that was great.. let me give you my scenario yes.. if i go slo.. it builds up and goes.. but it never down shifts.. i have to manually downshift.. thats why i was at 35mph and then hammer the throttle.. lol.. second.. i have a complete MSD ignition system.. all pretty much has less than 5000 miles on it.. the timing is set to 36* at 3000rpms.. gap on the plugs is at .042 brand new accel shorty header plugs.. just trying a new brand.. and these seem to work good.. about 40 miles on them compression... i did a compression test after i built the engine.. not sure what the readings were, but they were all within 20 psi of each other. i will do another compression test next week. i am off work all next week. the cam.. when i put it in.. i never "dialed" it in.. i just lined up the pointers as best as i could.. i would almost guarantee that this is the problem.. and why it runs hot in the summer time..i would like to get a bigger cam .. but right now i am working on the rear end and new rims and tires... after the rearend.. body work and paint.. and then cam, lifters, roller rockers, new springs. then heads. thanks for all the help..
I see what your saying.... There is many reasons why engines overheat,,, Sometimes radiators dont flow as good as they should,,, What cam do you have? the E303??? That is a great midrange camshaft if you have it, and when they install them, they flow alot more air, but I have seen them used with cast iron heads,,, It sounds like your runing out of fuel on the top end, normally I run the primary system richer, so it give it more of a lopey idle, and give it alot of fuel on the primary circuit. This helps start the process with fuel delivery, but, if your not getting the fuel mix rich enough at the beginning, the secondary is not going to help much,,, More air flows in, and yeah the jets do add fuel, but if the fuel is running out before the secondaries open, it starts to get hot before the secondaries open and deliver more fuel, once it starts heating up from leanout,, it wont cool off very quickly. Cyl temp is already above what it should be, and the added fuel from the secondary will not cool it off, it only carries over, and tries to burn the fuel up faster from the heat alone. Also, when the gasses build up and you have a restricted exhaust port, the flow is slower and the heat has to go somewhere, and is absorbed into the heads,,, making engine temp skyrocket. The fuel does help keep the engine cool, if your not running enough, its going to run hot, even at normal cruising speeds. But if its hot before the air charge reaches the cyl, it evaporates bout half the charge, leanout then occurs again,,, Plug color is the best way to tell if it is running efficiently without being on a dyno,,, if they are any lighter than cocoa brown while under a load, its lean, not lean enough to do damage, but enough to cause heat. Just remember, when your tuning, your not tuning for gas milage, your tuning for power,,, and it should drink some fuel at high rpms, not dribble it in there,,, but feed it as much as it can drink. What kind of fuel you using???? Chad
Stock, no they are both vac seconds. though the one i used last had been springed and set to act as close to a double as can be had with a vac sec.
If You Have One Of Those Little Glss Filters Try A Differnt Kind And See If It Changes I Have Heard They Restrict Flow I Had A 460 In A Bronco And It Happend To Me Give It A Try
the edelbrock 600 carb jets are .104 in front and .100 in back rods are .073 x .047 cam is XE256H Comp Cams Extreme Energy... .477 int .484 exh lift.... radiator is 4 row from 67 mustang and then i had the bottom hose moved from one side to the other to fit my water pump. don graham looked at my plugs this saturday at SIR and he said they looked a little on the rich side.. but not by much. seems to me that i am running too rich.. i need an exhaust gas analyzer to be certain..
For anyone who has been keeping up with this...well, I am back in town from Christmas with family in CA, and got a little time to mess with the car. I took the tool box on the road, and made some tests/adjustments, and never lost the hesitatation, and it got worse, in fact, the more I drove it. Worked out that it wasnt the timing by putting the vacuum advance hose on the full vacuum port on the carb, giving me 25 degrees or so advance at idle. It ran worse. I put in the richer metering rod, which got the plugs a nice light brown color, and they don't seem to be fouling at idle/cruise, and the temp never got above 180, and it is 80 outside today. So, I made improvements there. But, one time under the hood, I heard that nasty tapping sound, and noticed that #6 spark plug was arcing to the header. This was a problem I knew would eventually happen, as I originally had the headers too close to the plug boots, and when I spaced it out, the boots on two plugs were getting crispy. Well, it started to run worse because that one plug finally got so there is exposed metal on it, and it is running a nice thick 3/8" arc to the header. So, bought 2 of those fiberglass boots to shield the #6 and #7 plugs, and will order a new set of replacement boots. That should solve the hesitation problem. Then maybe I can focus on tires and new carpet...
Chad, good to hear you are quite experienced. Were much the same. There is another way hesitation can result and is easy to look at. The vacuum ignition advance could be going into momentary retard from the sudden drop in manifold vacuum at fast throttle openings. Put a timing lite on and jazz the throttle while watching what happens to the advance. If you see this happening, remove the vacuum to the dist and plug. Then advance the inital timing to about 15* and road test. Now the power will be down from lack of advance except the centrifigal action, but the hesitation cause is what your trying to prove out. If the hesitiation is gone you have found the cause and need to look at where on the carb the vacuum signal is being taken from as well as the vacuum advance unit. Some of them are adjustable. On a Holley carb there usually are vacuum ports both above above and below the throttle plates.
i drove the mav today... nice cool day.. well cool for around here.. about 70 degrees or so... and man did it drive peppy... WOW.... this car really can get up and go... with spinning wheels... i need traction so bad but no hesitation at all.. and i can still smell the purple race gas fumes... mmmmm.. race track smells.... no rear end work yet... problems popped up AGAIN.. as always.. so my car stuff gets to take the back of the priorities... AGAIN
