Thread: Kind of a Drag

Tweet

Hiyall,

Distributor is a street fire with the module taken out so I can use the Street fire box. I just shimmed the endplay yesterday and unplugged the vacuum advance. Cap and rotor is MSD just a week old. The electrode is a low resistance one that I bought separately because the MSD ones didn't hardly protrude out of the cap.

Timing chain is a true roller with 2 degrees slop in it. Crank pully indexed in the stock position. Not sure of the crank timing my timing light quit working. timing was steady when my light worked.

Compression is 160- 165. Pistons are 4 valve relief flat tops I think the compression is between 9-10 to 1.

Vacuum runs nominally at 19-20. With the edelbrock 1406 600 cfm it idles at 950 rpm and 12 on vacuum. With a quck fuel (Aka Holly) 750 cfm it idles 950 rpm at 19 vacuum. Almost 20.

Fuel filter is a little billet casing with a bronze chevy filter. They won't let you use the glass filters at the track now. I don't like bronze filters.

With the Edelbrock the fuel pressure is 5 With the quick fuel it's 6. I have a pressure regulator and a gauge. The gauge is in line after the fuel filter. The choke is electric and operates just fine. The Edelbrock is tuned a stage and a half richer on power and cruise ran good for a while. I rebuilt the carb at the last gremlin showing. Air filter is a K&N with the filter top also. I just cheaned it too.

Wires are Taylor 8 mm silicone that I replaced when this gremlin first showed up. I added heat shield wrapping on 4 that hung close to the headers. The wires are also loomed. Plugs are Bosch racing shorties to clear the headers.
Gas is 91 octane.

Heads are fresh World heads 2.02-150 750 cc chambers I THINK. I had to change the rocker studs to accomodate roller rockers 1.5.

Cam is a Lunati barebones The middle offering. Flat hydraulic lifters.

Oil is 50w cause I need oil with the zinc in it and 50w was the only oil the speed shop had.

The car does have a bottle in the trunk but I haven't used it since this gremlin first showed up.

I also checked for vacuum leaks and changed the carb gaskets and checked bolts on headers and intake, checked hoses ect.

All ground wires are connected to a bronze clamp at the battery with gold connectors. So is the positives too. I have two ground straps at the rear of the motor and a wire from the frame to the alternator bolt then from there to the battery side post I checked the connections too.

So, here's exactly what happened Gremlin shows up doing that trip to Gardner. At the same place on the freeway! I'm just cruising along at 65 MPH at 2800 rpm. First the right side exhaust, Pop!
I lightly touch the throttle Pop through the intake. Steady cruise, Pop, bang, pop! intake and exhaust. Cars move away from me. People put their phones down and grip their steering wheels. Pop, Bang Pop Bang, rumble, Pop bang I turn up the radio and grow red with frustration. I get to where i'm going. At idle, occasional pop through the exhaust right pipe. I pop, bang all the way back home. I go to the speed shop. I get talked into a rediculouly large carburetor, Boo! I buy a new MSD cap and rotor and a different low resistance elecrode. I put them on in the parking lot. Start.. The problem is gone! Yay! Celebratory burnout on the street. Next day play with big Holly clone. Paid 20$ for speed shop employee drag racer to get the car to launch. NO gas mileage but man, what a launch! Drove it to Gardner for work. Used up most of the gas BOO!. I went home and put the Edelbrock 1406 back on and reconnected the vacuum advance and retarded the distributor by ear. Ok .Next day go back to Garner, Same place, same speed, same freeway. Exhaust says Pop. Touch throttle Pop throgh the intake, coast, pop through the exhaust right side. It only seems to pop throgh the intake if I give it throttle. but just a couple time and then it catches and accelerates as much as I want. At cruise it seems to pop,pop,pop through the exhaust. I go home, take the distributor all the way out and inspect cap, rotor, hall effects switch and all connections. Nothing wrong. I twisted the rotor shaft back and forth and noticed some slop so I reshimmed the shaft and tightened it uo to about 10 t0 about 15 thousands end play., Cleaned up everything and checked all connectors. Put it back together and drove to Olathe. Still Pop,pop,pop in all the wrong places. Went back home and parked with the engine running. I open the hood and rapped the throttle and the engine races quick and fine no pop. Idles normal, no pop. I shut it down and cry to Mrs Goodwrench. She' says try new 750 with 70 jets in the front, 80 jets in the back and a 6.5 power valve. She's also been encouraging me to put in a higher stall torque converter But I say let's save the money since i'm unemployed. But I digress. So I wrote this first. And there you are!


PS, Yes I know a 750 is TOOO big for the car but it IS vacuum secondaries and the guy at the speed shop says, " Forget the math buddy! What matters is it works at the track, It'll be like night and day" Well I had to step up on the acelerator cam. But well, it is a strong carb. The guy says, Let me step the jets down 2 notches, 30$ please! I havent tried it yet, he still has my carb. I really don't want it. I want a 650 instead but nobody listens to me. I launch the Edelbrock and the tires break but only slightly and the 750 they don't break at all. I forgot to say I bought a Grand National limited slip so both tires grab now. Midrange is much better and the acceleration pins you to the buckets even at 5000 rpm. It just keeps climbing. The Edelbrock kind of flat lines at WOT.
I sure hope sombody can halp me figure it out. It's still our only wheels. And for the first time in decades, i'm stumped!

Originally Posted by Good Wrench

Vacuum runs nominally at 19-20. With the edelbrock 1406 600 cfm it idles at 950 rpm and 12 on vacuum. With a quck fuel (Aka Holly) 750 cfm it idles 950 rpm at 19 vacuum. Almost 20.

The vacuum readings above points to a problem with your Edelbrock carb. And if I remember correctly this is the carb with the whistle. It appears the carb has a vacuum leak, look for a cracked throttle base (not uncommon if over tightened), or an open passage way at the carb base, possibly an incorrect carb to throttle base gasket.

Originally Posted by Good Wrench

I went home and put the Edelbrock 1406 back on and reconnected the vacuum advance and retarded the distributor by ear.

Move your vacuum advance to venturi port and re-set your initial timing correctly.