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Rebuilding A 2nd Gen Rotary

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Old 11-24-17, 07:41 PM
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Rebuilding A 2nd Gen Rotary







Hello All,

Let me start off by saying I am not a mechanic; much less rotary savvy. I have ordered Mazadtrix's rebuild DVD and I have been watching plenty of You Tube videos. The engine overheated all of 5 minutes and blew a water gasket. Prior to this; the engine was running fine. I decided to rebuild this engine and make this a father and son project. I plan on re-using all the hard parts and only replacing all the O-rings and gaskets. The engine was running a racing beat Holley 4 barrel carb and intake.

What brand of gaskets do you guys recommend?
BTW- the engine has an aggressive street porting, per the last owner.

I have finished cleaning and prepping the first iron. Can you guys let me know if its ready or does it need more cleaning?

Any recommendations for removing hylomar from the rotary housing?

The water pump was a bit crusty, here is what it looks like after some cleaning. Does it look reusable?

Thank you all for your time.


JM

Last edited by str8maxn; 11-24-17 at 07:44 PM.
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Old 11-25-17, 07:43 AM
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I would not reuse that water pump, it looks pretty crusty. New ones aren't expensive, even if that one works it just makes more sense in my opinion to buy a new one. Otherwise you will find yourself replacing it in a month or two anyways.

Also, if the inside of the water pump is that gross, inspect the rest of the coolant passages too. Make sure nothing else has corroded.
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Old 11-25-17, 08:08 AM
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someone sure overdid the sanding..
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Old 11-25-17, 11:32 AM
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That is not a 2nd gen (FC) engine.

Looks like RX-4 / RX-5 13B irons.

And a fairly terrible port job. :-)

Laquer thinner removes Hylomar. I like the little Dremel brass wire wheels for this purpose.

Atkins gasket kits are fine.
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Old 11-25-17, 02:15 PM
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Thank you all for the replies...... Unfortunately, the last owner did the port job. I was going by the mazda 86-88 shop manual that was inside the trunk for identifying the engine.

I'll be less aggressive with the sanding on the next iron.
After posting about the water pump, I come to the same conclusion about replacing it.


Aaron, If your the guy with the Cosmo on the you tube videos, your one of the reasons I decided to rebuild the engine myself. They are really informative.

Aaron, can you please post a link to the Atkins kit that will work best with a Holley Carb and intake?


JM
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Old 11-25-17, 07:20 PM
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Originally Posted by str8maxn View Post
Thank you all for the replies...... Unfortunately, the last owner did the port job. I was going by the mazda 86-88 shop manual that was inside the trunk for identifying the engine.

I'll be less aggressive with the sanding on the next iron.
After posting about the water pump, I come to the same conclusion about replacing it.


Aaron, If your the guy with the Cosmo on the you tube videos, your one of the reasons I decided to rebuild the engine myself. They are really informative.

Aaron, can you please post a link to the Atkins kit that will work best with a Holley Carb and intake?


JM
the type of intake and fuel source has NOTHING to do with which rebuild kit to get for the engine
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Old 12-01-17, 04:31 PM
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Hello All,
Before I move forward on this project; Can you guys let me know if the irons are usable?


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Old 12-03-17, 10:07 PM
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BUMP... Any input.. would be appreciated
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Old 12-04-17, 11:25 PM
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like Aaron said, those are vintage 70's irons, not from a 2nd gen originally, the big giveaway is that they are not nitrided. What exactly are you building? if your wanting a everyday driver I would be getting newer style irons

another question, what do you have for rotor housings?? Just wanting to make sure you don't have newer housings and older irons, cause it would never work
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Old 12-05-17, 11:13 AM
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Hello Iduley,

Here is a pic of the housing.. The engine was in my son's Datsun 510; for the most part , it was running fine until it overheated and blow a water seal. It will be a cruiser and not a daily.


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Old 12-05-17, 12:46 PM
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they're GSL-SE rotor housings, the irons would at least need to be milled.

probably better using newer irons anyways, you can see where the old dual side seal rotor chewed up those irons pretty good.
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Old 12-07-17, 01:42 PM
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Thank you for all the help.

Question, Could I take a 13B from an S4 remove everything from it (fuel injection etc) down to the bear block. Then Re-use my Racing beat intake, Holley carb, Racing beat headers, swap the distributor, and swap out the front engine cover so I could use the existing engine mounting points?
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Old 12-07-17, 04:38 PM
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I am in the middle of a similar rebuild of a 12a right now. I think you have some good parts there, you could probably put it back together with new gaskets and o-rings and it would run as well as it did before. If you put in new apex seals and side seals you would be into it for around $800 in parts, and you would gain the experience of building something interesting.
You could also use an s4 engine as you mentioned, you would need to modify your intake manifold to fit on a 6 port engine, and you could sell the parts you have to help recover some of the costs of the s4 engine.
I bought my rebuild parts from Atkins rotary, they have a Christmas promotion in December, 10 percent off. I am happy with the parts they sent me.
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Old 12-07-17, 05:08 PM
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Originally Posted by tim. View Post
I am in the middle of a similar rebuild of a 12a right now. I think you have some good parts there, you could probably put it back together with new gaskets and o-rings and it would run as well as it did before. If you put in new apex seals and side seals you would be into it for around $800 in parts, and you would gain the experience of building something interesting.
You could also use an s4 engine as you mentioned, you would need to modify your intake manifold to fit on a 6 port engine, and you could sell the parts you have to help recover some of the costs of the s4 engine.
I bought my rebuild parts from Atkins rotary, they have a Christmas promotion in December, 10 percent off. I am happy with the parts they sent me.

Tim, Assuming I take the gasket and o-ring route; what gasket kit would I need on the atkins website?
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Old 12-07-17, 05:58 PM
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Take a look at their rebuild kit A it is called ARE27 .
It looks like it would be a good start.
You could measure your apex seals and decide then if you want to put the old ones back in, or buy new. Same with the side seals.
The Mazda service manual says the grooves in the irons can be .004 " or less.
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Old 12-07-17, 06:15 PM
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Originally Posted by tim. View Post
Take a look at their rebuild kit A it is called ARE27 .
It looks like it would be a good start.
You could measure your apex seals and decide then if you want to put the old ones back in, or buy new. Same with the side seals.
The Mazda service manual says the grooves in the irons can be .004 " or less.
Per the last owner, the engine was rebuild and only had a few thousand miles on it before I blew out a water gasket. He provided a receipt showing the parts he purchased for the rebuild but I can't seem to locate it.
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Old 12-07-17, 07:08 PM
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I think an old 4 port 13b is a great choice for a 70s Datsun 510. If you have more questions, you are probably going to get better advice in the first generation section, or the old school section. Those guys are more likely to know what works with a hot rodded 4 port like yours. The newer stuff is different because it is easier to get new parts.
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Old 12-08-17, 01:48 PM
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Thank you Tim for the info.
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Old 12-09-17, 05:48 PM
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Sorry for so many questions.. I can put the engine together in stages? Meaning, can I assemble the front iron , front housing and front rotor today and build the rest a few days later? Or do I need to start and finish on the same day?

JM
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Old 12-09-17, 06:12 PM
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Well, there are the legs at the base of the housing by the oil pan, and they need sealant or they will leak. If you use RTV, you will need to complete the whole thing and torque it up before it hardens. But if you are using hylomar as a seal, then you can take your time because it never hardens. Here is a manual I downloaded, it helped me alot.
http://wright-here.net/cars/rx7/80_manual.html
Or there is a series of videos on YouTube by Blake Martinez. They are excellent with alot of detail.
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Old 12-10-17, 10:03 AM
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Hi,

i will also do a rebuild on my 13b REW. I will buy all parts at Atkinsrotary. And your side housings docent look. so good any more. Maybe you find better.

Br Christian
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Old 12-10-17, 11:38 PM
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Hello I just wanted to share the pic's of the the irons after cleaning and hand lapping. Per my feeler gauge, I am within spec of .004. Let me know what you think. (Thank you Tim)

Tim do you have the discount code for atkins?

FRONT



CENTER side 1




Center Side 2




REAR

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Old 12-11-17, 02:58 AM
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You have been busy!
The coupon code is winter2017 and it is good till January 3rd.
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