Hi there,

I'm new to the rotary since I made my childhood dream of owning an FD true 3 weeks ago. I'm located in Germany, so please forgive me if my english is not perfect.

I have already read a lot on this forums, but I'm at a point where I think I need some interaction to make the right decissions.

The car I bought is a silver 1994 FD3S with 47000 miles on it, imported from Japan to the UK in 2013. It got a rebuild at SVA Imports there and was imported to Germany in 2014. The rebuild was done at 43000 miles.

Some changes were already done to the car, mostly in Japan I think:
Blitz! ECU
Bigger injectors, no clue wich ones though
HKS downpipe, 100 cell cat and Tanabe Muffler
HKS high performance air induction
Mazdaspeed coilovers
Rays Gram Lights 57F 17x8.5 front and 17x9.5 rear

I allready have some minor problems with the car, here they are:
- warm start takes up to 4 or 5 seconds (cold start is almost instantly)
- I would say, idle is rough. But since I never heard an FD idling, it could also be normal or the tuning. Engine vibrates quiet a bit when idling though.
- very rarely the idle rpms drop below 500 and the engine is starting to struggle, I hit the gas when this happend. It happend only at one city drive of aproximately 6 miles when the car was warm. I parked it for 2 hours and when I drove home everything was fine again. I noticed the oil pressure being very low when the rpms dropped (nearly zero), but could not tell wether the rpms dropped because of the low oil pressure or the other way round. This dropping oil pressure occured one more time at a later city drive, I held the rpms at 2000 with the gas pedal then so the oil pressure rose to 2 kg/cm². Idle rpms didn't drop that 2nd time.
- I found white resedue, you could name it slime or fat, at the oil filler cap. It was not there after a highway drive of 230 miles but after some city driving with rare full boost. The coolant level did not change through aproximately 370 miles, neither under the 2 filler caps nor in the expansion reservoir. I dumped the engine oil into a see-through tank, there was no separated water layer later.
- I made a compression test with a normal compression tester, from which the valve was removed and filmed it with a video camera. The results where:
Front rotor 3 times 5.5 bar (80psi)
Rear rotor 4bar (58psi) / 5bar (73psi) / 5,5bar (80psi)
(I hope psi is the right unit)
The engine was cold and without engine oil.

I'm pretty unsure now whether to make a rebuild again by myself (Got the 4 DVD set on rebuilding the 13B REW from www.diy-re.co.nz) or to drive the car a little longer to fully test everything out before doing this "extreme" step. If I go the route further testing I would make a second compression test with oil in the engine, warm and cold and a camera that makes more fps for more exact results or go to the local mazda dealer. I am aware that the absolute results have no strength without knowing the rpms of the starter, but haven't quiet understood why this is that way.

The second big point for me is the OMP. I really want the engine and turbos running on appropriate engine oil, since the car will be a tracktool only. (I'm aware the cooling system needs attention for this application)

I've read about the Oil messuring pump adaptor from Rotary Aviation and also the possibility of deletion of the OMP and going premix. I thought the first would be the best option since it is strictly separated, one oil for each purpose. But then I read this thread https://www.rx7club.com/3rd-generati...x-60867/page2/ in which I learned that there is quiet a complicated way of controlling the amount of oil that is injected. Since I will never run the OEM ECU that would become pretty complicated (I would most probably go with a MegaSquirt in the near future, till then the Blitz ECU will stay). So I thought the easiest way would be the deletion of the OMP and premix, but then all say its a big PITA.

As Oil I wanted to use Q8 F1 10W50 full synthethic, since my 200.000km KL-DE engine in my current tracktool, a Ford Probe 24V, ran minimum 6000-7000km only ontrack without any problems with this.

Oh, and speaking of tracktool, would you guys say the Mazdaspeed coilovers (blue dampers, golden Eibach springs, 10,5 front, 11,9 rear) are up to the task of track driving for the beginning or shouldn't I bother and go with another option? My current tracktool is equipped with a KW Competition (pretty much the same as a KW V3 with other springs and more support by KW) with drastically changed spring rates compared to standard, so I'm pretty spoiled on that side..

I'm sorry, that is really much text, I appreciate if you came this far. I'm sure I can learn a lot on this forums, hope you guys aren't fed up with newbies asking the same questions over and over again. Since I'm no native speaker, I find it quiet difficult to find the right terms for the search engine. It took me almost a day to find the term OMP or oil messuring pump for the german "Oelbeimischpumpe". Mazda has some quite weired names for some things here. So if you don't want to write an epic answer on all my questions (if they allready have been answered elsewhere) just give me some search terms instead please.


Thanks to all in advance and Merry Christmas!

 

welcome to the board. congratulations on your dream (or maybe nightmare) come true.

your likely cause of your issues is the low compression. i'm not sure how much they differ between hot and cold, and you did state you did the test while the engine was cold. it may be worth doing the test again when the engine is hot and seeing what you get, but everything you mentioned CAN fit with a low compression situation.

i usually say leave the MOP alone if you have no reason to believe it's misbehaving, but since you're planning on using this as a race car, then i don't think it much matters. personally, i wouldn't put an MOP adapter on a race car, i would premix, but the decision is yours. all options are open to you. you will likely need to address the engine compression first anyway before you will be able to hit the track.

i can't speak on your Mazdaspeed coilovers, so i will just leave that topic alone.

 

^Agreed. Hot start and those readings cold and lumpy idle all point toward a rebuild. FWIW, the few JDM cars that I've been able to see in person or detailed pictures of STRONGLY suggest that their idea of "routine maintenance is way different than mine.

I'm not a tuner, but last I knew, not many (if any) had success with Megasquirt on the FD. I'm not exactly sure why, but there are probably better choices.

OMP/MOP...if you truly will be tracking it, I'm again with diabolical, it's your call. I would probably pre-mix at a rate above the standard (1 oz. oil to 1 gallon fuel) and consider auxillary injection for additional cooling, knock and carbon control. There's an AI section here with more info in the stickys.

 

Thnx for the warm welcome!

I looked into the AI section of the forums, but in my understanding this has nothing to do with injecting oil into the engine for lubrication. AI is not what I'm planning to do, at least not in the near future. The reason I want to get rid of the OMP or use a dedicated oil with an external tank is that I want to use synthetic oil for the engine and turbos.

First priority is to make the car run like it should and than optimize it for track use.

I think I will do the following as next steps:

- delete the OMP, premix
- put in new engine oil (fully synthetic)
- put in new radiator coolant
- put in new spark plugs (leading NGK BUR7EQP and trailing BUR9EQ? Which ones are the leading? The lower or upper ones?)
- bold in a AEM wideband and fit gauge
- fit boost gauge, oil temperature gauge and water temperature gauge (not present at the moment)
- make a new compression test, warm and cold, with more fps
- drive the car a little longer and watch all the engine related data carefully plus watch the oil- and coolant levels / look for more white foam
- maybe put in the stock ECU for comparison

Here are 2 videos of the car idling, maybe you could say if this is normal idling:
cold
https://www.youtube.com/watch?v=TJtj3tQ0JX0

and warm:
https://www.youtube.com/watch?v=tKftstdxY_w

 

Indirectly it might. Both AI (alcohol/water) or WI (distilled water) injection will help to reduce carbon deposits from that oil that's being injected and suppressing knock. The latter particularly critical on a rotary and important if you're spending 20 minutes track sessions at high rpm load. AI is good at reducing IATs and WI is good at cooling the combustion chamber which reduces load on the rest of the cooling system.
* I'd also change the gear oil in the transmission and differential with synthetic. And brake fluid and pads for sure before tracking.
* Leading = Lower Trailing = Top
The cold idle almost sounds like some porting has been done. The warm idle actually doesn't sound all that bad....just not a fan of that exhaust.

 

The steps I stated are just the steps before I make my final decision whether to rebuild or not. Of course I will change all fluids before the first track event.
Oh and sorry, I just re-read your statement regarding AI, got that wrong. I will consider this when the car runs like it should.

According to the last owner, no porting was done to the engine, and on the rebuild bill there is nothing mentioned in that direction. But of course, can't be sure though..

Thanks for the memory hook concerning the spark plugs, thats easy to remember! For compression testing I should use the trailing, right? Last time I used the lower ones..

 

There seems to be some conflicting information as to which plug holes one should use for a compression test. Personally, I lean towards the Leading plugs (lower) as it would seemingly give a lower reading for a worst case scenario in engine health.

As far as the previous rebuild at SVA Imports, your gut feeling is correct. Rebuilds don't die after 4000 miles, nor do they produce ~80psi in a compression test. I would wager that they dumped some oil in the engine and charged for a full rebuild, leaving the engine with worn out apex/side seals. Fortunately, nothing has blown yet on it, so you can rebuild it now and most likely won't have to replace things like the rotors/housing or irons.

Something you may want to keep in mind is that with such low compression, it will start when cold, but refuse to when hot. This is why my engine has struggled to fire up recently. On a cold start, it will stall in 15 minutes just by idling. During that time, it runs rougher and rougher untill it just quits. Right now, it is putting out ~60psi on all rotors/faces. The only solution is to rebuild it.

A good source for rebuild kits is Atkins Rotary - Rx7 | Rx8 | Mazda | Rotary | Engine | Parts and here is an excellent demonstration on how to rebuild your engine:

 

Thnx, I think I already watched some parts of this build, really cool project. I will have a look at this video and will watch the first of the New Zealand 13B DIY rebuild DVD's I got from a good friend for christmas right away.

Btw: Your username makes me smile everytime I read it. I love Initial D!

I made a video today through the lower spark plug holes while spinning the engine with a ratchet, unfortunately the video quality of the endoskop usb camera is pretty shitty. But since I uploaded it to youtube for friends, I thought I could share it here aswell. I can not judge the looks of the apex seals, maybe some of you can?

Front rotor:

Rear rotor:
You can skip at around 9:20

The prices at Atkins are pretty, uhm, hefty.. Since I have to pay duty and shipping to germany, I will end up a good amount over 2200 dollar for the cheapest kit with apex seals. Are they really that much better than the cheaper sets? If no, which ones can you also recommend?

 

Hello again,

I've made a new compressiontest, it doesn't look better than last time:
Rear rotor cold 60 - 75 - 85 psi
Front rotor cold 78 - 82 - 80 psi
Rear rotor warm 60 - 70 - 85 psi
Front rotor warm 82 - 85 - 87 psi

"Warm" is relative here, the engine was running for max. 5-7 minutes, the watertemperature gauge just started rising when it was shut down. The throttle was fully opened and in the cold test, both lower spark plugs where removed, in one port at the time there was the pressure gauge. In the warm test, the other spark plug was not removed.

I'm planning on using the Zoom Zoom cleaner as kind of a last resort, any dissenting votes to that?

Is there a possibility that a mod could move this thread to the "normal" technical section?

 

Moved to 3rd gen Tech per request,

 

AI is the first thing you should plan to do unless you like rebuilding motors and the expense associated with it. For a stock car with no mods it's not required but a modded car with additional boost pressure will have a much shorter life without it.

A track toy will see even more heat with sustained boost for 20+ mins at a time. I suggest you reconsider your goals or prepare for a painful realization of the limits of the rotary engine.

 

As I said, I will consider AI, but first of all, the engine needs to run the way it should.

 

NEVER RUN engine oil (fully synthetic)

I have 90,298 on my car. I run 10-30 NON synthetic. You are not suppose to run engine oil (fully synthetic)

 

What is your vacuum reading? That's another good gauge of engine health. Should be 15-17 in/Hg.

If you have low compression I would stop dicking around with it and just pull the engine. It's time for a rebuild. You risk causing more damage to the engine AND turbo hot side if you drop an apex seal with continued driving.

As far as kits go Atkins is a good deal if you're in the US. Whatever kit you buy, just throw the oil pan gasket in the trash

Nah, you can run synthetic. Many people on here do even with the OMP. Myself included. To each their own tho. This subject has been beat to DEATH.

 

Agreed. Just a proven gasket maker. I like Hondabond.

Agree x 2. And yes...we know what the manual says. It probably also recommends you use the pan gasket.

 

I can't tell the vacuum reading, because I have no boost gauge yet.

Over the last few days I put Ballistol universal oil in each chamber and let it sit for one day before I processed with the next chamber. A friend with very much experience on the 13B suggested this as an alternative to the Zoom Zoom Cleaner.

The new compression test results:
Rear rotor cold 90 - 102 - 70 psi

So it worked, but the difference between the best and the worst is still much to high. So I think I have no other choice but to rebuild.

I made a quick list of thinks I would need from atkins, of course I would only buy after I opened the engine and messured everything. Can someone please go over it and have a look whether I missed something important?

86-95 Rx7 13B 2mm Apex Seal & Spring Kit (ARE132) SKU: ARE132 216,00 USD
86-95 Rx7 13B Side Seal Set (N3Y1-11-C11) SKU: ARE96 175,00 USD
86-92 Rx7 13B Side Seal Spring Set (N326-11-C17) SKU: ARE84 27,00 USD
93-95 Rx7 Corner Seal Spring Set (NF01-11-C24) SKU: NF01-11-C24 45,00 USD
86-95 Rx7 13B 2mm Solid Corner Seal Set (ARE88) SKU: ARE88 69,00 USD
86-11 Rx7 & Rx8 Atkins' Thermal Pellet (ARE50) 8,25 USD
86-95 Rx7 O-Ring Kit (ARE316) SKU: ARE316 160,00 USD
69-11 Rx7 & Rx8 Tension Bolt Washer Kit (0839-10-455) SKU: ARE104 40,00 USD


--> 740,25 USD

Thank you guys for your advice, this forum is great!

 

If you have any cracks/chips in seals, or uneven sealing surfaces the oil will fill in those gaps and artificially raise compression. Occassionally I have heard of people de-carboning the apex seals and gaining back lost compression. Never come across that myself as I always premix.

Atkins rotary would be the best to ask about that. They are the ones selling those kits and know them best. That said, I have just bought the full rebuild kits in the past. A full gasket set is good to have on hand.

 

It took me pretty long to put all the sensors and gauges in the car, but yesterday it was finally time for the first drive with them all installed.

Here are the results.

The watertemperature doesn't rise above 167°F, even after several short WOT runs on the autobahn. Speed around 80-140mph.
When idling however, it goes up to 221°F pretty quickly, I shut the car down when it reached this temperature and heard pretty loud gurgling from the radiator area. But after all, I recently changed all the coolant and the car didn't run in the meantime, so could be air in the system.
The oiltemperature shows quite a similar behavior, goes not over 149°F under the above mentioned circumstances, but rises quickly to around 212°F when standing.
Boost: when going full throttle at 3000rpm, the boost goes to around 10psi. At 4500 the boost goes up to nearly 14psi for a second and goes back down to 9psi. Towards the end of the rpm range its well over 7psi.
I finally could also take the vacuum readings: its -6psi when idling and around -9psi under deceleration.
AFR: Under full throttle its allways 11.5-12, never higher. With rising rpms it goes to around 11.
At the above mentioned boost peak around 4500rpm it goes pretty lean though. I couldn't watch the gauge exactly because I was to busy keeping an eye on the road and the boost gauge, but I think it was between 13 and 14. I assume this is no good news..
When idling the AFR is between 10 and 11, I think when could it even goes below 10, but I assume the AEM gauge can only show 10.0 as richest. Not sure about that though.

The wideband O2 sensor replaced the original O2 sensor and was configured to give a narrowband signal to the ecu.

Here are the mods on the car once again so you don't have to scroll all the way back to the 1st post:

Blitz ECU ("Access Computer")
Bigger injectors, no clue wich ones though
HKS downpipe, 100 cell cat and Tanabe Muffler
HKS high performance air induction

Oh, and the car shows error code 11, Intake air temperature sensor. I have a new one but couldn't change it yesterday because time was running out and I think the UIM has to come off to change it. Or is there another way?

 

Unless you plan on re-locating the sensor, I know of no other way to change the IAT than to take the UIM off. I'd get a new UIM to LIM gasket. I don't think they cost all that much.

 

You really have to burp this coolant system properly. It involves using a tight fitting funnel and letting the car come up to temp with the system open to atmosphere.

-6 psi is 12 in Hg so that is low. Should be 16-18 in Hg.

Sounds like you have no control of your boost pressure. Yeah, that's bad.

 

I was driving it today again for filming boost and afr. After several WOT runs I lost boost from the first turbo (until 4500 or 5000rpm), boost is 0 psi. Than comes the second, but it only boosts 4 to 5 psi.

I think I should reconsider rebuilding the engine and check the turbos on the way..

What could be causing the low vacuum reading?

EDIT: Oh and the AFR at the boost peak was 14.9..

 

Vacuum readings are dependent on a lot of things. RPM, altitude, temperature, load, porting etc all affect vacuum. At idle, no load (coolant fans off), 720+or- 30rpm, vacuum should be 17-19inhg or so assuming it's a stock port motor. Anything lower could potentially be a vacuum leak. If you have a vacuum leak, your idle will be higher than it should be. If your vacuum fluctuates rhythmically and with RPM, then I might suspect internal failure of the motor. This is usually hand in hand with hard starting, rough idle, smoking, etc.

Matt

 

Well, your compression results being as low as 70 psi would point to the engine getting tired. Looks like your engine is on borrowed time. If I had to guess it's because you were leaning out.