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Old 02-09-2009, 12:31 PM   #1
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I am starting my fresh build within the next few days...so I am running into a problem. I have worked on SBC and BBC...but not so much on the smaller Aluminum blocks. Who are the people in the Capital Maryland area whom I might call on for assistance? I feel confident in my abilities...but I have fresh parts and the last thing I want to do is build the motor and it fail upon startup. Any help/suggestions would be appreciated.
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Old 02-09-2009, 12:36 PM   #2
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BP's have a cast iron block, aluminum head. Are you doing a stock rebuild or a forged build? There's a lot to building a motor. If you don't know exactly what you're doing, and have all the tools and know how to use them, have access to a boring machine, lathe, etc, you're better off to take it to a machine shop that does engines. If it's a performance minded build (IE-gonna get turbo'd), make sure you find a good machine shop that specializes in performance builds. A lot of little things change for performance built engines. It's best to find a racecar engine builder or the likes if you want a solid motor.
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Old 02-09-2009, 01:30 PM   #3
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Thank Pat...was under under the impression that BP blocks were aluminum (don't exactly know why). I shut down the motor building portion of my shop about 2 years ago...so I do not have my machining equipment any longer. I didn't want to take this to a shop, but I guess it would be best.

Now, I am going to turbo...probably Begi S kit or the like...I have a freshly built head (3 angle valve job but not much else) and the motor that came from my car. I was going to just put the stock bottom half back together with a long nose crank. Should i throw any extra parts on? (ie, forged pistions, rods, crank) or should the stock (rebuilt) motor withstand 10-15psi? I heard the forged pistons aren't really worth the money compared to stock pistons (but I am open to suggestions)

Basically, since my mother passed...I have had alot more free time and I am getting back into working on these cars. Once I build them both...I am selling one and keeping the other as a DD...so nothing outrageous.

Suggestions are welcome!
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Old 02-09-2009, 02:03 PM   #4
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With stock pistons, rods, and rings, you could withstand 13psi with an intercooled kit, around 220 hp. With better rods and rings, 300hp is easily obtained.
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Old 02-09-2009, 02:14 PM   #5
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Yeah...did more reading and the "dyno" numbers are RWHP whereas the other numbers people are throwing out is CHP...grave difference between the two.

OK, so my *stock* bottom half and fresh head will get me a solid 10-12PSI

BUT, if I install new rings and connecting rods...I could push 16PSI

I guess I am still confused as to whether or not the forged pistons are nessecary or even suggested. I know this seems redundant...but I really haven't found many people one way or the other on this topic.
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Old 02-09-2009, 02:20 PM   #6
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I think all the numbers thrown around here are wheel horsepower. Not many people have a good way of measuring crank hp.

250whp is when rods start to bend, so if you stay below that you should be fine... except for your diff.
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Old 02-09-2009, 02:48 PM   #7
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My opinion:

a) buy a used engine and swap it in and run it for cheap.

b) Rebuild your engine and buy forged rods and pistons. No sense in spending a bunch of time and money rebuilding a motor to stock specs. There's dozens of good used BP's out there if you just want a good stock motor.

Don't waste any money on anything else though. No billet OP gears, no ARP hardware, no BPSP, no fancy anything else. Keep it simple. You're just beefing up the reciprocating assembly. It's all that's needed. Then you have a solid foundation.
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Old 02-09-2009, 02:55 PM   #8
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Quote:
Originally Posted by patsmx5 View Post
Don't waste any money on anything else though. No billet OP gears, no ARP hardware, no BPSP, no fancy anything else. Keep it simple. You're just beefing up the reciprocating assembly. It's all that's needed. Then you have a solid foundation.
Why do people replace the OP gears? I understand the cam gears, to give adjust ability. What is BPSP?
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Old 02-09-2009, 03:04 PM   #9
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Quote:
Originally Posted by skidude108 View Post
Why do people replace the OP gears? I understand the cam gears, to give adjust ability. What is BPSP?
OP gears= oil pump gears
BPSP= the wrong way to abbreviate main bearing support plate. (properly abbreviated MBSP)

People change the OP gears because they heard that some guy that said that someone he knew heard that his friend's OP gears broke so they're all junk and everyone should "upgrade" theirs.
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Old 02-09-2009, 03:28 PM   #10
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Billet OPGs are cheap insurance. After the rods, they are the next weakpoint in the engine. Maybe you never need them, maybe you miss a shift and shatter the stock gears and then you're pulling the motor and the oil pan back off to do something that you should have just spent the $150 on to start with.

Built shortblock: $2k
Not installing billet OPGs: save $150

Breaking stock gears in a built motor: $get laughed at here
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Old 02-09-2009, 05:00 PM   #11
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If I was to do a build right now, I would get the belfab engine kit, with 9.0:1 pistons, if you ever think of revving higher than stock, some OPGs, ARP studs, and your head.

This way you can push 300+ hp no problem, except for your drivetrain.

BTW, get a 7 inch diff from the 1994+ miatas, your 6 incher will blow.
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Old 02-09-2009, 06:05 PM   #12
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Quote:
Originally Posted by Savington View Post
Billet OPGs are cheap insurance. After the rods, they are the next weakpoint in the engine. Maybe you never need them, maybe you miss a shift and shatter the stock gears and then you're pulling the motor and the oil pan back off to do something that you should have just spent the $150 on to start with.

Built shortblock: $2k
Not installing billet OPGs: save $150

Breaking stock gears in a built motor: $get laughed at here
Yeah, look at all the people running a harmonic balancer that break them.... Oh wait, there aren't any. I'll see how many threads I can find where someone broke a piston or rod. I believe there are several. See how many you find of people with broken OP gears that ran a harmonic balancer.

Sorry, OP gears are 100% JOKE!
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Old 02-09-2009, 06:08 PM   #13
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Yeah...I know about the diff - Thanks for the heads up though.

I'll invest in some forged internals for the build...thanks for the input guys!
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Old 02-10-2009, 09:13 AM   #14
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So I enlisted help of people in the Mercedes forum I'm on...4 people offered to help!?! Crazy...I thought Benz owners were all snobs - I'm obviously corrected.

As for the motor build...Now I am going 1.6L, ported and polished head, forged internals, knife-edged crank, built by someone who knows what the **** their doing, and turbo kit (haven't decided DIY or Begi)

Thanks for the input everyone...plenty of pics and vids to come.


If anyone wants to give suggestions on paint color...I'm up for it! Already heard pink...so find something original.
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