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Old 03-16-2012, 10:04 PM   #1
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Default to build or not to build

I lost my job a couple years ago and left town. I parked my miata at a friends and during that time it got neglected. I recently moved back and started tuning it back up. I noticed some smoking and did a compression check. My compression is terrible in the 4th cylinder ~70-90. When i do the wet test it goes up to about 125-150. So now i'm faces with a decision and here are the factors.

My car is a 1990 with a long nose 1.6. I have a 2560 Garret, IC, MS1, 460cc inj, torsen out of an early 2000's miata. 2.5" Exhaust . My turbo mani is a bell log style & i have an S style downpipe. Wideband is an Innovate LC1.

I don't want someone to make a decision for me but i'd like some perspective. I've looked around for some replacement motors but all i seem to find around here are 1.8's. I can pickup a 95 1.8 with 140k on it for $325. I can pickup a 99 with 90k on it for $400 or I can rebuild my 1.6.

I'm not afraid to get my hands dirty but I've never rebuilt a motor myself. I know everyone says put a 1.8 in when given the chance. If I do put in a 1.8 then I will need a new turbo mani which is ~400 + 170 for the fm kit. im at ~970 before fluids and misc. Should be pretty easy to sell my old mani i guess right? I'm kind of uneasy about buying the 1.8s because they aren't in running cars and I can't run compression tests on them. I have never done a leak down test nor have the tools.

Is a rebuild something I should consider doing myself? I have some body work and painting i need to do to my car as well. I'm not restricted by budget but would like to be practical.

The 99 motor I was told was out of a front end collision and before the guy bought the motor it ran in the wrecked car and that was about 2 months ago. He planned on putting it in his miata but decided to sell it because he's moving (or so he says).


something worth noting. this is not my daily. I have an A6 4.2L Audi .
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Old 03-17-2012, 12:51 AM   #2
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There's machining costs even if you assemble the thing yourself. Plus you have to factor in bearings, rings, gaskets etc at a minimum. You'll probably be thinking "oh why not throw some forged internals in while it is in bits" so you'd be looking at another grand for that.

Alternatively you could pick up the 99 engine you mentioned and leave it the hell alone. You would need a new manifold but you will already be ahead in terms of power gains due to the decent flow of the head and extra capacity.

I guess it comes down to how much power you want to make, but if I were in your shoes I'd probably go with the 99 engine and build that up if you get bored with 10 pounds.

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Old 03-17-2012, 01:04 AM   #3
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Unless you can find a 1.6 stocker ^ is the best option.
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Old 03-17-2012, 10:03 AM   #4
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A rebuild will almost certainly cost you more. There is satisfaction in doing it though. But it seems like your priority is cost.

People upgrade to tubulars and sell their cast manifolds all the time. I would think you could pick up a manifold for a lot less than $400 if you watch the FS section or post a WTB.
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