The Stovebolt Site Forums The Shop Area The HiPo Shop Engine problem 283 c.i. w/HEI

While cruising my 52 Chevy 1/2 ton pick up, I stepped on the gas to enter freeway on ramp, engine started to hiss and spit or backfire through the carburator, with a loss of power, ran it on down the road to my exit, engine seems to have lost some of it's get up and go, and it also had a problem at idle. Drove on home and let cool. Went out and started engine up although it will start and run as long as I give it a little gas, but it won't idle on it's own without dying. Not sure if it's a gas or spark problem or something more serious. Will start the troubleshooting process in the morning. Any ideas, thanks HUGH

Vacuum leak?🛠

Hmm, after a visual inspection it may be worth pulling the valve cover and looking at the rocker arms and push rods.

Start with a new fuel filter. Then vacuum connections. Check that the mechanical weights in the HEI are not stuck.

Backfire? ops...........If it keeps backfiring...... timing chain. Check with timing light ASAP. If not, as said, vacuum. If not, as said, plugged fuel delivery system....filters, lines, tank screen, carb (accelerator pump), bad gas, gas cap/tank vent, FUEL PUMP.

Does not sound like electrics (now that makes it electrics).

First: see if dripping, squirting, dribbling gas down throat keeps it from dying. (in other words: manual fuel injection). and we always say check to see if carb squirts with motor off.

Don't start too early tomorrow, you will scare off Santa Claus.

Purchased a set of spark plugs, gapped and installed, replaced the PVC valve right behind the distributor shaft. Purchased a new set of 8mm accel plug wires as my old ones are pretty well dogged, will replace them in the morning. No access to a timing light till later on in the week. Will check for vacuum leak by removing the hoses and checking them out real close with my eye. Will replace fuel filter Tuesday morning. The engine will run nice if I start it up and leave my foot ever so slight on the accelerator to keep the idle up a bit. Seems as this shows it is getting gas? What are the mechanical weights on the HEI, how do I check to see if they are stuck and how do I unstick them? This motor has only approx. 5000 since a complete rebuild according to the individual I purchased it from Back in Jun 2015. Truck is driven and not hot rodded, although I do drop it from drive to second and back to drive once in a while to open it up, as the truck does not have a kickdown linkage (turbo 400)

Check for vacuum leaks using an unlit propane torch. If the engine speeds up, there’s your leak. Easy peasy lemon squeezy.🎄🛠

Truer words were never posted

Distributor weights are under the distributor cap. Turn the four hold down screws 1/2 to 3/4 turn to release the cap from the housing. The screws are spring loaded, so push down as you turn. Once the cap is off ( you can leave wires attached ) move out of the way enough to lay your hand on the distributor rotor. It should twist and spring back into place. Doesn't matter which way it twists as long as it does and it springs back. If all is OK, put cap back on and move to next inspection item. If it doesn't spring back, take a Phillips screw driver and pull the two screws holding the rotor in place. The weights and springs are under the rotor. WD40 and wiggling / twisting will get them freed up. The cap has a small index lug which aligns with a cut-out in the housing, be sure to sign them up.

Does the exhaust smell rich? More gas like or more like rotten eggs?
What carburetor are dealing with?

HEI will all most always work till it quits, when they quit, you are walking, they seldom miss or cut out. Are you providing full battery voltage to the HEI? You cannot use the stock resistor wire, HEI needs all the power you can throw at it.

Joe

A large (8) wire Is best.

Ed

I did have an intermittent miss/engine shutoff with an HEI one time. It turned out to be caused by the wire coming from the tach lug on the distributor.
I had the "great idea" of having a short pigtail coming off of the tach lug of the distributor cap so that I could quickly connect a tachometer to it for tuneups.
Problem is, if that particular wire makes contact with the engine (ground), the engine will shutoff. I believe that the wire doesn't actually have to make direct contact for it to cut off the engine.

If You have a Holley Carb. A backfire can blow the power valve diaphragm out , causing it to Run rich and run very poor. Happened to me once.

Does sound like gas delivery. You may have to do a new fuel pump or carb rebuild but vacuum exam first. It is sometimes faster and easier to install a new fuel pump than test it, unless you are rural. I wouldn't mess with the HEI yet. If it runs with foot in it a little, it's got spark. Advance problems show up at higher RPM's and it won't die at idle due to bad advance.
Set the idle up on carb linkage so as to keep it running by itself so as to examine, play with it and do vacuum testing.

I think I would start by checking to see if the distributor hold down clamp is loose and let the distributor turn, if tight then check points for be burnt and fuel volume.

Fuel pump, filter, float, needle valve, accelerator pump, tank clog, gas cap, line/hose, accelerator pump. Vacuum leak.
If it's electrics/HEI, I'll eat my condenser.

Well here goes so far, replaced inline filter last night, cleaned gas filter at carb this morning. Moved onto opening the distributor cap to check the weights inside distributor, upon opening or removing the distributor cap plastic pieces and one weight fell out and hit the floor below, the rotor was only 2/3rds there the pins that hold the springs were knocked out, one spring mangled. Closer inspection revealed a 3 in. crack at the bottom of the distributor cap. Not sure how much of this is replaceable or if it's even feasable to do so. Might just replace with a whole new HEI unit, Will see if this cure my spark to gas ratio problem.

HEI doesn't mean "never service anything"! There are still mechanical bits and pieces of the advance system that need periodic inspection and lubrication. Don't get tempted to buy one of those bargain-priced HEI knockoffs manufactured in some 3rd.-world country. They're not all that and a bag of chips, sort of like the repop sheet metal parts from the same places. Try to find a good-condition OEM unit.
Jerry

It would not have even run like that? This is a weird happening. Elves? Never ever heard of an HEI coming apart, having catastrophic failure, rotor broken....... and motor runs if you give it some gas.
I guess "motor rebuild" did not include new Dizzy.

It was pretty common to see worn out or rusted solid centrifugal advance systems after 100K miles or so with no inspection and/or lubrication. Lots of folks never even opened up the distributor unless the pickup coil or module failed, even if they did do the occasional spark plug or wire change. BTW, I wonder how many stovebolters have ever looked under the breaker plate in their distributors? That's where the advance weights and springs are!
Jerry

Used GM HEI's are fairly cheap. I have a MSD Street Fire #8362 in my 350, for several years now. Two different engines in fact. The only problem was the mechanical advance would go too far. Which was dealt with.

As stated engine would run if i rode the gas pedal a bit, and it did get me home, about 7 miles after I started having problems (problems I never had before) and yes I was surprised of all the damage, approx 1/3 of the rotor was cracked/missing loose metal parts springs, c clamps, posts, and one loose weight, and alot of broken plastic, and about half of the bottom on the dizzy cap cracked. There was a code on the coil of 8 9 83, not sure if this is a code or date, it is an ACCEL with a tan dizzy cap. Stated OEM street legal for all fifty states. Ordered a ACCEL OEM legal for all fifty states from SPEEDWAY, should be here by Wednesday. Made two measured position references and photographed it for the ease of replacement. Will let yaw know how it goes, thanks for all the quick responses, HUGH.

Good job, that should do it. Don't rotate motor while dizzy is out. Let us know how it runs after, will you? Don't want to eat my condenser if I don't have to.

In the process of taking off that nut off that holds the clamp that holds the dizzy, it rolled off to the drivers side and hit a linkage spring and bounced out of this universe. Have checked the frame rail underneath and the surrounding floor to no avail. Does anyone here recall the size of this nut as I want to have everything ready when this dizzy arrives, and again all, thank you so much for the quick and informative responses, HUGH.

3/8 N.C.

3/8" got that, what is N.C.

Not North Carolina, National Coarse, vs. National Fine. .375" x 16.

Ed

I received my dizzy from JEGS, this past Wednesday. Found time today to attempt the repair. Using the 2 measured points of reference I carefully positioned the dizzy using care not to crimp the gasket at the base of the dizzy shaft. The measurement for the vacuum advance was an exact science, the rotor not so much as the measurement came up a 1/4" short and no matter how much I tried I could not get it to drop all the way into its hole. Got to looking at the slot in the bottom of the the shaft and the recessed area in the oil pump shaft, was off a hair, I carefully inserted a long handle screwdriver and carefully turned the slot in the oil pump shaft a hair making it possible for it to fall in all the way. Buttoned everything back up and gave it a once over making sure no tools left in the engine bay. I went and tried to fire it up to no avail. I checked the carb for fuel, plenty of gas. Went and checked what I could as I don't have access to timing light right now. Found the battery wire off dizzy, the clip was loose, crimped it a bit so it would not fall off again, went inside it coughed and spit a bit and fired right up, had to turn the dizzy a hair till it sounded like it normally does, tightened the 3/8 nut and let it idle. That is all for tonight. Will get the timing checked this week for good measure.Thank you all for your help and your quick responses.

Timing set, off to the races, no further problems, all is well, Thanks for all the quick responses and assist, Hugh.