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Discussion Starter #1
I'm about to start saving for my racing shortblock. Its gonna be a Dart block based 347 turbo motor destined for high 8's

I'm probably gonna get a reputable shop like DSS or keith craft to build it for me, but before I do, I was hoping we could start a discussion on tolerances and assembly practices that go into street motors, and race motors.

Reason I am asking is that I was a race motor, but I want to be able to drive it to the track and back. I need to know what sort of problems I will run into on the street with a motor like this, and what can be avoided as repercussions of how the shortblock was built.
 

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The reason race engines are assembeled with greater tolerances is due to HP equals heat, The greater the HP the greater the heat. The spent energy in a race engine is greater thus parts need more room to expand. As far as assembly goes make certain you measure all tolerances at and prior to assembly as well as everthing needs to be very clean, ie work area and components.
 

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Of course you will be able to drive a motor with eight thou piston to wall clearance, three thou main clearance and 30 thou compression ring gap on the street... but why? Trailers are cheap and you won't kill your motor at the same time. Solid roller springs don't live long lives... not to mention cylinder wall loading, etc.
 

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Discussion Starter #4
n8s_stang said:
Of course you will be able to drive a motor with eight thou piston to wall clearance, three thou main clearance and 30 thou compression ring gap on the street... but why? Trailers are cheap and you won't kill your motor at the same time. Solid roller springs don't live long lives... not to mention cylinder wall loading, etc.
Sounds like you've been doing yer homework nate :D

Yes trailers are cheap and I have a truck and anthony has a truck, but it would be nice to drive around on the street still... not much like under 1000km a year but still I cant build a car STRICTLY for the track... it would be boring !
 

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There are a number of ways to do what you're talking about... the biggest issue being your wear factor. Race engines are designed to race, not drive 100,000 miles so keep that in mind.

If you're speaking with someone who knows what they're doing on the build then you shouldn't have to specify these tolerances, they should know.

Also keep in mind that mail ordering it is going to cost you 50% for US labor, as compared to having someone in Canada assemble it.

Brian
 

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Discussion Starter #6
Eagle said:
There are a number of ways to do what you're talking about... the biggest issue being your wear factor. Race engines are designed to race, not drive 100,000 miles so keep that in mind.

If you're speaking with someone who knows what they're doing on the build then you shouldn't have to specify these tolerances, they should know.

Also keep in mind that mail ordering it is going to cost you 50% for US labor, as compared to having someone in Canada assemble it.

Brian
you're saying mail ordering and having the place assemble it at the same time would be cheaper right ?

Why is that ? (although I plan to have that done)

Also do you do engine assemblies or just sell parts ? I heard you're the man to talk to about buying rotating assemblies
 

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What I'm saying is that it would be cheaper for you to buy the parts and find a shop in Canada do the work.

For the price of the exchange, shipping, ect. I would bet you're better off having it assembled locally, in addition to receiving a better finished product IMO.

$.02

Brian
 

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jonathan said:
Sounds like you've been doing yer homework nate :D

Yes trailers are cheap and I have a truck and anthony has a truck, but it would be nice to drive around on the street still... not much like under 1000km a year but still I cant build a car STRICTLY for the track... it would be boring !
What... you think I had no input as to that short block in my garage? ;).

I agree with you. I do plan on driving my car around on the street, but I have NO intentions of driving it to and from the track an hour or more away. If I put more than 2000 kms on it per year I would be surprised.
 

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It also seems to me that you need some pretty specific info on tolerances in the context of heavily boosted motors. When you get to the power levels you're talking about and the boost that's required, you really need a builder/parts supplier that understands the implications of (relatively) lower revs and lots of boost.
 
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