Fixed A Major Problem Tonite!!

[Mustang_Geezer]

As some of you know, I havent been totally satisfied with my latest engine upgrades which included more port & polish work, oversize valves, 1/2 point bump in compression, double roller timing chain & gears and alcohol injection to name just a few of the upgrades I performed last winter/early spring.

I'm running a 500 cfm Holley and have had problems with the lack of power through the whole RPM range but especially in the 4500-6000 rpm range where this engine should really pull but seems to want to lay down on the top end.

The highest mph in the unofficial qtr mile is still in the 90 mph range like it was last summer on my other engine.....spent lots of money but no real improvement in hp or qtr mile times....

I've been getting help behind the scenes from various forum members and William mentioned this to me several days ago,

I even posted a reply to him having to go 6 jets richer on his holley 500 cfm. I questioned him on this choice, i wonder if he has fuel starvation, & is just trying to cover up the loss of pressure or volume by just richening up.

I pulled the spark plugs tonite to inspect them and the damned things were still white! Which shouldnt be because they are number 75 or 76 jets in a Holley 500 cfm 2 Bbl with a 6.5 power valve....it should be running rich IMO but is not....

So I thought about what William said and decided to check a few things out...

I replaced the fuel filter last weekend and replaced the power valve (again) so I knew they were not the problem. Pulled the fuel line and cranked the engine over and sprayed plenty of gas in a cup so I knew it wasnt a bad pump or plugged line.

Fired it up and pulled the sight plug off the side of the bowl...no gas in sight...Hmm...raised the level by 1/2 turn...no fuel...another 1/2 turn...still nothing...I ended up raising the level by 2 1/2 turns!

I must have bent the float arm or somthing because I inspected it and it looks fine.....just wasnt getting enough gas!!!

Took it for a test drive and it is now a entirely different car!!! I think I might have to make another tape for ya Mike!! 8)

Major power increasce all through the rpm range and now my "unofficial" qtr mile trap speed is 97 mph and that includes major wheel spin on take off!!!

Now I have to tune it all over again!!

I guess I should have checked the simple things first!!

Thanks William!!!

Later,

Doug

 

[AzCoupe]

Glad to hear you found your problem. I'll be looking forward to a new tape.

When I was in college, the class with the highest failure percentage was diagnostic and trouble shooting. Its those little things that are the hardest to find, simply because they are overlooked. So don't feel to badly.

 

[Mustang_Geezer]

I still feel like an A$$ though!!

Somthing so simple to fix, yet I overlooked it all this time!!! :roll: :roll: :roll:

I am really happy with it now though!!! 8) 8) 8)

Later,

Doug

 

[wsa111]

Doug, glad to hear the great news about the fuel problem. See my post on holley carbs, you might want to get the glass sight plugs for the holley & the quick change jet bowls made for the holley carbs.
http://fordsix.com/forum/viewtopic.php?t=16497
I knew something was not kosher especially when you go that many jet sizes with a holley.
From past experience i smelled a rat. I like my fuel level just at the edge of running out the sight plug. Anything higher & you have a rich condition.
After you get this straightened out you should have a super strong engine.
Glad to be of help. william

 

[Anonymous]

atleast you have a checklist. I still have to do major reading here to just get a CLUE.

congrats on your fantastic ride pulling harder...

 

[Mustang_Geezer]

You know you might have just helped me out. I had to lower my float bowl just to get the engine to run. It was flooding out. I have since started driving the car and rejetted from a 74 main down to 71 and again to 65. The plugs still look to rich. I'm going to try lowering the float bowl a bit more and see what happens. I'm also running a Holley 500cfm 2bbl. It runs much better with the rejetting but not like it should. I am around 4500ft above sea level but still 10 sices down on the mains is alot.

I will let you know how it goes. Later.

 

[Mustang_Geezer]

That is a pretty cool set up on the Holley! How much did it cost? I picked up a clear sight plug set (will install it this weekend) and I have been having pretty good luck with the blue non stick gaskets.

You might want to try lowering the fuel level some more...it leaned mine way out! I didnt realize it made that big of a difference.....

Thanks,

Doug

 

[wsa111]

Doug, with your 500 cfm carb the shiney bowl with jet plugs is only available in chrome. The kit from summit costs $53.00. but double check them using the part #s from my post. if i were going to start the tuning process i would try 71 jets with the stock .028 accerator discharge nozzle, & if your accerator pump cam is white in color try it. I you still have a stumble off idle, then go to the red pump cam in the #2 position on the throttle lever. Bring the fuel level just at the lower edge of the sight glass. If you keep lowering the level that means you are too rich on your jet size. this tuning is an art. It can be made easier if you have access to an air fuel ratio sensor. I have tuned many a holley carb. The carb on my el-camino is crisp gives decent fuel miliage & has the response of a fuel injected vehicle. The only problem is fuel miliage, you just cannot beat modern electronics. but you can match the power or in some cases better it. Keep the float level as i specified, then keep dejetting if necessary. When you are done your throttle response will be crisp & the power will be there when you have a 12.5 air fuel ratio at full throttle. That will put you in the ballpark. Good luck, feel free to give a shout. William

 

[Anonymous]

I have to condemn the clear site plug, they may start out clear but get very foggy after a little while and can sometimes break off.

 

[wsa111]

RogueS, what brand clear sight glass did you have problems with?
holley,moroso,mr. gasket & probably several other makes are available.
And how old was the sight glass?? : william

 

[Anonymous]

They were the ones that came with the Street Avenger carburetor.