Out with the new, in with the old...

[rossiz]

thanks cap'n - i fabbed up a quick 'make-do' clamp to get me going but it will be great to have the proper bits on there!

[Mark Maras]

Hey Geoff

I'm doing the "Snoopy happy feet dance" for you in Portland. Your description of a cold start is spot on. Sounds like you're very close to perfect. You're gonna love the carbs. Who knows, Maybe you can even convince Sarah that they aren't evil.

Can't wait for the results from the butt-dyno run. So, is the new ignition sys. going to be installed, before or after the new build goes in?

Great job.

Mark

[rossiz]

thanks mark - the snoopy dance image is a hard one to let go of... i'll be chuckling all day about that one 

the distributorless ignition system is going on the new build - that will take some time to set up, so i'll do the initial install with the zx dizzy and then do the swap. i'm trying to do the engine in stages, setting up one system at a time and proving it out (carbs first on the current motor, then new motor w/existing dizzy, then the DIS) vs. doing it all at once and having to deal with the nightmare of having to troubleshoot/tune everything at once. the DIS also requires some programming, which will be easier once the engine is basically running and tuned.

[rossiz]

just a quick follow-up on this thread:

 

i completed my F54/P79 rebuild and swapped it in, transferring the carbs exactly as set up for the old motor and i've been delighted with how well it runs. the the new motor is broken in with about 700 miles on it and the carbs are performing flawlessly - beautiful, steady idle at 600rpm and silky smooth right up to 7K (haven't revved any further than that yet). i'm pretty sure there's more to get from them with some fine tuning, but that will wait until i install a 6-2-1 header and the dual O2 sensors to really understand where it's at. i'll report back when i dig into that in a few months.

[Patcon]

Fabulous. congratulations

[siteunseen]

just a quick follow-up on this thread:

 

i completed my F54/P79 rebuild and swapped it in, transferring the carbs exactly as set up for the old motor and i've been delighted with how well it runs. the the new motor is broken in with about 700 miles on it and the carbs are performing flawlessly - beautiful, steady idle at 600rpm and silky smooth right up to 7K (haven't revved any further than that yet). i'm pretty sure there's more to get from them with some fine tuning, but that will wait until i install a 6-2-1 header and the dual O2 sensors to really understand where it's at. i'll report back when i dig into that in a few months.

Hey Rossiz, I thought I'd share some information I've gotten from Jeff G 78 on his 02 sensor placement on the header.  He just put one in, Innovate MTX-L 3844, and said there is very little room down there where the header runs against the tranny so the right angles of the bung are critical.  I know I had to grind off some of the transmission so my 6 to 1 header would fit on my '77, it was touching before the grinding.

 

I'll put up what he told me in a PM, hopefully he won't mind. 

 

"The bung comes with the kit.  Most bungs are 1/2" tall, but the one that comes with the kit is 1" tall, so if you buy a bung, you might want to get a tall one.  Get a plug if you don't plan to install the sensor right away.  The instructions say that the O2 sensor tip should be flush with the inside of the collector to protect it which is the reason for the tall bung.  The sensor body and lead wire with a 1" tall bung is very tall, so finding a spot where it fits is critical.  It has a range of angles where it can be installed from vertical.  I came very close to screwing up.  I thought I had the angle right when I marked it, but I underestimated the length of the sensor plus the wire.  I should have tipped it up a few more degrees.  As it is, the sensor wire touches the transmission and could rub.  I will add some convolute to protect it.  

 

The bung is also flat on both ends.  You will want to grind the pipe end to create a saddle so it fits the shape of the pipe to make welding easier.  It took 5 minutes with a die grinder to get the shape close.  A friend TIG welded it for me.

[rossiz]

hey site,

 

good info - thanks for the post. and thanks jeff G for passing on the experience. i have a dual-sensor unit and my plan is to swap out my current 6-1 for a 6-2-1 and put the sensors in the Y collector which will give me separate readings for the front and rear carbs. this will put them a bit higher into the engine bay and while it should eliminate tranny interference, i'm gonna have to watch out for the fender well - i'm hoping the angle of the Y will wind up putting them below/in front of the break booster. i'll be sure to post up when the time comes

 

these are the pics i'm using for reference:

 

MSA 6-1 (current)

 

MSA 6-2-1 & Y adaptor

 

[siteunseen]

Okay, I see what you mean by 6-2-1, I was thinking you meant 6 into 1, just quick typing.  

 

Sounds good.    

[Zedyone_kenobi]

I currently run the 6-2-1 header but I only went with one O2 sensor at the end of my Y pipe.  I have been very happy with the results for many years. I have no idea how long the O2 sensor is good for, but she is chugging along with no issues. I have absolutely no idea if it is still accurate though

 

I love me some SU's they are wonderful carbs.

[rossiz]

finances and a new job have occupied me completely as of late, so i haven't had any time/extra cash to fiddle with the car (much less for a new exhaust system) so i've just been running on my "shade-tree" tune - my O2 sensors at present are comprised of ears, nose & eyes...

 

she's running rich, but not terribly so, and i'm sure when i get the O2 sensors installed i'll have fun dialing in the needles, but for now i'm quite impressed with just how reliable and hassle-free these carbs have been. i know the car isn't tuned to perfection yet, but it's running well, starts easily and the warmup/choke ritual is perfectly predictable. 

[rcb280z]

I loved the SU's when I had them on my 77 rossiz. I had no trouble with them. IIRC they were on the Z for almost 7 years when I lived in Nevada. When we came back to California I had to put the EFI back on it. Wouldn't pass "visual" part of the emissions testing with the SU's. I do miss them. 

[Mark Maras]

Geoff, How dark are the plugs?