Advice on U67 Head swap

[wagoon]

My thermostat crapped out, I loosened the bolts off from the housing to place a new one, they broke from years of rust. It was just plain out corroded real bad. Next I was going to change out the thermostat housing, 1 bolt broke. I also was changing the temp switch and that housing broke. So there is rust all in the front of the manifold so the 1st bolt broke. Rust sucks!!!

 

Now, I have a spare U67 head ready to drop in in replace of my stock L16 head. So I have the L16 block and a U67 head.

 

1. This is my 1st head swap, I need some tips on best gaskets to use...felpro or ? Do I need that copper gasket sealer?

 

2. Do I need new head bolts?

 

3. What kind of power gains can I expect?

 

4. I plan to use my wagon as a DD, will it ruin my awesome mpg?

 

5. What else do I need to know?

[Skib]

replace all the valve stem seals and dont drop the chain lol

[hobbes_the_cat]

The U67 is an open chamber head so I would expect a huge drop in compression and likely a loss of power on an L16. The stock L16 head has tiny combustion chambers compared to all the other L motors, even if you swapped on a peanut chambered head you would still suffer a small loss of compression. I'm not saying for sure this head won't work for you, but I would do more research if you haven't already. olddatsuns.com has a rundown on all the L series heads and their specs. Maybe datzenmike can chime in too.

[datzenmike]

1. This is my 1st head swap, I need some tips on best gaskets to use...felpro or ? Do I need that copper gasket sealer?

 

Use an L20B head gasket to fit the larger U67 combustion chamber. An L16 gasket would be smaller and exposed to too much heat.

 

 

2. Do I need new head bolts?

 

No. Head bolts are completely reusable as long as they are not damaged.

 

 

3. What kind of power gains can I expect?

 

None, possibly a slight loss. But it will run ok. The compression will drop from 8.58 down to 7.72 so not even one point difference. You may loose 5% power I'm guessing. You probably can advance your timing slightly with this compression drop.

 

4. I plan to use my wagon as a DD.

 

I don't see a question.

 

5. What else do I need to know?

 

The U67 head does not have holes for the coolant passages in your L16 intake. These are essential to good running. Just put the new L16 manifold gasket up to the head and drill 1/2" holes where they are needed.

[wagoon]

Kind of sounds like the U67 is a waste of time and I'm better off taking all the rust from the manifold and just changing my exh/intake gaskets. Am I right? Whats the be way to get off a broken exhaust bolt?

[datzenmike]

Best to leave the manifolds in place and fix the broken thermostat bolts.

 

 

Have you removed any of the manifolds yet?

[banzai510(hainz)]

I dont think youll loose power putting a U67 head on there. it has bigger ports and you could match port the intake.

however swapping a head is a bit of work and if you never done it before it could be a big issue.

 

if it were me I would find a whole WORKING stat housing that is already together and just bolt to to the head.

[H5WAGON]

When removing the thermostat housing, you could have another bolt break. The one closest to the carb, tends to get rusty. The back side if it is expose to coolant in water passage.

 

Please post a pic of your mess you have going on.

[DISLEXICDIME]

u67+l16= around 7.1.1 compression  if i per jason grey's specs if  remember right .

[datzenmike]

3. What kind of power gains can I expect?

 

None, possibly a slight loss. But it will run ok. The compression will drop from 8.58 down to 7.72 so not even one point difference. You may loose 5% power I'm guessing. You probably can advance your timing slightly with this compression drop.

 

Stock L16 with 38.5cc open chamber 210 head replaced with 45.2 open chamber U67 head with crushed gasket thickness of 1.2mm

[DISLEXICDIME]

that will teach me to not read all the posts first . lol

[datzenmike]

lultz

[wagoon]

Just need to scrape and loosen intake, and exhaust.

The donor head U67, I also have been dreaming KA24.

[banzai510(hainz)]

I wouldnt even swap the head,so no need to loosen the intake exahaust

 

just swap the housing and hope the exhaust dont leak where the bolt broke and just run it till you have more time and resources ans extra parts

[datzenmike]

This.

[wagoon]

Looking outside the box...yer right Hainz, just thermostat housing and call it a day?

 

Is it good to use Blue RTV on the housing?

 

Temp switch...do I use teflon tape?

[banzai510(hainz)]

I would leave the temp switch on from the other housing depend on what housing you have as there were variations of outlets ect...

 

The temp sender trying to remove them? As most break off also or crack the housing .

I have used teflon tape on new units and seem to work

[datzenmike]

Trace the housing on some cereal box and cut out. Go to the dolla store and get a hole punch for the bolt holes. If you own a Datsun you need a hole punch.

 

RTV was invented for chevy owners and their shitty fitting parts. Datsun parts are tighter tolerance and it will squish out into the cooling system. Next the little lumps block the rad cores.

[banzai510(hainz)]

O rileys can get those gaskets if needed

stat to head gasket look under felpro and enter your vehicle and a SKU number should come up for datsun gaskets or make them like mike says.

[wagoon]

Alright already...that was a simple task. I guess I just hate it when rusty bolts break and cannot find an immediate solution. Problem solved. Replaced with u67 thermostat, left the old temp switch in, new gaskets in, torqued to 10lbs and called it a day. Now time to save up for the motor.

[Jayden71]

Just for reference, I am currently running a U67 head on my L16. I have a weber and a Offenhauser intake. I did not notice a loss in  power. The engine does run a little cooler now that it can breathe better. Yes the compression dropped but I really like the way she runs. Also of note, I really don't drive my 521 too much and I am not out to see how much power I can get out of her. Just happy she purrs down the road at 60mph.

[wagoon]

Now I have the temp switch sender plugged in but I took it for a test spin and the gauge went pretty high approx 3/4 hot. I noticed the top of the valve cover of the motor was hot but the top of the radiator/ and hose was still cool. Whats going on with the gauge, is it bad?

 

Might I add that the old thermostat housing had an outlet that came out with a small hose that connected to the intake manifold. I had chopped it of because my U67 thermostat housing did not have that small outlet so now it bypasses the housing and straight from the left side of the block to the intake manifold. Hope that makes sense.

[banzai510(hainz)]

Might I add that the old thermostat housing had an outlet that came out with a small hose that connected to the intake manifold

 

this is the heated manifold line.

Most U67 dont have this as the heads did not have a water passage.

 

You might have to open the stat up and drill a bypass hole say 1/8 so it lets the air out. But its a guess on my part ,buy has worked for me. maybe put a new state in there with a hole?

Hope this dont break also.

[Z-train]

You wanna sell or trade that U-67 head?

[Z-train]

Just for reference, I am currently running a U67 head on my L16. I have a weber and a Offenhauser intake. I did not notice a loss in  power. The engine does run a little cooler now that it can breathe better.

You did lose power.And the cooler temps resulted from a problem being "fixed" not the U-67 head being installed.And down low in the rpm band,it actually breathes worse.