12a SP Build-Up Winter Project
11-25-12, 04:46 AM
#1
12a SP Build-Up Winter Project
The cold weather is here once again in NYC and for me that usually signifies that it is time to freeze my ***** off building something. This winter I thought I would take a different approach. Instead of being outside where I am fighting short daylight hours or inclement weather, this winter I will be putting together a motor in the climate controlled bliss that is my basement. 
I have been slowly gathering parts over the last few years, and finally have enough pieces to put this together
here are some of my key pieces...
First up are some nicely ported and lapped plates I picked up from Sean (82 Trans-am) on here I think
for you Jeff
To compliment I was thinking of using some early 12a housings from a half bridge motor I took apart a while back. They are in fair condition, with the rear housing starting to show just the tiniest bit of flaking. I have housings nicer than these, but I figured that since they were ported already (and I have NO SKILLS in this area) that these would be a nice match.
here is a pic of the flaking one
since these came from a motor that was BP there are notches in the housings but they do not extend into the water jacket so I figured it would be ok to use in this build
I have been slowly gathering parts over the last few years, and finally have enough pieces to put this together
here are some of my key pieces...
First up are some nicely ported and lapped plates I picked up from Sean (82 Trans-am) on here I think
for you Jeff
To compliment I was thinking of using some early 12a housings from a half bridge motor I took apart a while back. They are in fair condition, with the rear housing starting to show just the tiniest bit of flaking. I have housings nicer than these, but I figured that since they were ported already (and I have NO SKILLS in this area) that these would be a nice match.
here is a pic of the flaking one
since these came from a motor that was BP there are notches in the housings but they do not extend into the water jacket so I figured it would be ok to use in this build
Last edited by cfamilyfix; 11-25-12 at 05:00 AM. Reason: fix the pics
11-25-12, 05:09 AM
#4
here is my work area...its no monster garage, but at least I will be out of the elements for a change
I have a rebuild kit that consists of new apex seals and springs, new corner seals, fd corner seal springs, new side seals and springs, and new oil control o-rings.
I am considering using goopy or atkins apex seals since I may have a tough time during break in with a less than perfect housing. I havent really measured my oil control rings yet either and might have to spring for a set of those as well...ouch 300 bucks!
I have a rebuild kit that consists of new apex seals and springs, new corner seals, fd corner seal springs, new side seals and springs, and new oil control o-rings.
I am considering using goopy or atkins apex seals since I may have a tough time during break in with a less than perfect housing. I havent really measured my oil control rings yet either and might have to spring for a set of those as well...ouch 300 bucks!
11-25-12, 05:17 AM
#5
I am hoping for about 165hp or so. I will be running a weber IDF carb setup from Rotary Engineering and long primary exhaust with RB prima flow muffler, as well as all the supporting ignition upgrades (1 msd box and direct fire on leading with all msd coils and stock trailing with msd coil)
11-26-12, 12:46 PM
#7
Ray, he's going to need a good set. Later. After his engine has been together for a few miles, because it will smoke at startup and then smoke all the time.
Why would I predict such an unpleasant outcome? Remember what I said about resurfaced nitrided irons?
Sorry to be a downer.
I don't like the port job on those housings either. Looks uneven and I don't know what the port timing is.
cfamilyfix, use those plates and housings since you have them, but plan on another rebuild after this one starts to smoke. Things get better with practice, right?
Why would I predict such an unpleasant outcome? Remember what I said about resurfaced nitrided irons?
Sorry to be a downer.
I don't like the port job on those housings either. Looks uneven and I don't know what the port timing is.
cfamilyfix, use those plates and housings since you have them, but plan on another rebuild after this one starts to smoke. Things get better with practice, right?
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11-26-12, 01:22 PM
#8
Can I re nitrate the plates? Yeah I was reading what you were saying in one of Ray's threads about that...I look at it this way...none of my rotories are daily driven, in fact the GLC gets driven the most and in 3 seasons I have put at most 1700 miles on it so if 10k is the limit on a engine with non nitrided plates I might still be in good shape lol. How does mazdatrix and racing beat do it? Don't they insist on resurfacing with even a base rebuild? They have to offer some kind of a warranty as well. As for the port timing on those plates...I am a little concerned as well, but maybe putting them next to a stock plate will help to determine the ports timing. I will just have to see. Thanks for the concerns and keep them coming. I also read something you posted about using fd corner seals as being a bad move as well especially with non nitrided plates. Wish I read that before I purchased
11-26-12, 01:53 PM
#9
Like I said, build this thing. It's your first time. It doesn't have to be perfect. Use your parts. Like you said it won't be daily driven, so have fun. Blow it up. Or baby it. It doesn't matter. It's a wear item. It's just that your particular engine will wear everything out a lot faster than a better selection of parts would have. So don't worry about it.
My first build wasn't all that great, but it ran. Then the guy overheated it. The second build was better and is still together and alive today.
You know, I'm curious how well a resurfaced engine will actually run. I know it will have higher friction on all seals on the sides of the rotor, leading to hotter temps, leading to quicker spring death, but that won't happen for a little while yet. I wonder if this engien will be harder for the starter to crank? Especially on cold days?
Oh to answer your question about why big shops recommend resurfacing, it's how they make their money. It's a service. Lots of shops charge big bucks for "service".
Racing Beat also insists that only the GSL-SE came stock with a so called high volume oil pump, in order to sell you one if you've got a different model, thus placing the mighty GSL-SE on a pedestal. But we know the truth that there were a lot more models that had this pump, mainly all 83 and later 12As, which are easy enough to grab. And that's just one example.
Another is the RB prepped Holley where they perform 500 dollars worth of mods to make it run on a separate runner manifold. But we know that any off the shelf Holley will work on a rotary with just an open spacer under it to allow the reversion pulses to lose their strength and act more like an open plenum on a V8, which the carb was designed for in the first place. RB was just after big numbers like 550cfm and later 600cfm. But how do they run? Hit or miss. I've got an RB 600 I got in a trade and it seems my Nikki is more fun to drive - the race prepped one I posted about a month ago, and would much rather use it in my MG, if I could make it fit under the low hood. Currently working on a solution for that...
They also push "streetable ports" or streetports which honestly work better on the track than they do on the street since you do lose noticeable amounts of low end torque - my personal finding. I prefer 74 spec ports for the street, but these are stock on some models (74-75 and all T2 and FD) so no money can be made unless you're just selling a template which anybody could make themselves with access to a stock 74 port to copy.
So buyer beware.
But we as a community wouldn't be where were are today without them, well without the forums and the internet as well I suppose. We've come a long way. With every noob building an engine, that's one less sale for the big shops. You're taking food off their tables, man! You're supposed to be made to feel guilty, I guess. I don't know, maybe this is becoming tangent talk now. Well, have fun with your build!
My first build wasn't all that great, but it ran. Then the guy overheated it. The second build was better and is still together and alive today.
You know, I'm curious how well a resurfaced engine will actually run. I know it will have higher friction on all seals on the sides of the rotor, leading to hotter temps, leading to quicker spring death, but that won't happen for a little while yet. I wonder if this engien will be harder for the starter to crank? Especially on cold days?
Oh to answer your question about why big shops recommend resurfacing, it's how they make their money. It's a service. Lots of shops charge big bucks for "service".
Racing Beat also insists that only the GSL-SE came stock with a so called high volume oil pump, in order to sell you one if you've got a different model, thus placing the mighty GSL-SE on a pedestal. But we know the truth that there were a lot more models that had this pump, mainly all 83 and later 12As, which are easy enough to grab. And that's just one example.
Another is the RB prepped Holley where they perform 500 dollars worth of mods to make it run on a separate runner manifold. But we know that any off the shelf Holley will work on a rotary with just an open spacer under it to allow the reversion pulses to lose their strength and act more like an open plenum on a V8, which the carb was designed for in the first place. RB was just after big numbers like 550cfm and later 600cfm. But how do they run? Hit or miss. I've got an RB 600 I got in a trade and it seems my Nikki is more fun to drive - the race prepped one I posted about a month ago, and would much rather use it in my MG, if I could make it fit under the low hood. Currently working on a solution for that...
They also push "streetable ports" or streetports which honestly work better on the track than they do on the street since you do lose noticeable amounts of low end torque - my personal finding. I prefer 74 spec ports for the street, but these are stock on some models (74-75 and all T2 and FD) so no money can be made unless you're just selling a template which anybody could make themselves with access to a stock 74 port to copy.
So buyer beware.
But we as a community wouldn't be where were are today without them, well without the forums and the internet as well I suppose. We've come a long way. With every noob building an engine, that's one less sale for the big shops. You're taking food off their tables, man! You're supposed to be made to feel guilty, I guess. I don't know, maybe this is becoming tangent talk now. Well, have fun with your build!
11-26-12, 02:58 PM
#10
You know Jeff, no sooner than I had a set of irons lapped (to the tune of $280) I read your comments about losing the nitride being a bad idea, and then just a few days later I tore down a 12A that had crappy rotor housings (what else is new?) but almost perfect irons, the nitride surface still in great shape. Just my luck, now I'm in the same boat as Colin, a great set of freshly lapped irons that probably won't perform as well as if I'd left them alone.
And your analysis of the "big shops" is spot on, I'm convinced the folks who lapped my housings were much more concerned about providing a "service" than about the quality or expense of the rebuild I'd end up with. (I'm sympathetic with the professional rotary shops, they do need to make a living, I'd just prefer it not be my dollar).
The lapped irons do look great, however, just like the one's in Colin's pics, and this does seem to be an ideal starting surface for a rebuild, if it weren't for the friction and softness.
So is there any way to:
A) get the freshly lapped surfaces retreated with nitride? I read up on this, it seems to be a fairly common procedure in the industrial world, although it involves using a pressurized plasma, a procedure that would be hard to reproduce without the specialized equipment usually used.
B) otherwise treat the surface to harden it and reduce friction? I'm thinking cermet here, a metallic-ceramic treatment that some claim works for rotor housings.
And thanks Jeff and all you other wizened rotor heads for sharing the street knowledge!
And your analysis of the "big shops" is spot on, I'm convinced the folks who lapped my housings were much more concerned about providing a "service" than about the quality or expense of the rebuild I'd end up with. (I'm sympathetic with the professional rotary shops, they do need to make a living, I'd just prefer it not be my dollar).
The lapped irons do look great, however, just like the one's in Colin's pics, and this does seem to be an ideal starting surface for a rebuild, if it weren't for the friction and softness.
So is there any way to:
A) get the freshly lapped surfaces retreated with nitride? I read up on this, it seems to be a fairly common procedure in the industrial world, although it involves using a pressurized plasma, a procedure that would be hard to reproduce without the specialized equipment usually used.
B) otherwise treat the surface to harden it and reduce friction? I'm thinking cermet here, a metallic-ceramic treatment that some claim works for rotor housings.
And thanks Jeff and all you other wizened rotor heads for sharing the street knowledge!
11-26-12, 07:13 PM
#11
I definitely appreciate the advice. I will keep this updated as I move foward with assembly. I just kicked out for my last order to mazdatrix for all the little stuff...corner seal plugs, front and rear seal, pilot seal etc. The only other money I may spend at this point is on a different set of apex seals (goopy etc) I have brand new oem that I waas gonna use but I will save those for the 85auto's rebuild since that engine will likely not see any additional porting and will be using my minty housings if need be. With this build I am already so far out of the box, what's one more variable???lol. Plus I figure since these housings have just a minor bit of flaking that I will need all the compression I can get and a shorter break in time to boot
12-05-12, 12:49 AM
#12
Well since I posted in Ray's thread, I figure I would update hear as well. Just ordered a fresh set of Atkinks apex seals, since I too, am committed to using less than perfect rotor housings. Also got in my hylomar and front a rear main seals so assembly will begin as soon as the Atkins seals arrive
12-07-12, 11:07 PM
#15
Well the last bits of engine rebuild stuff has arrived so it will be time to start assembling this monster pretty soon. I'excited to finally start. The only part of this process I am a bit unfamiliarwith is grinding the the side seals to fit properly. I;m half tempted to take a junk rotor and make a jig to cut the proper angle on the seals, but I might just do it free hand alla Aaron Cake. Here are the new apex seals that arrived yesterday from Atkins...
Maybe this is why they cost 47 bucks to ship.....
here is the bill to prove it...
and some other bits from mazdatrix that have arrived...when did hylomar not come in a permetex container any more???
Maybe this is why they cost 47 bucks to ship.....
here is the bill to prove it...
and some other bits from mazdatrix that have arrived...when did hylomar not come in a permetex container any more???
12-10-12, 12:58 PM
#20
my advice: if this was a business for you, then you might have to consider time, but since this is a winter project, i would say do what i do. get like a 100 or 220 grit wet/dry sandpaper and setup a space with a nice flat surface. go to town, maybe do 1 or 2 a day. that's how i do mine. it's fairly simple to get the right angle with clean sheet of paper. just be cautious because your two dangers are being cut or breaking the seal if you are two forceful with it.
12-10-12, 02:20 PM
#21
Glad you're getting some use out of those irons!
I got massively overcharged for shipping with atkins last time I bought some gaskets from them as well. Charged me over $20, and tacked on a fee for using paypal and then sent it in a postal envelope to the tune of $3.... I emailed them about it and never got a reply. What a joke.
Anyway, good luck with the build! I'll have to check it out once you're done.
I got massively overcharged for shipping with atkins last time I bought some gaskets from them as well. Charged me over $20, and tacked on a fee for using paypal and then sent it in a postal envelope to the tune of $3.... I emailed them about it and never got a reply. What a joke.
Anyway, good luck with the build! I'll have to check it out once you're done.
01-15-13, 11:33 PM
#22
Well time to update this a bit...got my rotors all pre assembled, cutting down the side seals wasnt all that bad. I found it fairly easy to get the perfect shape by using a fine file and a feeler gauge...ummm I believe .02 to.05mm between the side seal and corner seal is correct but dont quote me as my manual is not in front of me, lol. still want to paint my rotor housings and then final assembly can begin. Also I got a few front spacers (T, V, Y amd I think X) as well as some torrington bearings from mazdatrix so when it is time to set my endplay I wont be fishing around for what I need. I found a nice set of oil control rings to install my new orings in and a fresh set of used springs...oil control ring protrusion was right where it needed to be so I went for it. Pics to follow later this week as well as painting and final assembly.
01-26-13, 11:30 PM
#23
Time to move this along...the weather has been so bad outside that the only place to build was in the basement...
painted my housings
and started assembling...
The keg is finally complete...there were a couple of "o **** " moments along the way. I managed to break a corner seal on the front rotor and had to remove the rear rotor after rear housing install due to corner seal miss allignment. Called in a friend's help along the way and all is well. Here is the video of me turning over the motor by hand after torquing it all down...
it turns smoothly and makes all the correct noises so I think it will turn out ok.
painted my housings
and started assembling...
The keg is finally complete...there were a couple of "o **** " moments along the way. I managed to break a corner seal on the front rotor and had to remove the rear rotor after rear housing install due to corner seal miss allignment. Called in a friend's help along the way and all is well. Here is the video of me turning over the motor by hand after torquing it all down...
it turns smoothly and makes all the correct noises so I think it will turn out ok.
01-26-13, 11:35 PM
#24
still have to set my end play and install my flywheel and counter weight as well as my oil pick up and oil pan, but I think the hard part is behind me. Not sure what vehicle this is going into yet, but I think the 81 is the best candidate since that is my experimental build anyway
02-04-13, 11:38 PM
#25
End play and flywheel should be done this weekend, but undecided on a clutch set up. I have a very extreme brass button clutch that I could use with a very heavy pressure plate, but I am thinking of going for something along the lines of a street/ strip set up from mazdatrix