lz22 headgasket problems

[Rollover_Red]

ive gone through 3 head gaskets in about 3k miles. it runs great for about 1k miles, then start idling low(then goes to a slight misfire), starts over pressurizing the cooling system, and eats through coolant somewhat quickly. ran fine until a few days ago. 

 

so ive gone through everything and had my block and head inspect multiple times and there are no cracks. 

 

im using arp head studs

 

im using the z22e felpro headgasket(modied for the l16 head), but 2 out of 3 have blown from the stock drilled holes, not the modified ones. 

 

ive used copper gasket on 2 and none on the third.

 

always follow the torque spec/pattern. always retorque after a heat cycle and full cool down.

 

just checked the head studs to make sure they are still to torque spec and they are.

 

the engine has less than 5k miles on it(new pistons, rings, bearings, etc....)

 

the head and block both got resurfaced right before this third one. both were checked for warping and both were fine. 

 

the head was rebuilt about 3k miles ago when i first built this engine(new valves, new valve guides, 3 angle valve job, new valve stem seals)

 

also using a koyorad, 1250cfm electric fan, and 165 degree thermostat.

 

havent done a compression check yet, but from past experiences, this is another blown head gasket. 

 

im running out of patience with this engine. 

 

could too much fuel/ bad cam timing, or bad distributor timing cause this? too much fuel for the cylinder?

 

any other suggestions? its not a crack or else it would run like shit from the start. i always make sure its warm before i start driving.

[kelowg]

Well shit,sorry to hear. so coolant eats hg around coolant ports or what? nissan spec is like 65 ftlbs,right? arp have their own torque specs i think. what bout using coppercoat spray? always use it on mine,never have had hg issues

[datzenmike]

First I would run a much hotter thermostat like 180F at the least. If over heating is a problem, and the reason for the 160F thermostat, then you have too small a rad or plugged. Engines are more efficient when running at proper operating temps. Remember metals expand when heated and that gasket is much tighter squeezed when the head and block expands. 

 

You have an L16 210 head? on a 2.2 liter engine?? That would be 11 to one compression and likely the cause of the blow outs. Get a better quality head gasket for that compression. Sure it's not an open chamber A87 from an L18 that's .... 9.84

[Rollover_Red]

First I would run a much hotter thermostat like 180F at the least. If over heating is a problem, and the reason for the 160F thermostat, then you have too small a rad or plugged. Engines are more efficient when running at proper operating temps. Remember metals expand when heated and that gasket is much tighter squeezed when the head and block expands. 

 

You have an L16 210 head? on a 2.2 liter engine?? That would be 11 to one compression and likely the cause of the blow outs. Get a better quality head gasket for that compression. Sure it's not an open chamber A87 from an L18 that's .... 9.84

 

 

im running a w53 and it lasted the longest with the 165 thermostat. and the radiator is brand new. was thinking about running the nismo head gasket and calling it a day

[datzenmike]

W53 closed would be 9.44 compression. Not that over the top. Make sure the gasket cylinder holes do not extend out over the bores. The 'fire rings' must be between the head and the block or the combustion temps will erode it and fail.

 

But why the 165F???

[wayno]

Is this a used block with a rebuilt L head?

Was the block bored out, what pistons?

[Rollover_Red]

But why the 165F???

 

 

it would tend to overheat with the 195 one(maybe it was 185). it loved the 165 one. never went past the halfway mark until it overheated this one time. 

 

Is this a used block with a rebuilt L head?

Was the block bored out, what pistons?

 

used complete block, z22e all stock rebuilt 3k miles ago. 

[wayno]

OK, what thermostat housing are you using, does it have a bypass hose or is it the L16 thermostat housing?

If you are using the L16 thermostat housing, have you been drilling an 1/8th inch hole in the thermostat itself?

[Rollover_Red]

OK, what thermostat housing are you using, does it have a bypass hose or is it the L16 thermostat housing?

If you are using the L16 thermostat housing, have you been drilling an 1/8th inch hole in the thermostat itself?

l16 housing and no. i just pulled the spark plug on cylinder number 4 and cranked the engine. it shot out some coolant. so its blown again. same cylinder as always. 

 

could the fuel ratio cause the head gasket to break? i might be running too rich. either way, ill be ordering a nismo gasket and trying that out. if it pops again, ill take the engine to my machinist and have him take a look. 

[datzenmike]

Fuel has nothing to do with this.

 

Same cylinder? Check for warp. You said it over heated since the build. Should have checked or re-checked the head the first time it blew. Do it yourself this time, don't take someone else's word for it. Borrow a straight edge and if you can get a 0.003" feeler gauge to slip under anywhere, you have a problem. 

[wayno]

OK, it is hard to understand this, and it takes a while to explain it, but here I go again.

The thermostat is on the outside of the head in it's own thermostat housing, it is cooler out there, so the original thermostats for the L16 came with a hole in them as a bypass, the new thermostats have a jiggle valve in them, it is enough to let the air out of the system, but not enough to act as a bypass, so if you are using an L16 thermostat housing, you need to drill a 1/8th inch hole in the flat part of the thermostat around the outside.

Nissan upgraded the thermostat housing to have a bypass hose, this hose lets a lot of hot water by so it gets to the thermostat, the reason is that if it doesn't have a functioning bypass the coolant inside of the head has to get super hot to get the coolant in the thermostat housing high enough to open the thermostat, all that cold water in the radiator cycles thru and the temp gauge drops way low and the thermostat closes and then the temp starts creeping back up again, finally the water will get hot enough to open the thermostat again and super hot water hits the gauge sensor and it shows very hot again, this happens a lot on the hiway, my gauge was all over the place, after a while the temp inside the head will get really hot once before the thermostat opens and the engine will basically overheat and blow the headgasket, mine only lasted a couple weeks after it overheated before the headgasket went bad.

You either need to drill a hole in the thermostat itself, the bigger the better, or you need to convert over to a L20b thermostat housing and piping that has a bypass, otherwise you will likely keep blowing headgaskets, I know all this because I went thru it myself, but I had a clue, my temp gauge would not hold a steady temp on the hiway, but it overheated on a country road where I was only driving 50mph, what likely happened was that my radiator fluid level got to low from getting hot all the time and it could not recover as it stayed hot that last time. 

[Charlie69]

Great explanation Wayno!

[shacks510]

What wayno said. I thought I had a bad 180 thermostat because the temp would spike way too high as it was warming up, then immediately come back down. So I got a 160 tstat and drilled I think two 1/8" holes, and it never spiked again.

[banzai510(hainz)]

try a nissan gasket.

 

 

too lazy to read everything but if you have flattop pistons in this motor Headgasket failure is more common

 

seen it alot on L20 with flattops and I assume Felpro gaskets

[scooter]

I have seen this temp spike too but I havint had any issues yet. I'll be drilling my thermostat soon.

 

As for the head gasket, pretty sure you the same guy on facebook ratsun. Maybe it's time to get someone else to put it together as you've had no luck. With a fresh decked block and head and studs there's no reason this should be happening. I'm using the Grey yucky composite type shitty head gasket with shit tons of compression and nitrous and not having any head gasket problems at all. Somethings not right.