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Thread: advice on sr20 rebuild

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Posts: 1-10 of 17
2012-03-30 09:20:24
#1
advice on sr20 rebuild
Hi everyone. I recently purchased my brothers 180sx off him but it has a blown head gasket and is currently not running, the engine is currently turbod but I need it p plate legal, although he has a spare NA sr20 in the shed but it's broken too, we will be putting the NA sr20 in the car after we rebuild it but I need some advice on some good parts to get to make it run better and how to get maximum power out of the engine when we rebuild it.

Thanks
2012-04-01 03:19:17
#2
Are u staying NA or boosting it later also what's ur budget and what's wrong with the other motor
2012-04-01 13:12:46
#3
Staying NA for about 2/3 years then boosting it. Don't really have a budget just something Of a decent price and blown head gasket I'm pretty sure
2012-04-01 21:10:33
#4
Well boost is cheaper than na at a given whp. So if you cant afford to boost it. I doubt you will be able to do much in terms of improving whp na. If you have all the turbo parts from the det why not use the best parts of both engines to build a reliable engine. NA motor has better cams (at least one of them is more aggressive ).
Best bang for the buck headgasket is the cosworth. If it needs to be na then beyonf that get an intake ot make one and up the timing to 19* and put higher octane (91) in.
2012-04-01 22:11:12
#5
If you need to rebuild either motor, why waste your time on the non turbo motor? It takes the same amount of work typically to rebuild either one. This is assuming the turbo specific parts (turbo, exhaust manifold, etc) are all still good; just a blown HG.

With that in mind, take the motor apart down to a bare block and bring it to a good machine shop to check the block for cracks, warpage, and other issues. If everything checks out, just hone it out and reuse the pistons and rods with some new bearings and rings. Do the same with the cylinder head, just put in new valve seals. If you plan to use a metal HG (I recommend Cosworth or Apexi), make sure you take it to machine shop that can surface the head AND block with a near mirror finish. If you have to bore out the block, try to use a torque plate for better ring seal. Not using a TQ plate will result in bore distortion up to .0015" (which is a lot). While the motor will still run, it will have more blow-by and less power. Also, if a bore is needed, try to only go to 86.5mm, not 87mm. The more you bore the cylinder walls, the thinner they become and less material you have to work with in the future if the scenario ever arises.

Another good thing is to check the oil pump clearances. If it's bad or you aren't comfortable with checking it yourself, replace it with a new one.

Hope that helps.
2012-04-02 09:49:19
#6
Thanks heaps both of you guys, I'll take that advice in and get it done
2012-05-13 13:36:52
#7
87 mm is perfectly fine in a non sleeved det, the op isn't trying to make super high numbers..

Go with a set of 87mm 9:1 pistons and eagle rods...

For a super budget build get you set of oem z32 turbo pistons and use your stock rods...

Just my $.02
2012-05-18 21:37:41
#8
Originally Posted by 2_Liter_Turbo
If you need to rebuild either motor, why waste your time on the non turbo motor? It takes the same amount of work typically to rebuild either one. This is assuming the turbo specific parts (turbo, exhaust manifold, etc) are all still good; just a blown HG.

With that in mind, take the motor apart down to a bare block and bring it to a good machine shop to check the block for cracks, warpage, and other issues. If everything checks out, just hone it out and reuse the pistons and rods with some new bearings and rings. Do the same with the cylinder head, just put in new valve seals. If you plan to use a metal HG (I recommend Cosworth or Apexi), make sure you take it to machine shop that can surface the head AND block with a near mirror finish. If you have to bore out the block, try to use a torque plate for better ring seal. Not using a TQ plate will result in bore distortion up to .0015" (which is a lot). While the motor will still run, it will have more blow-by and less power. Also, if a bore is needed, try to only go to 86.5mm, not 87mm. The more you bore the cylinder walls, the thinner they become and less material you have to work with in the future if the scenario ever arises.

Another good thing is to check the oil pump clearances. If it's bad or you aren't comfortable with checking it yourself, replace it with a new one.

Hope that helps.


Oil pump clearances... could you expound?
2012-05-18 22:31:37
#9
Dude machine shops with torque plates are not readily available. I thought a torque plate was only necessary when boring the block? You need it for honing too???
2012-05-18 22:56:24
#10
No, a TQ plate isn't really needed for just honing. And I rent my Mazworx TQ plate out to anyone who wants to use it.

As for the oil pump, check your FSM, it goes into detail about the clearances in the oil pump.
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