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Author Topic: Welp, shit.  (Read 7766 times)

Gaz

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Re: Welp, shit.
« Reply #15 on: February 28, 2017, 12:27:27 PM »

+1 on Matts comment. I took that sucker out real quick. There is a reason Mazda used the cam that they did.

I see. Pistons, then?
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chrispoe

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Re: Welp, shit.
« Reply #16 on: February 28, 2017, 09:05:31 PM »

I would think that the tensioner would take up that slack in the effective length of the belt couldn't possibly physically change.

The tensioner pulley only adjusts on the intake side of the timing belt.
When you deck the head or put a thinner head gasket on, you shorten the distance between the crank and exhaust sprocket.  The length of belt is still the same and causes the intake and exhaust cams to retard counter-clockwise.

All lot of the Miata folks due this cuz they found retarding the cams shifts the power band slightly higher in the rpm range to make more hp. The small bump in compressing helps keep the low end power, while also increasing the power in the mid and upper rpms too.
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greywolf27030

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Re: Welp, shit.
« Reply #17 on: March 01, 2017, 10:35:25 AM »

Good thought Chris.

Jack Byrd
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Jack Byrd

WashiestSnake

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Re: Welp, shit.
« Reply #18 on: March 01, 2017, 11:53:25 AM »

If it really has all those benefits it sounds worth doing.
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azgtx

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Re: Welp, shit.
« Reply #19 on: March 01, 2017, 09:38:14 PM »

A lot easier to just add some boost isn't it?
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Rocketman

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Re: Welp, shit.
« Reply #20 on: March 02, 2017, 12:47:16 AM »

A lot easier to just add some boost isn't it?

This, times 10.

Decking the head can also have other negative side effects - you're removing material. It may be easier to warp, the valves will run closer to the pistons - I personally wouldn't mess with it.

Yeah, grab some proper forged pistons with a higher CR if you want to bump the CR.
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Gaz

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Re: Welp, shit.
« Reply #21 on: March 03, 2017, 11:36:13 AM »

A lot easier to just add some boost isn't it?

This, times 10.

Decking the head can also have other negative side effects - you're removing material. It may be easier to warp, the valves will run closer to the pistons - I personally wouldn't mess with it.

Yeah, grab some proper forged pistons with a higher CR if you want to bump the CR.

Well, yeah. I was only going to have it decked if the block was warped, but that doesn't seem like a common occurrence on these. What's the farthest bore you can go with on this? . 20?
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WashiestSnake

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Re: Welp, shit.
« Reply #22 on: March 03, 2017, 01:48:21 PM »

.20 would be really pushing it to fo it right youd have to get the block sonic tested. Only a few select b6 blocks havd enough wall to do .20 overbore
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Rocketman

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Re: Welp, shit.
« Reply #23 on: March 03, 2017, 10:47:25 PM »

.20 would be really pushing it to fo it right youd have to get the block sonic tested. Only a few select b6 blocks havd enough wall to do .20 overbore

How far did you overbore yours?
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WashiestSnake

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Re: Welp, shit.
« Reply #24 on: March 03, 2017, 11:08:20 PM »

I was speaking out of thought. My thought process was that the b6 itself allready is a stroker motor. I believe IRCC that Mazda developed it by taking another 4cylinder and then boring it out, that being said I didnt think that it would have to room for that overbore. Ive never once said, or implied I was a expert, and Id like to say that I was probably wrong. Im not a trained mechanic, im just a 20 year old whos hobby is working on his Capri. Id like to think my knowledge has increased greatly over the last year. That being said I get your point Matt and ill shut up about things that I have no real clue on.
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chrispoe

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Re: Welp, shit.
« Reply #25 on: March 04, 2017, 01:07:12 AM »

IMHO… forged pistons don’t make sense in a b6t unless your goal is 300hp+ and even then, I’d say you would be better off spending the money on a BPT instead.

I’ve seen b6’s with their heads decked over .08 which in turn bumped the compression nearly 2 full points.  I personally would never going that far though, cuz once you go beyond .04 or so, you’ll be turning the motor into an interference type engine and requiring adjustable cams too.

Whenever I’m doing a head gasket job now a days, I just take the head to the local machine shop and have them shaved regardless.  Nothings more irritating then having to redo a HG job a month latter because you were too cheap/lazy to do it right the first time.

Overall I have to agree with azgtx, If the block isn’t leaking or knocking, then just freshen up the heads.
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chrispoe

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Re: Welp, shit.
« Reply #26 on: March 04, 2017, 01:08:59 AM »

I was speaking out of thought. My thought process was that the b6 itself allready is a stroker motor. I believe IRCC that Mazda developed it by taking another 4cylinder and then boring it out, that being said I didnt think that it would have to room for that overbore. Ive never once said, or implied I was a expert, and Id like to say that I was probably wrong. Im not a trained mechanic, im just a 20 year old whos hobby is working on his Capri. Id like to think my knowledge has increased greatly over the last year. That being said I get your point Matt and ill shut up about things that I have no real clue on.

The 1.6L is an overbored 1.3L


A .2 overbore is easy….. just go to your local junkyard and pick up a BP engine cuz that’s what a .2 overbore is (and a tad bit more stroke too).
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greywolf27030

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Re: Welp, shit.
« Reply #27 on: March 04, 2017, 11:11:06 AM »

I did a B6 single cam .03.

Jck Byrd
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Jack Byrd
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