namura
- Thread starter lowkhalbalr
- Start date
don't know what the hell that means. but they are really close to a stock piston if not exactly the same
If you keep a good healthy check on the engine and change out your piston before it completely fails, there's no problem running a cast piston.
I didn't want it to sound like cast pistons are the plague, simply that I won't recommend people install one because MOST people don't do a monthly compression check and re-ring twice a year. That's what it takes to keep a top end "fresh".
An unfresh top end can blow up and a blown up cast piston will crumble into a million billion little round aluminum balls and get into the crank bearings and possibly lodged under the crankshaft against the crankcase and break it requiring you to replace case halves.
I didn't want it to sound like cast pistons are the plague, simply that I won't recommend people install one because MOST people don't do a monthly compression check and re-ring twice a year. That's what it takes to keep a top end "fresh".
An unfresh top end can blow up and a blown up cast piston will crumble into a million billion little round aluminum balls and get into the crank bearings and possibly lodged under the crankshaft against the crankcase and break it requiring you to replace case halves.
yea that sux. just got my blaster a few weeks ago and the guy said the top end was redone recently but u know ppl BS.. i should do a compression check to be safe. btw how DO i do that? 
Amazon.com: Actron CP7828 Professional Compression Tester with Storage Pouch: Automotive
#1 Buy a compression tester
#2 take out the spark plug and turn off the petcock valve
#3 screw the correct adaptor into the head
#4 hold the throttle wide open and kick it until the needle stops moving
#5 repeat several times and take the average of the number (it really shouldn't vary but I always say take the average because it can be off a few PSI from test to test)
130PSI is perfect for a blaster engine, 120 PSI is alright but will need attention eventually, 110 psi really needs a re-ring, less than 100PSI and you need to stop kicking the kick starter and go get the tools to take the top end off right now.
#1 Buy a compression tester
#2 take out the spark plug and turn off the petcock valve
#3 screw the correct adaptor into the head
#4 hold the throttle wide open and kick it until the needle stops moving
#5 repeat several times and take the average of the number (it really shouldn't vary but I always say take the average because it can be off a few PSI from test to test)
130PSI is perfect for a blaster engine, 120 PSI is alright but will need attention eventually, 110 psi really needs a re-ring, less than 100PSI and you need to stop kicking the kick starter and go get the tools to take the top end off right now.
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hmm.. thats pretty pricey but cheap i guess compared to other sites like ebay. damn i gotta get this AND a leakdown tester from awk.. going BROKE! another thing how would i know what size to get for the ring? its stock size but who knows
I just picked up my Actron tester on Amazon. You don't need the $30 one but it's useful if you need it for other projects. My $20 one works fine and if you buy something else small like fuel tubing, you can get free shipping with all of it.
which 1 is the $20 one? kinda on a budget hehe this 1?Amazon.com: Actron CP7803 Vacuum and Fuel Pressure Tester Kit: Automotive
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Blaner
Your Friendly South African Ambassador
Just did a complete rebuild on my '89. Did some research on pistons and found that namura pistons are not cast. They are forged from a solid block of aluminum therefore making them much stronger than a wiesco cast piston.
Blaner
Your Friendly South African Ambassador
Namura pistons are CAST! however they are Hypereutectic cast, with higher silicon content than say a ProX. Eutectic is a geological term used in igneous petrology phase diagrams, ie a graph of how the nature, (liquid, solid or both) and composition change as a result from increasing pressure, x axis and temperature, y axis. so you get a temp and pressure where the rock (or in piston case - aluminium or with silicon added) is liquid. This is called the liquidus. this forms a fluctuating line because as pressure increases, less temp is needed to melt the substance and more heat means less pressure is needed. Now there are two end members in terms of composition, ie silicon is one and aluminium(alloy of sorts) is the other, So below the line where its liquid, it can either crystalize as silicon rich or alumium rich. the EUTECTIC point is the position on the digram where the two crystallising line meet. Hence HYPEREUTECTIC means the piston has a balance i silicon and aluminium whereby the silicon is naturally infused by adjusting the correct pressure and temperature of the molten piston fluid until the desired amount of silicon is crystalised in with the aluminium, in other words they adjust the eutectic point by altering the temp and pressure until they get what they want.
they then rapidly cool the moletn fluid by dropping the pressure and quenching. Things that cool fast crystalise into very fine crystals...thats what you want in a piston!
So there is a bit of thought into this process, they do know what they are doing...
they then rapidly cool the moletn fluid by dropping the pressure and quenching. Things that cool fast crystalise into very fine crystals...thats what you want in a piston!
So there is a bit of thought into this process, they do know what they are doing...
As Colby said I'm runnin one in my little 06 blaster- one tank of fuel so far and still holding up
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