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Old 08-10-2011, 06:14 AM   #1
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Default Doing my own mild motor rebuild...?

The rings in my 1.6 motor are showing signs of weakening. Although the motor is still going strong, I know that at some point I'm going to need to get a fresher motor.

My long-time plan was to get just another used 1.6 when this time came, swap it in, and see how long it handled boost. Nice and cheap.

I am beginning to think though that I might prefer to do a rebuild on a used 1.6 so that I can put it in the car confident that it will be good for the next 100,000 miles. It makes sense then, if I do this, to upgrade a few key items in the motor so that the motor can live happily at 10-14 psi for a long time...

First of all, I've never done any motor work, is this something that I could self-learn and do in a garage?

What do you guys think would be a good budget recipe for my goals?
A couple of the weak points I see for a turbo 1.6 are the rods and the rings..
Here's what I'm thinking:
Rebuild kit for ~$400 that include all the bearings, head gasket and other gaskets, etc. as well as new OEM spec pistons
-Upgraded rings on the OEM spec pistons? (can you get stronger rings by themselves or do you have to buy aftermarket pistons if you want stronger rings?)
-H-beam rods - maybe 949 racing $309
- Should I take the block or head to a machinist to get anything done?
-Any other things I'm not thining of that you guys think would be crucial? What should be done to the head to freshen it up and ensure it will be good?


If I did all this, I'd take the opportunity to also have the manifold to turbine surfaces machined so they seal together nicely, add Inconel studs, and rebuild the turbo (another thing I've never done but am sure I can learn).
Thanks for any input, just trying to save the $$ but I want to enjoy the car for thousands and thousands of miles more so trying to figure this all out.
-Ryan

Last edited by ThePass; 08-10-2011 at 06:25 AM.
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Old 08-10-2011, 10:37 AM   #2
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Low comp coated top pistons. Run shitloads of timing and win.
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Old 08-10-2011, 11:38 AM   #3
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this is something i would like to do also(eventually). i think it can be learned if you take it slow and make sure you have all the tq specs correct.
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Old 08-10-2011, 02:56 PM   #4
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Quote:
Originally Posted by Faeflora View Post
Low comp coated top pistons. Run shitloads of timing and win.
Shitloads of timing and shitloads of boost.

Actually how much power do you want?
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Old 08-10-2011, 03:04 PM   #5
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I'm pretty interested in doing this also. Is engine rebuilding something that is commonly done by hobbyists (I use that loosly to mean non-professional race mechanic) with good results?
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Old 08-10-2011, 04:04 PM   #6
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I blew a headgasket in my old car and when pulling the head I decided to go ahead and do rods as well. I swapped in the rods and new headgasket and reused EVERYTHING else (bearings, pistons, rings, headstuds, water and oil pumps, even the timing belt). I later parted the car out and swapped the motor into my '99. I've been daily driving the motor over 10k now without any issues.

I would never suggest that someone do what I did, but it's at least a testament to what is possible. On top of that, I'm as prone to screwing stuff up as anyone I've ever met and I managed to pull it off, I'm sure others can as well. It's really simple and straight-forward work.
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Old 08-10-2011, 05:18 PM   #7
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My understanding is that at a minimum, you must hone the block to use new pistons & new rings, and it would be better to have it bored out (plus you get a few percent extra displacement doing that). Aftermarket pistons are cheaper than OEM, so you might as well go lower compression/forged.

Consider that rebuilding costs the same on a 1.6 or a 1.8, so there's a case to be made for picking up a high-mile 1.8 in need of a rebuild and using that as a starting point instead. You could probably sell your 1.6 for not much less than you'd pay for that 1.8 starter afterwards and come out with an extra 200ccs almost for free.

I assembled my engine last year, there's no rocket science to it. Just go slow, be careful, keep it all clean, and have a friend or two available who can provide advice.

--Ian
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Old 08-11-2011, 06:11 AM   #8
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Thanks for the input so far guys.

Here's the type of rebuild kit I'm referring to:
http://nopi.com/dsp_parts.php?vsubpcdesc=Engine Compartment | Engine - Rebuild Kit
$373 - includes all bearings, all gaskets, new pistons, new rings.

Interestingly, they also have a "Re-ring kit" which is all of the above minus the pistons, but since I've had hints of detonation on more than one occasion, I think it would be best to get the one that includes pistons.

On the subject of rings - can one buy better (stronger or whatever) rings and use them on stock pistons?

I'm thinking that this rebuild kit + H-beam rods + better rings (maybe) + hone the block (required for new rings) + DIY in-garage build just might equal awesome win on the cheap for a 15 psi max setup and could last a long time...
Total cost is <$700 for parts + ~$150 for the donor 1.6 + whatever the machine shop would charge.... that's not bad. Add to that $60 for a turbo rebuild kit (more DIY yay), $110 for FM inconel studs, and whatever a machine shop wants for machining the turbo and manifold mating surfaces, and I'm probably at $1,100. Pretty cheap.

Tell me what you guys think

-Ryan

Last edited by ThePass; 08-11-2011 at 06:26 AM.
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Old 08-11-2011, 06:16 AM   #9
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Quote:
Originally Posted by codrus View Post
Consider that rebuilding costs the same on a 1.6 or a 1.8, so there's a case to be made for picking up a high-mile 1.8 in need of a rebuild and using that as a starting point instead.
To swap to 1.8 I would also need a few extra things, including a new ETD manifold to make my existing TD04 work, so that adds a good $500 to the costs.

The focus of this build would be A) freshening the motor up B) making the motor more turbo-friendly in a few key areas. Power comes from the turbo - if I need a bit more I can turn it up another 1 psi, I want to avoid adding to the costs by searching for more power with more displacement. If I were shooting for big numbers, it would be a different story, but I want to keep it within what could arguably be done on a stock motor, just hopefully be able to do it reliably for a long time with the additions and refresh.
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Old 08-11-2011, 08:49 AM   #10
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The link wouldn't display any products for me but having built 5 or 6 bp's I'd say good quality (not necessarily "race") parts make alot of difference. Cheap bearings won't last like oem will, oem won't last long if you're not meticulously clean during assembly.

I had no problem on the motors I put together for 323 gtx's running 9:1 (up from 8.6:1 stock) pistons with a 20 thou head shave and 10-14psi on a gt 2554 sized turbo. They had stock rods (since it was a 1.8 gtx they were regular 1.8 rods) and standard 9:1 miata pistons 3 angle valve job port matching and some bowl work.

The trick is torquing everything to spec (you need a big and little tq wrench), getting all the clearances right and assembly lube. Oh and don't mix up any parts while it's apart.
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Old 08-14-2011, 04:59 PM   #11
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$373 for pistons, rings, bearings, and all seals is scary, scary cheap. New pistons/rings from Mazda is 300, bearings should be 140 for the set, a full set of OEM seals/gaskets is 300ish IIRC. Then you add tb/wp, tensioners, etc. Non-oem seals makes me super nervous because if one of them leaks, it is a ton of work to correct it.
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Old 08-25-2011, 12:06 AM   #12
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My suggestion is IF possible, go to one of those u pick/ u pull jyards and tear a few engines apart.

Take pictures, pictures of everything before you began, as much as you can. Once you start tearing things apart have zip lock bags, label them with Sharpie, big stuff like starters put them in supermarket bags with all bolts etc.
Collect coffee cans, empty milk gallon containers, etc, to put nuts, bolts by area. For example, cylinder head, exhaust, etc.

Do your own honing, no need to take it to a machine shop. Same deal, buy the stone at harbor freight or auto zone and to the junkyard to practice, and really its no big deal, just a simple quick cross hatch, the less metal the better.

As long as the crankshaft has all the journals in standard you are good. Simple if they look shinny and pass the nail test they are good. Some 600 or 1000 sandpaper with WD40, or fine valve lapping compound with fine emery cloth to make it smooth and shinny and ready to go. Do the basics, front and rear main seal, timing belt pulleys, cam seals, new rings, bearings.

Let us know how it goes, like I said if possible grab tools and to the junkyard to tear things apart. Before you know it is second nature were everything goes, do buy a quality torque wrench, stay away in this case from the HF ones.

Note: Same deal, good used pistons can be found at the junkyard. I pulled a set of Kia Sephia 1.8 pistons with more than 100,000 miles for 20 bucks. Took them to 2 different machine shops and both stated they were fine. If still want new stuff, Mazda new pistons can be purchased on EBAY easily for 100 or less, just got to do your homework.
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Old 08-25-2011, 12:10 AM   #13
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Quote:
Originally Posted by mazpr View Post
do buy a quality torque wrench, stay away in this case from the HF ones.
BTW the HF 1/2 drive torque wrench often on sale for ~9.95 did great in Grass Roots Motorsport Magazine's tests. They compared it to a Snap On and a Sear IIRC.
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Old 08-25-2011, 01:02 PM   #14
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My understanding is that pretty much any torque wrench will work perfectly fine for a while, but the quality ones can go much longer between calibrations. I'm not sure if that was addressed in that GRM test or not, but I for one believe this is a tool that shelling out a hundred extra bucks could save you a lot more in the future.
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Old 08-25-2011, 01:20 PM   #15
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I did this. Costed me loads more time and money than I anticipated. Way more. All I did was a re-hone of the cylinders and got all the parts that wear out and renewed them.
I have an advice: buy a second motor. Put it in your car and rebuild the engine you got out. That way you can keep driving and doing your engine rebuild at ease.

It is not a hard job to do. The engine is fairly easy. Do not forget to replace the exhaust valves on the way as they are prone to fail / wear out.

If I had to do it all over again... I would have bought a fresh 1.8... I ended up having a super fresh 1.6 that would have bought me 2 nice 1.8 engines with less then 50K on them.
Then again.. You would like to mod that too in the end...

Quote:
Originally Posted by Faeflora View Post
Low comp coated top pistons. Run shitloads of timing and win.
What did I read about a ban ?
I also heard pink IC piping will make you run even more timing :-)
Lol.
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Old 08-25-2011, 01:24 PM   #16
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Quote:
Originally Posted by mx5autoxer View Post
My understanding is that pretty much any torque wrench will work perfectly fine for a while, but the quality ones can go much longer between calibrations. I'm not sure if that was addressed in that GRM test or not, but I for one believe this is a tool that shelling out a hundred extra bucks could save you a lot more in the future.
I think they just tested various torque wrenches they had around the shop.
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Old 08-25-2011, 05:06 PM   #17
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http://www.nopi.com/dsp_part_detail....pinum=102+0454

fyi here's the kit he's referring to
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Old 08-25-2011, 05:21 PM   #18
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I only use OEM or Felpro gaskets and seals. That kit is going to be a huge waste of time and money if you ask me. Do it right once and be done with it. Otherwise you will have to spend the time/money to pull the motor again and do it right the second time.
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Old 08-25-2011, 06:37 PM   #19
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I used Elring.
By the way... Do not forget to seal the crank-flywheel bolts like I did...
It will leak and you have to pull out the trany to fix it.
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Old 09-09-2011, 04:00 AM   #20
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In for the goods
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