A huge thanks to Tom and his Wife!!!

[jwalton]

Let this be a message to anyone and everyone thinking about force inducting their Miata. As I write this, I'm sitting in the beautiful Phoenix International Airport awaiting my flight home to L.A. I drove my '01 out yesterday at Tom's invitation (including staying at his home!!!) to help tune my BRP hotside with his PC Pro/E-Cool setup to get rid of the nastiest case of the pings you've ever heard. I hadn't been there more than 10 minutes and he already had my popping the hood and inspecting stuff. A new SC nose pulley here (another of the crappy BRP cut units), a boost gauge there, and his laptop talking to my OBDII everywhere else. After he had verified a few things (like just how nasty the ping is (anything above 4 lbs of boost and anything near WOT) it was enough for the night and off this morning to the dyno. 3.5-4 hours of dyno time later and a whole bunch more troubleshooting later, and now I'm flying home instead of driving.

Why you ask? Hmmph. A little track time is good, a lot is great (for me anyway, just not the car...) but has it's consequences. The car has 111,000 and change miles (all normally aspirated) and a bunch of track time and the number 2 and 4 cylinders have, shall we say, some compression and leakdown opportunities. Hmmph. Suffice it to say, with the SC trying to pressurize the crankcase via the number 4 piston's rings, the intake tract (again) through the number 2 piston's intake valve/s and the cat plugging up whatever decided to make it through the motor, I only made 150whp instead of the 180-190 we thought it should.

Watching Tom and the guys at Arizona Dyno Chip beat their heads against the wall trying to troubleshoot the car was educational to say the least.

By the way, these comments come with no discounts on anyone's part, just an honest description of the last two day's events. Trust me, I'm gonna pay and pay dearly. With the issues uncovered and the honesty with which I was told, I'm left with little alternative but an engine rebuild. The call home to my wife from the dyno was not one I was looking forward to, but it is what it is and the car needs to be fixed, with or without my dreams of forced induction.

Before you start plopping down credit cards, do yourself a favor and compression/leakdown check your engine. Make sure that it's up to snuff before you ask it to do anything extra. Also, upgrade your radiator!!! I did (Koyo 55mm) and I'm really glad that I did. Also, consider the coolant re-route up front. The hot 4th piston issue is very real and if you track your car at all, it's really, really important. Hmmph. :(

The bottom line for me is that I left my car with Tom who is going to bring it up to his Mechanic of choice Mike at, conicidentally enough, Mike's Place for a engine rebuild. We are going to take a '96 short block with it's low compression pistons, marry it up to my soon to be rebuilt '01 head, and do a coolant re-route. There's some other stuff at the same time like an ACT clutch to replace the stock one while eveything's out of the car and what I'm sure is a new cat based on the testing this morning. Hmmph, again, and again, and again.

Finally, I really have to thank Tom and his Wife again for their hospitality. They invited me (and my wife incidentally when I return for the car) into their home with open arms and were genuinly concerned with my predicament today. To rebuild or not (ie, no SC'ing), stock or built, or hybrid (like I'm doing).

Well that's my story and I'm sticking to it. Financially I'm kinda obligated at this point. :)

Hmmph.

[Banshee]

You know the customer service is excellent when people are left smiling when told they need an engine rebuild.

Tom,
If this FI business doesn't pan outk you can always open up a bed and breakfast.

[Elphaba]

:censored: That blows about your motor dude... Sorry to here it. Rest assured your car is in very safe hands. Mikes place (The Miata Mecca) is the very best place in the American southwest for your car to be. He specializes in Miatas and is the ONLY one Ill have work on my Elphi.

[ThomS]

:censored: That blows about your motor dude... Sorry to here it. Rest assured your car is in very safe hands. Mikes place (The Miata Mecca) is the very best place in the American southwest for your car to be. He specializes in Miatas and is the ONLY one Ill have work on my Elphi.

It is the best place in the united states... That is why I drove to AZ from Ohio to have work done on my 02, And Tom and his wife really took care of me for three days.

[JMann]

Jwalton Why are you going to use a 96 short block??? The 01 has a knock sensor on the side of the block that tells the ECU to retard timing. You can use the 94 to 96 pistons in you block and get the same compression. All 1.8 pistons well interchange. That is what I am going to do if I have anymore issues with these 10 to 1 pistons in my 02. I would want to keep that knock sensor for the ecu. Mikes is a great garage, they did my install and it ran great, even with some burned valves and I well second your idea whole heartaly about having leakdown test and compression test done first. I would have found my valve issues if that had been done. Tom said he would do no more installs without first running th cars on the dyno first to see if they come up to horsepower stock. I also stayed with Tom and Kathy for 3 or 4 days and you can' find nicer people anywhere, although Tom gets a little grumpy now and then,LOL, probably cause my car was driving us both crazy. I replaced my motor which had broken pistons and burnt valves with a used 03 and like I said if I have any issues again on the track with them I am going to take my old engine and install 94 to 97 pistons in it, might anyway so I can run a bigger crank pulley. Good luck John

[Tom @ Fast Forward]

I'm pretty sure the 96 has a knock sensor too.

[jwalton]

Jwalton Why are you going to use a 96 short block??? The 01 has a knock sensor on the side of the block that tells the ECU to retard timing.

You raise a great point that I'll have to talk to Mike about on Tuesday.

Thanks for the encouraging words everyone. I wouldn't quite call my attitude happy, more like resignation. In a lot of ways, I'm happy I went through the financial experiences of owning a 3rd gen RX-7 to put everything into perspective. It still sucks, but it's all relative. The Miata is actually a pretty inexpensive car to own, even when you embark on "Project Stupidcharger."

[JMann]

Tom I think Mazda started with the knock sensor in 01, that was my understanding, I think before that you have to add a knock sensor. Since they are going to rebuild the 96 engine, I was curious as to why not use his 01 engine??? with the 94 to 97 pistons???

[cmetzner]

I think that I was told that my 99 retards timing as much as 4* through the stock knock sensor. Also, I have to check the J&S knocksensor site; their product for a 99 splices into the stock knocksensor.

I suppose I should check before I shoot off my keyboard.

[Tom @ Fast Forward]

I know the 99+ all have knock sensors. I don't know about the earlier 1.8L engines though. My 99 has the knock sensor in the same place as my 05.

I don't know about prior years, but the 05 can drop 10+ degrees in a heartbeat on knock sense. We have monitored that at the dyno.

If there is no spot for the knock sensor on the 96 block, I have special mounts made to locate it on the motor mount and we tested my 99 by moving it over there and it worked just the same so we put it back on the engine. I was trying to get it to not read SC noise as knock. I had a J&S and it was registering knock when I was even simply cruising at 60MPH. I'll supply one of them to Mike if needed.

[JMann]

Yeah I stand corrected, I do see where the 99 up had it, but I can't find it on the earlier ones, but sounds like you have a cure for that. Cheers

[jwalton]

I'll supply one of them to Mike if needed.

Thanks Tom. Once again...

JMann: The reason we decided to use the 96 short block was because, theoretically at least, the block they have just needs to be cleaned up and assembled. If we used my block, the cylinders would probably all need to be re-honed if not bored due to potential damage from the rings on number 4. Also, the bearings et. al. have 50k less miles on them. That's the reasoning anyway.

Tom: Considering everything's coming off/apart anyway, how much would it be to get the valve cover and upper intake manifold powder coated with that crinkly type finish that would match the supercharger, dummy throttle body and cross-over tube?

[Tom @ Fast Forward]

It cost me ~$200 to do just the valve cover on my 99. It is close but not quite a match. A little light in color. I also had to drop it off for a couple weeks for them to fit it in.

[Mathrips]

I used a 96 block to replace my 99. It had the same hole tapped and ready for the 99 knock sensor.

[jwalton]

I used a 96 block to replace my 99. It had the same hole tapped and ready for the 99 knock sensor.

Thanks Mathrips, that makes me feel a lot better.

[bogey]

Considering everything's coming off/apart anyway, how much would it be to get the valve cover and upper intake manifold powder coated with that crinkly type finish that would match the supercharger, dummy throttle body and cross-over tube?


You can paint the valve cover with off-the-shelf crinkle paint and get excellent results for under $10. Just clean it well and follow directions. If you screw it up, you can always strip it and try again or powdercoat it.

[jwalton]

Thanks bogey.

A question for all. I got a call from Mike at the shop and he said that the knock sensor wasn't working so the ECU didn't know that it needed to pull any timing due to knock/ping. Given that, in a pinging engine, do the cylinder temps rise due to the overly advanced timing? Would this be causing elevated engine temps? There is a chance that the motor may not need to be rebuilt (slim, but I'm holding on to any shred of hope), because the compression and leakdown tests were nowhere near as bad when measured today vs. on the dyno after making a bunch of runs. Mike is thinking that just maybe the engine was overheating and causing weird readings (sticking valves, loosening clearances on the number 4 piston and the cylinder, etc.).

Any thoughts would be appreciated.

[JMann]

How do you test to see that a knock sensor isn't working????

[FormerDatsun510Man]

If it is pinging, with or without the factory ECU making timing adjustments, I would think the engine would run hotter. Probably the easiest thing to do would be to replace the knock sensor and see if this improves things. If the the knock sensor isn't working, you would need to replace it anyway for engine #2.

[Tom @ Fast Forward]

Not the best way, but it works. You monitor timing with an OBD II reader and, when you hear knock, you should see timing retard. If it doesn't, the knock sensor is not functioning.

We always do a timing check on the dyno as you could have knock but NOT hear it. The ECU will pull timing if all is working and it picks up knock and that would make the knock go away and you would not hear it. Not sure about pre-99 but 99+ runs the timing at 24* at WOT if there is no problems. If you don't hear any knock but see 18*, for example, there is a good possibility that knock exists and has been corrected.

[cmetzner]

Tom -

I just never thought of checking for knock that way. I have an OBD reader. I'll step on the gas and see if the ECU pulls timing.

I can also log the activity on the Auterra software. So, any early ping will show as a blip on the timing curve?

[Tom @ Fast Forward]

Chuck,

You should see ~10* at idle, 30-35* cruising down the highwat at 70MPH on the straight and level and ~24 at WOT.

[jwalton]

I can't speak for anything other than the '01 cars, but Mike at Mike's Place troubleshot the knock sensor based on some imported Mazda manuals that describe how and when it's supposed to work. Based on our conversation, the knock sensor in my car is working properly. Mazda's ECU only listens to it at low RPM's and heavy loads. My high RPM pinging could be easily heard by a knock sensor in China, it's just that the ECU doesn't care. Further, at the low RPM, heavy load condition that it will adjust for, it'll only pull up to 8 degrees of timing.

[Kyp J]

I can't speak for anything other than the '01 cars, but Mike at Mike's Place troubleshot the knock sensor based on some imported Mazda manuals that describe how and when it's supposed to work. Based on our conversation, the knock sensor in my car is working properly. Mazda's ECU only listens to it at low RPM's and heavy loads. My high RPM pinging could be easily heard by a knock sensor in China, it's just that the ECU doesn't care. Further, at the low RPM, heavy load condition that it will adjust for, it'll only pull up to 8 degrees of timing.

Verrry interethting! (my impression of a German accent a la Laugh In)

Maybe the '01+ uses VVT instead?

[Banshee]

Verrry interethting! (my impression of a German accent a la Laugh In)

Maybe the '01+ uses VVT instead?

according to Bill, it uses vvt to retard intake timing. That's why they came out with the vvt hack.