Thread: Loss of power...???

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Ok yet another problem, i think i get a new one weekly with this thing. Noticed this a bit yesterday and again today. When I first start the car up, wait till water temp gets to be about 140 then start to drive.... the car is very responsive and has loads of power. Once the car reaches about 190 it feels like im stepping on a sponge when pressing the gas pettle.... the car just isn't as responsive as it was. Shut it down, let it cool, runs great again until temp gets to 190.

Today installed my MSD Street Fire distributor, MSD wires and new plugs, it solved MANY other issues but not this one. Any Ideas??? I'm thinking possible carb issue???? Holley 650 dual feed with a trick kit just installed about a year ago, had no prblems with it up until this point.

P.S. I pick up my 6A box tomorrow.

Dunno, perhaps you have a plugged water jacket somewhere downstream of your temp sensor? This could cause one or more of the cylinders to run hotter than you think and it could actually be overheating that portion of the motor. Just a thought.

Where is your temp sender? Firechickens probably right overheating problem. Could be causing the intake to get hot and the gas to evaporate before it gets into the cylinders.

Now that I'm a little more awake, and have had a chance to think about this a little more, you might have a leaking gasket somewhere allowing coolant to seep into the A/F mixture portion of the manifold when the motor heats up and the metal starts to expand a little. In my line of thinking, this could cause a lean condition and depending on the science involved and where it is actually leaking, the resulting steam could produce a little back pressure against your primarys and perhaps cause the feeling you have at the gas pedal.

Now, please note, that I am not an expert, and I have never seen anything like this happen. This is simply my hobby and I may be completely out to lunch here; but, I figured I'd throw it out as a possible theory and in turn learn from the real experts if could be possible.

Anyway, good luck.
Dutch

Temp sensor is in the passenger side head. ok setup is a 350, 360 cid, 64 cc, 2.02/1.6 valves, lunati voodoo 60102 cam, edelbrock performer rpm, holley 650 dual feed w/ mechanical secondarys. The exhast actually burns your eyes a little if you stand behind the car... so wouldn't this be a rich mixture???

Everybody's getting a little off the basics here. What's the carb? Electric choke? Have you made sure the choke is opening? Check it after you reach operating temp. If you floor it, is it still sluggish?

Oldman

Holley 4777C, Choke is wired open all the time. It's feels quite strange, it is still responsive but just has about half the balls as it did up to that temp. The carb is probably 10 years old, has been rebuilt once and I installed the trick-kit last year which after it ran great, much better than it did the 9 years prior.

Originally Posted by HellCaminoKid

Ok yet another problem, i think i get a new one weekly with this thing. Noticed this a bit yesterday and again today. When I first start the car up, wait till water temp gets to be about 140 then start to drive.... the car is very responsive and has loads of power. Once the car reaches about 190 it feels like im stepping on a sponge when pressing the gas pettle.... the car just isn't as responsive as it was. Shut it down, let it cool, runs great again until temp gets to 190.

Today installed my MSD Street Fire distributor, MSD wires and new plugs, it solved MANY other issues but not this one. Any Ideas??? I'm thinking possible carb issue???? Holley 650 dual feed with a trick kit just installed about a year ago, had no prblems with it up until this point.

P.S. I pick up my 6A box tomorrow.

Are you 100 % sure it happens when it hits this temp?
Lets go back and look at other issues first.Timing,jetting,fuel line dia. etc.
Tell us a little more about your set up.

Ok, yet again spent pretty much the whole day, installed the 6A box, tweaked the carb a little more, and adjusted my timing, first with the light *failed attempt* then again by ear and how it felt driving it *much better success* well the issue with the loss of power dosn't seem to be as bad now, could it have possibly been bad gas?? I also noticed that before installing the new distributer and ignition box, I had a good bit of moisture that would build on the threads and base area of my plugs, now with the new ignition, it doesn't seem to be happening anymore.

In my experience, bad gas will act lean rather than rich. It sounds like changing the ignition system is giving you a better spark to burn the A/F. Good. I am assuming you changed your plugs as well, right?

Also, with the light, what is your timing set at now that it seems to run better? How far did you have to advance it to get "much better success" by ear? If you're still having problems, that double pumper may need a tune-up, time to break out the vaccuum guage and tach after your timing is set (with the light).