Break in procedures are a weird thing, everyone you ask will give different advice and say it works because they didn't have an issue with their method. So I'm going to do the same. Run the BR30, run it for ~20-50 miles, change it with more BR30 for another 100-150 miles. Then switch over to your preferred oil and enjoy life. The short duration of the first oil is intended to get any potential debris out.

 

How many manufacturers use break in oil in new engines as a factory fill? Over the past 100yrs there have been hundreds of millions of engines produced and how have they been successful.

In the past there were a few engines that had flat tappet lifter issues and we would often contemplate using different lubes to solve the issue. Mainly this was big block chevrolet engines which had canted valves and high spring loads. Break in oil is not a legitimate topic in ICE engineering.

Oil has become a religion. I have been shying away from making suggestions or voicing my opinion because it has become personal. I'm only changing my practice for this particular case where it is becoming a distraction from the real issues.

 

Basically what I did the first time around, I did 2 oil changes in about 10 miles to get the assembly lube and anything else out.

I think I'll do the same, I like that. It didn't seem right to me to let all that gunk sit in the pan for a couple hundred miles so I'll do 1 BR30 change as you've said. Thanks!

 

Hi Leo, I don't entirely disagree, people love their certain oils. I'm curious are you saying in this particular case, meaning my build, theres a different issue?

Just to reiterate, I think my biggest issue was all the misfire cranking on initial start when I had ignition wires crossed and dumping fuel in the cylinders. Its possible without that problem, I may have been fine even with the VR1.

 

Yes, the oil was not your issue.

 

Conventional instead of break in is fine, I’ve just seen glazed rings when synthetic was used. 5-10 miles is ridiculous, go at least 200 miles, if not 500 miles on the first break in oil. If anything gets picked up, it’ll go through the filter. I typically start and engine, break it in on the dyno, change the filter, and swap to synthetic after a track session or two. Change that up a bit for a street car, but you get my jist, change the filter rather than the oil it’s filtered.

 

Most new engines come filled with semi-synthetic or full synthetic oil.

Most ring sealing issues are from an out of round bore, wrong finish or bore finish degradation. I have not found oil type to be the root cause on a fresh engine. When there is a large difference in expected cylinder compression it is usually caused by a valve issue, incorrect valve timing, bore roundness, damaged rings or incorrectly installed rings. I have seen a combination of several of these be the cause. Number one cause is valve sealing and 2 is bore roundness. Small engines are very sensitive to bore roundness. Very often I see new valves installed that have not been surfaced when they needed to be. Pretty does not equal concentric or round.

 

My initial run procedure for this type of engine is to change the oil/filter after the first 15-20min and then at 300-500mi. More details below. I often use 5,10-30 M1 because I usually have a fair amount on hand. Any oil will be fine for the first fill. I would not hesitate to use a jug of plain conventional oil like chevron 5,10-30 or any reg synthetic. I would avoid high end products initially because of the cost.

I start the engine, top off the coolant, limit the idle time and do 3-5 pulls to 3/4 rpm with 1/2-3/4 throttle. Then drop the oil and filter. Filters have bypass valves, and the bypassed oil is not filtered. These bypass pressures can be low for these small engines, not unusual for them to be 5-10dpsi. They will bypass more from engine acceleration and being a little more clogged than normal from some assembly lubes. I cut the filters open, inspect them and the drained oil. I then install the oil that the engine is going to run and maintain the 3/4 rpm & 1/2-3/4 throttle until the next change at 300-500mi. At this interval I pull the valve cover to check the valve lash and do a compression check. Then I use it as intended.

 

Hey Leo, thanks for all the input. I am worried it could be related to bore roundness but it was bored with a torque plate so I think it should be ok. Unfortunately, that was never measured as far as I'm aware and I don't have the knowledge or tools to do that. I like your valve lash and comp check idea, I'll plan on that as well.

I'm also going to disconnect the wastegate so its running naturally aspirated and has no chance of making any boost for the first 500 miles.

Quick update... I got the engine back in the chassis. I couldn't find anything about the ARP pressure plate bolts so I went with 30ft/lbs with blue loctite. This weekend I'll try to make some progress getting the driveshaft in, all the sensors hooked back up, etc.

Also debating on removing the power steering and depowering the rack now. I really want to move my air filter to where the fluid reservoir is and get rid of some of the engine bay clutter. I need to find a local miata without it to see if I can live with no PS or not.

 

Tried to start her today, just cranking with no catch at all, I think my timing is off? Not sure how... anyone got any ideas before I spend tomorrow pulling everything apart?

(comments on each pic are right below)


cam sensor looks good, crank seems weird and I think the red lines are desync, which is bad.





exhaust side cyl 1 cam facing out for TDC



fluidampr timing marks seem in the wrong spot



red arrow is first timing mark, far before the T on the timing cover



during assembly, timing looked perfect. How did it get messed up?

 

How old is your fluidampr? IIRC there was an early batch with incorrect timing marks.

Here, found the thread: https://www.miataturbo.net/engine-pe...g-marks-97656/

 

ahh good reminder, I forgot about that. I think its around 2021 but it should be working since I verified base timing with those marks on the last build and it ran fine.

I'm thinking I put the cam gear onto the wrong nub off the camshaft itself and then just timed based off the gear. So the gear is correct but the camshaft itself is slightly off. I'll just redo timing tomorrow and see if I wasn't paying close enough attention. Can't remember exactly if the cam gear has multiple slots for that little nub.

 

The cam gears absolutely have multiple slots for the nub and can be installed wrong. There should be a notch that points straight up towards the cam, and another notch that points towards the mark on the backplate.

 

Appreciate the confirmation, I'm sure thats what I did. Will report back tomorrow

 

Welp, I didn't mess up, the mechanical timing is good. I'm all out of ideas, no clue why the composite log is showing all that desync and weird crank timing. Probably going to try a flyin miata trigger wheel, new crank position sensor and see what happens. The cam sensor seems to be working perfectly fine. Also going to reach out to the folks at Fluidampr tomorrow and see if my crank marks are correct, not that that will help the engine start, but I'm curious if I have an incorrectly marked one.



crank is also at TDC for this

 

Couple of things you might try and look for.

1, I've noticed with anything but the stock 4 tooth wheel, I need to set the sensor gap to be extremely tight. Stock says .020-.060", Try .010-.015.".

2, I had one trigger wheel, forget the brand, show up with a small gouge in one of the teeth, I believe from laser cutting. This caused the sensor to detect it as 2 teeth instead of one, causing a no-start condtion and a lot of sync errors, so you might check yours for similar damage.

 

Thanks Curly! I'll gap that sensor tighter. I have a new one on the way, as well as a FM trigger wheel. I noticed the Fab9 one didn't seem perfectly flat and I did have to drill out the holes way back when to get it to fit initially. It ran before but maybe I just got lucky.

I'll be out of town so I won't get back to installing this for another week and a half. I'll install, take another composite log and hope for the best. I'm running out of runway on my abilities, so she may end up at a shop in the near future.

 

Hey Matt. For this problem: "Found the source was the rear cam cap and circular seal. I put grey RTV on it and took it out last night, still leaking pretty bad." Did you ever find a solid, recommended solution? I found the same issue when I pulled my NB1 engine recently. And BTW, I was doing good on my build until I broke a 2nd compression ring today, so now I'm waiting for a new set.

 

Hey Mark, good to see you here! Sorry about your ring, thats some rotten luck. If you aren't already, make sure to use a ring installer that is made for your bore size and not one of those adjustable ones that have a higher chance to catch and break the ring during install.

As for the leak/cam cap...not really. That was merely the symptom and the cause was all of the blow by pressure. I didn't touch it during the rebuild so its still sealed all the way and hoping this time around it stays dry and the catch can gets all of the vented air. If yours is leaking there too, well it shouldn't be. Likely the head is getting pressurized from either the rings or valve issues. If its high mileage and the valve cover hasn't been off in a long time, perhaps it just needs a fresh dab of RTV on the valve cover corner.

 

Thanks for the other feedback about the crankcase pressure and sealing it up again. I've used a Wisco piston installer on my MSM, with an 85.5mm bore, so I had to buy a new, 83.5mm one for this NB build. Pushing a ringed piston into a cylinder with just thumb pressure is too rewarding to ever imagine going old school again. I just got the new ring set and put my final 2 rings in place using my fingers instead of the pliers to play it safer.