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[I'm BLUE]

Mike just saw your edit, 60lbs really on the Headbolts? FSM,Haynes (which I think steals info from the FSM), and OldDatsuns.com lists 43lbs... Maybe that could do something.

 

Correct

[Laecaon]

Correct

Correct as in torque to 60lbs? Just want to make sure...

[ggzilla]

L18 spec is 47-61 ft.lb.

 

L16 may have different torque specs for different years/grade of head bolts (like other Datsun engines0.

[wayno]

Not using the block with the snapped Headbolt. Used the block that was in my goon (only ditched it cuz I had an L18), I had no problems with the block while in my car.

 

I agree about the leak, but one can hope...

 

There is a coolant line from the intake to the coolant inlet (into waterpump) the side that the lower radiator plugs into.

 

 

Ok, there is a coolant line going from the intake to the lower radiator hose connection housing, but is there a tee in that hose in the middle that goes to the thremostat housing, I made the mistake of using a L16 thermostat housing without that hose, and for no reason my engine overheated, even though the temp gauge looked good till that moment. I have been lead to beleave that the L16 thermostats had a hole in them which in theory would replace that hose going to the thermostat housing. You need that hose, it makes the thermostat work properly.

[Laecaon]

Hmm, there is no coolant line from the thermostat housing... Never seen one of those. My L18, was L16, has no coolant lines from the thermostat or intake,I have an offenhauser intake on it whick had no coolant lines in it, and it has no cooling issues, even in 90 degree weather. I have two extra lower thermostat housings, one with no extra ports on it and another with a port with a plug in it. Really I just thought of using that port as an extra tempature sender for my L18 with an after market gauge. Hmm.

[Laecaon]

Oh would you look at that, found the issue... or at least something not helping. One of the manifold studs (front, exhuast/intake combo) decided to break on us. Didnt tighted that much. That of course means massive amounts of coolant loss out of the intake passage at the head. and blah...

 

Time to fix that.

[banzai510(hainz)]

L16s are about 40-45 pounds on that I do mine.

last on was about(This summer) or close to 45pounds on my L16 521 I did

 

280zx bolts are about 60/65 pounds

[HRH]

The old Haynes book I have for L20bs (70's era) says tighten the head bolts 20-47-61ish, like Mike said. I can't imagine it being any different for the L16s. Bolts are the same size to my knowledge. Lack of torque could certainly cause a head gasket leak. I'd take it off, throw a new gasket on and torque in three part sequence. 20 the first torquing, 47 the next, up to 61. I've never had an issue with a Fel Pro head gasket on an L motor. 40 final is definitely way too loose.

[wayno]

This is the hose I am talking about, I used the L16 thermostat housing and my engine overheated for no reason, I remember while I was on the hiway my temp was all over the place, but it didn't overheat except that once, then I put this proper housing on and have had no trouble since.

http://community.ratsun.net/topic/35311-jons-521-l20b-5-speeed/page__view__findpost__p__569320

[Laecaon]

That one with the spring? On his truck its going to the intake manifold. My goon has a plug there.

[wayno]

All I can say is I had big temp issues till I put the proper thermostat housing back on it and connected that hose to it. I thought it would be clean without it, but it wasn't worth smoking the new LZ23 engine over. I figure I don't show the truck anyway, so it don't have to be clean, it just needs to function properly.

[Laecaon]

Sounds good. I think we will try the "drill a hole in thermostat test". Sounds like hainz has success with that and is cheaper than getting more piping.

[wayno]

Sounds good. I think we will try the "drill a hole in thermostat test". Sounds like hainz has success with that and is cheaper than getting more piping.

 

I heard the L16 thermostats already had the hole in them, that is what I heard though, don't know for sure, never had to change one in a L16.

[Laecaon]

Well this one did, but it looks like if there is remotely any pressure behind the plate (as in the direction of flow making pressure) it would close the hole...

[H5WAGON]

If t-stat is good radiator clean , proper coolant, should be fine without extra piping....I have no extra water line....I do run a hose from intake manifold to t-stat housing. L20...510 L16 radiator....not sure if t-stat has a hole or not.

 

Even when I ran straight water, when I first got it on the road, it ran cool.

[ggzilla]

In the later 70s, Nissan started fitting thermostats with a 'jiggle valve'. This has a small hole (which should be installed with the hole at the top), and in the hole is a small piece of metal. As it vibrates, it lets air out and coolant in.

 

But that won't necessarily replace the exterior hose, should your engine require it.

[Laecaon]

So started working on the 521 again today. Tried welding a nut to the broken stud. It sheared flush with the head then. So tried again, and kept braking the weld. So we weighed the options of trying to drill the stud and tap it, or trying an easyout, or just helicoil it.. and chose to just use another head and use new gaskets, same price but no worries of braking an easyout or something.

 

Well then we pulled the head and discovered cylinder 1 blew the head gasket. And that the oil was a nice milk color! so 3rd oil change in a month for this truck.

 

So now we are prepping the other head, and waiting for some gaskets.

 

 

Also does anyone know where to find the head guides (the sleeve like things that go into the block to guide the head on)? Or if we might be able to use something else? We are missing one.

[motavated]

dealer

[HRH]

I have a bunch of them from torn down motors. Any pipe the same size will do. We used to sell locating dowels at NAPA, I think we still do. Have them look in the Balkamp book under head dowels I think. May be able to get them new. Bring a sample or measure beforehand.

[Laecaon]

So Success! I think at least so far.

 

So cleaned up the other head today, new valve stem seals on it. So paint to make it look fresh again. Cleaned up all of the surfaces with a razor blade then some degreaser. Went to put the head on. Everything torqued to 20lbs. Then stepped to 35. Very last bolt to torque in that run suddenly stripped. Oh awesome, well at least we were prepared. Head came off, tapped the hole, helicoiled it. So since we only got to 35lbs on the bolts I figured the headgasket would be fine to go to 45lbs. So then did the steps up to 45lbs. Gonna run it for a few days and then retorque it again, also do another valve adjust since it then had some time to run and settle a bit. Get everything back together. fill the fluids. And we need to jump it since it died trying to get it start last week when everything went wrong, and well other problems which I will get to in a bit.

 

So we jump the truck and it sounds nice and even, maybe a slight valve tick. Find 1 coolant leak out of a heater hose, fix that (just moved the clamp to a new spot and tightened it). Go take it for a test run. Everything sounds great, though I think we need to jet his carb better(I think its currently over jetted, probably would run great on an L18...).

 

So we kill the truck. Then go to start it again and it wont even turn over... Now it will only start with a jump. But since it doesnt die right away after a jump, and that about a month ago we voltage checked it at idle to be about 14.6V, alternator seems fine. We are guessing the battery is dead since it has no power to start, but is fine once it running.

 

So I would call today a success, with just another problem that time creates. Battery has a sticker that says 7/08, and says "ECONOPOWER!" like its a good thing... Makes me think it was a bad battery to start.

[banzai510(hainz)]

14.6 at idle is a little high. what does it do when you rev up the motor?

does it load down when you put the lights or heater on . If it does then its OK

If it Doesnt and maintains the SAME or higher when revd up then the volt reg is most likely bad which in turn can cook the battery and evap orate the water out thus making the batter look bad. Ck to see if its low on water.

[Rustina 510]

Pics.

[ggzilla]

14.6 volts is within specs. The voltage varies with the temperature.

[Laecaon]

Ok well just got a call, he found a multimeter. Now it is only reading at 12.6 volts. As for dash lights coming on, I want to shoot the PO for the hack wiring job on that truck. There is house wiring under the hood...

 

So now need to check the voltage regulator.

 

It will get sorted. The truck is now able to start on its own, but that is with a fresh battery... Yea he simply bought a new battery without doing any actual tests :blink:

[DRIVEN]

I've got a good regulator (not pictured) from my wagon along with a bunch of other random 521 switches and relays if you guys are interested.