ZS carbys

[Workshop Help]

And, if it is any comfort to all present, your dear, sweet, ol' Aunt Mildred will be diving deep into the front Z-S carburetor here in the machine shed to replace a sticking float needle. This is a new needle that must be defective.

It was replaced last week as the prior after market 'Gross jet' was flooding the bowl. This new one is doing the exact opposite by not letting fuel into the bowl. Unlike our friends below the earth's equator, the winter temperatures make ones achy joints a serious chore to be dealt with. Perhaps, on Friday afternoon when the sun warms the machine shed up a bit, it will be a good time to redo the needle valve.

In the meantime, the TR7 has been switched around to allow the niece's BMW to be used to run errands.

This morning, just over the hill, regular gasoline is $1.82 per gallon. The longer we wait to fill up, the more the price drops.

Mildred Hargis

[FI Spyder]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Cobber</i>


I beg to differ, L-jet injection was more about emissions than power.
A pair of Weber DCOE side draft carbies, properly set up should leave a L-jet car behind in it's dust.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

That is partly true. The FI car didn't have more horsepower but it did have the driveability that the carbs didn't. FI's were basically only available in US and had the 8 to 1 compression. Up that to 9.25 to 1 and you get more power. It will respond to any upgrades like tuned exhaust (bung for Ox sensor needed), K & N air filter from Land Rover, open up input to air filter as it's rather small (input air hose after filter is huge), play with distributor mechanical weight profile and springs as well. If HP goes over 110 or 120 you need to go up to next higher injectors as maximum use should only run at 80% of their capacity.

If you're not in the US, FI will be scarce as hen's teeth and a custom modern system may be more practical. But regardless of the route FI is nice to just not have the bother of carbs (just drive it) unless you like carb twiddling. Nothing wrong with that either if you like that sort of thing.

That being said power equals efficiency of burn. You don't get more power pouring more gas into the engine if it's not going to be properly burnt and nothing does that as good as L jetronic.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[FI Spyder]

Interesting to note the TR8 hp jumped from 135hp to 150hp with L Jetronic using same 8 to 1 pistons. It didn't use the Bosch ECU though but a Lucas unit that was similar to one in the Land Rover. I don't know if the V-8 was more susceptible to FI or was it only the ECU that made the difference.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[ugmw177]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by FI Spyder</i>

[quote]<i>Originally posted by Cobber</i>


I beg to differ, L-jet injection was more about emissions than power.
A pair of Weber DCOE side draft carbies, properly set up should leave a L-jet car behind in it's dust.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

That is partly true. The FI car didn't have more horsepower but it did have the driveability that the carbs didn't. FI's were basically only available in US and had the 8 to 1 compression. Up that to 9.25 to 1 and you get more power. It will respond to any upgrades like tuned exhaust (bung for Ox sensor needed), K & N air filter from Land Rover, open up input to air filter as it's rather small (input air hose after filter is huge), play with distributor mechanical weight profile and springs as well. If HP goes over 110 or 120 you need to go up to next higher injectors as maximum use should only run at 80% of their capacity.

If you're not in the US, FI will be scarce as hen's teeth and a custom modern system may be more practical. But regardless of the route FI is nice to just not have the bother of carbs (just drive it) unless you like carb twiddling. Nothing wrong with that either if you like that sort of thing.

That being said power equals efficiency of burn. You don't get more power pouring more gas into the engine if it's not going to be properly burnt and nothing does that as good as L jetronic.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Amen. I didn't say the FI would give you more power but assumed one would upgrade compression and exhaust etc. if they wanted more power. The L-jet is a great system compared to any carbs. Oh, and I would never suggest the downdraught webers [worse option than ZS or SU]

[Hasbeen]

Well I don't know about carbs being a bad way to go. I love Webbers, but I also love SUs.

Not such a fan of ZS they have too many ancillary bits you have to play with to make them work, or to go wrong.

After throwing out the electronic ignition the Brabham Repco F1 became a moderately reliable racing car. The main problem we then was the Lucas fuel injection had a problem getting 150 miles, without going off tune.

Compare this to my own F2 Brabham which competed for 20 months, without a spanner touching the Webbers, after the initial tuning sessions on the dyno, & the track.

Also compare it to the SUs on my current 7. They have not been touched in a couple of years, & were only touched in the last 10 years because they came off for the engine rebuild.

My experience with ECUs on modern cars is that they are great, until they break, then they are useless, & expensive to replace.

Yes I'm a reactionary old git, but I'll keep to the tested gear, this Johnny come lately modern technology doesn't cut it if you get too far out into the bush, [the real world].

The old kiss, keep it simple stupid principle works best for us old blokes.

PS. I'm thinking of improving my S2000 Honda, by throwing the bloody awful electric power steering in the bin where it belongs, & fitting a TR7 rack. Well I would if it were that simple.

Hasbeen

[Workshop Help]

Here's an update from the Machine Shed. The temperature warmed and my arthritis subsided enough for delving into the front carburetor this afternoon. Dropping the bowl found it full to the proper level. The float height was rechecked showing it to be set correctly.

Next the air slide was pulled to examine the diaphragm condition. It was fine. With aerosol carburetor cleaner, a healthy squirt was directed down the jet from the venturi side then followed up with a shot of compressed air. If any debris was clogging the fuel flow, it's gone now.

So far, nothing seemed out of place. The float needle functions by filling the float bowl, yet there is no leakage past the bowl gasket. All is well with this critical component. The air slide appears normal and the air chamber is clean. The slide needle is likewise clean. Sewing the carburetor back together, the engine was fired up.

Where before, the engine was rough and acting lean, it settled into it's usual idle pulling 19.5" on the vacuum gauge. The temperature gun showed a consistent reading for all the exhaust ports indicating normal combustions. Timing was checked remaining at it's setting. Air flow was checked with minor idle speed tweaking. Also, the idle trim screws were slightly screwed in to achieve a smoother idle.

The engine is running fine. I'm not sure why. Perhaps the fuel in the tank had passed bit of water to upset the fuel quality. I am convinced the more we drive our cars, the fewer problems we will have. Even short periods of being parked can produce problems.

Mildred Hargis

[Hasbeen]

Of course, as with that old grey mare in the song, SUs aint what they used to be.

We had "PROPPER" floats, nicely made of copper & brass, all soldered together. None of this moulded float, with their tendency to partially fill with petrol by osmosis, & raise the float level.

We could bend the copper fork that ran on the float to adjust the float level. For competition work we would set the float level with the fuel 1/16" down from the top of the jet.

This not only gave a little more power, but quicker throttle response.

I had one of the plastic floats in my second 7 take in some petrol. It had probably building up for years. As I had a club run the day after I discovered it I drilled a small hole in in the float, shook the fuel out, & plugged the hole with a bit of a kebab stick, suitably trimmed to fit.

I planned to replace the float but promptly forgot it. 12 months later when I remembered it, I found the float still empty. Petrol obviously makes wood swell in the same way that water does to seal a hole. That bit of Kebab stick was still doing it's job a couple of years later, when I sold the car.

One of my more successful bodge jobs.

Hasbeen