NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   Building A Rotary On A Budget (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/building-rotary-budget-33183/)

turboaddict 02-04-2004 02:29 AM

Alright here's my dilemma, my motor has blown and its junk. Too many miles and a hard life. I picked up a s4 with 53k that had a engine fire about a year ago, tore it down and inspected it. I was planning on porting it and building it when i had the money. Well i don't have the money , but i need my car up and going. So what I need is to know if what i can afford to do will be compatible with my future plans for the car.If it is not then i will have to save alot more for a jdm motor. I dont wanna ruin this motor just becouse im in a pinch.

So i have this plan in mind:

*Rotary Aviation basic rebuild kit

*Street port using racing beat templates (this would be my first porting job on a rotary and i dont wanna risk screwing it up)

*Porting the exhaust as per Itos tutorial

*Port match all runners and manifolds

*Atkins gasket set (yeah i know it has the o-rings also but its still the cheapest way to get all the gaskets i need)



The plans for the car would be stock boost levels at first , but as i got more money: fuel, turbo and intercooler upgrades would come. meaning the car would be expected to put out decent power levels= 300hp +. I figured that the lower comp. rotors would be better with higher amounts of boost to avoid detanation.Is this a feesible plan or should i just wait to build my motor till i have the money and save for a stock replacement? Is there any suggestions otherwise that would be a better plan? Any other parts that should be replaced with the rebuild?

Thank you for all your help i just dont wanna shoot myself in the foot.

ryosuke_fc 02-05-2004 02:09 PM

Hmmm... I don't think I quite understand. Are you planning to rebuild your S5 motor? You mention the S4, but I don't see where it comes into your plan, except you said you might want to use the rotors. What I've figured out is that lower comp. rotors allow you to run higher boost, while higher comp. rotors give you more low-end power and response, but they're more prone to problems caused by improper tuning. You can use either set of rotors. I believe that you just have to have a counter-weight that matches your rotors.



You won't know what needs to be replaced until you tear the engine apart. I bought a full rebuild kit from Atkins including bearings and everything for around $1000, but I probably could have got away with a lot less because my engine had only 60k miles on it. It had just been carbon-locked from sitting in a garage for 5 years or more. My only suggestion is to make sure you take a lot of time when you clearance the rotors and seals and everything. I made the mistake of getting in a hurry at this point, and I paid for it in the end. My car runs alright, but compression isn't where it should be even after a few thousand miles. I'll probably be tearing the engine down in the spring when I drop the transmission to replace a couple of synchros.

rmaiersg 02-05-2004 02:42 PM

It's difficult to get a solid engine on a slim budget. Especially if you want to modify your engine. Stuff is going to want to break more often. With the stock ECU and old housings it might get sketchy with porting but i don'thave any experience with porting on my own. Simply heresay and my intuition.

turboaddict 02-05-2004 08:27 PM

okay im sorry i thought it was clear the motor i would be rebuilding is out of a 88 turbo 2 with only 53k on it. the motor is clean and everything is in specs. just needs a basic rebuild. I know its hard to get a solid motor on my budget. But im not looking for a super high power motor. i thought 300hp would be a realistic goal and i dont plan on this motor lasting indefinately just for maybe 2 years then another motor would come.

thanks for your input

banzaitoyota 02-05-2004 08:45 PM

shortcuts are only only asking for trouble. Be happy with the stock output on a budget rebuild


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