You tighten the bolts down onto the structural beam. This is my guess

 

the bottom of the bolt rests on a support beam INSIDE the head, to further support this area and help it not lift from the block. this bolt does not go all the way to touch the block, that would well destroy everything, lol. it is super hard to get a picture down through that hole to show it to you.

 

not reverse thread. there is no directional rotation in the head, lol. therefore reverse threads would make no difference. the upper nut is just a lock nut to keep it from backing out. plus you will need to seal it in as it is going into a cooling passage. this is basically a permanent mod that would never need to be removed, so you could use some pretty nasty stuff to lock it in.

 

bingo!!!

 

It's not touching the hg. It is just supporting the bottom of the head. It's not touching the cylinder walls either. It's just acting as a brace between the cylinder for the head. It's keeping the thin area between the cylinders down. Here's a pic of the bottom of the head. There's only 2 of them per head.

 

you can also see in the pic from mrc, how this area is the thinnest area for combustion to make it into the cooling system. that is a slit inbetween the cylinders that is a steam crossover.

 

ok, I see now...

 

Yo man pm me with you # I want to talk to you about this...

 

Ok I have a question, I am trying to understand where the loads come from and where they are applied on the head that would cause that section to lift.

Could this be because people building motors are normally going to 0.020 oversize on the cylinder diameter but the head is not being machined to match therefore leaving a small ledge providing a surface to have load on it?

 

it would not matter at all if there was a ledge left on it, the whole combustion dome is what is holding the combustion in, thus the lifting force acts against that. this area between the cylinders is the weakest link. i am trying to come up with a good analogy, hmmmm......

ok, take a high pressure water line, like 10" diameter. put a cap over the end, and just use 4 bolts to hold the cap in a nice semetrical square pattern. now pressurize that water line till you get a leak. where do you think it will leak first? at the areas least supported, directly inbetween the bolts holding the cap down. now what would happen if you put a whole bunch of weight on 2 sides of the cap, they will no longer leak. not sure if that is more confusing, but the idea is the same, lol.
on my car and others, the center cylinder has been the prob. not to say this is across the boards, but there seems to be a pattern. the center cylinder, on both sides of it, is closest to the water passages. more "weight" needs to be put on the sides of this cylinder to help keep the leaking at bay. that is what this mod does. not neccesarily more weight, but a more solid surface less prone to movement.

 

Talk about being slow....I just finally got a grasp of this problem..

So in a nutshell, there is a leak in the head to cylinder mating surface due to the higher pressure from F/I. In turn, the leak is contained within open deck portion of the block which also happens to be the coolant passage. This is what is causing the excessive high pressure in the coolant system forcing all the engine coolant into the overflow bottle..
Is this correct??

Would it be possible to further remedy the problem by o-ringing the head? Essentially, you could just machine a small groove around the perimeter of the combustion chambers on the head equal to the diameter of the cylinder bores, minus a few thousandths. Then just drop in stainless o-rings, your head gasket & torque away. Combined with this mod it should totally eliminate the problem..

 

yup, you are finally up to speed, lol. i personally plan to o-ring my motor. it can only help.

 

Now that you have the Stud and Anti-Spinout Lock Nut issue explained. O-Ring ala Supra will take the sealing issue to a Engine Tear-Down level.

Your Load Head fix is nice because the Head is not removed. And only requires
the Valve cover to be removed.

O-Ringing is a Engine out.

Cheers Amy -

 

yes, this is truely a stroke of luck this can be accomplished with out pulling the heads and only the valve covers. this is as easy as it will ever get for this type of mod.

 

Oz, will this work on the revup heads?

 

OverZealous:

I know the Japan Side of 350Z people will be on your door soon. Get a Patent or Patent Pending.. A few bucks now and If Nissan adds it to the common block - you will score big time.

Sounds Small - Upside Big.

Cheers Amy -

 

i personally have not torn into the rev up motor yet. i could not imagine nissan changing the casting process though.

 

you have a good point. i have a feeling there is a handful of people already on this site searching for this bolt size, lol.
btw, just to help you guys out, if you pull your motor apart to figure out the thread size and pitch, you won't find it local (99% of you atleast) and your car will be down for days, even if you do find it, for shipping. just a warning, so you don't end up with downtime if your car is already running.
will call a patent attorney first thing in the morn.

 

Good for you man yeah do it ... I hate to see someone else claim this mod.

Keep all your notes, copy of this thread, anything that shows when you started working on this mod..

 

Thats f**king awesome Scott! You gotta PM me a link to these threads when you start them lol. I just found this one and its already 4 pages long. You are one sick f**k trying to fit that 6-71 on your Z, but I like it . If anyone could figure it out, its you. I will have to get one of these kits from you for sure! Got anything else coming up that I will want to buy?