magnumP5's RX-7 Build Thread

[magnumP5]

So I went out and fiddled with things again; this time I took some video. I don't know how to embed these so direct links will have to suffice.

First, here's the behavior when cold:
https://picasaweb.google.com/lh/photo/u6TsKh2YTvH9LikTqEkGxA?feat=directlink

Next, fully warmed up:
https://picasaweb.google.com/lh/photo/FvA0WS0LMlvR9v6QA9J2gg?feat=directlink

Last, here's after revving the piss out of the engine. Notice the coolant level:
https://picasaweb.google.com/lh/photo/-Q8k7YU_jl-OYVVNQa8rvQ?feat=directlink

Just for giggles, I think I may have found an exhaust leak. Yes, I know I should not be revving the engine like this:
https://picasaweb.google.com/lh/photo/N3860T8fvZsqOt4EZniGaw?feat=directlink

Any ideas what this might indicate?

 

[Signal 2]

I don't know, maybe I'm missing something, but nothing seems that out of the ordinary to me. In the order of the videos, it looks like you have...(a) coolant warming and expanding because the system isn't pressurized, (b) coolant beginning to boil for the same reason and (c) coolant boiling hard.

Have you checked the line going to your overflow for kinks or blockages? If you've ever considered upgrading to a larger all-metal radiator suitable for track duty, maybe nows the time. Just look over everything from top to bottom while your at it.

 

[magnumP5]

I don't know, maybe I'm missing something, but nothing seems that out of the ordinary to me. In the order of the videos, it looks like you have...(a) coolant warming and expanding because the system isn't pressurized, (b) coolant beginning to boil for the same reason and (c) coolant boiling hard.

Have you checked the line going to your overflow for kinks or blockages?

Yep, checked that yesterday and everything seems fine; I mean, I can blow through it with ease. The issue is, with the radiator cap on the system is constantly venting. When it's fully warmed up there are gases being constantly vented into the overflow bottle and occasionally it takes coolant with it. When I add more coolant to the radiator (with the car on) it all just bubbles out until what you saw in the third video is left. Finally enough coolant is pushed out and the low coolant buzzer comes on now matter how much coolant I've added. To me, this isn't normal - I mean, my truck's overflow bottle is never bubbling no matter how hard I drive it.

 

[mymmeryloss]

i would wait and see what everything does when u install the new radiator and then test it out...

 

[magnumP5]

i would wait and see what everything does when u install the new radiator and then test it out...

I could do that, but I think I'm just going to tear everything down just to be sure. If I'm lucky it's just a soft seal failure so that'll be like $200 for a seal kit plus the time it takes to do everything. It'll also be a good learning experiment.

However, if I tear apart the engine and notice significant wear or failures it looks like I'm going to be in the $1k+ range for just rebuilding this engine! This puts me at a point where a decision needs to be made, so I'm looking for advice. The decision would be to either rebuild the (6-port) engine or to go ahead and start my long-term engine plans (4-port). Sure the latter will be more expensive because it would also involve the purchase of another engine on top of a rebuild kit but I'm not sure I want to spend $1k on an engine I may end up ditching in a year or two.

The "long-term" engine plans involve taking a turbo (4-port) motor and swapping in the higher compression rotating assembly from the N/A (6-port) engine. That, on top of an ITB intake system, custom exhaust, porting and a standalone ECU should yield some good power numbers, but obviously cost a lot of money and require a lot of down time. I'm currently trying to determine if I can run the 4-port motor in the N/A configuration off the stock 6-port wiring harness and ECU. If that's possible that may just work as an intermediary until I have all the funds for the standalone, intake and exhaust systems.

Of course I could just say "screw it" and drop in a 20B or, Heaven forbid, a LS1 or just give up and sell the thing...

 

[o0n8]

i guess it depends on how comitted to the car you are. If this is the car you want for a long time I'd say do the turbo 4-port since you're tearing it down anyway. I wouldn't do the ls swap unless that's what you wanted that for the long term. To me it would be pointless to do the ls swap because it doen't sound like that's what you want.

 

[Lewis7789]

I agree with Nate, Jon. Your RX-7 is in really good shape body wise and you said you've wanted a project car. So I think you've got the perfect platform. And you've already got money invested in the suspension and wheels. Think of it like the older hot rod guys think about their projects, they work on the for years and have them for decades.

I met a fellow last week with a 90 TurboII that was absolutely gorgeous. (I'll post pics when I get home, I took them just for you). And he's had the car since 95. Married, 4 kids and no plans on ever selling it. I think that's how a lot of us will be in 20 years, still all hanging out and still owning our Mazdas.

Don't get discouraged and count your blessings and look on the bright side. Sorry, I'm an optimist. If you need any help, let me know, buddy.

 

[magnumP5]

Thanks for the input guys. LOL, and Evan how you have anxiety and be an optimist?! Unfortunately, I'm a pessimist by nature. It's too bad you guys are so far away or I'd have you over helping me tear crap apart every weekend.

I figure my current plan is to just tear down the existing engine and go from there. If it's just soft seals I'll spend the $200, rebuild it and just call this a learning experience. If it's more serious than that I'm looking for a turbo motor. I'm currently looking into getting it running on the existing ECU and wiring harness but if that doesn't work it'll just be down longer as I accumulate the more expensive parts. There's someone local parting out a '88 TII so I'm going to call and inquire about the engine.

In either plan some other tasks will also be completed such as P/S (and maybe A/C and gutting the heater core) removal and battery relocation.

Sit back everyone - there's going to start being a lot more pictures around here!

 

[Wagonbacker9]

now driving an LS2... I can say you wouldn't be sorry you went that route. A couple weeks back I stumbled on a 240 that had an LS2 swap. But that said, I think you should stay rotary.

 

[THE Phen]

I know this post may get flagged for this comment, but it was said by my friend Brian a long time ago, and it still resounds in my mind from time to time...

"A V8 swap in an RX car is gayer than two dicks in the same asshole."

When he first said it, I choked on my beer. But... it stuck with me like a bad case of the clap.

 

[mymmeryloss]

I'm with phen, v8s have no place in an rx imo!

Do what u want to do, but please keep it rotary!

And a good project always costs a lot, but is always worth it even if it never runs again!

 

[magnumP5]

LOL, I knew the V8 talk would stir some people.

Well, any doubts that something was seriously wrong internally have been silenced. I barely got the car to start after work. It sounded like it started on one rotor and then the 2nd kicked in about 30 seconds later. After I got home and changed it took me 30 minutes to get it started (hot start) again! Same thing, sounded really week and could barely hold idle and after some throttle input and 30 seconds later it kicked into full life and the low coolant buzzer went off, LOL!

So far the intake, battery, oil cooler and radiator assemblies have been removed and all the fluids have been drained. Now is the tedious task of labelling wires and hoses before disconnecting them. I'm really not looking forward to unbolting the transmission again...

 

[Signal 2]

......it was said by my friend Brian a long time ago, and it still resounds in my mind from time to time...
"A V8 swap in an RX car is gayer than two dicks in the same asshole."

^And your friend Brian would know all about weird gay sex how?

My history with a rotary goes back to 1981. Owned my FD for the past 8 or 9 yrs. Do all my own maintenance and rebuilt the engine once. That said there is absolutely nothing wrong with a WELL DONE LSX swap. Just another perfornance mod...albeit a major one. Expensive too if you do it right.
Guys running around making off-hand comments like the above, waxing on and on about this "soul of the car" nonsense...it's just that. In some cases at least, it's a rationalization for all the money they shouldn't have dumped into their car. In others it's simple jealousy. And in still others they've only owned the car a few months, they're infatuated like little boys with a new puppy... and are just clueless.

Magnum,
First, sorry about getting off-topic in your thread. Second, I'm with you now....with the stumbling idle that clears up on it's own I have no doubt about a coolant seal failure anymore. That was one of the major symtoms that I had been looking for in combination with the others.
Either way you go with the engine replacement, you might look into Auxillary Injection (methanol/water or just water) to help with longevity and knock, especially if you go forced induction.

 

[magnumP5]

Well, I had this long drawn out post going and the forums crapped out so I lost everything. You'll have to deal with pictures and terse narration now...

Battery removed. All this space will remain open because I'm relocating the battery to the storage bin behind the passenger's seat.

Same thing on the other side. Airbox removed.

All fluids drained, belts removed, P/S pump detached from it's bracket and I think I had removed the fan as well at this point.

Radiator and shroud removed.

Now I had originally intended to not remove any of the intake manifold until the engine was on a stand, but because the primary wiring harness is routed underneath the VDI manifold it all has to come off. First the throttle body; you piston guys have it easy as this thing is MASSIVE. It has three barrels and two sets of butterflies. Unfortunately I didn't take any pictures of it.

Upper intake manifold removed.

Here's the engine with the VDI manifold and the secondary fuel rail removed. This manifold will have to go back on before I pull the engine as one of the hoist points is on it.

The funny things you find when you pull apart a car for the first time... You're looking at the oil injectors for the primary ports. Note the front injector line is missing a huge section. Who knows the last time that injector saw any oil and that couldn't have been good for the engine.

Above the strut tower on the passenger's side is where the cruise control and sub-zero start coolant bottle existed. The cruise control is going away for sure but I'm considering keeping the coolant bottle. I'm thinking of filling it with two-stroke engine oil and plumbing it to the oil metering pump. This way I can retain the factory oil injection system but it won't be using oil from the engine so I can run synthetic in the engine.

Here's the engine as it sits now. All the remains before the engine can be pulled is to remove three more bolts on the transmission and the oil temperature and pressure sensor wires.

The new radiator also came in. A comparison shot of the stock versus the new Koyo:

So after seeing the engine bay stripped down I've just about convinced to ditch both P/S and A/C for good. I'm also about certain I'm going to eliminate all the airpump crap so that means either wiring open the VDI and auxilliary ports on the intake manifold, which will hurt power and torque down low, or going with a 4-port engine. This should leave the bay wide open for any future work.

 

[mymmeryloss]

4 port!

And I'm still amazed how small these engines r. Once its unbolted u could throw it on ur shoulder and lift it out of the bay urself! Haha

 

[Signal 2]

Damn you work fast. Curious to see what the housing looks like from that broken OMP line.

 

[magnumP5]

4 port!

And I'm still amazed how small these engines r. Once its unbolted u could throw it on ur shoulder and lift it out of the bay urself! Haha

Well the 4-port won't be turbocharged but it'll certainly make things simpler, which is what I want. They may be small but appearances are deceiving. I'm sure you know how much they weight but a stock 13B weights about the same as an all-aluminum small block chevy engine. Now Racing Beat offers aluminum "irons" for about $1k a piece and if used the total weight of the engine is around 100 lbs - definitely "throw it over your shoulder" weight.

Damn you work fast. Curious to see what the housing looks like from that broken OMP line.

Ha, this was working for about 3 hours last night and about 5 hours today - I feel like I'm taking forever. I probably wasn't as deligent with labelling hoses and wires as I should have been. I figured I'll either be getting rid of them, or because they're moulded it shouldn't be too hard to figure out where they go.

 

[magnumP5]

More progress today. Got the last hoses and wires disconnected and unbolted the starter and transmission. Made a gamble that Harbo Freight would be open on Easter and won. Picked up a one ton engine hoist and 1000 lb engine stand for less than $200. Now I just need an adaptor so I can mount the engine on the stand.

And here's the obligatory empty engine bay shot. I need to get one with me standing in there but I'm all by myself. Technically, I could have been standing in there with the engine still in but that just isn't as cool. I'm already dreading the reinstall and getting the transmission to line up. One step at a time...

 

[Lewis7789]

Jon, you were in our thoughts and Mazda prayers today doing all this work yourself. I wish you lived closer so we could all help! Looking good though, mate.

 

[PrinceValorum]

Jon, you were in our thoughts and Mazda prayers today doing all this work yourself. I wish you lived closer so we could all help! Looking good though, mate.

I was just thinking how we talked about that today. If you were closer, you'd have help for sure! And people to take pictures of you in the bay, lol. I can't imagine doing all that stuff by yourself. Big respect.