hit a snag, head bolts

[WANTSOM]

Why are you rebuilding the motor?

[stariontron]

Why are you rebuilding the motor?

me? im converting from sohc to dohc. thought i should get the whole bottom end freshened up at the same time seeing as i'd be changing pistons anyway

actually just looking at the two gaskets (evo vs starion) theres a few galleries which appear to be non existant on the evo (or they were just never meant to extend above the cylinder top?)

also some of the holes in the evo gasket are smaller than the galleries in the block/head... the starion gasket looks like it might be more applicable?

who actually has an evo head on their car? or has everyone else gone with galants

:?

[stariontron]

ok some pics to help clarify:



here's the starion gasket next to ....uh a bunch of holes in the deck



heres the evo gasket in the same place. smaller holes. the head holes match the block ones.



two holes in the back of the deck



the starion gasket has holes to match, the evo one (silver) doesnt. the head has no holes to match. unsure if the SOCH head does... perhaps the galleries only extend this far?

[stariontron]

on closer inspection and based on the colour (i was running antifreeze i swear) it looks like all the holes mentioned there are water galleries. still no idea if i can get away with the smaller holes in the evo gasket though

[dirtygalant]

where's your thermostat housing, off the back of the head? My understanding is that the smaller holes on the Evo gasket promote the coolant flow from the front to the back of the head how the Evo cooling system is set up from factory - whereas the Starion SOHC head has the thermostat housing coming off the front of the head more or less.

That's my understanding of it anyhow.

[stariontron]

water pipe inlet is into the back, im guesing thats where the factory thermostat goes too.. odd though, the evo head only has two very small additional galleries that the starion block doesnt have. i really think that those two large noncircular ports are just the top of the water jacket. does anyone have a pic of the underside of an 8 valve head?

[OLD FART]

I just bored the block to match the TC head & gasket water galleries and have zero overheating probs

[stariontron]

here's another comparative picture. the head gasket matches the starion block completely, so we can use it as a representation of the block itself. i'm more than happy to alter the new head gasket to suit the block anyway.



so theres only a couple of places on the head where the block has slots where it doesnt - the two jacket galleries at the back of the block. comparatively, the head has two smaller galleries at the front of it, while the block has nothing there.

the head also has a whole bunch of slots around the combustion chambers which arent mirrored by the block. i might have to get a pic of an evo block to see if they have slots there.

the last difference is the circular holes just inboard of the head bolt holes on the evo head. (green) the head has them on both sides, between every cylinder. the block is missing two on the inlet side. i wonder if theyre oil related?

[dirtygalant]

everything circled is coolant related, there's only the one oil feed and the oil drains around the head. You want the coolant flow to be the same as the original Evo head/motor - so I would be inclined to just use the Evo head gasket and Evo head as a pair. If you were running the thermostat housing off the front of the head, that's when you need to do some modifying to the gasket and block to promote the coolant flow from the water pump to circulate right around the head before exiting back up at the front of the engine, whereas in the Evo/VR-4 engine and yours with the thermostat housing routed in its original location off the back of the head the coolant will be flowing from the front to the block through the head and out the back of the head.

Now I haven't done this swap myself but from what I've read and taken in over the years when I was going to do my DOHC swap this is what the general consensus was.

[stariontron]

so youre saying its good to go? last thing is those slightly smaller holes in the evo head gasket. i wonder if i should enlarge them to suit the holes in the head/block

[fugazi]

Putting this up for comparison:


Starion head (+180000km)
1g Galant (+200000km)

(Mods can delete, if not relevant)

[stariontron]

well the vr4 and evo ones look pretty similar... maybe there's nothing to worry about then. still not sure about the smaller holes in the head gasket though.