Pissing water out manifold

[Jbone32]

Surfaced head by hand. New head gasket. Leaking at manifold..Quick question why in the hell does water flow through intake?..i mean whats the point?.cooling of manifold?..why water through intake?

[captain720]

It regulated temperature of manifold both warming it up on cold days and cooling it on hot days, stable temp mixture makes more power, optimized fuel atomization, and helps prevent gas boiling

[datzenmike]

In addition it flows water OUT of the head down the side rather that it having to travel all the way to the front at the thermostat housing. This will circulate cooler water from the block up into the rear and mid cylinders rather than them running slightly hotter that the front. L28s that are raced are even longer from back to front and the EFI intakes don't need this so owners often drill several passages into the side of the head to move more water.

 

[datzenmike]

Leaking at head/intake interface??? That's just improper clamping of the gasket. The bottom bolts (4) use a cone washer to bridge across the exhaust and the intake flanges and tighten both.

 

The exhaust can hang on the 3 studs in the head. Lower the intake into place and LOOSELY hold in place with the top 4 bolts. Install the 4 bolts along the bottom that share tightening both the intake and the exhaust. These four have a very thick curved washer that goes on with the curve towards the engine. Tighten to 9-12 foot pounds. Now tighten the top intake bolts and exhaust studs. Check the bottom ones once more. No need for sealer, Nissan didn't use it.

[captain720]

Nissan didn't use sealers, but sometimes previous owners have scored the aluminum and it will either need to be surfaced or a lightweight sealant like gasgacinch used

[datzenmike]

I'm thinking most owners don't know when to use a sealer and once on you'll never get it off, or getting it back off, it will be a total bitch to scrape it clean again. I've been on the wrong end of oil pumps, thermostat covers, carb spacers and timing chain covers and oil pans almost permanently welded on with a sealer by a well meaning owner. Sealing is what the gasket does.