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 Post subject: 1981 Mazda CB 626
PostPosted: Sat Feb 05, 2011 2:26 pm 

Joined: Wed Apr 14, 2010 7:16 pm
Posts: 32
Location: Australia
I am currently restoring my 81 626 MA motor and have a couple of questions.
What other cars in Mazda's range do the CB 626's share common parts with. I have heard that they share the same floorpan as the early model RX7's and possibly have parts in common with other models but am unsure.
My other question is I am toying with a 12a conversion and am wondering if I can use the original engine mounts and gear box mounts?, if I keep the MA 2ltr does anyone know of any producers of aftermarket parts for the MA motor like better bearings and so on.
If anyone can help me out it will be greatly appreciated.
Thanks


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 Post subject:
PostPosted: Sun Feb 06, 2011 5:45 am 
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Joined: Mon Mar 15, 2010 4:37 am
Posts: 174
Location: Ballarat
Mate,
Having just finished converting my 626 coupe to 13B power, forget
what everyone else says about 626s sharing common parts with RX7s, they have no f@#&ing idea! :evil:

Pic of 626 cross member vs RX7 cross member vs RX4 cross member.
The RX4 cross member is used most often because it is the same width as the 626 chassis rails. This moves the motor way forward so most guys then have to fit a spacer block to try and move the block back.

Image

You can use:
RX7 front strut and brake assemblies but will need to fit camber plates, and also when fitted are about an 1.5" lower than the original strut.
RX7 radiator
Clutch slave(providing it's not leaking)

Parts I used from an S2 RX7:
Alternator
starter motor
end and tall port centre plates
Throttle cable(perfect length)
Engine mounts
Igntion coil mounting bracket
Oil cooler
Earth cable (battery to block)
Starter motor cable (battery to starter)

Parts used/adapted/fabricated:
Complete engine cross member - made to bolt in
RX3 front engine mount
radiator mounting brackets
oil cooler mounting brackets
Radiator(3 core)
Radiator hoses
Oil cooler lines
Overflow bottle extension bracket
Gear box mount extension bracket
Drive shaft( original 626 made 75mm longer)
Ignition coil mounting bracket
Throttle cable extension bracket(mounted to carby)
Fuel regulator mounting bracket
Entire exhaust system (DO NOT waste your time trying to adapt an existing RX exhaust system to fit. It WILL NOT FIT!!!!!!)
Heat shield - unless you just fit an entire RX7 12A engine with reactor
box and attached heat shield, etc.

Just to give you an idea:
Image

Image

Image

Image

Image

Finished product - :D
Image

GO FOR IT and GOOD LUCK! :D


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 Post subject:
PostPosted: Wed Feb 09, 2011 5:03 am 
JNC Fanatic
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Joined: Tue Jan 15, 2008 3:40 am
Posts: 902
Location: Villeneuve, Qld, Australia
Sweet build Philip, that's an awesome example of the hardtop, damn I so want the metal bumper version!

Yeah Oven, he's right, not a lot is really common despite the stories you hear on ausrotary, built one too

_________________
Too many Mazda's in the collection. 4 Mitsubishi's, 6 Toyota's and now 3 Datsun's as well.
Putting together a Mazda/Japanese motor museum. New bigger venue for the museum has been bought, watch this space!


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 Post subject:
PostPosted: Fri Feb 11, 2011 3:20 am 
JNC Enthusiast

Joined: Mon Jun 08, 2009 9:26 pm
Posts: 770
Location: Melbourne, Australia
Keep the MA, get it to breathe properly with a good exhaust and a decent manifold and carb a bit of lowering, some good tyres and enjoy it.

that's just my opinion anyway. :)

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 Post subject:
PostPosted: Fri Feb 11, 2011 4:52 am 

Joined: Wed Apr 14, 2010 7:16 pm
Posts: 32
Location: Australia
Thanks heaps for all the info.
I think I am going to stick with the MA and fit a 32/36 Weber, extractors and exhaust as well as getting the rotating assembly fully balanced and shotpeening the rods and crank amongst other small things I think will get her going a little better.
Thanks.


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 Post subject:
PostPosted: Sat Feb 12, 2011 4:33 am 
JNC Fanatic
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Joined: Tue Jan 15, 2008 3:40 am
Posts: 902
Location: Villeneuve, Qld, Australia
Mate, besides the baggings you hear, the MA was a brilliant engine. I've supercharged them, turbo'd them, bored them to silly oversizes etc. If only Mazda had kept it's quality into the FE/F8 2.0 litres.

I've got a 2001 E2000, where the crappy FE died, I'm planning a MA swap into it, yeap, manifold are the other way around but least it will go on for a long time . A good friend and I, just finished a MA turbo, straight LPG with a four speed auto, bloody rocketship!

Good idea with that work you're going to do, get the cylinder head checked and if it hasn't been done, get the casting ports welded to stop any leaking. They are the two flat 'welsh plugs' under where the cam runs. A trick too for young players that haven't had one apart b4 too, the inlet and exhaust rocker arms + the rocker shaft springs are different so don't mix them up. A little trick I do is to get some auto wire and tie it around all four rocker arms before you lift it up...otherwise the whole lot springs apart everywhere!!

Good thing I find, with a lot of chaps in Australia doing rotary conversions, ebay has all the bits for Mazda piston engines quite cheap!

_________________
Too many Mazda's in the collection. 4 Mitsubishi's, 6 Toyota's and now 3 Datsun's as well.
Putting together a Mazda/Japanese motor museum. New bigger venue for the museum has been bought, watch this space!


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 Post subject:
PostPosted: Sun Feb 13, 2011 5:16 pm 

Joined: Wed Apr 14, 2010 7:16 pm
Posts: 32
Location: Australia
Hi, can you please explain the difference between the inlet and exhaust rocker shaft springs? As I think mine have been mixed up.
Is it worth me modifying my alloy rockers to accept the hydraulic tappets that were in the earlier model motors as I have just picked up a set of cast iron rockers with these tappets in them that were apparently out of a 1500ss.
Thanks.


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 Post subject:
PostPosted: Wed Feb 16, 2011 9:16 pm 
JNC Fanatic
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Joined: Tue Jan 15, 2008 3:40 am
Posts: 902
Location: Villeneuve, Qld, Australia
Just to let you know, all the early motors were adjustable tappets, really wasn't until 12 valves that they got into hydraulics that and even then early 2.2l still had adjustable versions. The commercial engine versions went on for years, my 2001 E2000 still has adjustable tappets in it!

Would you have a photo of those rockers? Yes the UB 1500 engine (1966 until bout sept 1968 then they went to the alloy type) did get cast iron rockers but they did have a habit of cracking so just make sure they haven't been welded as I've seen it done and it doesn't really work when using a larger cam. Also the series 1 1500ss and series 2 1500ss cylinder heads were differed slightly so the early motor rockers will miss your exhaust valves in a MA rocker gear set.

Those springs are longer on the exhaust side although after years of service they end up about the same length due to the heat around the exhaust side of the cylinder head.

_________________
Too many Mazda's in the collection. 4 Mitsubishi's, 6 Toyota's and now 3 Datsun's as well.
Putting together a Mazda/Japanese motor museum. New bigger venue for the museum has been bought, watch this space!


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 Post subject:
PostPosted: Fri Feb 18, 2011 1:14 am 

Joined: Wed Apr 14, 2010 7:16 pm
Posts: 32
Location: Australia
I have been warned off of using the hydraulic tappets I have and just use the original solid ones as the hydraulic ones apparently need to be set to a certain pre-load and thus they cause more wear on the cam and follower end of the rockers.
If I chose to use them I was going to get my aluminium rockers drilled to provide a passage for oil to feed the tappets from the main rocker shaft and have the ends welded back up where they have been drilled.
I am still not sure which way to go?


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 Post subject:
PostPosted: Tue Feb 22, 2011 6:01 am 

Joined: Fri Oct 22, 2010 2:01 pm
Posts: 26
Location: Reykjavík, Iceland
ewokracing wrote:
Keep the MA, get it to breathe properly with a good exhaust and a decent manifold and carb a bit of lowering, some good tyres and enjoy it.

that's just my opinion anyway. :)


What do you mean by a decent manifold and carb? Would like some details with that if you would be so kind ;) From another Mazda or some aftermarket stuff? Weber? And could I order some online maybe?


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 Post subject: Re: 1981 Mazda CB 626
PostPosted: Wed Nov 02, 2011 2:22 pm 
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Joined: Mon Mar 15, 2010 4:37 am
Posts: 174
Location: Ballarat
Here Kristjan, this is similar to what ewokracing is talking about.

http://www.ebay.com.au/itm/MAZDA-TWIN-S ... 27bfbf3224

http://www.ebay.com.au/itm/MAZDA-SIDEDR ... 2a156886fb

http://www.ebay.com.au/itm/MAZDA-MA-NA- ... 3f021c3bde


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 Post subject: Re: 1981 Mazda CB 626
PostPosted: Wed Nov 02, 2011 10:29 pm 

Joined: Fri Aug 12, 2011 9:20 am
Posts: 37
Location: Atlanta,GA
nice find! anyone have any experience with the weber? Im on the fence about FE3 Dohc swap in my CB, deep down id like to have a healthy sidedraft MA under the hood.


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 Post subject: Re:
PostPosted: Thu Nov 24, 2011 7:49 am 
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Joined: Fri Aug 01, 2008 12:00 am
Posts: 42
Location: Moscow, Russia
B1500boy wrote:
Good idea with that work you're going to do, get the cylinder head checked and if it hasn't been done, get the casting ports welded to stop any leaking. They are the two flat 'welsh plugs' under where the cam runs.


B1500boy, can you please show me on the picture of cylinder head where exactly these ports which i need to weld? Meybe you have photo of unmodified head & head with already welded casting ports to show the difference?

Right now I'm modifying my round port cylinder head so you info will be good before I've put it back on engine :roll:

_________________
1976 Mazda 929 Hardtop Coupe
1977 Mazda 929 Hardtop Coupe
1977 Mazda 929 Wagon (donor car)
1981 Mazda 626 Coupe
1984 Mazda RX-7
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http://www.mazda-929.ru
http://www.oldmazda.ru


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 Post subject: Re: 1981 Mazda CB 626
PostPosted: Fri Nov 25, 2011 1:57 am 

Joined: Wed Apr 14, 2010 7:16 pm
Posts: 32
Location: Australia
He is talking about the two small alloy plugs in the top of the head.
When looking down at your head from above in it's installed position(combustion chambers facing down) they are the two small alloy plugs that are under the cam (approx one third in from each end) you cant miss them.


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