304 HEI converssion problems! HELP!!!

:? 304 HEI converssion problems! HELP!!! :?

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I bought a HEI ignition converssion in 4wheelparts.com and when I put it on and crank the engine start backfire out of the carb. I put the piston #1 in the TDC and the rotor pointing to piston #1as it was before and the firing order was good then I crank the eng. and turn the ign. and nothing.
Pleace I need some help or I going crazy.

1973 CJ5 Jeep

 

The wire going to the distributor should have full 12V when the ignition is key-on and cranking.

Backfire out of carb? Sounds like you messed up the distributor position. Pull the #1 plug and disconnect the 12V from the distributor. Crank the engine over slowly with your thumb over the #1 cylinder hole until it blows hard out the plug hole. That's pretty close to TDC. You can then pop off the distributor cap to see where the rotor is pointing. Mark where the rotor is pointing on the distributor base with a Sharpie and then put the cap back on and just reposition the wires correspondingly. That'll get you close enough to fire it up and time it.

By the way, which distributor did you use? My buddy had some problems with a cheap Chinese HEI conversion distributor. He finally junked it and bought a DUI from Performance Distributors. His 360 runs like a raped ape now.

 

You have an incredible way with words.

Wouldn't be the first time those cheaper HEI conversions caused problems. Just do a little searching...

 

Are you sure you are on the compression stroke?

It actually sounds like either you are not or you just got a couple wires crossed, but if you put it to TDC before you pulled it, then I would guess you have a couple wires crossed. Did it run fine before the conversion?

 

I bought an HEI from AI and had the wrong gear on it.... took out the cam gear... had to pull the entire front off the engine to replace BOTH gears.... runs great now but what a problem!! also during installation, how i found out is i would install the dist, and it would run... for a second... I would take another look and the timing would slip almost 180* and backfire through the carb... sound familiar?

And lastly... yes make sure you pulled the ballast resistor... dont need it for HEI

 

when I installed mine, i thought I had it all lined up, but it ended up being way retarded from where I though it was. If you are sure you are at true TDC try working the dist incrementally in both dicrections untill it starts running better.

 

Having the piston at TDC doesn't mean you were on COMPRESSION STROKE...

There is a TDC of Exhaust Stroke also, so you could have the distributor in 180 degrees out very easily.

You have to VERIFY compression stroke,
Then you have to VERIFY TDC of #1 piston,
Then you *SHOULD* VERIFY the balancer ring has the 'Hash' mark at the 0 degree indicator on the timing scale.

Once you have done these things,
Then, AND ONLY THEN, can you set the distributor in the engine correctly.

With the #1 spark plug out, it's VERY EASY to coast past TDC of compression stroke since there is no back pressure in the cylinder,
So make sure you take the time to VERIFY COMPRESSION STROKE.

Once you have the engine at TDC of Compression Stroke on #1,

Decide which plug terminal is going to be #1,
Mark the distributor base UNDER the cap, on the distributor housing so you know where #1 is supposed to be pointing when the distributor is fully installed...

Back the rotor up about one spark plug terminal COUNTER CLOCKWISE before you install so the spiral cut of the gear is compensated for,
And drop the distributor down on the camshaft.

As the distributor gear engages the camshaft gear, the rotor will rotate to the #1 plug terminal mark if you backed the distributor rotor up correctly...

If the distributor DOES NOT SEAT on the timing cover,
Which is common, since the oil pump drive shaft often does not let distributor seat correctly,

Then turn the crankshaft over TWO FULL ROTATIONS.
One Rotation will put you at TDC of Exhaust,
The second rotation will put you back at TDC of COMPRESSION stroke, and the oil pump shaft should have aligned and let the distributor seat.

If the rotor is pointing at the #1 mark you made, then you are pretty much ready to try and start the engine.
If it's not,
Pull the distributor, and correct the rotor position so you will come up directly on the next try.
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When you buy these cheap China made knock-off distributors,
You REALLY need to do a few tests first!

1. Rotate the gear 90 degrees to the roll pin, and try to drill into the gear with a 1/8" drill bit.
If the gear drills easily, then don't drill into the shaft, and you have a soft enough gear to let your camshaft gear live.

If you can't drill into the gear other than to scratch or polish it,
You have a hardened gear, and it will kill your camshaft gear.
You should change it before you install so it doesn't chew up your camshaft gear and fill your engine with metal slivers.

A replacment gear you can count on will run you about $50.

2. You may have to use a longer power steering belt, and adjust your power steering pump farther out in it's bracket.
Most of the HEI clones for V-8 engines have the vacuum advance installed in the wrong place, and the nipple/hose gets into the stock power steering belt/pulley.

3. Check for cheap aluminum terminals in the distributor cap.
If you have cheap aluminum terminals, then it's for sure you have a cheap, under insulated coil that will arc internally, and there is a cheap rotor center button that will come apart and fill the cap with conductive carbon dust, and you will have the cheap rubber insulator between coil and cap that will give you problems.

You are always money ahead to use the best brass terminal cap you can find, and use the best insulated coil, center button, and insulator disk you can get your hands on.

The arc over damage is cumulative, so the longer you run this thing, the worse it gets, and the more problems you will have in the long run.

A good cap, rotor, center terminal and insulator will run about $50.
A good coil that will live a long life giving you correct performance is about $55.

4. Advance on these clones is always WAY too much.
You will probably experience engine knock when at part throttle cruise on the highway, along with power loss or 'Bogging' when you try and add a little speed at highway cruise.

The 'Snap' you get on take-off is from the advance being WAY to far advanced for part throttle cruise operation,
And that causes detonation and engine destruction over the long run (some MUCH sooner than others!)

Limiting the vacuum advance, pulling back the centrifugal advance, will help get the advance curve under control and keep your pistons, rings and valves in the engine.

5. Your vehicle has a FORD type spark ported vacuum source,
While the HEI clone has a GM type vacuum canister.
That means you are going to pull WAY TOO MUCH vacuum advance at idle and during part throttle operations.

There are adjustable vacuum canisters out there, but they run about $35... Again, an oversight by the guys that stuck these random parts together without tuning or understanding how they all worked together with Jeep engines...

6. Cheap Plug Wires is a very good way to limit the amount of spark energy getting to the correct spark plug gap!

Use GOOD QUALITY PLUG WIRES, which will run you about $70.

7. An ignition resistor IS NOT required for an HEI distributor.
If you have a resistor in place, the engine will probably run, the ignition will probably work, you just won't have nearly the spark energy potential realized the HEI is capable of.

Most people leave in the old ignition switch wiring, tach, engine harness, pot resistor or resistor wire and can't figure out why they aren't seeing the gains people claim with an HEI.

The *BEST* Way to wire in an HEI is on a separate power line with ignition relay.
Reliable, functional, cheap & easy to do, and it feeds the HEI/Clone with a solid, direct supply of current so the ignition can work the way it was intended to.

8. Add a dedicated ground wire to the distributor it's self,
And one to the engine heads so the spark plugs get a good ground...
Otherwise you are wasting time and money.

Some copper based 'Never-Seize' on the spark plug threads will help get the plugs grounded to the heads, and a dedicated ground wire to the heads will get the heads grounded.

9. Don't forget, most of the clone places recommend 0.050" to 0.060" spark plug gap with an HEI,
And that is a REALLY BAD IDEA!

When you open the plug gap that far, you are robbing your usable spark energy of DURATION & AMPERAGE.

DURATION is the actual physical time the spark dwells in the plug gap,
While AMPERAGE is the part of the spark energy that actually does the work... Amperage is HEAT of the spark.

When you open plug gaps way up, you drive VOLTAGE way up, which robs from Amperage and Duration to do so...
So you wind up with a fast, thready, cold spark that is way too quick and cold to do anything...

Stick with about 0.045" max gap on the plugs, and the HEI will give you MUCH better service,
Without cooking the cheap coils they use so fast!

10. Stay away from 'Super Duper' spark plugs,
Platinum, Iridium, goofy electrode shapes, ect.

You STILL don't have enough ignition to fire Platinum tipped plugs reliably, so they are a waste of money and a failure point.

Stick with the 'Plain Jane', common, copper core, resistor plugs you can get for 99¢ to $1.50 each. Saves a lot of problems in the long run...

 

I bought a cheap hei from them also. I installed it and the jeep wouldnt run, messed with it for a couple hours and then bought a new coil for a chevy hei at the local auto parts store and it ran. 4wd wouldnt send me a new coil, they wanted me to send the whole hei back before they would send me a coil. I dont buy from them anymore.

 

Common problems one and all with the 'Clone' HEI distributors...
Buy a $100 ignition, you get a $100 ignition!
Replacing a bunch of the parts right off is one way to ensure it works for a little while anyway!

 

Ditto. I had the same issue when I installed a CRT performance HEI distributor.

 

thanks for your advises, I fix the problem and its working good but if I put the bacum advance and you drive it it have a lost of power,
I tookit of and advance the timing 5 deg. and is working beter but not how I was expecting.