Float level advice, please.

[DaveR]

On 7/27/2016 at 1:53 PM, siteunseen said:

Yes, take it apart for sure.  They sent me a bad one and I had a helluva time trying to figure it out, my first time ever fooling with one.  I called and explained the deal and they overnighted one to me.  Good people to do business with.

You did notice the different heights between the front carb and the rear one right?  I think I ended up just adding one extra washer onto the front.  It needs to be deeper in the float chamber to make up for the fuel sloshing back when you accelerate.  If I remember right??? 

This is the first I had heard about the different heights of the float level (front to back Carb). Is that really a thing? The only thing that could have been different about the housings would have been the "ears" on the float housing cover possibly having some higher or lower through holes for the pivot pin.  I honestly didn't check which one is in which location.

Also, i opened up the grose jets and attempted to stretch to the spring out a bit.  Didn't have much luck and I think I would have deformed the spring way too much if i pulled it any further. The first bit of the pins travel really has no strength to it. Sinks down with almost no effort so its no surprise that the float (however light it may be) pushes it down. This is the case with both sides (both jets)

Should the float be resting on the retaining clip? Seems to be contrary to what I've read, but what do i know.

Edited August 11, 2016 by DaveR

[siteunseen]

There were two different lengths of valves originally, I think the front one was longer.  Here's something I grabbed from MSA's site

" Image Note:
In the image you can see two needle valve housings. One is for the front carburetor and one is for the rear (they are different lengths). The interior valve assembly is pre-installed in one of these two. Match the housing length up to the carburetor you are rebuilding, and install the valve assembly in that housing, if not already in the correct housing. Each kit includes both housings, so one will be unused."

http://www.thezstore.com/page/TZS/PROD/11-3151

In your picture above that float should be parallel to the lid and higher in the front, opposite the valve side.  Do you have the SU DVD from Ztherapy?

[siteunseen]

here's something from rockauto.com that shows that they are different lengths.

This is the front , longer

 

[DaveR]

Got Bruce @ Ztherapy to chime in on this.  Few things that have made a lot of sense to me. Maybe others know this, but it was news to me.

First off, he said to ignore the SU DVD about setting the float level, as it is outdated. (at least in regards to the method) Ztherapy no longer uses grose jets, they use a simple needle and seat.  This means that there is no way that needle and seat could support the weight of the float when inverted. And if the float is resting on anything it would be the retaining spring which is obviously not the desired effect.

Because it cannot support the weight, you must do your adjustments upside down (like I did).  Let the needle and seat hang, lift the float up until the valve would shut off, and set that height (between float top and float housing cover bottom) to .55".

This is exactly what I did, so I should be in good shape to begin my tuning.

Also, he mentioned they only sell 1 length of needle and seat, and apparently he had only seen one version of carburetors that had different heights of the grose jets. He was unsure as to why this was, but had no comments or concerns whatsoever about the front and rear carb adjustments being anything other than exactly the same.

 

Now that said, it would appear that some of the other more robust ways to set the float level talked about in this thread would probably still be the best advice. (Backing it down 10 turns and checking for fuel level etc) I will probably employ these if I don't have good luck with my initial float setting.

Thanks all

Edited August 11, 2016 by DaveR

[siteunseen]

I was raised to respect my elders so please don't take this as my attempt at arguing, I'm just puzzled.  I've rebuilt 2 sets of 3 screw round top SUs and the front float valve is about an 1/8th of an inch longer.  To make my valves from Ztherapy work I had to add an extra aluminium washer under the front float valve.  

I've read many post about the front carb needing the extra depth for when the fuel all goes to the back of the bowl on acceleration.  Am I wrong @Blue @Jarvo2 @jonathanrussell?  It wouldn't be the first time and sure won't be the last but it is what it is.  I apologize for disagreeing with Mr Palmer, he is a very nice man and they may work without that extra washer but to keep the tang on my float from being bent almost straight down I added that extra washer.

A quick google search, https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1BOFA_enUS494US494&ion=1&espv=2&ie=UTF-8#q=240z different lenghth float valves

Picture of another set of SUs I have for parts.  You can see the difference on the float pins ears and the valves laying beside the rear float.  How could "one size fit all"?

 

[DaveR]

My float pin ears are the same front to back carb. If the ears were different then I could see why you would want different jet heights. The adjustments I had to make on mine weren't unreasonably bent. My car was very much unmolested, so I have no reason to think those aren't the original lids.

Actually my float lids are identical in all ways. I couldn't tell you which one was front or back. Even the vac line to the air filter is in the same rotational position and not mirrored. 

Looks like your floats might be slightly different from one another as well. Either way it can all be made to work after checking on the car, but it doesn't appear like every car from the factory had a different setup front versus back, but apparently some did.

Really good post here: 

Seems like regardless of setting, due to the slant of the engine, the float levels will be slightly different for ideal mixtures.... regardless of how you get there.

 

Edited August 11, 2016 by DaveR

[siteunseen]

Dave I'm so sorry! I had know idea your ears were the same. That explains everything. All mine are 3 screws. The front lid overflow bung is on the rear closet to the motor side. The rear carb that overflow is closest to the fender. I'm so sorry. I feel foolish. Sorry Mr Palmer too.

[DaveR]

No need to apologize to me, I have no idea what i am doing.  My car is 13 years older that I am, and I have yet to get it properly running.   I'm like you, read a lot and hope I can make sense of it when I get it in front of me.

Edited August 11, 2016 by DaveR

[240260280z]

To set the level to be the same on both carbs when I can't measure fuel depth, I hold the lid assembly upside down and blow into the fuel port.  While doing this I rotate the float and note where it shuts off the air flow,  I then bend the tab and repeat until the air stops when the float beam is parallel with the lid (see picture below to see the parallelism). 

It is important that the beam and float  on Hitachi carbs are not  twisted (the beam and float top should also be parallel).

Doing this method is easy because the assembly is literally in front of your nose. It seems to do the job reasonably well.

 

 

[siteunseen]

Thanks Dave, I'm bad to get tunnel vision or tunnel thinking.

Blue thank you too, I adjusted mine very similar to what you're saying. The floats should be parallel to the lids. I've always set mine to.55" upside down. It's running very well now so it may be awhile but I want to try what Dave did, have them dangling down, not resting on the pin and see if there's much difference that way. But I'm not touching them until I have to. 8^)

And the floats in my last pic are the worst two of six. Those are my parts/core set.

So the moral of my hiccup or foul up, for my information is the earlier 4 screw SUs have equal depth float pin arms or ears. Learned something new today. Thanks.

[jonathanrussell]

@siteunseen....

So, I understand the theory behind the longer float ears and the longer needle jet but after much work trying to make it work, I gave up. I have a decent amount of spare parts so I ended up using a short ear float lid on my front 3 screw carbs, matched of course with the shorter needle jet. Then, I followed the process I described earlier to make the fuel level in the nozzles match at 10 turns down with the domes removed. What is my theory? I just think that the longer ears change was flawed. By lowering the front float 4mm in the float bowl and since it appears to me that the float bowl is tapered a bit, I believe that the rubber float gets restricted in terms of its movement / travel in the bowl (it hits the sides of the bowl) at the point where it should theoretically be in adjustment. The end result for me is that I can never get the float adjusted right.

So, to answer what I think was your question, I treat my 3 screw carbs like 4 screw carbs and adjust the front and rear the same....at the float and where the fuel hits the nozzle.

Maybe a 2 sensor wideband so I could measure while accelerating would change my mind.... 

[Namerow]

5 hours ago, siteunseen said:

I was raised to respect my elders so please don't take this as my attempt at arguing, I'm just puzzled.  I've rebuilt 2 sets of 3 screw round top SUs and the front float valve is about an 1/8th of an inch longer.  To make my valves from Ztherapy work I had to add an extra aluminium washer under the front float valve.  

I've read many post about the front carb needing the extra depth for when the fuel all goes to the back of the bowl on acceleration.  Am I wrong @Blue @Jarvo2 @jonathanrussell?  It wouldn't be the first time and sure won't be the last but it is what it is.  I apologize for disagreeing with Mr Palmer, he is a very nice man and they may work without that extra washer but to keep the tang on my float from being bent almost straight down I added that extra washer.

A quick google search, https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1BOFA_enUS494US494&ion=1&espv=2&ie=UTF-8#q=240z different lenghth float valves

Picture of another set of SUs I have for parts.  You can see the difference on the float pins ears and the valves laying beside the rear float.  How could "one size fit all"?

 

According to my notes, these were the changes to the carbs that occurred as of Jan. 71 production and the emergence of the so-called Series 2 cars...

Different, front vs. rear…  Front = long-ear, long-needle;   Rear = short-ear, short-needle.  Drain fittings added. 3 screws for float bowl covers. (S1 carbs used 4-screw float bowl lids, with long-ear / long-needle for both front and rear.  Bowls did not have drain fittings.) For the 72 that I no longer have, the carb re-build kits that I bought had entirely different part no's.