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Picked up an 85 Mazda Rx-7 for $3400. Was in decent shape but definitely a 10 footer paint job. With lots of random dents and paint chips. Interior was pretty nice.
Plan was to build a 13:1+ high compression 5.3 street car (e85) without aftermarket short block parts. Wanted to simply Mill a ton off a stock 706 heads to get around a 42cc chamber (ended up milling .100 to do it!) Then bolt them to an untouched JY SBE 5.3 and fly cut pistons myself as needed. Doing it more for the sound than anything… Then I want to pair the high compression to an Individual throttle body intake.
Car came with:
8.8 solid rear and 3.55 gear LSD.
Wilwood disc brakes FWD/REAR and 5 all around
Summit Warrior Drag wheels with M/T 275/50’s.
Last edited by Forcefed86; 01-31-2024 at 04:08 PM.
Picked up a “ticking” GEN4 Alum 5.3 for $650. Immediately sold the intake, heads, power steering pump and bracket, harness, and a few other odds and ends and made $550. So I have a $100 alum short block to work with at this point.
Dropped it in and went to work on the engine mounts with a “universal” $40 Amazon motor mount kit.
Then went to work on dropping the steering rod with some 1/4" plate steel. Ended up having to go back and cut out the part in red for more steering angle. Still seems plenty strong. Used a 1" aftermarket steel sway bar I had laying around.
Bought a set of $125 706 heads. Took them to a local machine shop and had them mill .100! Took 8 passes per head they said. They charged me $400. (ouch!) So I have $525 in the heads at this point with 42cc heads. With .045 HG’s and the valve reliefs I ended up cutting it net me about 13.4:1.
The $1450 ITB speed master intake setup came in and looked great. These are normally $2400, but were 40% off for Black Friday. 10x the quality of the Ebay ITB cross ram setups on ebay I had experience with.
Last edited by Forcefed86; 01-31-2024 at 02:51 PM.
Pulled the motor back out and dug into it a bit. Found the usual bum DOD lifter & cam lobe. The rest of the motor looked great. Replaced the DOD lifters with used OEM lifters I had. Cleaned the ring lands and gapped rings at .22. Plugged the DOD ports with bearings. Added new trays, cam, and oil pan and the short block was ready to go for the most part.
Bought:
$30 new trays
$332 Cam (228/232 .550"/.550" 110+5)
$109 low buck BTR ls6 spring kit W new seals.
$130 China “hot rod” oil pan w pickup.
Bought the DIY Fly cutter tools. Basically, a valve with a cutting surface you install in the head and then cut the piston to the depth you need.
Went .070 and .040 for peace of mind. Little over .0100 clearance on the exh side and well over .080 on the intake. Tools took some getting used to, but work well. Took a solid hour to get the first one right and figure it all out. The other 7 flew by. They look less deep than the factory reliefs in the newer pistons. Only about .75cc worth of relief total after measuring the best I could.
Installed bearings in the DOD ports. Used the factory head bolts and set of .045 $50 head gaskets torqued at 65ftlb. Basically had a long block ready to go at this point.
All went as planned budget wise, until I bought the manual trans.
It was MUCH more expensive than I anticipated. Decided on a new CD009 (350z 6 speed) vs the used T56 route with rebuild. The CD009 gear ratios aren’t as ideal for a drag car, but this is just a street toy (no cage) to play with. Luckily Billet ICT is just down the street and they had a factory new CD009 display unit with the shifter and LS adapter already done for $2800. Putting me at a bit over $3100 once you figure a pressure plate and flywheel kit. Compared to a used questionable T56 and then a semi questionable rebuild from a local… plus down time. I felt this was the best I could do for the $. Installed it on the motor setup clutch and dropped it all in. Fabbed up the trans mount at this time as well. 10k budget isn't going to happen with $3100+ in the trans.
Here is a good article explaining the CD009 trans if you aren't familiar with it.
Always thought it was funny, but you can use a spare flex plate to hold the flywheel in place while torqueing the crank bolts.
Bolted the $130 ebay china turbo headers and the ITB kit. Its getting pretty close! Getting started on the wiring and need to finish up 2 dozen loose ends. Hope to have it fired up by spring.
Last edited by Forcefed86; 01-31-2024 at 04:07 PM.
Any sort of filter system or scoop planned for the intake?
Plan to cut a hole in the hood for now. No scoop plans. Just letting the intake horns stick up through the hood. Been wanting to get into 3d printing, would be cool to print up a scoop. But that'd be down the road once its complete.
Haven’t built the fuel system yet but I have all the parts. AEM400 inline pump fed by the factory supply. And -8 push lock line to the filter.
I usually go with the spin-on farm style filters but a friend convinced me to use this beast. It’s a $20 77010WS Bosch inline filter with AN8 ends.
Here it is next to a summit EFI filter to show how big it is. They supposedly flow a ton. Should be more than enough for my NA needs and a little easier to package than the large farm filters I typically run.
And -6 return off the regulator. Found this new swedge lock return fitting that allows you to mount without welding to the OEM tank. Never used these before but they seem really trick! Hope it works out. As you tighten the bolt it crushes the shank like a rivit to seal it.
The filter also comes with little brass crush washers for both sides. Fittings were sourced from amazon "evil energy" fittings and hose. Used them several times. Seems to be ok quality wise. Their fittings and generic push lock hose seem to hold up well with E85. On a side note to save someone if you go to the "amazon warehouse" search. You can buy returned fittings and hose from them cheaper than the "new" prices. Always shows up looking like new for me anyway.
Less room than I had hoped for exhaust. Right now I just have some 90’s on the exh manifolds dumped. Plan to run cutouts on them so I can adjust the level of obnoxious on the fly. Would love to get a set of raspy corsas on it. But that will be down the road.
My twin turbo Notch had nothing but 3” dump tubes with cutouts on the end. With the cutout closed all but an 1/8th of an inch it quieted it down a ton. No mufflers or actual exhaust system to speak of.
01-31-2024, 01:46 PM
85 RX-7 13:1 Junkyard Screamer with ITB's 
$3100 once you figure a pressure plate and flywheel kit. Compared to a used questionable T56 and then a semi questionable rebuild from a local… plus down time. I felt this was the best I could do for the $. Installed it on the motor setup clutch and dropped it all in. Fabbed up the trans mount at this time as well. 10k budget isn't going to happen with $3100+ in the trans.
