View Poll Results: When will it it blow?
Next time you drive it/any minute now!
5
20.00%
First track day
1
4.00%
In another 5,000 miles
5
20.00%
More than 20,000 miles
9
36.00%
Forever as long as you learn how to shift!
5
20.00%
Voters: 25. You may not vote on this poll
So how long will my stock NC motor last
12-14-2009, 09:37 PM
#21
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I hope you guys can elaborate on this some. Last time I built a motor I went through boring and honing, and from what I did then the big issue was the ring to bore gap...where you want it a certain amount for boost/vs nitrous/vs NA; with forged pistons requiring a slightly larger one since they expand with heat more than cast. I was hoping to avoid a machine shop altogether since I can do all of the assembly here. Since its a sleeved block the goal was to leave the bores intact with whatever coating it came with from the factory. That and I don't know of any machine shops with a torque plate for this motor locally so I have to weigh the pros/cons of just going with a low mileage block and not machining vs spending an extra 500 bucks for the machine work that might be questionable...
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12-14-2009, 09:53 PM
#22
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I hope you guys can elaborate on this some. Last time I built a motor I went through boring and honing, and from what I did then the big issue was the ring to bore gap...where you want it a certain amount for boost/vs nitrous/vs NA; with forged pistons requiring a slightly larger one since they expand with heat more than cast. I was hoping to avoid a machine shop altogether since I can do all of the assembly here. Since its a sleeved block the goal was to leave the bores intact with whatever coating it came with from the factory. That and I don't know of any machine shops with a torque plate for this motor locally so I have to weigh the pros/cons of just going with a low mileage block and not machining vs spending an extra 500 bucks for the machine work that might be questionable...
Lets say you get forged pistons. Lets say your clearance now is something like .0015 between the cylinder and the piston. Forged pistons almost always require more clearance. So if you need .004" clearance, you have to hone/bore/whatever you want to do to enlarge that cylinder. Then it has to have a certain surface finish that will be ideal for the type of rings you have.
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12-14-2009, 10:20 PM
#24
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Maybe we should do an official pool to see 
as some of you saw in the dyno day thread it put out 283 whp on my "conservative" tune with peak timing of like 13 degrees at 7k.
Since then I dropped it down two more degrees and added a bit more fuel without any noticeable loss in power (11-11.5 AFR), and put in two baffles in the muffler to slow down the boost creep (jumped to 14 psi at 20 degrees last week!).
Currently running 8psi to 4k, 10 psi 4-7k rpm. Peak torque is ~230 or so vs 140 stock.
For those who don't know the 06-08 NC motor has 10.8:1 compression, all cast internals. Motor was overrevved at least twice at the track with a 4 to 2 money shift last year prior to boost. (hit the same damn bump at the etown straight right at the 3-4 shift point!) Compression numbers were 210 dead even on all 4 just prior to turbo.
It's my second car so I only drive it to beat the crap out of it...in other words, if it was human it would be tiger woods. It has a few auto-x events on it, some 'local' drifting, and will see a track day or two again next year, some official drift events, and maybe hill climbs. About 41k on the car, 4k with boost.
At this point I'm torn--do I build the motor before it blows or let it die a natural death? I know honda guys run their hi comp cast motors to 10+ psi with few issues when actually tuned, with the duratec focus/mz3 crowd usually blowing trannys first, but they supposedly only go to 260 hp or so.
I'm thinking to just ride it till it blows since they are so damn common and cheap. Then I can just pick up a low mileage block and get forged internals and not have to worry about boring and honing. Poll only goes to 20k because that would take two years for me to do if not more and by then I'll definitely be building it.
This is the car...
as some of you saw in the dyno day thread it put out 283 whp on my "conservative" tune with peak timing of like 13 degrees at 7k.
Since then I dropped it down two more degrees and added a bit more fuel without any noticeable loss in power (11-11.5 AFR), and put in two baffles in the muffler to slow down the boost creep (jumped to 14 psi at 20 degrees last week!).
Currently running 8psi to 4k, 10 psi 4-7k rpm. Peak torque is ~230 or so vs 140 stock.
For those who don't know the 06-08 NC motor has 10.8:1 compression, all cast internals. Motor was overrevved at least twice at the track with a 4 to 2 money shift last year prior to boost. (hit the same damn bump at the etown straight right at the 3-4 shift point!) Compression numbers were 210 dead even on all 4 just prior to turbo.
It's my second car so I only drive it to beat the crap out of it...in other words, if it was human it would be tiger woods. It has a few auto-x events on it, some 'local' drifting, and will see a track day or two again next year, some official drift events, and maybe hill climbs. About 41k on the car, 4k with boost.
At this point I'm torn--do I build the motor before it blows or let it die a natural death? I know honda guys run their hi comp cast motors to 10+ psi with few issues when actually tuned, with the duratec focus/mz3 crowd usually blowing trannys first, but they supposedly only go to 260 hp or so.
I'm thinking to just ride it till it blows since they are so damn common and cheap. Then I can just pick up a low mileage block and get forged internals and not have to worry about boring and honing. Poll only goes to 20k because that would take two years for me to do if not more and by then I'll definitely be building it.
This is the car...
Awesome dyno #s! I may have to get a PHRT NC in the future.
I think it should last at least thirty miles more.
If I were you, and I have been in some regards (I ran 12 pounds on my '03 w/ 10:1 factory pistons), I would buy another motor, build it, and then swap out your stock motor while it's still alive. If your stocker has good compression still, you can sell it and pay off your build costs
Please show us 1.8'ers the potential of that engine and make even bigger numbers. I have not heard of anyone making big power on the NC yet!
Last edited by Faeflora; 12-15-2009 at 08:44 AM.
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12-14-2009, 10:30 PM
#26
Either way Mann, take Savington's advice. There is no such thing as a built motor without a trip to a machine shop. No matter how much of a pain in the *** it may be, it is a necessity. If you do it right the first time, you will be very happy with the results.
I know what it is like to cheap out on something, and regret like hell that I did not take the step that deep down I knew was the right step. Or worse, when I did not take the advice of someone who had much more experience than me.
I know what it is like to cheap out on something, and regret like hell that I did not take the step that deep down I knew was the right step. Or worse, when I did not take the advice of someone who had much more experience than me.
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12-14-2009, 10:52 PM
#28
Guys. You buy rings for a bore size. There is nothing wrong with using the standard bore to fit new pistons/rings into. ASSUMING it is still within tolerances. You then simply hone it and gap the rings and you are done.
And to the Martinez guy... it isn't about the right honing stones. It is typically about hone angles for different rings/ring materials. Typically set by the ring supplier.
There is so much cross talk and people misunderstanding each other here its silly.
And to the Martinez guy... it isn't about the right honing stones. It is typically about hone angles for different rings/ring materials. Typically set by the ring supplier.
There is so much cross talk and people misunderstanding each other here its silly.
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12-14-2009, 11:08 PM
#29
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And the sky is blue. Doesn't change the fact that he was talking about wall clearance.
Yeah, you can hone a cylinder to take new rings and drop a set of forged pistons in, but good luck finding aftermarket forged pistons that are sized exactly correctly to your OEM bores.
where you want it a certain amount for boost/vs nitrous/vs NA; with forged pistons requiring a slightly larger one since they expand with heat more than cast.
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12-14-2009, 11:15 PM
#30
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crap I can't remember what the hell I was talking about, I just remember choosing some damn number to suit the forged pistons and turbo, it might very well have been ring gap as they would expand with the piston and ultimately dictate the ring to wall clearance....whatever
in any case I still think I can just do a rough hone job at home on a low mileage block, and as long as the ring gap is fine it should work and they ought to seal just fine.
I just can't see the point in spending cash on a half assed machine job as long as the numbers all check out. And hell if a 10k mile block has numbers out of spec then I think I'm probably screwed on the deal anyway.
in any case I still think I can just do a rough hone job at home on a low mileage block, and as long as the ring gap is fine it should work and they ought to seal just fine.
I just can't see the point in spending cash on a half assed machine job as long as the numbers all check out. And hell if a 10k mile block has numbers out of spec then I think I'm probably screwed on the deal anyway.
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12-14-2009, 11:23 PM
#31
Is it really that bad if you do not have a torque plate? Torque plates have not been around that long, and many a high performance engine has been built without one.
Correct me if I am wrong on this guys, but I think that having a fresh bore is the way to go if you are taking the time to do a whole new engine, even without the luxury of a torque plate.
Correct me if I am wrong on this guys, but I think that having a fresh bore is the way to go if you are taking the time to do a whole new engine, even without the luxury of a torque plate.
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12-14-2009, 11:52 PM
#33
Just pony up and buy a Cosworth longblock with cams and valvetrain. Then you don't have to worry about machine work etc. Of course, you are going to be working a lot of overtime to buy back your soul but who cares right?
My subaru cossie longblock is so awesome I barely miss my soul.
My subaru cossie longblock is so awesome I barely miss my soul.
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12-15-2009, 03:29 PM
#34
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This is terrible, terrible, awful logic. Built motors are bored to match the set of pistons you supply the machinist, and then they are honed to match the rings. (something about the material or design, not exactly sure what, but my machine shop wanted a set of rings both times.) Do not think for a single second that you can buy forged internals and shove them in a low-mileage block without machine work.
Stephanie
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12-15-2009, 06:07 PM
#36
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that's interesting Stephanie that's probably the same thing I read at some point on the mz3/focus boards when researching this as I have no idea where else I could have heard it.
So then the question then comes down to honing, can I just use my drill mounted hone at home to lay down a crosshatch or will that screw up the bore size, or do I even need to do it all if the block is less than 20k miles old...
So then the question then comes down to honing, can I just use my drill mounted hone at home to lay down a crosshatch or will that screw up the bore size, or do I even need to do it all if the block is less than 20k miles old...
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12-15-2009, 06:14 PM
#37
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You still need to hone, though. If you know what you're doing, it's a garage job, but you still need to tear the motor down to get the pistons in.
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12-15-2009, 07:23 PM
#38
I'll admit that is pretty slick. My only question would be the consistency between bore to bore, motor to motor, on Mazda's part. If a batch of motors came out .002-.003 large, that's all it takes to wreak havoc.
You still need to hone, though. If you know what you're doing, it's a garage job, but you still need to tear the motor down to get the pistons in.
You still need to hone, though. If you know what you're doing, it's a garage job, but you still need to tear the motor down to get the pistons in.
I think we will both agree though that even with the clearance built into the piston, it would be dumb not to mic all bores and pistons to verify the clearance you will actually net.
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