Tuning this 3.0 on SUs...

[Stanley]

http://www.improvedtouring.com/forums/showthread.php?23288-Which-Intake-Manifold-for-a-240Z

Found this today, interesting bit about dashpot oil, piston rise etc.; about racing with stock engines.

Edited May 12, 2015 by Stanley

[oranngetang]

I've been in the Kootneys sitting in hot springs and canoeing, thanks for the link. I'll catch up on some reading. There seems to be opposing opinions on even the SM needle being 'fat' on that first page.

In other news, still havnt heard from the folks in Salem, so this evening I reluctantly spent another $100 bucks on two pairs of needles to work with from elsewhere.

I have zero luck with US based businesses.

[oranngetang]

On a side not and until I return home, I've been encountering a starting issue with this engine and have somewhat assumed it's just a sympton of a higher compression engine.

The car will crank endlessly without issue when cold, however once it's being driven and either stalls or is turned off it can barely crank. The pinion engages and the engine will rotate but gets stuck on a compression stroke and often takes several attempts before it kicks and I'm on my way again.

Would installing a new or 'gear reduction' starter possibly help?

I should note that for some reason immediately after this occurs, the ammeter shows nearly a full 55 amp deflection for a short period of time and then returns to a normal 5-8 amp indocated draw.

I have a 60 A bosch alternator with internal regulator, most wiring between battery/starter/tach/coil, etc. is new. Battery is a fresh yellow top.

$200 CAD shipped for a gear reduction starter on ebay from the normal vendors.

[oranngetang]

http://api.viglink.com/api/click?format=go&jsonp=vglnk_14320456598798&key=ae923c8ceda7d3ad0f0ac558ac54d711&libId=i9veh02t0100rmwn000MA9bo4ihkl&loc=http%3A%2F%2Fwww.classiczcars.com%2Ftopic%2F48994-starter-troubles%2F%23entry8&v=1&out=http%3A%2F%2Fwww.biopatent.com%2Fsolenoid.html&ref=http%3A%2F%2Fwww.classiczcars.com%2Findex.php%3Fapp%3Dcore%26module%3Dsearch%26do%3Dsearch%26andor_type%3D%26sid%3Da5a0c881e67d18ab1771b97f5339d59d%26search_app_filters%5Bforums%5D%5BsortKey%5D%3Ddate%26search_app_filters%5Bforums%5D%5BsortKey%5D%3Ddate%26search_app_filters%5Bforums%5D%5BsortDir%5D%3D0%26search_term%3Dstarter%26search_app%3Dforums%26st%3D50&title=Starter%20troubles%20-%20Electrical%20-%20Classic%20Zcar%20Club&txt=Addition%20of%20a%20Relay%20to%20a%20240Z%20Starter%20System

For my future reference

[Kurbycar32]

Using a gear reduction starter from a 280 made a huge difference on my car.  I haven't tried it with the new engine but I think i paid around $40 at my local parts store

 

 

[oranngetang]

Thanks Kurby. I see Rockauto has them for very cheap; cheap enough I'll just order one. They tend to send via Purolator, who just leaves stuff at my door, and/or has their depot across from where I work.

[Kurbycar32]

Get those needles figured out so i can shamelessly apply your knowledge to my clone-motor

[oranngetang]

Working on it... I'm finding it hard to believe that the only place I'm successfully having stuff put in a box and mailed to me is from the people that say the needles won't fit the carbs. The guys that rebuilt my carbs can't seem to be bothered to take an order or reply. I've pretty well wasted $200 bucks and a couple of weeks of driving the best highways in BC in the luckiest weather break ever, because someone can't get an envelope in the mail.

 

I'm curious how yours runs on your stock needles, or did Dave grind yours aswell?

[bartsscooterservice]

I'm starting this thread to keep track of my findings, but please chime in if you have any thoughts, suggestions or critisisms on the matter.

 

The engine is a fresh 3.0L Rebello "Full-on" package, which have my zTherapy 4 screw round tops bolted to it, on a smoothed balance tube, and a 6-2-1 header. Compression is said to be 10.1:1, I noticed the head is slightly ported, and the valvetrain noise is overly aggressive even with a fresh lash adjustment. Cam is a '99DI', IIRC, which Dave himself said runs very loud. Rebello Racing bored these to 48 mm, and as it appears did some crazy grinds on the needles to put down 282 HP on my dyno sheet.

 

That said, my experience with the tune has a been a little frustrating.

 

For starters, this engine will not idle. With suspicions of the car running overly rich, I purchased an Innovate DLG-1 dual wideband gauge to monitor with banks of my header at the 3-2 collectors. The gauge has told me a lot, but most importantly that the engine IS running rich. How rich?

 

With the float levels at 20mm from top of bowl, at 3 turns down (2.96 mm by caliper), I'm putting down 9.1-10.1 AFR at WOT, through the rev range, and >20 AFR at an idle of 800 RPM.

 

With the float levels at 20mm from top of bowl, at 1.5 turns down (1.48 mm by caliper), I'm putting down 10.8 - 12.4 AFR at WOT, through the rev range, and the engine is much snappier above 2000 RPM, but below it has no power and will idle for only a few seconds with the idle screws generously opened up.

 

I suspect these fancy looking needles may have some, if not ALL to do with these problems. Thanks goes to Blue for walking me through uncovering them.

 

needles.jpg

 

With the amount of material removed, it seems to be that I need to set the mixture to be excessively lean to compensate, leaving no fuel for the engine to idle on.

 

I'm going to try playing with these a bit, and am pondering the idea of spinning some SM or stock needles a little to see how it effects my specific engine.

 

In the mean time, I'm kind of wondering if setting these needles set higher into the piston, or filing off a tidbit of material at an idle/low end position may assist with the idle issue.

 

Better drop those needles in the trash and buy some decent ones...

My god looks like a hamster has been eating on those needles..

 

You could ask Ztherapy for a right set of needles for your application.

[oranngetang]

I have, several times.

[Kurbycar32]

I did get the "big bore" adjustment done, but i have not seen the needles in person yet.  Perhaps you can post a link to the conversation you had with blue to extract the needles from the carbs.

 

Without too much of a threadjack my motor is in.  I probably need another 3-4 hours of hook up and plumbing to get it running.  Kids baseball is killing me..

Edited May 19, 2015 by Kurbycar32

[oranngetang]

1. You need to unscrew and remove the black damper caps, they're thumb tight and slide out with a damper-plunger on the end, they may be wet with oil, FYI.

2. Unscrew the 3 or 4 screws that hold the dome down and lift it straight up. this will uncover the piston and piston return spring.

3. Remove the spring (it just lifts out)

4. Very carefully lift the piston straight up, the needle is attached to the bottom, so lift straight up until it is free. The centre of the piston where the damper came out of may be FULL OF OIL, so be careful not to tip it by accident. There may also be a plastic washer that sits below the spring, so don't lose that.

 

Those are your needles. If you decide to remove them, note that there is a shoulder at the thick end that isn't beveled. That shoulder must be flush with the lower area of the piston, not the notched out groove it's mounted in.

 

For example, when re-seating this needle it would be wise to turn your jet adjustment nut all the way up so the top of the jet nozzle is flush with the jet sleeve. Slide the needle into the piston, but not all the way, tighten the needle screw enough you can still move the needle into the piston without much force, hold the bottom of the jet asembly UP and lower the piston into the chamber. This would seat that needle at the same height as the nozzle sits, in each carb.

 

If anyone has anything to add or remove, please speak up as I'm new to these things.

Edited May 19, 2015 by oranngetang