Stu's NA6/SE

[PaulF]

Those crank bolts can be a real bastard. I usually get it by keeping the timing belt tensioned and locking the cams using a tool similar to this:


But I did manage to snap a timing belt doing that once!

[bruce]

If they get torqued correctly at assembly, do they self tighten over time?

[greenMachine]

Well they are supposed to come out every 100k kms, so they shouldn't be in there for much longer than that ...

[StuwieP]

Well, all back in and buttoned up. I also have oil pressure. Which is good, obviously. I also discovered the sensor was dead

So I probably replaced the pump for nothing - although I should have replaced it when I built the engine anyway - and learned a valuable lesson: always double check your readings with an analogue gauge before jumping to conclusions.

New oil, new filter, solid oil pressure, no bad sounds. All good, except the waiting for a new sensor to arrive...

[bruce]

Yay!

[StuwieP]

Thanks Bruce, my thoughts exactly.

That'll learn me though...

[StuwieP]

coronavirus update #1: I'm continuing to be an idiot...

So I'm still trying to locate exactly where the cold side oil leak is coming from... I'm fairly sure it's from the sandwhich plate/stock cooler/filter area but haven't quite been able to pin it down - really trying to avoid having to pull anything out again but it's looking inevitable unfortunately.


Brief happy intermission - met a friend

I've also been struggling with fouling plugs. New plugs fixes the problem (briefly) but obviously isn't the root cause. I was also having an issue with my wideband not reading properly (just pegging -19.6 or something which I think was basically "0V" or "no signal"). I suspect these issues are related because when the wideband (intermittenly) works, I can see from the Haltech datalog that it is pulling fuel in certain situations - so when it's not working I'm often a bit overfueled. Fortunately while it was reading 0v it wasn't trying to remove fuel or I'd be picking up bits of the motor all along the road.

I think the calculation goes like this: Too much fuel + too much boost + too widely gapped plugs = no boom.
Obviously this problem has a tendency to make itself worse over time, getting more and more fouled, and misfiring more and more. Reducing the plug gap made a big difference but the misfire continued to manifest after a while of driving (presumably constantly running a bit rich adds up even with closely gapped plugs).

Ultimately after multi-metering various things (still showing battery voltage at the power outlet) I discovered the ground wire was a bit loose. That was promptly tightened - and in the process I may have removed an annoying rattle which was (it seems) caused by the ECU cover/kick plate not having been done up tightly. The ground was floating around and occasionally allowing the wideband to work, but mostly not...

Then, to just make sure I had more work to do, idiot me goes to test drive it without having the wiring loom hooked properly up out of the way on top of the gearbox and melts the wiring loom together, because it falls down and touches the downpipe (apparently, that gets hot...). Now I've got 100%/5v voltage instead of 0v (super lean 22+ AFR showing on the dash) and the ECU is trying to compensate by dumping all the fuel into the cylinders to avoid detonation.


This is what it looks like when you melt your wideband loom - you can see the exact moment the wires cease to maintain correct social distancing

Fortunately not too tricky to fix - just a pain and setting me back a nearly complete car for the new week of working from home (I know that I am lucky that I still can).


Crimped and heat-shrinked. They will be properly stowed this time...

[bruce]

Above parking lot is in Box Hill South?

[StuwieP]

Yeah at Repco, stocking up with 4 valuable spark plugs ( Pre-lockdown! )

Although I think I could still call that essential...

[StuwieP]

Each problem fixed results in another. I think the oil leak is sorted (stock oil warmer/cooler was not tight enough). It is now. Hopefully that's the oil issue all resolved - pressures look good at least. Not a lot of opportunity to drive to find out so the problem solving process is long and tedious.

I have now discovered a coolant leak on the hot side - I haven't touched anything there for ages, but it's new, so go figure. This weekend's issue...

Also I think my CAS sensor might be going out the window. I have similar issue to the one Magpie posted about on the Haltech forum here https://forums.haltech.com/viewtopic.php?t=11678 and possibly also in his build thread from way back in 2015. I was basically driving along with eveything finally working (except that coolant dribble which I noticed as a consequence of this problem) and then it sputtered, coughed, jolted about and barely ran, giving me just enough time to get off the main road before it just gave up on running completely. Grateful for the quiet roads as my sister could come and tow me the 3kms home around side streets that would usually be full of home-bound traffic at 6:30pm on a weeknight.

It idles OK but any load causes misfiring, sputter and death.

Hopefully Magpie's cable-tie solution solves things but I will pull the sensor and make sure everything in there looks OK just to be sure

[bruce]

So many problems!

[StuwieP]

Bruce, tell me about it. I knew building the car was always going to come with troubles but I know from the first drive home from Newcastle that it can run well - because it did! Absolutely perfect for that first interstate run.

Magpie's quick-fix worked wonders. No more missing CAS signals. I have a spare on the way from MX5Mania just for good measure but (fingers crossed) it seems ok.

Spent this morning working everything else over. Checked all coolant hoses and tightened things for good measure. No sign of a coolant leak. Perhaps it was just a spill I hadn't previously noticed from the re-installation, or an overflow from the reservoir (although it's not that full). In any event I will keep an eye on that side of the engine bay for further leaks but hopefully that's resolved.

I also installed a pair of catch cans over the last fortnight. It will be interesting to see how much blowby is captured. They are nice little units from mishimoto, filtered, baffled and seemingly well made.



Also had my mum drive me around for 15 minutes so I could watch the tuning pages and see what was going on. It was very difficult to encourage her to use much more than 10-15% throttle I believe the misfire has been a spark issue - certainly it's not going lean ever so that is a positive. I keep fouling spark plugs and I decided to try to increase the dwell setting on the toyota COPS from 2.5 to 2.75ms. A (mostly) full-throttle run onto the freeway gave me no hesitation, misfire, anything - just a nice smooth pull to 7-odd thousand RPM

Hopefully the extra 10% dwell won't fry my COPS - I'm willing to run that risk for the moment: if they give up I will at least know exactly where the problem lay. Maybe a reason to move on to the LS-coils spark set up if it does re-emerge.

So, hopefully I will get a few hundred trouble-free kilometres before the next problem arises if only we weren't all locked inside!

[StuwieP]

So far so good, everything still seems to be running right. Turns out I had also managed to reinstall everything with the cam timing out... That's fixed too!

Now for the moment of truth - booked into a drive day next Friday (spot suddenly opened up) so, assuming we don't all get locked back down again before then, it's time to find out what breaks first!

So, time to give everything a once-over, put the race pads on, and find out how much I need to learn

[bruce]

Good stuff.
Half a chance we may go back into lockdown (Melbourne that is).

[StuwieP]

Not much to say about today. It was short lived.

Engine failure at cylinder 1 at the end of my outlap (discovered after parking up). Maintained oil pressure, back to the pits.

Lotus engineering crew loaned me a compression tester... 0psi

So... yeah.


Rebuild time.