how do i put in a block guard?
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Honda-Tech Member
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From: Local Ice cream man / bay area 510/925
how do i put in a block guard?
i want to BOOST mt B20, but never done a block guard b4....anyone seen a how too? is it just as easy as changing the head gasket? does it have to go to a machine shop? can it go in crooked? just some questions.....pics would help me understand it to....i dont have anyone around in my area that would know....thanks...i asked alot
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From: South Sound, WA, USA
This is something you have a professional shop do. I would never try this yourself if you are asking how to do it.. I highly doubt you will be able to.
This article in SCC talks a little about the different ways to have one installed. Obviously the more expensive way is your best option.
http://www.sportcompactcarweb.....html
About half way down the article...
All is not lost, though. To solve this problem, racers have been using several approaches. The cheapest and easiest involves installing a block guard. A block guard, available from Nu-Forms and STR, among others, is a CNC-machined piece of aluminum that is tapped into the top of the block deck, filling all the voids between the water jacket and the free-standing cylinders. The block guard is supposed to support the cylinders and keep them from moving around or cracking. The block guard has holes drilled in it so cooling water can flow through it to the head.
The block guard is highly regarded by some people and sworn at by others. I tend to be in the swearing category. For one, there are a lot of misconceptions of how to install a block guard, due to some misleading articles in the enthusiast press. One article showed a block guard being installed in a completely assembled, still-in-the-car engine merely by tapping it in place with a hammer. This sort of installation greatly distorts the upper part of the cylinder bore by up to several thousands of an inch, causing poor ring seal at best and seizing at worst. One very well known Quick Class competitor had his block and cylinders crack right at the point where the block guard was installed, probably because of the cylinder distortion and the huge stress riser the block guard created. There were also signs of seizure on both the piston and the cylinder wall in the area of the block guard.
If a block guard is to be used, the best way to install it would be the way JG and other engine builders do it. They hand fit the block guard to the block for a close fit before any other machining operations are done to the block. The block guard is then TIG welded in place. Skip welding is used to minimize distortion to the rest of the block. After welding, the builder machines the deck of the block flat, then the final bore machining is done. In my opinion, this is the correct way for a block guard to be used. At the very minimum, the block's bores need to be machined after the block guard is installed. Again, in my opinion, a block guard should never be installed in an assembled engine that is sitting in a car with its head off; instead, it should only be installed when building a new engine and the bore honing can be done after the block guard is installed.
This article in SCC talks a little about the different ways to have one installed. Obviously the more expensive way is your best option.
http://www.sportcompactcarweb.....html
About half way down the article...
All is not lost, though. To solve this problem, racers have been using several approaches. The cheapest and easiest involves installing a block guard. A block guard, available from Nu-Forms and STR, among others, is a CNC-machined piece of aluminum that is tapped into the top of the block deck, filling all the voids between the water jacket and the free-standing cylinders. The block guard is supposed to support the cylinders and keep them from moving around or cracking. The block guard has holes drilled in it so cooling water can flow through it to the head.
The block guard is highly regarded by some people and sworn at by others. I tend to be in the swearing category. For one, there are a lot of misconceptions of how to install a block guard, due to some misleading articles in the enthusiast press. One article showed a block guard being installed in a completely assembled, still-in-the-car engine merely by tapping it in place with a hammer. This sort of installation greatly distorts the upper part of the cylinder bore by up to several thousands of an inch, causing poor ring seal at best and seizing at worst. One very well known Quick Class competitor had his block and cylinders crack right at the point where the block guard was installed, probably because of the cylinder distortion and the huge stress riser the block guard created. There were also signs of seizure on both the piston and the cylinder wall in the area of the block guard.
If a block guard is to be used, the best way to install it would be the way JG and other engine builders do it. They hand fit the block guard to the block for a close fit before any other machining operations are done to the block. The block guard is then TIG welded in place. Skip welding is used to minimize distortion to the rest of the block. After welding, the builder machines the deck of the block flat, then the final bore machining is done. In my opinion, this is the correct way for a block guard to be used. At the very minimum, the block's bores need to be machined after the block guard is installed. Again, in my opinion, a block guard should never be installed in an assembled engine that is sitting in a car with its head off; instead, it should only be installed when building a new engine and the bore honing can be done after the block guard is installed.
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