HEI installation questions from a newbie.

No - you must use a timing light. The timing is set with the engine running.

No.

If you had set the timing on the exhaust stroke, the engine would not run at all.

 

When setting timing with a timing light, remove that rubber hose from dist. That is your vacuum advance. When timing is set , replace hose.

 

Allright, here is what ive done.

1. Took HEi out again, verified it was compression stroke.
2. Fixed spark plug gap to 1,25 millimeters.
3. Measured voltage on from HEI to ground, 12 volts, when engine is not running, and 14 volts when engine is running. 14 seems high ?
4. plugged everything back in, started engine.
5. measured timing, with timing light. Put timing to 6,5 degrees @ idle = about 600 rpm.
Drove a trip, engine is was better than before i did this.

Now i need to set the timing @ 1600 rpm, right??

When i accelerate in 2 and 3 gear is seems as if i could need a liiiitle more torque, as if the timing is a little off at the higher rpm.

So therefore i measured timing at 1600 rpm, and it said 18 degrees BTDC. Is that okay?

Taking the vacuum hose off changes nothing.

Just to clarify that i measure in the right way, heres how its done:
The pistol have a wheel i can turn on. I start engine,wait for it to idle down. I start blinking, and then i turn the wheel on the pistol, until the mark on the harmonic balancer is at 0 TDC, and the i read the degrees on the pistol. Does that seem correct, or should i have used 6 degrees as the reference? And does this sound like the way to do it? Remember, im newbie, and still learning!

 

By the way, the mark on the harmonic balancer moves just a little up and down at each blitz, is that okay?

 

I think they ask for 1600 RPM because the vacuum advance will not be active at idle (600 RPM). The timing should change some with the hose on or off.

The timing should be set when the engine is at full operating temperature.

I know my '82 manual has the timing settings in a table, but the earlier manuals may not. There was a "tuneup supplement" for the '70s I think... this may be the one case where a Haynes or Chiltons manual is more useful than the factory manual.

If the mark jumps around with each flash (blitz!) I suspect your timing chain and gears are worn. The slack in the timing chain would let the cam timing move around wrt the crankshaft. The distributor is driven by a gear on the camshaft.

I never use the dial on the timing light (I recall my timing light does not have one). Instead I would use the marks on the timing cover to judge the degrees of advance. I put some white-out (correction fluid) in the mark on the crankshaft pulley. You can also put paint on the timing cover, but the marks are usually quite easy to see.



hth!

 

well if i turn the dial to either side, the mark moves up and down, so it have to be done this way, and then read on the pistol...

 

Should work fine. Whatever the instructions say.

It's late there ... 11:30?

 

Did you bypass the ballast resister ? You won't need that anymore either and you'll need the full 12 volts for the HEI to perform properly.

 

Move the dial on the pistol to zero. With the engine running at idle (600-650) and the vacuum line removed from the distributor and plugged (the engine should be at operating temp). Set the distributor so the timing mark on the flywheel reads correct degrees (5* or 8*) (what ever is specified). Lock down distributor. Connect vacuum line. Now rev the engine while holding timing light on flywheel and watch the mark on the wheel rotate to the advanced position. Now move the wheel on the pistol until the mark on the flywheel reads zero. If you were at 1600 RPM when you set the wheel on the pistol, you look at the pointer on the pistol and it will show 15 or 16 or 17 or what ever. This is the advanced degrees the engine has gone to at that RPM. Wide open throttle should advance up to about 32* and depending on the mechanical advance curve in the dist and the vacuum advance can, it can be even higher than 32*.

 

Oh, and 14V while the engine is running is normal.

 

yes it was late here.. 23:30

 

I do not know what a ballast resistor is, and where it is located..

 

Another question:

If i set timing to 6 degrees at curb idle, rev to 1600 rpm, set a new timing there, then the timing at curb idle will change rigjt?

Is it a good idea to set timing at 1600 rpm? Or should i just set it at curb idle?

What should the timing settings be ? I cannot fint it in my engine or emission manual (the original ones)

 

The Prestolite system does not use a ballast resistor.

 

Yes, the timing will change depending on the engine speed.

This is a '74? The only specs I have are for an '82 - like you, I have the factory manual which does not include the "Specifications." In 1982, Jeep calls for 8 degrees BTDC at 1600 RPM, vacuum hose disconnected. The manual calls for 15 degrees BTDC for California cars.

Doubtful the timing will be ideal with the factory specifications and the HEI distributor. You can try a little more or less advance to see how the performance changes.

 

You are absolutely right, doubtful if i can trust factory specs. I have to try it. When will if know if it is too much? And how can i tell weather to retart timing, or advance?

If i change timing at 1600 rpm, it will also affect idle timing, correct?

 

this is really a good thread for people who try to do this swap. I see confusion as I read threw these.
You should time at IDLE. not at 1600rpm. thats is what has been suggested. forget about the 1600 RPM. Also You need to unplug the vaccuum advance hose and PLUG it while you are timing the engine only. make sure it is plugged completely! I use a golf tee.
My HEI dist that is just like yours. came with instructions that said to time at 12d. I could not believe this when I first installed it. I timed it a 6d but have since changed the timing and it made a world of difference. Check your instructions!

 

If it was mine I would get the engine to temp with vacuum lines properly connected. Adjust the timing light pistol dial to 9* and hold the engine at 1600 RPM. Adjust the distributor so the timing mark on the flywheel reads 0* and then lock the distributor. Road test unit. This will be at least a starting point.

Sparky 74 has the experience so he may be more accurate than my idea.

 

So you would time it to 9 degrees at 1600 RPM ? Is that correct understood?

 

My instructions does not tell anything about degrees, just how to install at 0 TDC and bla bla. I guess there is no facit list to this, and it seems to be about what the jeep likes best at the time...