Cams from a B6 dohc miata

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95_MX3_RS
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Cams from a B6 dohc miata

Post by 95_MX3_RS »

I have heard from a few of you that this is a nice minor upgrade to swap miata cams to the mx-3,
as they have better lift or duration. And this mod is good for a few ponies. I found some used ones on ebay for
cheap, and would like your opinions on how they look. (I know it's hard to tell from a picture)

Also what exactly is the procedure to swap them? I know you swap the exhaust and intake cams, but do you
have to mess with the distributor drive setup that typically goes on the exhaust cam?

FYI: I have a freshly rebuilt motor head to toe. And I know that I should of done this upgrade then!

Here's the link:

http://www.ebay.com/itm/1989-1993-Mazda ... fb&vxp=mtr
95_MX3_RS
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Re: Cams from a B6 dohc miata

Post by 95_MX3_RS »

Another thing I have heard about is advancing the timing but installing the belt one tooth off,
Is there any merit to this either?
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SuperK
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Re: Cams from a B6 dohc miata

Post by SuperK »

don't look at those, the automatic transmission miatas had extremely low lift/duration, you have to get ones from manual transmission.
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Josh
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Re: Cams from a B6 dohc miata

Post by Josh »

One cannot simply swap miata B6 cams into an MX3 B6 DOHC engine. look at the engines real close the distributor is on the opposite side of the miata.

I was the first one to miata cam swap the MX B6 eons ago now. you have to have adjustable cam gears to do it properly but each cam will have to be timed 180deg out from where it is supposed to be, or about. You have to use the Miata Intake cam on your exhaust and the exhaust cam on your intake. I made gobs of power doing it. Though I used some pretty large cams. They were like 232 duration and 10.4mm lift. they were as big as one could really go using factory valve train.

One option would be to do the exhaust cam swap, which there is a write up on Club Protege. but this is good for a 5 to 10 HP increase. It involves finding another exhaust cam gutting the distributor part off and moving the pin for the cam gear, and running it as an intake cam.
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SuperK
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Re: Cams from a B6 dohc miata

Post by SuperK »

I think I was the one that bought your cams, Josh... I bought someone's cams, forget whose.
The way I did is, with a set of feeler gauges, measure the height from the face of the head to the center lobe of the camshaft on the first lobe closest to the cam gear, on the stock cam, then used that measurement to set the new camshaft in the exact same height, only 180 degrees out.
There was a cast line that ran exactly down the middle of the lobe, so I think I just got lucky. Patdiesel and I did it all ghetto style.
However I forgot since it was 180 degrees out, to set the crank at bottom dead center instead of TDC, so I then had to put the distributor upside down. and that was weird.

needless to say, it was a very weird and ghetto way I got mine put in... but you would have never believed... it actually was timed! as well as it could be without adjustable gears.
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Re: Cams from a B6 dohc miata

Post by Josh »

SuperK wrote:I think I was the one that bought your cams, Josh... I bought someone's cams, forget whose.
The way I did is, with a set of feeler gauges, measure the height from the face of the head to the center lobe of the camshaft on the first lobe closest to the cam gear, on the stock cam, then used that measurement to set the new camshaft in the exact same height, only 180 degrees out.
There was a cast line that ran exactly down the middle of the lobe, so I think I just got lucky. Patdiesel and I did it all ghetto style.
However I forgot since it was 180 degrees out, to set the crank at bottom dead center instead of TDC, so I then had to put the distributor upside down. and that was weird.

needless to say, it was a very weird and ghetto way I got mine put in... but you would have never believed... it actually was timed! as well as it could be without adjustable gears.
I did mine with stock gears to initially.. actually for several years. After I did it i received calls from a couple of machine shops and was contacted by many to help them with theirs. Most could not understand or get it to work with factory gears so it was easier to tell them to get adjustable gears and measure them. when you do it, all you have to remember is the peak of the first cam lobe should be just under the edge of the lip of the head where the VC sits. I had a spare motor sitting there measured it up and mimicked that. It was so strong. That is why I was dynoing my B6DE at over 230WHP with a VJ14 turbo at like 10 psi.. It was the cams and the porting work i did. it was even a low comp motor at 8:1.
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