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Old 01-28-2010, 09:04 PM   #1
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Default Rods now or later?

Hey guys,

I'm in the process of putting together parts for my turbo setup. I am debating whether or not I should build the bottom end now, or wait for an explosion? Can I install pistons and rods from the bottom of the engine or do I have to pull the head off? I just want to keep things under control because it's easy to get to the "I've already gone this far, what's another part" stage. I'm not planning to go near 300whp, but if I can slip in some rods with the engine out without removing the head, I'd go for it.

yes I know the engine must be pulled.

Thanks.
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Old 01-28-2010, 10:03 PM   #2
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Been discussed a couple times recently. Here's the biggest thread of late...

https://www.miataturbo.net/forum/t42749/
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Old 01-28-2010, 10:05 PM   #3
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Thanks, I came across that earlier, but he's talking about with the engine still in.
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Old 01-28-2010, 10:34 PM   #4
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I would pull the head for easy access.
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Old 01-28-2010, 10:38 PM   #5
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I view this more as a "build a motor" or "keep replacing" kind of decision.

You might as well leave it as is until you figure out what kind of power you're putting down. If you're close to 250whp...start building. No sense just putting in rods...might as well refresh everything.

I'm doing the same since I don't want to toss in another 1.6L every six months only to have rings die and risk a ventilated block. Forged rods, stock slugs, light headwork, new rings, bearings and gaskets. Drive happily up to 300whp without worries.
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Old 01-28-2010, 11:36 PM   #6
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I want to get a set of the M-Tuned rods at the current GB rate. If it's possible to do this without separating the head, then it would be a lot 'simpler'. Is it just as easy from the bottom?

I'm really hoping for no more than 260whp. And if a $300 set of rods is the only thing in the way of very good reliability and extra room for error then I'd rather do it (all other tuning variables aside)
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Old 01-29-2010, 01:19 AM   #7
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I wouldn't waste anytime trying to remove and install rod/piston assemblies from the bottom of the engine. How are you going to get the rod/piston out the bottom without removing the crankshaft? How are you going to avoid nicking the crank rod journals if you have to remove the crank while the rods/pistons are still in the engine? Even if you manage to get everything out, it is going to be even harder to re-assemble from the bottom. It will be difficult to fit/use a ring compressor on the bottom of the cylinder....
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Old 01-29-2010, 08:14 AM   #8
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Umm....how about how are you going to compress the rings and get them into the cylinder. You pretty much have to do this from the deck, ergo remove the head.
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Old 01-29-2010, 10:19 AM   #9
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Quote:
Originally Posted by dgmorr View Post
I want to get a set of the M-Tuned rods at the current GB rate. If it's possible to do this without separating the head, then it would be a lot 'simpler'. Is it just as easy from the bottom?

I'm really hoping for no more than 260whp. And if a $300 set of rods is the only thing in the way of very good reliability and extra room for error then I'd rather do it (all other tuning variables aside)
This. Do you really need to do pistons too if you're staying around 250whp? I could do $300 for rods, but then pistons and all the other stuff to have a "built" engine really starts to add up.
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Old 01-29-2010, 10:44 AM   #10
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No, I'm doing just rods.

Supposedly stock pistons and a good tune can go up to 300whp...with ABSOLUTELY NO DETONATION. Det will kill the ring lands.

Price for pistons adds up, especially with the required machine shop work.

Either way I don't see how you're going to swap ANY internals without pulling the motor and completely disassembling anyhow.
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Old 01-29-2010, 10:46 AM   #11
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Thanks guys. I figured the crank would get in the way of the piston ring compressor and inserting the assembly.

I just liked the idea, since the Mtuned guys are local to me.
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Old 01-29-2010, 11:43 AM   #12
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Same situation I'm in and I'm really thinking about getting the M-tuned rods and running stock pistons still
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Old 01-29-2010, 12:24 PM   #13
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Quote:
Originally Posted by johnmatt View Post
Same situation I'm in and I'm really thinking about getting the M-tuned rods and running stock pistons still
Some of Marc's recent posts indicate that this is the best route for those of us that just want to play around with a little more than our 250whp limit and aren't going to push the tune to the ragged edge.

I'm looking for 275whp, dependable and daily driveable without concerns...on the cheap.
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Old 02-01-2010, 07:59 PM   #14
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Quote:
Originally Posted by gospeed81 View Post
Some of Marc's recent posts indicate that this is the best route for those of us that just want to play around with a little more than our 250whp limit and aren't going to push the tune to the ragged edge.

I'm looking for 275whp, dependable and daily driveable without concerns...on the cheap.
If you check out my build thread that's exactly what I'm doing too.

Stock pistons, forged rods, 275ishwhp, and meth injection for safety
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Old 02-01-2010, 09:39 PM   #15
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Quote:
Originally Posted by greenday3437 View Post
If you check out my build thread that's exactly what I'm doing too.

Stock pistons, forged rods, 275ishwhp, and meth injection for safety
Great minds think alike.
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Old 02-01-2010, 09:44 PM   #16
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Quote:
Originally Posted by gospeed81 View Post
Great minds think alike.
They also live in Texas
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Old 02-02-2010, 12:41 PM   #17
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Quote:
Originally Posted by gospeed81 View Post
Great minds think alike.


Been thinking about doing this same route for some time now.
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