TB42 valve springs?

[dansedgli]

After some searching on here I realized that the rockers needed adjusting every so often and thought that this might help cure the rattles I keep hearing.

I pulled the rocker cover off and other than noticing that the rockers needed heaps of adjustment I also noticed that the valve springs were a double valve spring type. A smaller spring inside a larger one.

Is this normal or has my motor had a going over?

My GQ is slow either way. It only made 63rwkw on a dyno a few weeks ago.

BTW my motor is heaps quieter after making the adjustments. I was surprised at the difference!

[PGS 4WD]

The springs are a duel from the factory. If the valves come loose more often than every 20 000k (the suggested adjustment period) then the hardening may be coming off the cam, there was actually a problem with some of these under warranty, I was replacing camshafts at Nissan as an apprentice in the early 90's. I've found with good fuel, extractors and electronic ignition and the timing optimized the carby TB42 on our dyno is good for between 70 and 80 rwkW.

Joel

[dansedgli]

Thanks Joel, that clears things up.

Ive got a electronic ignition on the way. I'm still undecided if I want to turbo it or not though so have put off getting extractors for it.

My gas system has stopped working out in the bush for no reason and been fine the next day. I'm a bit paranoid of it happening when I don't have petrol as a back up.

[PGS 4WD]

Sounds like a safety switch if it just dosent run at all sometimes and it runs fine when it is running.
Turbos are ace, I sold my straight gas tb42 and am building a LS1 turbo for my new ride.

Joel

[dansedgli]

When the gas plays up its only when I come to a stop in traffic. When the revs get low the car just dies. The day after the issue was gone.

LS1 turbo would be very nice! Is that for a 4wd?

I would be happy with anything over 100rwkw just so I can tow a bit better and keep up with my mates GU on the way to toolangi.

[mattsluxtruck]

Sounds like a mixture problem. I have the same drama and mine is its running too rich at idle. I gotta get it sorted one of these days...........

[dansedgli]

It is fine 99.9% of the time though, thats why im puzzled. It always comes good the next day as well.

[PGS 4WD]

Yea its for a mid wheelbase GQ ute.
I've seen where if the mixer isn't 100% sealed to the top of the carby you can get fluctuations in idle mixture and idle quality to the point of stalling and hard starting, also on some older 300A mixers the idle screw becomes loose and can move on its own, I usually screw then out and damage the thread slightly so it dosent twist as easily.
Is it impco or a European complex converter simple mixer design(idle adjusts on the converter).
Joel

[dansedgli]

That project of yours should be lots of fun!

My LPG setup is a simple mixer design I think.

Its got OMVL R90/E stamped on the convertor and a ring mixer on top of the carby. There doesnt look to be any adjustment on the ring mixer. There is a valve that looks adjustable by turning a screw on the line that feeds the mixer.

It was all fitted last year as part of the deal when buying the car.

A mate has a B2 convertor and a gas research throttle body from his commodore that he wants to get rid of.

Do you think this would be a more reliable setup?

[PGS 4WD]

Certainly it is provided you are OK with straight gas and you get it tuned by someone familiar with the product, The OMVL is the better of a bad lot, I'd normally run it on the dyno and make sure that it dosent lean out at high load low rpm as thats usually the problem area, with a bit of dicking around it is often possible to get an acceptable result by changing the angle and entry point of the gas mixer discharge tube in the mixer ring.

Joel