Help needed ASAP

[madkaw]

The temperature fix alone should make that engine run different and better.

[Captain Obvious]

The work sounds like it's going well. I like the part about the thermostat housing... It's always something!

the 4 - 7 psi pump is in place and working. According to my crappy little gauge, it is putting out about 3.5 psi with no load. I need to find a real gauge and a long hose to see what I'm getting on the track.

That 3.5 psi is "engine running, sitting still, with return line in operation", right?

About the thermostat, I wonder how much of a difference in required ratio the thermostat would make. By that, I mean... Is it conceivable that the change in temp from 130 up to 180 would change the optimum fuel/air ratio enough that maybe the carbs were working as designed all along, but it just wasn't enough fuel for an engine that was perpetually "semi-cold"?

[Jeff G 78]

The work sounds like it's going well. I like the part about the thermostat housing... It's always something!

That 3.5 psi is "engine running, sitting still, with return line in operation", right?

About the thermostat, I wonder how much of a difference in required ratio the thermostat would make. By that, I mean... Is it conceivable that the change in temp from 130 up to 180 would change the optimum fuel/air ratio enough that maybe the carbs were working as designed all along, but it just wasn't enough fuel for an engine that was perpetually "semi-cold"?

Correct on the pressure reading.

I was thinking the same thing on the A/F without a thermostat. It really surprised me that the temp stayed so cold last year on the track. We ran a 14.5 hour race at 80F ambient and the gauge barely moved off 120F. The thermostat was in place with the valve itself removed. I would have sworn that it would have enough restriction to allow the engine to get up to temp. I guess I learned a tough lesson...

I'll let everybody know how today goes.

Thanks to all who have helped!!!

[madkaw]

Not trying to be a di@khead, but I couldn't imagine not knowing the temperature of my engine(especially aluminum head motor) and intend to race this car. This is basics and you can't properly diagnose other issues without atleast covering the basics. Just about every tuning adjustment specified in any manual- specifies to warm the car to operating temperature.

[cygnusx1]

Don't overlook your air intake system either. I have no idea what you are running, so I say this blindly. Also MUST confirm cam timing.

[Jeff G 78]

Intake system is the stock '72 orange airbox. On the cam timing, keep in mind that this engine ran this way before and after a rebuild and with two different cams. I have rebuilt plenty of L6 engines, so I'm sure that it is correct. I matched both the bright links on the chain and verified everything physically before and after assembly.

I agree that not having a temp gauge isn't good madkaw and I should have know better.

For those who haven't followed my journey, this car was purchased as a complete basket case for $350 and was built from the ground up with virtually no money in 9 weeks. Every mechanical system on the car was either shot or screwed with by previous owners. The 9 week build included the car being gone for 2 weeks getting a cage installed. LeMons and ChumpCar World Series isn't like any other form of racing. It's all about racing real $500 cars, not who can spend the most money. Rather than stiff springs, race shocks and adjustable suspension, the stock springs were cut, the 25(?) year old dampers were kept, and suspension tuning was done with tall spring aid jounce bumpers and LCA pivot point relocations. Rather than rebuilding the engine, we tore it down to inspect and clean it and reassembled it with new gaskets only. The body was painted with Rustoleum applied with rollers and so on. Almost all of the parts that we did replace before the first race came from my vast stash of used parts. Gutting the thermostat is a common LeMons practice that *normally* works fine. The car has run well at times when it gets enough fuel, so low engine water temp was never considered as a cause for any of the running issues we've experienced.

After the first few races and lots of track days, we have replaced a few things and recently rebuilt the engine, but for the most part, it's still nothing more that a $500 race car.

Take a look at the build photos in this link http://www.facebook.com/media/set/?set=a.105973052763868.11825.105972559430584 to see what we started with. Click on the first pic and scroll through them so you get the captions as well.

[madkaw]

I honestly didn't realize this was a lemons car-very cool!

My money is still on floats just need to be juiced up-throw out the you measuring tool:)

Make sure your getting 14 volts to the battery.

Get her to 180 degrees!

I would suggest mechanical advance, but you've changed dizzys.

Good luck

[cygnusx1]

Not sure why the thermostat gets gutted? Might be off topic. The only reason I can think of, is to prevent it from failing in the closed position? I make lots of power in my stock motor with a stock thermostat and have no cooling issues; even on a road course. I am not good with SU's so I can't help there. I would suggest electrical issues in the coil charge circuit. Is the coil getting a strong 12volt charge, at speed? Plug wires, plugs... Good luck.

Just thought of this after looking at the photos...is the throttle linkage opening the throttles all the way?

Edited October 2, 2011 by cygnusx1

[Captain Obvious]

I think the car is beeauuutiful and if I were closer to you, I'd offer to come to the race and turn a wrench or two. Would probably get in the way more than not, but I'd be there in a heartbeat to help out where I could.

So are you going to be able to get any track time at all before the race to see if the fuel pump and/or thermostat made any improvement with your WOT at high RPM issues?

[Jeff G 78]

Hey Captain, you aren't THAT far away. The race is at Nelson Ledges in NE Ohio near the PA line which is about 5.5 hours from Philly.

Yes, we have a Friday test day at the track to prove out our fixes.

I raised the floats a bit, but didn't want to raise them way above the FSM specs. According to Bruce, the fuel should be 1/16" below the nozzle in the carbs when tuned. I raised the floats several mm, but still couldn't get them near 1/16". If needed, I'll raise them some more at the track.

I have a question for those of you who have performance cams. My cam specs are .450 lift, 260/260 duration. What kind of vacuum do you get at idle? I'm getting about 13" hg which would be low for a stock cam, but I can't recall what it should be with that cam.

[Captain Obvious]

Hi Jeff,

I took a look at a map and it's not "close", but it is closer than I thought. I don't think I'm going to make this one on short notice though. I should have started thinking about it two weeks ago in order to have arrangements in place.

As for your cam, I have no idea. Again, I'm very surprised that you haven't gotten lots of responses from people who have done cam swaps!

[Jetaway]

[edit]

For those who haven't followed my journey, this car was purchased as a complete basket case for $350 and was built from the ground up with virtually no money in 9 weeks. Every mechanical system on the car was either shot or screwed with by previous owners. The 9 week build included the car being gone for 2 weeks getting a cage installed. LeMons and ChumpCar World Series isn't like any other form of racing. It's all about racing real $500 cars, not who can spend the most money.

[edit]

You know, I gotta admit when I began following this thread and responding, I was beginning to wonder if you were sane or that perhaps it was some sort of social networking experiment.

All is clear now.

Run those "works" teams into the ground!

Chris