quiz time!

[180barp]

Ok fokes quiz time! ;D I got a 76 180b with the L18 and twin su's. Only just put in the su's they are old factory standard ones.

The problem is this:

Runs ether very rich or hardly at all
Very slow off the mark
looses power up hills

Any tips on trouble shooting? Where to look, what do i test and how?

[mrbluebird]

blocked up at all? maybe getting them professionaly cleaned?

[ricecutter]

Where are you, 'cos twin tuna cans is a simple one hour demo and a bit of practice.

i have L20 with Tuna's and it goes comfortably up the outlet in 5th at 80, and will pull away.

Electric fuel pump is better, as is a rising rate reg if you are flush. Set float level, eyeball linkages for sync, wind mix half turn from lean end on both. Fire it up, adjust idle screws (it has resin on it, or had) when even you can hear it sucking. listen to both when same lock screws with the nut. move now to adjust for mix. Which will be easy if previous steps are correct.

[Datsunreal]

easy way you give me a carton and i tune them up
SU's are great but can be a bitch. i just spent the morning fiddling with mine so i could get to work

1) they have to be synchronised = air sucking noise must sound the same for each if you listen through a tube. this will get them about 80% in synch (i have a synchroniser tool which is spot on)

2) THICK OIL IN THE DAMPERS 25w50 about 2cc. dont listen to anyone who says to put thin oil/ATF/Sewing machine oil/CRC/ ect its rubbish. take damper rods out and make sure the piston drops smoothly and seats with a click onto the jet-if not take apart and clean.

3) screw the nuts LEFT for lean RIGHT for rich (when viewed from above) i suggest screw them up to the stop (left=lean) and then .5 or 1 turn (right = rich) for a start anyway. (if these are the ones from craig the needles may be too big for a standard car. )

PM me if you need a tune up, (Cascade Lager cans)

[Datsunreal]

if you have round top old style SUs (the good ones) get yourself a 1500/1600 roadster (SP310 SP311) carby kit from ebay. the good ones come with 2 pairs of needles, rich and lean which are very useful for tuning. if the needle profile is too agressive they will idle rich and be pigs. Rintin1600 had this problem.

sitting around with floats full of fuel will gum them up as the fuel evaporates, so a good clean and the above rebuild kit is probably a good idea.

i run round tops on my A14 with lean roadster needles, = perfect

[datfreak]

When I first put my SUs on one of the floats had a hairline crack in it. This caused the float to sink and fuel to bucket in. They are a very basic carby... Not much to go wrong. Worn needles are the biggest killer.

[180barp]

This information is gold lads. Thanks very much!

mrbluebird: "Maybe getting them professionally cleaned? "
To true, i was a little keen on putting them in. Should have put a kit threw them as advised. In the end i stuck a couple of diy paper gaskets on the float chambers and a little bit of a spray with the carby cleaner. Pretty bloody agricultural (as the bloke from nuts and bolts tas would say) but Ill fix that up on Sunday.

ricecutter: “Electric fuel pump is better”
I was thinking about this. Then I got to thinking if I was to tec it up a notch perhaps entirely unnecessary, what about an electronic distributor? I read some where you can grab one off a blue bird no probs?

Datsunreal: "thick oil in the dampers 25w50 about 2cc"
Thicker oil you say. Cant remember what I put in in the end I think it was 10w 30. And Judging by the thick cloud of smoke that she blew, I promptly burned off the over fill. Ill give it a go.

and: "(SP310 SP311) carby kit from ebay"
That was my next question. Where to get kits, more specifically jets and needles? After all the tidy advice on and off the forums, plus my usual stab in the dark tricks, needles are the next port of call. And yea mate “they are” so that seals it. Just as soon just as I can lay my hands on some.



So an update.

Old mate with a few years xp with SU's came over the other day and he's got them running much smoother than my hack job. Gota get a smile out of the way he took a deep breath and twiddled his fingers before going to work, bit of showmanship goes a long way when it comes to SU's apparently. Additionally I put in a new coil based on an irregular performance under the timing light (didn't help the light but Im sure it helped something). Messed with the float levels a little to try to make her a bit leaner (ta datfreak) probably have to set them back latter on but.........she now takes off well and climbs hills.

Result!

Still rich as hell but well fix that

Datsun Owners Of Tasmania: 10/10

[ricecutter]

Go electric dizzy, best performance increase item for L series.

Use good fuel, Premium.

If you find new needles the bidding will be HOT.

[ricecutter]

Does recommending Datsunreal (who has The Touch) gain a Cascade commission.

[Datsunreal]

No worries mate, thats what we're here for.

the rebuild kit i bought was reasonably priced, about $60 plus postage from the US. there are a couple on the bay atm but with no needles. i do have a spare pair from my kit, for the 1600cc roadster. too rich for my purposes could be just what you need.

Electronic ignition is gold, paired with NGK iridium spark plugs and a good coil its platinum.

im down on electric pumps for carby vehicles at the moment std mech pumps are good, sounds like you have more than enuf fuel anyway. and i didnt think the Ricecutter was a drinker

[boost]

Oct 16, 2009 15:58:54 GMT 10 datfreak said:

When I first put my SUs on one of the floats had a hairline crack in it. This caused the float to sink and fuel to bucket in. They are a very basic carby... Not much to go wrong. Worn needles are the biggest killer.

2nd that $37.50 brand new from nissan about 3 Years ago

[180barp]

Scuse my absence iv been running about like mad these last couple of days. Ricecuter the dude with the magic fingers was actually a triumph man from down cygnet way. And yea I'm sure there would be a few beers in the recommendation when I manage to get to a meet. Cracking a few coldies over the hood of the Datto sounds alright to me. I have been trying premo fuel recently as well and your right the difference is substantial.

I plan on running a kit threw at some stage but I'm thinking needles and jets are a priority at the moment Ill sort her out when I get time (running quite nice at the moment).