1 (edited by zanzabar88 2017-10-12 02:49 PM)

Topic: Lancia Butt race recap and troubleshooting

Here's what happened to us at Buttonwillow - it was a bit of a saga:

Arrived Friday AM and pretty much worked on it nonstop with lots of help from Chris Overzet and Spank.

Saturday 10:30AM - We are finally done with tech after fixing the kill switch wiring and some other stuff and ready to race. Driver #1 suits up and hits the track for one lap, comes in, everything looks ok, goes back out for 2 laps, coolant expansion tank cap (borrowed from Supertroopers...no worries, not your fault guys, and thanks for the generosity!) blows off in a giant cloud of steam on 2nd lap. Driver #1 pits with car overheating. Temps reached 300+ degrees on the head. What a wonderful and not-at-all-auspicious start for the Lemons Lancia!

Saturday noon - Borrow replacement expansion tank cap (from random team's Ford truck tow vehicle, again many thanks!) while other team member drives to parts store for new one, we get more water in it and bleed the air out again, Driver #1 does one lap and comes back in to report that everything seems ok, temps hanging out around 195, goes back out for 5 more laps and pits.


Saturday sometime in the afternoon - Driver #2 gets in car and does 5 laps of terror because mirror situation is terrible. We decide to stop driving to avoid crashing into someone. Another trip to parts store and rigged up an alternate bracket that allows us to affix mirror in much better position.


Saturday evening - install drivers and passenger side mirrors, change engine oil and transmission oil. Overall feel pretty great about the car actually running and hoping we are going to run well on Sunday with everyone getting at least 1 hour driving the car.


Sunday 9AM - Driver #3 drives for 45 minutes and comes in reporting the car doing ok, temps hanging out around 195, 10AM Driver #4 drives for ~30 minutes and comes in reporting the car doing ok, temps around 200, 10:45 Driver #5 (forgets to turn fan switch on!) drives for ~60 minutes and comes in reporting the car was fine for 45 minutes then started losing power. Temps were around 210-220. Eventually it lost all power and stalled. Got it restarted and had to crawl back on the dirt back to the pits. It would run and stumble but had no power. We start troubleshooting ignition issues and look inside distributor and check the plugs, finding nothing strange.


Sunday noon - Driver #1 goes out for 1 lap and pits reporting stumbling/hesitation/misfire (after right turns?) still there. We then take apart the carburetor to clean jets and examine float and fuel bowl for debris or anything strange, finding nothing. 1PM Driver #1 goes back out and does 3 laps then pits reporting same problem occurs, but not until 3rd lap. We play with fuel tank pickup thinking that would fix it. Driver #1 goes back out and pits again. I can hear hissing/sucking sound at carburetor, suspect air leak in there somewhere (maybe, but maybe not). We try cutting frayed bit off of fuel line at carburetor intake port (possible air leak). Doesn't help. Driver goes out and pits again reporting same problem. We keep messing with fuel cell thinking perhaps it's a pickup issue, reposition pickup tube a couple times, and put 6 gallons more gas in. Eventually Driver #2 (me) goes out and milks it around the track for 30 minutes until race ends noting that fuel starvation occurs after every hard right turn. I can minimize the fuel starvation by going through right turns at part throttle and pumping the gas pedal following those turns getting full fuel flow and full power to eventually return. Temps hanging out around 220 throughout the afternoon. It was a hot day so we're unsure if that temp is excessive or not.


Our diagnosis is that carburetor is fubar and we need a new one. Possibly temperature related? Maybe the automatic choke (water temp driven, but the water lines are capped off) is getting triggered or stuck once a certain temp is reached...but then why only following right turns? Some sort of air leak in one of the seals in the carb is one more leading theory. Maybe the fuel bowl empties on those right turns and it takes a little while to refill? Maybe there's a fuel boil thing going on and the right turns cause it by putting something hot in closer position to the fuel line somewhere? Or perhaps it's a vapor lock situation in the fuel cell or fuel lines?

Thoughts? For next race I'm leaning toward upgrading to slightly bigger and simpler carburetor and adding a high quality fuel pickup (Holley Hydramat?) and checking the fuel cell vent as well as all fittings on the fuel lines. Other than that I can't figure out why we get fuel starvation after right turns.  Any ideas for how to fix this would be appreciated!

Captain of AFART Racing - 1987 and 1988 Toyota Supras
Captain of McDads/AFART Racing -1977 Lancia Scorpion (IOE Winner Sears Pointless 2021... wait, really?? YES, REALLY!!).
Captain of 42 Hours of MeLons (2013-14) - Vattenmelon Vagn 1984 Volvo 240, B-Class Winner: Arse-Freeze 2014

Re: Lancia Butt race recap and troubleshooting

Did the problem occur after you gained confidence in the car and started cornering faster, or did it work fine in high G corners before?  If you make slower right turns, does it still do it? 
It's lean if pumping the throttle helps.  Is the float set at the correct (high enough) height?  What carb is on it?  The Weber used on some Fiats has a known problem, and there are some fixes for it.

Re: Lancia Butt race recap and troubleshooting

I don't think a Hydramat is going to buy you much on a carbureted engine.  The float bowl should hold enough fuel to get you around a corner even if the fuel pump is sucking air.  I agree with Bill, the float height is probably set too low.  The Lancia will have a Weber 34 similar to what's on Bill's Yugo.

1990 RX7 "Mazdarita"  1964 Sunbeam Imp (IOE 2013 Sears Pointless) 2002 Jaguar x-type (Winner C-Class 2021 Sears Pointless)
Gone bye-bye
1994 Jaguar XJ12 (Winner C-Class 2013 Sears Pointless)  1980 Rover SD1 (I Got Screwed 2014 Return of Lemonites)

Re: Lancia Butt race recap and troubleshooting

It appeared to be a sudden issue. In other words, it was fine (while driven hard) and then it wasn't. The apparent fuel starvation occurred well after completing most of the corners. I'm definitely on board with the float height setting or some other float bowl issue causing this. Once I get a chance to pull the carb off and inspect the internals I'll hopefully find something wrong, and/or readjust the height settings.

We're using the stock carb which is a Weber 32 with a bunch of unused smog ports. I'm wondering if there's some kind of temperature related issue with the automatic (water) choke, or one of the vacuum ports that we just have plugged off...or the electric fuel cutoff solenoid?

Captain of AFART Racing - 1987 and 1988 Toyota Supras
Captain of McDads/AFART Racing -1977 Lancia Scorpion (IOE Winner Sears Pointless 2021... wait, really?? YES, REALLY!!).
Captain of 42 Hours of MeLons (2013-14) - Vattenmelon Vagn 1984 Volvo 240, B-Class Winner: Arse-Freeze 2014

Re: Lancia Butt race recap and troubleshooting

The water choke doesn't seem related.  If you are worried about that, just remove the butterflies from the top of the carb.  That's all the water choke does is close those when cold and kick up the idle speed.  If they can be easily flopped open/close, that's a problem but they usually have a spring to hold them.  Vacuum is likely a red herring as well.  In those smog years they did sometimes have to add stuff to keep the engine from running on/dieseling.  A lot of the time they had a dashpot type arrangement that held open the throttle stop while the engine was running and allowed the throttle plates to completely close when the ignition was turned off.  Some used a fuel cutoff which I suppose could possibly fail intermittently and give the symptoms you describe.  If you have one I'd jam it in the open position but I still think you have a float height problem.

1990 RX7 "Mazdarita"  1964 Sunbeam Imp (IOE 2013 Sears Pointless) 2002 Jaguar x-type (Winner C-Class 2021 Sears Pointless)
Gone bye-bye
1994 Jaguar XJ12 (Winner C-Class 2013 Sears Pointless)  1980 Rover SD1 (I Got Screwed 2014 Return of Lemonites)

Re: Lancia Butt race recap and troubleshooting

Are you sure it's fuel?  I have been in a couple of cars that would seem like it was fuel starved in left of right handers and it was an electrical short.

Team whatever_racecar #745 Volvo wagon

Re: Lancia Butt race recap and troubleshooting

Thanks for the shout-out, but I think I'm more deserving of a condemnation for helping to get that car into your hands.

rb92673 wrote:

Are you sure it's fuel?  I have been in a couple of cars that would seem like it was fuel starved in left of right handers and it was an electrical short.

^^this^^

Going around turns and the wires sway and arc.  You have some interesting color changes in your wiring harness mid-run. While I think you should certainly do the known fuel float mods (I think there's something with a primary jet mod as well) don't overlook the wiring, how it is secured, and where the connections are that could be pulling loose or shorting out.

Re: Lancia Butt race recap and troubleshooting

It EASILY could be wiring and I know where to look first - my ground wiring arrangement is a rat's nest and several of those were barely being held in place. I'll fix that first.

Good to know that vacuum and choke are likely not part of this.

I have found some additional info that might point to fueling problems:

"...  this design (in some or all versions?) can also suffer from fuel starvation, albeit less severe than in other designs and only in combined conditions of both high lateral-Gs and high fuel demand simultaneously -- i.e., when high fuel demand ... draws the float level way down whilst extreme cornering sloshes all the fuel into one bowl and away from the fuel pickups along the bowl walls.

I have also read that this can be mitigated with a short length of 1/8" copper tubing inserted into the fuel pickup ports on the bowl walls and pointed down into the bowl bottom to act as a fuel siphon "good to the last drop"; however, simply fitting a larger needle valve is much easier, reversible and foolproof, and this may be sufficient to supply enough fuel to keep the bowls from draining too low (altho' your fuel economy may suffer due to less-precise fuel metering of the larger needle opening)."

http://www.lancisti.net/forum/showthrea … n-Scorpion

I'm not sure how far to dig into this type of situation (go with larger needle valve just for the hell of it?). We're probably headed towards replacing the carburetor with a simpler and slightly larger version, though I would like to inspect the current one we have for float issues...it may have also ingested a significant amount of water and metal shavings while we were frantically wrenching on the car to get it out on the track.

If we have this issue again with a new carb, better groundings, and neater wiring arrangement, I'm gonna be very confused.

Captain of AFART Racing - 1987 and 1988 Toyota Supras
Captain of McDads/AFART Racing -1977 Lancia Scorpion (IOE Winner Sears Pointless 2021... wait, really?? YES, REALLY!!).
Captain of 42 Hours of MeLons (2013-14) - Vattenmelon Vagn 1984 Volvo 240, B-Class Winner: Arse-Freeze 2014

Re: Lancia Butt race recap and troubleshooting

You should just stick a turbo on it.  That will fix it.

Team whatever_racecar #745 Volvo wagon