soot

Okay! so the old 1.6 is primed to be pulled and I disassembled the VVT motor so I can get to refreshing it. This is my first bottom end refresh so I'm hoping for some input. Nothing fancy or high dollar here, just trying to snag the low hanging fruit while the block is opened.

Plan is:

• Stock pistons - how much scuffing on the skirt is acceptable?
• New Mazda rings - planning on .015-.016" top and .017-.018" 2nd ring gap, does this sound correct?
• Maybe Eagle/Manley/K1 rods
• VS855 valve springs
• ACL/King main and rod bearings, Mazda thrust washers
• New Mazda Crank pulley
• Cometic head gasket
• All new Mazda Seals

Machine work

• Tank and deck block and head
• Hone bores
• Lap valves - they look great and this has worked for me in the past

Engine will be in a autox/TT car that is occasionally street driven. Hoping for a ~7800RPM limiter for 2nd gear speed but happy to drop that for reliability if that is a tad too high. I currently have a c30-74 that was making 230WHP on the 1.6 and may move up to a c30-94 in the future (hence my though of getting rods).
The stock 1.6 bottom end lasted 4 years of hard boosted driving with a 7800RPM limiter and finally let go at almost 200K miles. Again, I'm hoping for input but tried to do my reading before making any plans.

soot

So apparently there are no STD ACL/King race bearings available and the soonest ETA I trust that I'm getting is April or so.

How dumb does it sound to slap this motor together exactly as it was and just run it for 1 season and tear it down and get the proper machine shop work/bearings rods etc next winter? Bearings look pristine, minimal scuffing on cylinder walls and pistons.

I could also run a set of non race kings ($80) or OE Mazda (~$200) but I feel like it's a bit of a mistake to put the money in on those just to rip and replace after a few months driving. Maybe I'm penny pinching too hard here, but I want to get some seat time again real bad but not looking to just toss cash in the process if I'm gonna do a proper rebuild next winter.

EDIT: Pulled my head out of my *** and I have a set of factory Mazda bearings and rings on the way and a set of eagles too. Gonna do it right haha

_slowboi

Is it too late to change this? Been seeing quite a few issues related to these. Id suggest ST Light Doubles at a minimum.

soot

ah ****, really? I tried to do some digging, but some of the resources I was looking at are a bit old. What failures are you seeing? I'm a bit hesitant because that would make the springs the most expensive thing about this engine. it's otherwise a rods+bearings motor

_slowboi

Most common has been the seats being beat into submission (not enough spring pressure) and then rapid degradation of spring pressure. There was a thread on here that had a bit more info by Eric on that topic. Have seen a few reports of the springs breaking as well.

soot

VS855 has higher spring pressure than stock springs, that has been confirmed several times now. I hadn't seen the reports of breaking though, I'll look into that.
AFAIK stock seat pressure is around 44lbs, VS855 should be ~66lbs

_slowboi

The problem was the spring pressure was degrading in very low hours of runtime. So you might start with 66lbs but it very rapidly declines. At that high of a redline and adding boost on top I would be looking for a bit more seat pressure than that IMO.

soot

I'm probably going to stick with them unless I see something real convincing. Springs are a wear item and the only seat wear issues I've seen in my research were from questionably cut seats or in crazy builds like TNTUBAs where's they're pushing crazy rpms/cams. I'm running stock cams and a 7800 RPM limiter for autox and shifting lower for track. Seen plenty of supertech problems too, so it doesn't seem worth paying 4x as much when I'm not going all out and revving past 8K

soot

Lol, so I finally got the 'dead' 1.6 apart and I'm kicking myself because I could have just slapped a new head gasket on it and kept ripping. Bearings etc were all good. Also stoked to see my old port work looking so nice and clean




hmmm... suspicious

soot

This was my second throttle body failure on this car :/. Well the machine shop said they're almost done with my stuff, so I guess I'm just gonna start slapping the 1.8 together soon. It's gonna be fun to get the little power bump

Gee Emm

Skunk TB on the way? That was my response to busted TBs.

soot

Yeah I was on a 1.6 before, now that I'm on a 1.8 I ordered a skunk ripoff. I'm a little spooked about using the ripoff currently, but it seems like they are about as crappy as a real skunk. Gonna red Loctite the screws and deburr/ re-tension the spring

soot

Ok so next time I build an engine I'm just going to get a full gasket kit because holy **** have I forgotten a couple things have have been frustratingly steep to ship. First was the brass oil galley plugs, then valve stem seals (stupid and obvious, thought I had ordered them from 949 already) and finally the oil pump o ring and dipstick tube o ring. Knock on wood that's the last thing I'll have to order.

In other news it's been neat to finally build my own bottom end. I know it's just a stock rebuild, but I was racing on a 200k mile 1.6 before, so I'm sure this will feel quick.

Here's some shiny parts:

First task with the HVLP gun, Rustoleum enamel on block-


Second HVLP gun job - Cerakote thermal coating on tops and microslick on the rest


United with eagle rods -



Circuit sports oil pan baffle -


This Weisco ring compressor is 100% worth the $30, pistons just popped right in -



And assembled! Just waiting on those stupid seals and orings before I can go any further.

soot

Why did I start painting things? I'm spending more time painting **** than actually working on the car

It looks so nice though. Gonna just do some plain gloss black on the lower intake manifold and the VVT actuator and hopefully I'm done - until I have to do the engine bay . Can you tell that I hate painting?

soot

General update - Engine is in and running. I started and blipped throttle off and on until it got up to temp, let it cool off, did it again and changed the oil. Ran in for 120miles staying under 5K or so and mid throttle with lots of coast down engine braking, changed oil to synth and gonna drive it for a bit. First oil change had some weird crap in it from the assembly lube and second change was quite sparkly but nothing of measurable size so fingers crossed I'm in the clear.

I'm still fighting getting the tach working and some VVT timing weirdness (my numbers look like I'm off by a tooth on the intake cam, but I have verified MANY times that I am dead on for timing).

But hey, it looks like my car again! Tetris-ing in the intercooler is not my most favorite thing, but it all fits so nice once it's in there.


Another unexpected bonus is that the low mount Rotrex setup now has WAY more clearance for the lower coolant hose to pass between it and the steering rack. I might be able to add my rack spacers back in and possibly drop the engine on its mounts to the low setting.



I'm also working on getting an external mic setup that doesn't max out from the sound of the BOV so I can get some nice driving clips. All of the lav mics I've tried so far are struggling. I'm open to any tricks you guys have found to get better audio without forking out for spendy equipment.

Back on the street:



And finally, more cat tax:

soot

Now I'm in the process of tidying things up in the car. Also facing a weird issue where VEAL will add fuel, and then I restart the autotune and it will pull fuel in the same spot (40-60 mph low load cruise cells), but I'm trying some things and working through that...

Finally mounted the ECU properly, I had a singular bracket, but it wasn't made for my old MS3 basic and I was feeling too lazy to make brackets to adapt it - finally got the idea of just using 3M VHB to bond the ECU to the bracket and it's working great. I also got a SD card extension cord so I can easily grab mobile logs and I VHB'd that up under the dash too.

I'm also starting on my Pi dash setup again since the last setup was stolen when the car was previously parked outside. I 3d printed this case off of Thingiverse. And this time I purchased a 4a power supply/switch from Mausberry Circuits. It hooks to your 12v/GND and then you wire it to your accessory circuit. It powers the Pi on when you turn the key on, and then sends a clean shutdown command to it through the GPIO pins when you turn the key off. You can also program how long of a delay you want before the shutdown is sent so you don't have to boot up again if you stall and have to restart the car. Everything bench tested great, I'll update when it's mounted and working in the car.



Pi mounted to back of screen

Power supply/shutdown circuit

Otherwise Engine compression tested 195-190 on all cylinders on my harbor freight tester at altitude, and feels healthy. It sounds a lot more clattery/buzzy than the 1.6 did but I think I may have a small exhaust leak.

First shakedown race went well and I managed to run a top 10 raw time with the ebrake pulled because I had to rebuckle my harness at the line and then forgot to release it after . Unfortunately that was my last dry run of the day so I did not get to best it.

Sorry that was a bit scattered, but I wanted to log the most recent updates.

soot

Just had a very successful race. 1st in class and 4th overall raw in a decently fast region. We have some awesome photographers in the club so I get lots of free eye candy. There is also metric shitloads of elevation change at this lot so people were 3 wheeling all over the place. Only car related trouble was the fuel feed popping off from a bad hose clamp and then also realizing my registration expired last year.







Here's a rad little triumph friend to round things out

Scaxx

That triumph has some meats lol. Looks like it was a fun event!

soot

The wheels on it always remind me of a little kid drawing a racecar they're absolutely massive.
It's such a cool ride though, and the owner is way nice. He was initially going to build a cobra but the triumph body came up for cheap and he said "why not". Love the end result

Roda

Is it just the perspective, or is that light pole really close to that turn...