MitsuStyle - HG install techniques

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HG install techniques

I've heard some things about certain sprays and such when installing the HG, could anyone give me the quick summary of whats up.

Re: HG install techniques

That and make sure the two surfaces that the HG is going inbetween are perfectly flat and have no defects. Also make sure that both surfaces are very clean.

I am not sure if you want opinions on the HG itself or the whole install or replacement of one. I guess this thread will be useful be either way.

CRAIG

Re: HG install techniques

So from what I understand, the whole purpose of coppy spray is to simply provide a supplementary adhesive force between the head and the block. This then allows you to simply run greater intake manifold pressure with a decrease change of blowing your headgasket. Couple this with a nice set of ARPs and you'll have a hell of a seal. What I don't understand is why is the the coppy spray necessary when people all over are running stock Mitsu headgaskets, no spray, a set of ARPs, and pretty decent boost pressures and not having problems; what am I missing here? Am I not correct with my above information?

Re: HG install techniques

Seems as if copper spray is just cheap insurance. I don't see any reason to not use it.

Re: HG install techniques

Quote:

Originally Posted by Matt D.

Seems as if copper spray is just cheap insurance. I don't see any reason to not use it.

Exactly, I sprayed mine just for this reason. I have accidentally run 30+ psi on a stock mitsu HG with ARP's and it has held just dandy(boost controller issues). I like to think that somewhere the copper spray may have had a part in that.

Re: HG install techniques

Since I'm new to copper spray, this is just a guess, but I wouldn't say its the adhesive qualities of the copper spray, but the fact copper is soft and can fill in minor imperfections that could cause leaks or failure

Re: HG install techniques

The spray is mainly used to fill in the imperfections in the head and block. If they are left open then air can start to work its way through. The copper spray blocks that. It also has the sticking capabilities too. Nash nearly held 40 psi on a copper sprayed stocker. It did hold 35psi with ARP's.

Re: HG install techniques

First, the copper spray is ONLY required when using the OEM Multi-layered Steel (MLS) head gasket. I have never used copper spray on any sandwich style gasket and never had any issues. I would def. recc. for most street cars to run an OEM headgasket (Or Victor) sandwich style gasket (Do not use Fel-Pro), with ARP head studs. Make sure both the block and head surfaces are clean and flat. This combo has been plenty good for many 10 and 11-sec cars.

Also remember that a headgasket is also a fuse. I'd rather blow a headgasket than melt a piston, etc. Going with a MLS gasket, ARPs, copper spray or even a copper headgasket and o-ring'd block and heads is nice, but not necc. for most cars. And while it will hold more before it blows, will your bottom-end hold up to the extra capacity? Kind of like running a ACT 2900 with a 6-puck clutch. While it will hold much more than a 2600 with a street disc, Is your drivetrain ready for it?

Wiz

Re: HG install techniques

Most people don't have a freshly prepped head and block, that is where the copper spray can help. It definately doesn't hurt. It can help fill in any imperfections in the head/block they may have.

Re: HG install techniques

That's what a gasket is for. It conforms to the irregularities and makes a seal. I have never used copper spray on anything other than MLS gaskets. As for a freshly prepped black and head.....you simply have to have it cleaned of any old gasket material. If you have never overheated the motor, then your surface are probably flat enough to seal tightly. I'm not saying you can't use copper spray....it's just not required. Kinda of like using silicone along with your valve cover gaskets. Which, I also do not recc. Ever seen what silicone does in oil? Nothing. It just clogs up the pickup screen and lowers your oil pressure. Seen it a lot on SBCs.

Wiz

Re: HG install techniques

Wiz, are you the west branch of HORT? Noone is saying that you have to do it. Will he be fine without copper spray? Probably. Will it be even better with copper spray? Probably. If the gasket doesn't get compressed in a gouge/scratch then it will have a weak spot there. The copper spray will help in that case. Personally I don't use it most of the time. I have lately on the silver car, but I don't on my daily driver.

Re: HG install techniques

How do you check for flatness?

Re: HG install techniques

Khadcar what are your car's modifications? Just what is listed in your signature?

Re: HG install techniques

The proper way to check for flatness is to put the head on a surface plate.

Re: HG install techniques

Quote:

Originally Posted by JET

The proper way to check for flatness is to put the head on a surface plate.

Or a certified straight edge as a minimum with feeler gauges.

Re: HG install techniques

Yeah, that will give you one dimension, a surface plate gives you two dimensions. The surface plate shows warping better than a straight edge does.

Re: HG install techniques

Ladies here is some good FYI information from headgaskets.com:

Quote:

The purpose of the head gasket is more than just to create a seal between head and the deck of the block. It acts as

1) a guide for coolant flow between the block and the head and

2) to promote heat transfer between them.

The head itself is also a conduit for coolant transfer to the radiator. Most older sportscars use gaskets that are made from a sandwich of very thin copper, a thicker fiber layer (typically asbestos laden) and thin steel. This gasket design makes it difficult to personally customize for racing applications and is inherently weak. It is also hazardous to your health if broken and the fibers are aerosolized and inhaled.

Heat is produced by the engine almost entirely at the combustion chamber. Coolant flows from the radiator to the block where it is pre-heated before it goes to the head where the temperatures are the greatest. The coolant then flows through the head to the radiator where it looses heat. Water is the heat sink of choice since it has the highest specific heat capacity.

In order for the coolant to be functionally efficient it needs to move in-mass from the rear of the head forward. Most engines have coolant holes in the gasket spaced from one end to the other. These gaskets allow the coolant to percolate through to the head less optimally. Generally, there are smaller coolant holes in the gasket place forward which are needed primarily for gaseous escape routes and less so for cooling purposes. Since racing engines produce more heat it would seem intuitive that the flow through the gasket be channeled to maximize cooling efficiency by having more of the coolant flow through the rear of the head. It should also be stated that the flow of the coolant has to be such that there is an adequate dwell time within the head to adequetly absorb heat. Additionally, the coolant should be free of any insulating contaminants such as air (in the form of micro-bubbles) that would preclude ideal heat conductance. Engines like to run efficiently at an optimal temperature typically above 180F but less than 220F. Running an engine hard prior to proper temperature is not good.

Torquing:

This can be a problem at times. It is critical that the fasteners you are using are better than "nominal". Use the best you can afford. A key factor that is not considered often is that the fasteners not only hold down the head but also PULL-UP on the block. The torquing procedure works in two locations

1) on the head side and the

2) block side.

The threads within the block maybe weak. Some spots within the block are weaker than others -depending upon how much metal is around them. When these weaker spots are stressed they "give" more than other areas. This can actually deform the block and dimple the deck surface a bit. This under-appreciated problem can create sealing dillemas. One method used to mitigate against this effect is to study each motor and relieve (chamfer) the holes where the fastener enters the block.

Bolt loading:

When a bolt is tightened a large portion of the tightening torque is used to overcome the resistance of the threads. Only about 20% (at most) of the torque is transmitted in tension to the fastener. An important factor in this is the surface finish of the threads. Some aftermarket fastener manufatures coat the fastener with a laquer based material that requires a high quality moly lubricant to be placed on the threads for proper torquing. If this is not done improper tightening will occurr. If you wish to use an oil on the threads for torquing -you need to remove this coating with a wire brush.

EXCESSIVE bolt loading will cause problems. Many backyard mecanics think that if 50 Ft. lbs of torque is good then 60 is better. In fact dynomometer testing has shown that less is best in most instances. Indeed extra horsepower maybe gotten by being "torque frugal". Why??? The more torque that is applied onto the block the more chance of distortion. This distortion is usually seen at the weakest places at the narrowes point of the bore and at the top of the cylinder. At the top of the cylinder where the compression pressures are always greatest any excess distortion will nullify any benefit of that extra clamping force. Blow-by of gasses will cause premature gasket burn through and less horsepower. "Less maybe best".

SURFACE FINISH:

The ideal situation is to have a finish on the flange surfaces (head and block deck) as smooth as possible. In older engines the typical surface finish was make buy using a fly cutter on a mill that created symmetric arcing lines. This finish was good for composit gaskets. The idea being that there was some imperfection in the surface so that it would "grab and hold' the gasket in place. Modern motors have bi-metal engines typically. Cast iron blocks and aluminum heads. These have different heat characteristics and therefore stretch at different rates. If these surfaces had the typical finish of yesteryear the gasket would fail due to shearing effects. Newer motors have very smooth finishes -in fact most machine shops don't have (but will have to eventually) the equipment to produce this finish.

When using copper gaskets in any motor ask the machine shop to get an RA (roughness average in Microinches) of about 60 for cast iron heads and blocks and closer to 40 for aluminum.

Re: HG install techniques

Quote:

Originally Posted by JET

Yeah, that will give you one dimension, a surface plate gives you two dimensions. The surface plate shows warping better than a straight edge does.

Agreed ;)

Re: HG install techniques

Jakey no, I have quite a bit more than intake and exhuast nothing crazy though, I am not planning on using ARPs because I don't plan on running the engine for that much longer, I just want my car to move and since the HG is the only thing stopping that I am going to replace it. The car was overheated so I guess I'll have to have flatness checked somewhere.