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Alex's 1968 'oldman special' HB Viva discussion....


yoeddynz

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When quality rebuilds was in Christuchuch, I spoke to the (now former) owner Barry Emmes about modifing a standard vac advance Diaphram to become a boost retard diaphram. He sold the company to a mob who are now in Auckland, but they may be able to convert one for you. The beauty of boost retard is that when you're off boost, but still stoking along you get the benifit of better fuel economy than you would without the added advance.

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I think the diaphram is dismantled, and then reassembled with the spring on the other side of the diaphram. So it runs Advanced under normal conditions, (May need to adjust base timing to suit) and then as the boost rises the pressure make the arm retard the timing. (I imagine the weight of the spring used would need to be a bit clever)

It's wholley possible the factory rotoray ones had two diaprams back to back, so that it could both advance from vacuum, as well as retard from boost. (Although, don't quote me on that one)

Another clever (But very costly) option would be to use something like an MSD 6AL BR module. These retard your timing electrictronically as the boost climbs.

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yeah bowl over dave. Plan to be re-fitting the seats maybe. The more help the better!

That dizzy idea sounds good. I have a feeling this is going to be a big learning curve! When i get it certified with a turbo does it matter if later on i was to change from carb turbo to injected turbo? Ie will the best slave just say rotary 12 a turbo or will it also mention carb?

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A while yet- hannahs mum is over from blighty so doing holiday things. Tramping able tasman next week.

Cant wait to fire it up though!!! Will have to sort it soon as its back to housetruck work once hannahs mums gone

Bloody wiring taking longer than i thought too- keep having to pop down to Jaycar for one of these or one of them etc. Finished my new improved version of Elfords over boost cutout

Also I tested the pressure switch's- they both work fine and turn on at exact pressure they should - indicated pressure on the boost gauge that came in rx7.

100220113438.jpg

I want another boost gauge though- one that reads up to 10 or 15 psi. The old gauge is in kg/cm2 which just seems silly. 5psi equals .35 or something dumb.

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Cool- very tempting. That is a very fantastic offer you've put up mr lego man. I will have to see how Viva goes and what happens with us and truck. We are already 4 months late on getting housetruck finished and moving south to Queenstown.

Hannah may be taking a local job here which will see us staying top of south till about may anyway so if thats the case then yeah!

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Hey alex,

Dont give up on it man, you've done all the hard yards already, when shit goes wrong I just think about how much money I would have to throw at it to fix it instantly.

So think about it this way, the absoulte WORST case scenario, go buy a whole running engine for $1000-$1500, because it will be simple enough to slot it back in (as you said, its all like factory wiring now).

You may not have the cash but remember, money is merely a material number, but a rotorized viva is something you can use and enjoy forever.

Keep that in mind, sleep on it, and it wont seem like such a hurdle anymore. Take apart the engine, diagnose and repair. Rotaries are supposed to be simpler than piston engines like anything it will take a bit of patience, and if I can rebuild a piston engine then anyone can.

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Cheers guys. Its does suck but I guess at least all the other hard work is done. Some friends on exile rotorsport have suggested it could be the front frost plugs under the oil pump cover- I didnt even think about them!!! And it makes sense as the water flowed so quickly into the sump it must be more than just the tightly squeezed water seals having gone. So this morning I'll fill it with water and see where its coming out- if the housings dont fill with water then its good and I'll pop the front cover off to hopefully expose loose frost plugs. wish me luck.

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