Video Log Of The Restomodding Of My '76 RX-5 Cosmo (New Vid Dec. 23/2018) - Page 5 - RX7Club.com - Mazda RX7 Forum

Go Back  RX7Club.com - Mazda RX7 Forum > Generation Specific > Old School and Other Rotary
Reload this Page >

Video Log Of The Restomodding Of My '76 RX-5 Cosmo (New Vid Dec. 23/2018)

Old School and Other Rotary Old School and Other Rotary Powered Vehicles including performance modifications and technical support

Video Log Of The Restomodding Of My '76 RX-5 Cosmo (New Vid Dec. 23/2018)

Old 11-15-10, 05:08 AM
  #101  
keep it original!!
10 Year Member
iTrader: (3)
 
boyee's Avatar
 
Join Date: Oct 2005
Location: SF Bay Area, California
Posts: 1,276
Thanks: 0
Thanked 0 Times in 0 Posts
awesome awesome work! im really enjoying and appreciating your videos! keep up the splendid work on restoring your classic cosmo!
boyee is offline  
Old 11-15-10, 10:13 AM
  #102  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
Originally Posted by rotarycrazy View Post
how big of an air compressor do you have?
It's a consumer grade Campbell and Hausfield 40 gallon compressor rated at I think around 7 CFM @ 90 PSI. I've added another 20 gallon tank to it on the bottom drain fitting. It seems to handle the sand blasting fine and doesn't seem to mind running 2-3 hours continuously. I really only use air for blasting, the little air gun, and occasionally the big impact or a grinder.
Aaron Cake is offline  
Old 11-15-10, 10:57 AM
  #103  
Leave my avatar alone!!!
10 Year Member
iTrader: (8)
 
rotarycrazy's Avatar
 
Join Date: Feb 2005
Location: Spartanburg SC
Posts: 1,656
Thanks: 0
Thanked 0 Times in 0 Posts
hmm I have a 60 gallon tank thats rated at like 10.2 cfm at 90. I might need to invest in a sand blaster then. Since i need to blast my RX2 that way I can just take my sweet old time with it.
rotarycrazy is offline  
Old 11-17-10, 05:06 PM
  #104  
Don't worry, Be happy
 
ssonsk's Avatar
 
Join Date: Sep 2010
Location: where the fish fly and the birds swim, (Ga)
Posts: 166
Thanks: 0
Thanked 0 Times in 0 Posts
Just watched all the videos and man i learned alot from them. When do you think you're going to put the engine together (if you haven't already)?

and which cosmos came with a 20b?
ssonsk is offline  
Old 11-18-10, 12:46 PM
  #105  
whats going on?
iTrader: (1)
 
SirCygnus's Avatar
 
Join Date: Mar 2004
Location: atlanta ga
Posts: 4,875
Thanks: 0
Thanked 2 Times in 2 Posts
Originally Posted by ssonsk View Post
Just watched all the videos and man i learned alot from them. When do you think you're going to put the engine together (if you haven't already)?

and which cosmos came with a 20b?
the jc cosmo.
SirCygnus is offline  
Old 11-18-10, 01:45 PM
  #106  
Don't worry, Be happy
 
ssonsk's Avatar
 
Join Date: Sep 2010
Location: where the fish fly and the birds swim, (Ga)
Posts: 166
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by SirCygnus View Post
the jc cosmo.
oh i see

Doesn't mazda racing still sell 20b engine components and rotors?
ssonsk is offline  
Old 11-18-10, 07:26 PM
  #107  
Trunk Ornament
5 Year Member
iTrader: (11)
 
AGreen's Avatar
 
Join Date: Sep 2006
Location: Goose Creek, SC
Posts: 3,047
Thanks: 0
Thanked 1 Time in 1 Post
Awesome work Aaron. If only I had the patience for body work like you do...
AGreen is offline  
Old 11-19-10, 12:10 AM
  #108  
whats going on?
iTrader: (1)
 
SirCygnus's Avatar
 
Join Date: Mar 2004
Location: atlanta ga
Posts: 4,875
Thanks: 0
Thanked 2 Times in 2 Posts
Originally Posted by ssonsk View Post
oh i see

Doesn't mazda racing still sell 20b engine components and rotors?
mazda still makes the eshaft, and irons. th rotors, and rotor housings dont need to be from a 20b
SirCygnus is offline  
Old 11-19-10, 01:07 AM
  #109  
keep it original!!
10 Year Member
iTrader: (3)
 
boyee's Avatar
 
Join Date: Oct 2005
Location: SF Bay Area, California
Posts: 1,276
Thanks: 0
Thanked 0 Times in 0 Posts
some more inspiration for body work http://japanesenostalgiccar.com/foru...pic.php?t=4426

in case you ever need it that is...
boyee is offline  
Old 11-19-10, 09:26 AM
  #110  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
Originally Posted by rotarycrazy View Post
hmm I have a 60 gallon tank thats rated at like 10.2 cfm at 90. I might need to invest in a sand blaster then. Since i need to blast my RX2 that way I can just take my sweet old time with it.
You should be more then set up for a typical 5 or 10 gallon blaster then. If you are going to blast the sheet metal and don't have heavy rust to remove, use crushed glass and keep the pressure around 90 PSI. Turn it up a little if you end up needing more power. It is really easy to blow through sheet metal or distort it with more aggressive abrasives. I didn't care so much because I was blasting a floor, but body panels should be treated with a bit more care.

Seriously though, once you have a blaster, you'll wonder how you ever made do without it. Instead of spending 20 minutes wire-wheeling a part, it takes 1 minute of blasting.

Originally Posted by ssonsk View Post
Just watched all the videos and man i learned alot from them. When do you think you're going to put the engine together (if you haven't already)?
and which cosmos came with a 20b?
I'm in the process of porting the engine, which should be done this weekend. The port job isn't very typical from what is normally seen, as I'm not going for all out power with this build. I still need to clean the engine parts again, blast them and paint them, so it will be a few weeks before the engine goes together.

The Mazda Eunos/JC Cosmo, sold in the early 90s Japan-only was equipped with the 20B

Originally Posted by ssonsk View Post
oh i see
Doesn't mazda racing still sell 20b engine components and rotors?
Most 20B parts can still be ordered at the dealer as previously mentioned. One exception is the "thick" center iron with the bearing. They seem to be no longer available.

Originally Posted by AGreen View Post
Awesome work Aaron. If only I had the patience for body work like you do...
I don't really have the patience for body work, it's just something I do if I have to. Floor patching and the like isn't really hard work. But I worry once I get into some of the cosmetic patching...

Originally Posted by boyee View Post
some more inspiration for body work http://japanesenostalgiccar.com/foru...pic.php?t=4426
in case you ever need it that is...
Holy crap...I don't know what to say. I'm going to have to spend the next few hours reading that thread.
Aaron Cake is offline  
Old 11-19-10, 12:59 PM
  #111  
Now w/ 12A SP
iTrader: (3)
 
PK_12A's Avatar
 
Join Date: Jun 2010
Location: Collinsville, OK.
Posts: 538
Thanks: 0
Thanked 0 Times in 0 Posts
Arron loving the Cosmo restomod and reading trough tina's resto you do awsome work and I will be observing the progress. Looks like a good base for what you want should come out great.
PK_12A is offline  
Old 11-19-10, 11:32 PM
  #112  
Don't worry, Be happy
 
ssonsk's Avatar
 
Join Date: Sep 2010
Location: where the fish fly and the birds swim, (Ga)
Posts: 166
Thanks: 0
Thanked 0 Times in 0 Posts
oh i see, one mroe question

are rebuilding rotary engines as easy as they look?
ssonsk is offline  
Old 11-20-10, 10:30 AM
  #113  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
It's pretty easy if you have some mechanical experience and skill. I'll be posting the video of the rebuild within 30 days I think, so you'll find out soon.
Aaron Cake is offline  
Old 11-20-10, 08:34 PM
  #114  
Senior Member
iTrader: (4)
 
raffer's Avatar
 
Join Date: Oct 2008
Location: Connecticut
Posts: 423
Thanked 0 Times in 0 Posts
Great work and good info . I been watching your videos .
raffer is offline  
Old 11-20-10, 10:23 PM
  #115  
Full Member
 
kevk's Avatar
 
Join Date: Jun 2010
Location: virgina
Posts: 104
Thanks: 0
Thanked 0 Times in 0 Posts
the best media to use to remove paint is baking soda itt does not leave a profile on the metal
kevk is offline  
Old 11-20-10, 11:00 PM
  #116  
Turbo vert
10 Year Member
iTrader: (33)
 
just startn's Avatar
 
Join Date: Aug 2005
Location: Elyria, OH
Posts: 2,696
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by kevk View Post
the best media to use to remove paint is baking soda itt does not leave a profile on the metal
You are correct sir. My personal opinion is its pretty expensive.
just startn is offline  
Old 11-20-10, 11:01 PM
  #117  
Turbo vert
10 Year Member
iTrader: (33)
 
just startn's Avatar
 
Join Date: Aug 2005
Location: Elyria, OH
Posts: 2,696
Thanks: 0
Thanked 0 Times in 0 Posts
Aaron, when you are done patching all the holes have you gave it any thought what rust proofing you will be applying?
just startn is offline  
Old 11-21-10, 10:21 AM
  #118  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
Baking soda (actually, remember that the industrial version has far larger grains) is also nice because it has a natural anti-corrosion effect. Soda blasted parts can generally hang out in bare metal for a few months without worrying about rust.

I'll be applying a zinc-rich weld-through primer on panels where the backside will be hidden after they are welded in. Then after all the work is done, there are several products with long nozzles designed for rust coating hidden spaces like frame rails and rocker panels. On surfaces that have both sides exposed, I'll use POR-15. The interior floor, since it rotted from the inside out, will get a full coating of POR-15. The underside is for the most part already well undercoated. I'm just trying to decide whether to give the engine bay the whole POR-15 treatment or to just give it a shot of some high quality black paint (POR-15 "Hardnose" black, or rocker guard).
Aaron Cake is offline  
Old 11-21-10, 02:56 PM
  #119  
Don't worry, Be happy
 
ssonsk's Avatar
 
Join Date: Sep 2010
Location: where the fish fly and the birds swim, (Ga)
Posts: 166
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by Aaron Cake View Post
It's pretty easy if you have some mechanical experience and skill. I'll be posting the video of the rebuild within 30 days I think, so you'll find out soon.
sweet, are you going to show the porting job?
ssonsk is offline  
Old 11-24-10, 09:58 AM
  #120  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
Yes, the porting will be shown. But as I mentioned, it isn't the typical porting job. It is very conservative, only bringing the exhaust ports just shy of stock 2nd gen timings and only moving the primary ports down a little to boost midrange. The secondary and aux ports aren't touched at all.
Aaron Cake is offline  
Old 11-26-10, 09:31 PM
  #121  
Dragons' Breath
 
gerald m's Avatar
 
Join Date: Sep 2010
Location: Pump Handle, SK. Canada
Posts: 1,126
Thanks: 0
Thanked 0 Times in 0 Posts
very interesting I just wanted to get down here and subscribe .. ==I love this stuff .. waiting for the port job..
gerald m is offline  
Old 12-04-10, 03:31 PM
  #122  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
Part 7: My 76 Mazda RX-5 Cosmo Restoration - Intake and Exhaust Porting

Has it been nearly a month since my last episode? Wow, time does indeed fly. I've been quite busy preparing to build the engine. So in part 7, I cover the intake and exhaust porting. The engine is being built with GSL-SE 6 port plates and the Cosmo rotor housings as the basis for a 6 port turbo setup. This port job is fairly conservative, only opening up the primary ports a little and bringing the exhaust ports close to 2nd gen RX-7 specs. The goal is to maintain fuel economy, low and midrange torque, and idle quality. This episode covers everything involved in porting including: marking out the new ports, grinding the port shape, smoothing the bowls, smoothing port to runner transitions, smoothing the runners, grinding and blending the exhaust ports.

http://www.youtube.com/watch?v=y1Gy5sVMK3o
Aaron Cake is offline  
Old 12-04-10, 03:57 PM
  #123  
Senior Member
iTrader: (3)
 
Gryffinwings's Avatar
 
Join Date: Apr 2010
Location: San Diego, CA
Posts: 434
Thanks: 0
Thanked 0 Times in 0 Posts
Those are very nice ports
Gryffinwings is offline  
Old 12-04-10, 04:18 PM
  #124  
Turbo vert
10 Year Member
iTrader: (33)
 
just startn's Avatar
 
Join Date: Aug 2005
Location: Elyria, OH
Posts: 2,696
Thanks: 0
Thanked 0 Times in 0 Posts
When you port aaron do you only use stones/sandpaper or do you use burr bits/stones/sandpaper?
just startn is offline  
Old 12-05-10, 10:22 AM
  #125  
Engine, Not Motor
Thread Starter
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Thanks: 0
Thanked 22 Times in 21 Posts
I use the grinding stones on the irons to get the port shape and runner transitions all worked out. Then I just use the sanding rolls to polish out any roughness left over from the stones and to adjust all the ports and runners so they match, if necessary.

The housings are a little more complicated because they are a mixture of a steel sleeve and aluminum casting. Truthfully, I dislike porting rotor housings for this reason. Generally I start with a grinding stone to quickly bring down the chrome/steel to as close to the final port shape as I can get it, then switch to a rotary file to eat away the aluminum. It usually takes several bit swaps between a grinding stone and a rotary file as the aluminum has to be ground away, then the steel/chrome again, then the aluminum, then the steel/chrome, etc. Then when the port shape is finalized and the runner transition is done, I follow up with the sanding roll to smooth everything out and make any final adjustments to both ports.
Aaron Cake is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: