HEI miss at 4600

[roybeckett13j]

Basically, 355 istock engine, HEI distributor...runs awesome to 4500 then starts missing, 4800 it misses so bad it won't get over 5100.

Tried new plugs/wires/coil at the track to no avail.

I'm thinking the module has given up, or no?

Ran great till it got onto the track then BAM! Won't get over 5100.

Sitting still or out of gear it runs great up to 4800-ish, then misses and sputters...any thoughts?

[Graff Spee]

Everything you have described leads me to believe you have a stock HEI. get a Davis or Pertronics set up for HEI and you will be fine. They are cheap.

[usafracer]

Make sure you have a good ground. Take any paint off the hold down and run a wire directly from the battery to the bolt in the hold down. If that does not fix the problem bypass any switches you have and run power directly from the battery to the distributor. That way you eliminate all outside problems before you start throwing parts at it.

[roybeckett13j]

Its an accel dist, but who knows what they put inside them. This is its third season since new, hence why I'm thinking stuff inside is going.

Tried unplugging the tach wire today, nothing.

The only thing that really ponders me is how suddenly it started. One minute its great, then this.

Hopeing I can get it going before this weekend.

[Egoracing]

How old are the valve springs? I would replace the module in the HEI and see if it clears.

[roybeckett13j]

Springs have maybe 5 races on them. Gonna check wiring, if that doesnnt fix it ill go grab a module if I can

[fast_crew]

Where valve spring pressures and installed heights checked at install?

[roybeckett13j]

Heads were build by a race engine builder, which is in good standing.

Tried a different module today, no joy.

Bypassed all the switches/wiring by running a power straight from the battery source, nothing.

Its like its hitting a rev limiter, just screams to 48-5000 and then just stops revving.

Could it be...

Broken valve spring?

The little button between the coil and the rotor?

Cracked dist cap?

I checked the valves before this happened, could it be a valve too tight?

Im really out of ideas guys, need some help.

[Dirtman29]

Have you compression tested the motor? My old SS (355 motor) did almost exactly what you describe & I was sure it was a dist/spark issue. Turns out I had a bent valve. May be worth checking into.

[roybeckett13j]

made some headway.

Pulled the valve covers off, no broken springs/rockers off/anything out of the usual.

Pulled the distributor, found something.

The plastic piece that all the wires go into, and even wire for the capacitor, looked a bit melty so i pulled it apart. the red wire had a split in it...enough that the copper wire was visible and looked discolored around the split.

wont get it back together until tomorrow....

[roybeckett13j]

Still no joy...

Swapping a different carb on sometime this week.

I have an msd setup I could pull off my street car, if SOMEONE thought it would fix it.

Another thing, I put a flow design spacer on it...one that's all machined. When I bought it, it said that a carb jet change would be required. Could this be the issue? Jets are 76's now, have a set of 80's I could try...just fishin in the dark now guys, could really use some help!

[stock car driver]

Roy are your plugs fouled?

Ive had a pile of issues this year and one of them was that when I dyno tuned my motor I had a vac leak so my jets were way too rich. The car would run great for 3 laps then fall on its face and turn way less rpm.

My plugs were fouled. I jetted down 4-5 jets and it was golden.

Another issue I had was low power to my ignition because of a broken ford solonoid all my power runs thru it. After a few laps it would get warm and a lot better ground on the broken part and cause me to have very low voltage and then I would foul all my plugs...

I ask about the plugs because a holley 4412 stock is 73-74 jets. My 15-1 406 takes a 72 and my 10.5 to one 360 takes a 78 its possible your pretty rich because I think you told me your running basically a hobby motor?

[ep33510]

HEI miss at 4600

roybeckett13j

Two things I can think to look at, look at the rotor specifically the steel/ brass tab in the center. If it has bent down to far or is damaged some way it will not transfer energy very well. Are you running a low resistance center carbon button? I have seen the stock version high resistance button cause a race engine to miss using a fresh Dist cap. Check to make sure there is the ground strap inside the cap that picks up the outside of the coil itself. I have seen these fracture with a small crack that causes the engine to run with no load but under load it will miss at some point. I hope this gives you some places to look!

ep33510

Pat Collins

TechWest Racing Services

704-995-4286
techwest@techwestracing.com

https://www.techwestracing.com

[roybeckett13j]

Checked and cleaned all plugs tonight, regaped them. Pulled the carb off to look through it.

Ill check the rotor tomorrow, see if something is going on there. Has a low resistance bushing in it

Motor is imca's 500 cfm stock car engine, is as far as I can take it legally, around 11:1. 76's seemed pretty good, but after the new carb and spacer they seemed a little white from what little it ran.

Maybe valve spring issue? Weak springs? Were new about 5 races ago, but idk...maybe they've gone weak.

[stock car driver]

Checked and cleaned all plugs tonight, regaped them. Pulled the carb off to look through it.

Ill check the rotor tomorrow, see if something is going on there. Has a low resistance bushing in it

Motor is imca's 500 cfm stock car engine, is as far as I can take it legally, around 11:1. 76's seemed pretty good, but after the new carb and spacer they seemed a little white from what little it ran.

Maybe valve spring issue? Weak springs? Were new about 5 races ago, but idk...maybe they've gone weak.

If youve pushed it to 11-1 you should probably check a leak down and make sure you didnt bend any valves.

I dont think that would limit the rpm though just hp.