have no signs of wear and I have been using the same head and cams since 2009

are you using an evo or galant head?

VR4 head

With a VR4 head the head bolt hole size does not change to allow the larger bolts/studs needed for a 6-bolt block and hence you wont have oil clearance issues.