Stock Engine Swap-in. Having Issues

[Sid_RallyX_82]

Got my engine. Gonna put it together this weekend. Can someone post up the Ford and Mazda part numbers for the proper thermostat? TIA

[Sid_RallyX_82]

***
Found it. Which is Ford and Which is Mazda?
•F201-15-171A
•8AK1-15-171-9U

[jawja jim]

8AK1-15-171-9U is a Mazda part. I have one sitting in front of me.

[Sid_RallyX_82]

Cool. Any particular recommendation for break-in oil?
Cheap conventional oil + zinc additive or?

[Dragonhealer]

At the risk of starting a flame war, our B series engines are NOT designed to be zinc compatable!

[Sid_RallyX_82]

Sooooo... What should I use?

[Dragonhealer]

I see no reason to spend money on fancy oils for regular engines, walfart cheap supertec 10W30, a quality oil filter is key, buy the Mazda, Motorcraft or Wix (someone mentioned the NAPA Gold is a Wix).
change every 3K miles or 4 months, whichever comes first.
I don't recomend Synthetic oil untill rings are seated and bearings are heat cycled enough to be fully hardened, could be 5k to 35K, depends on what parts are used.

[Dragonhealer]

Best break-in for these engines in my experience is moderate throttling, stop and go city driving, don't lug it, and don't rev over 5000 for the first 2K miles.
Our spec class engine builds (totally stock) go in the DD cars of certain wives to run errands for 6 months before they go in a race car and off to the dyno for final tune/adjust. These tend to make 4 more horse power than class allows, so we detune slightly.

[FestYboy]

Wait, you have a HP limit!?! Unless all engines are run on the same dyno, and with the same operator, how can they regulate the output?

[Dragonhealer]

Wait, you have a HP limit!?! Unless all engines are run on the same dyno, and with the same operator, how can they regulate the output?

BINGO!
Therein lies the rub! It's not uncomon in an SCCA Majors race for the top20 Spec Miata finishers to come off track and be lined up at a portable dyno to be tested, over 130hp all three of three pulls and you are DQ.
It took some experimentation to enter values in the presets of the Mustang dyno to get equivalent results. Obviously there are no guarantees, too many variables! This was SCCA's solution to rampant cheating in that class. Pretty sad for an "Ivy League Club"

[Sid_RallyX_82]

Main bearing gaps are wider than the spec in my book. Says they should be "0.024-0.042mm (0.0009- 0.00017 in)" [must be a type-o, because 0.042mm = ~0.0017in]. My plastigauge reads consistently between 0.051- 0.076mm (0.002- 0.003in). I applied assembly lube, spun the crank, wiped off lube, applied plastigauge, and torqued to spec. Is this usable? Or should I go back and get tighter bearings?

[Sid_RallyX_82]

I have a sneaking suspicion that my machine shop polished 0.002" out of the main journals and then ordered stock bearings...

[FestYboy]

BINGO!
Therein lies the rub! It's not uncomon in an SCCA Majors race for the top20 Spec Miata finishers to come off track and be lined up at a portable dyno to be tested, over 130hp all three of three pulls and you are DQ.
It took some experimentation to enter values in the presets of the Mustang dyno to get equivalent results. Obviously there are no guarantees, too many variables! This was SCCA's solution to rampant cheating in that class. Pretty sad for an "Ivy League Club"

That's some BS. What if the dyno is feeling particularly generous that day and throws all the cars that run at the limit over? They just DQ the whole lot and say tough luck???

[FestYboy]

I have a sneaking suspicion that my machine shop polished 0.002" out of the main journals and then ordered stock bearings...

If they polished that much out, they should have gone further to step into the next size bearing. What's the journal nominal clearance vs. actual? What's the T gauge read with the bearings torqued in?

[Sid_RallyX_82]

My other book says Main Journal bearing clearance should be "0.0007- 0.0014 (0.018- 0.036mm)"
Also says Service Limit is "0.0039 (0.100mm)"
I'm using plastigauge, not T gauge. It reads between 0.002- 0.003in (0.051- 0.076mm)
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