Freddie's Transplant

[pbrown]

Bring it to my place and we can spend a day getting it dialed in. IIRC, that carb is a Holley 390 (correct me of I'm wrong Gary. The first place to start is to get the idle circuit dialed in. The main jets do nothing at low RPM. The power valve should also not be in play here. We can install a power valve plug to eliminate it as a variable if needed.

Getting the idle tuned involved getting the idle jets dialed in. Start with the idle screws and tune to best vacuum. The idle RPM will change. Readjust it to a reasonable setting. Now don't assume that we're done with idle at this point. If the idle mix screws are out too much or in too far, you need to adjust the IFR (idle feed restrictor) and IAB (idle air bleed). The IFR is basically a jet for the idle circuit. It can and needs to be sized larger or smaller to get the idle mix screws in the sweet spot. I have all the tools and most of the parts to make these changes and can do it at my place to bring them anywhere.

Once idle is done, we can look at the main circuits. This involved playing with the main jets (how much fuel) and the HSAB (high speed air bleeds) to determine when the mains come active.

There seems to be a lot of voodo when it comes to carb tuning. It is actually very scientific. Start with idle, then cruise, then wide open (dyno needed for the last part). It really helps to have a wideband tool with MAP and TPS.

[pbrown]

Here are some helpful links regarding carb tuning with a wide band tool.

http://www.innovatemotorsports.com/r...FI_mileage.php
http://www.innovatemotorsports.com/r...rb-central.php

[Luva65wagon]

If his motor is overcarbureted should we all just sit back and say "ah, but it sure looks cool, doesn't it?"



FWIW I didn't know that it was, or wasn't when I posted. If it's really only a 390 CFM carb, then maybe not. But I didn't know that.

I guess you should just put it back together Gary and arrange a day to take it over to Patrick's.

[pbrown]

Ultimately this is Gary's call. I'll help in any way I can. He can certainly try the 2 barrel. I thought the carb he has was recomended when he bought the aluminum head.

[pbrown]

I see that Barry Grant has a nie 2-barrel available now.

http://www.barrygrant.com/demon/default.aspx?page=5a

[pbrown]

And then there is Holley's version of the same carb.

http://www.holley.com/0-7448.asp
http://www.summitracing.com/parts/HLY-0-7448/

Note that both are 350 CFM which is still large for a 200ci engine but could be made to work well with proper tuning.

Either the BG or this Holley would be a better start point than the 390 four barrel.

[MacDee]

Truly, the four-barrel is up on the little six mostly for WOW value. For me, the whole purpose of doing this project was to have something totally unique, and possibly even outrageous to show at car shows. A souped-up six is certainly unique. I see these occasionally at shows (like Roger’s wagon!) and I am impressed! Seeing a four-barrel on a CI aluminum head would be OUTRAGEOUS! So, of course, THAT’S what I wanted!


As for being over-carbureted, it is a model 8007, which is rated at 390 cfm. I did some Desktop Dyno studies, and according to that, my setup should be good for 265 hp @ 6250 rpm. Whether or not this is reasonable, it indicates I should size the carb to about 360 cfm. Hence, the selection of the 390 cfm carb.


In retrospect, I sincerely wish I had chosen to do something more conservative. My Desktop Dyno study also revealed that a milder cam (264 degree vs. my 274) would have provided much better torque and power under normal street operation, but I was seduced by big numbers, and impressed with a similar setup used by someone on the FordSix forum who’s six cylinder Mustang was running low 14’s in the quarter. There are vague plans in the back of my mind to someday perhaps “de-tune” to a milder setup.


In the meantime, I really need to get the old gal running decently so I can start to enjoy her again. I do believe, finally, that I am close. She does run pretty well except for her reluctance to “go” when I push the “go” pedal. I am encouraged, but it still needs to be better before I’ll “enjoy”.

I appreciate everyone’s input. Taking it all into consideration, I believe I will stand by the four-barrel, at least for now. With your encouragement, I’ve successfully taken the thing apart and found a couple of issues. This weekend I’ll put it back together and try setting it up again, from scratch. If I still can’t get it running acceptably, I’ll make an appointment with Dr. Brown.

[MacDee]

I read one guys putting a 4 carb on his 6 cylinder, wow.

See? Like I said...

[falcon cobra]

Gary what is the vacuum gage method ? do you have a timing light and a tach? what RPM does it idle at in netural and in drive...jh

[MacDee]

Gary what is the vacuum gage method ? do you have a timing light and a tach? what RPM does it idle at in netural and in drive...jh

Vacuum gage method is: set timing to where vacuum is just at its maximum, and then back off the timing until you lose 2" of vacuum.

I have a timing light, but with the multi-spark Street Fire ignition, the timing light shows the timing mark bouncing all over the place!

I have a tach, and it idles in gear at about 900 rpm. In neutral, it idles at about 1200.

[MacDee]

So,
I've got some time this Saturday. The carb is off, so I'm contemplating taking the intake off as well to re-connect coolant lines to it. (Yes, it IS necessary to remove the intake... to screw in the fittings!) Of course, if the intake is off, it's probably the ideal time to replace the heater core, right?

Can someone tell me if it's reasonable to do all this, plus re-install the carb and re-tune in about six hours... even for someone unRoger-like? Is there anything I should watch out for? I need to replace the heater motor as well. Is that easy?

Thanks!

[Luva65wagon]

Well... I can't speak for anyone else, but I'd have no problem.

[SmithKid]

This "anyone else" would like to help. It even looks like Ma Nature is going to help. What are the six hours you have available?

[MacDee]

I'll probably get started around 10:00. Got some debris to pick up out in the yard first.

I'll PM my address.

[pbrown]

Gene and I dropped by to help Gary. The heater rebuild was put on hold until Gary can order a heater box rebuild kit. There is some lovely duct tape covering the hole until next time.

We did get the intake installed and carb reassembled. I brought my handheld O2 sensor so we gave that a try. This engine combo is suffering from a very lean idle. The AFR is at about 19:1 AFR once running the best we could get it. It cruises nicely at 14-15 AFR. We just need to work on that idle. The Idle Feed Restrictors (idle jets) need to be enlarged. I didn't have my carb tools with me so this will need to wait for another day.