[Lawless_Jeep]

This is my "Ask JeepHammer Anything" thread. Rules? Of course there are rules.

1. Only one topic at a time. A new topic may be started upon completion of the current topic.

2. No asking the same question more than once. This is a simple thread to pick the brain of JeepHammer. Please take the time to crawl or search the entire thread for what you seek.

3. Anyone may participate and add to the thread.

4. No pissing and moaning, and by no means, NO BARROOM BRAWLS! If you disagree with an answer, that's fine, keep it civil. We're not here to see who has the best of anything here.

5. When participating, please make sure your questions are thourough. Year, engine, transmission, blah blah are going to be necessary for a full and complete answer. Photos are strongly recommended. Whenever possible, take photos. It's always nice to see what someone is talking about. To some, it's a tomato, but to others (we won't mention any Vice Presidents' names here), it's a tomatoe.

Enjoy this thread, and thank you JeepHammer for participating.



***********THREAD INDEX**********

1Distributor Advance Curve Tuning - Page one, Post #2
2Headers/Header - Page 3, Post #43
3Camshafts - Page 4, Post #54

[Lawless_Jeep]

First topic covers the tuning of the distributor curve.

[Lawless_Jeep]

Upon JeepHammers' request, I ordered MSD Timing Tape Part Number 8985. I got mine from SummitRacing.com for $3.95. http://store.summitracing.com/partdetail.asp?part=MSD%2D8985&autoview=sku
I was also advised to have a timing light and a vaccum gauge handy.



This is what the MSD Timng Tape looks like. You will need to know what size of Harmonic Balancer is on your vehicle.



Here's what mine looks like.



Here's a photo of my timing notches.

[JeepHammer]

First Order Of Business....

What makes you think I want to participate? (or is that 'Participateo'? )

--------------------------

SECONDLY,
GO BUY SOME ENGINE DEGREASER AND BRAKE PARTS CLEANER!

There is NO WAY you are going to be able to find the '0°' (Zero) mark and advance marks in all that grease & grime!

Once the grease is cleaned off the timing scale on the front timing cover, you might want to use some 'Touch Up' paint or 'White Out' to highlight the '0°' mark on the scale.
Don't worry about the rest, you won't use them, the tape will give you the degree reading in bright black and white!
----------------------------

THIRD,
Once Clean...
You MUST VERIFY all your components, otherwise you are wasting time and money.

How you do this is...
A. Take Out the #1 spark plug.
If it's an I-6 engine, #1 it will be the FRONT cylinder.
If it's a V-8 engine, #1 will be Drivers Side Front.

B. Turn the engine over BY HAND with a wrench on the crank bolt in the middle of the front pulley...
Keep one finger over the spark plug hole until you feel pressure building.
When you feel pressure, that is compression stroke starting.

C. Use a small wooden dowel rod, chop stick, ect. (NO METAL) in the cylinder to feel for the piston coming up.
You are looking for when the piston is EXACTLY at the top of COMPRESSION stroke, or TDC of Compression Stroke.

D. Once you find TDC by feel, You are ready to check the harmonic balancer.
Harmonic Balancers CAN NOT BE TRUSTED!
The outer ring with the mark is mounted in rubber, and they come loose all the time.
Most of us are using balancers that are 22+ years old, so DO NOT trust the timing mark on the balancer until you VERIFY IT!

If the balancer mark has stopped within a few degrees of 0° mark on the timing scale, then your balancer is probably pretty close to correct.

IF it DID NOT come up at 0°, it's time for a new balancer before you proceed!

*IF* you are desperate to get it timed right away, you CAN make a mark on the balancer at the 0° mark on the scale, and use THAT MARK YOU MADE to set the correct timing,
But the ring can't be trusted, it's going to continue to move around and can't be trusted from one day to the next...
-----------------------------

FOURTH,
DO NOT CONTINUE TO MOVE THE CRANK ONCE YOU VERIFY TDC OF THE #1 PISTON.

HAVING TDC NOT MOVE is the basis of getting everything VERIFIED...

When you put the timing tape on the balancer, you MUST put the "BTC" or "Before Top Dead Center" numbers to the RIGHT of the timing marks!
THIS SEEMS BACKWARDS TO THE TIMING SCALE!
(It is, but the timing scale uses a single mark and fixed scale,
But the tape uses the fixed 0° mark, and the scale is on the TAPE, moving with the balancer relative position!

Start at the factory groove in the harmonic balancer, and as you are looking down at the balancer from above, The BTC numbers on the tape should be to the RIGHT of the balancer mark since the engine rotates CLOCKWISE from this perspective, and 'ADVANCE' will show up to the RIGHT of the orignal timing mark...

You would not believe how many people put the tape on backwards the first try or two!
(Even I do it or say it backwards occasionally!)

CLEAN, CLEAN, CLEAN or the tape won't stick!
----------------------------------

FIFTH,
Time to VERIFY the distributor placement/rotor location.

A. Take a look at your distributor placement.

If it's a V-8, the vacuum advance nipple should be pointing (more or less) just behind the top drivers side corner of the radiator.

This is a graphic showing a properly installed V-8 distributor.
The rotor should point directly at the #1 plug terminal when the cap is off.



If it's an I-6, the vacuum advance nipple should be pointing (more or less) at the front of the engine block.

This is a properly place housing and rotor for an AMC I-6 engine.


ANYWHERE ELSE IS INCORRECT.

Find the #1 plug wire on the distributor cap.
Mark the location of the #1 plug wire TERMINAL ON THE DISTRIBUTOR BASE.
(This is so you know where #1 plug wire is when the cap is removed)

Flip the cap, and see if your rotor is pointing at #1 or not...
If it's NOT pointing at #1, when the vacuum advance is pointing in the correct direction, you need to adjust your distributor so it IS correct and VERIFIED.

(About 1/8 of you I-6 guys with pitiful running engines are going to find your rotor is pointing 180° away from the #1 plug wire terminal... This is a COMMON mistake, and you need to correct that problem!
AMC I-6 Engines WILL run 180° out! They just don't run well!)
----------------------------------

TIMING CHAIN SLOP...

Procedure for finding TIMING CHAIN SLOP before you do a lot of timing work for nothing...

Turn the engine BY HAND until you get the balancer mark to the 0° mark.

Flip the distributor cap, and have a look at the rotor.

Turn the Crankshaft BACKWARDS (Counter ClockWise) until the ROTOR BARELY begins to move...
And I mean just TWITCHES!

Mark the 0° line on the balancer.
The difference between the first mark on the balancer, and the second mark you made on the balancer is the timing gear 'Slop' expressed in crankshaft degrees.

More than about 5 degrees, and things are getting serious, between 7 & 10 degrees and you have impending timing chain failure!

Once everything is VERIFIED and in the correct place, it's time to get down to business

----------------------------------

[Lifesgoodhere]

How to adjust the high idle and low idle on your carburetor. I can't figure it out.

I have a single barrel Carter, model W-O.

[JeepHammer]

IF YOU DO NOT have a timing computer on an I-6 engine and all V-8's...

Start the engine, time it up at about 6° or 8° BTDC,
REMEMBER to disconnect the vacuum advance hose from the distributor, and DO NOT reinstall it until I tell you to do so!
........

Initial doesn't matter right now, we are just getting the distributor advance base line mapped. Somewhere between 6 and 8 degrees before TDC is where most are going to idle well and give good intake vacuum...
---------------------------

1. Write down what you have for Initial Advance.

Well say 6° for the sake of argument...
------------------------------

2. Rev Up the engine to about 2,000 RPM and check the timing again.
This will tell you much TOTAL CENTRIFUGAL ADVANCE there is in the distributor right now.

Write down the number you see with the timing light on the TAPE...

Should be around 13 to 15 degrees more than initial.
Around 19 to 21 Total right now at 2,000 RPM.

19° Total - 6° Initial = 13° Centrifugal
21° Total - 6° Initial = 15° Centrifugal

This is why you write the Initial down, and the centrifugal down...
------------------------------------------

3. Do the same test again, but rev the engine VERY SLOWLY while watching the timing tape with timing light.

Take CAREFUL NOTE of when the advance starts to increase, and have your helper tell you what engine RPM the increase starts.

You or your helper need to take note of when the increasing advance STOPS increasing...
You want that RPM also!

This will tell you the RATE of the centrifugal advance.

Centrifugal advance STARTS at 1,100 RPM and STOPS at 2,100 RPM, it's pretty LATE for performance, but good for highway driving with big tires and 2.73:1 gear ratio at low RPM's...
The TOTAL is 13 or 15 Degrees,
The RATE is starting at 1,100 RPM and all 'IN' by 2,100 RPM. Rate is slow.

Small advance Totals, coming in at 'Slow Rate' is good for 'Lugging', Trying to keep up with traffic at part throttle,
Pulling trailers on the highway, ect.

LARGE advance Totals, coming in VERY QUICKLY is good for fast Acceleration, or the 'Jump' you feel when you crack the throttle open.
It's VERY HARD on drive line parts when wheeling, since you have a lot of gear reduction, everything is in a bind, and you are SHOCK LOADING the drive line components.
AND,
It's very hard on engines at 'Part Throttle Cruise' on the highway...
Causes 'Spark Knock', 'Valve Clatter', 'Dead Spots', these are ALL detonation related problems from too much advance too soon with a lean fuel mixture and too heavy a load on the engine (Slow RPM's)
------------------------------------------

4. Use about 2 feet of CLEAN vacuum line and vacuum pump, or even your mouth, to suck vacuum on the distributor.
The advance will change at the balancer.

You DO NOT have to rev up the engine for this.
RPM will advance, and engine will gain RPM as the vacuum brings the VACUUM ADVANCE into play, but you don't have to add a bunch of extra RPM...
AND,
You want to stay below the threshold of the CENTRIFUGAL ADVANCE so you don't wind up mistaking the Centrifugal advance with Vacuum Advance.

Vacuum advance in the Jeep/Motorcraft distributors is usually about 6 to 12 degrees, so we'll say 9° for an 'Average'...

6° Initial + 9° Vacuum = 15° Advance.
------------------------------

5. TOTAL ADVANCE.

15° From Initial & Vacuum + 13° Centrifugal = 28° TOTAL ADVANCE.

To confirm that, rev the engine to it's top CENTRIFUGAL mark, say 2,100 RPM, or say 2,500 RPM just to be 'Safe' everything is in, then pull vacuum on the vacuum advance canister again...
You should be showing 28° TOTAL advance on the timing tape with the timing light.
-----------------------------------------------------------

[Lawless_Jeep]

Um, there is ZERO grease and grime on this motor. Now, I may need to remove some paint from the notches, but definitely not grease and grime.

[Ridin' Around]

How will we know that a topic is complete so we can ask a new question?

[JeepHammer]

NOW.
To Change The CENTRIFUGAL ADVANCE of your distributor...

'78 to '91 Jeep/Motorcraft distributors.

The 'RATE' or how soon the advance starts and comes fully in is VERY EASY,
It's two springs in the bottom of the distributor!

You DO NOT have to use the same size springs!
It's the TOTAL SPRING RATE that determines the point when the CENTRIFUGAL ADVANCE starts, and therefore is completely 'IN'.

HEAVY springs make the CENTRIFUGAL ADVANCE LATER, OR HIGHER IN THE RPM RANGE.

LIGHER Springs make the CENTRIFUGAL ADVANCE SOONER, OR LOWER IN THE RPM RANGE.

Lighter springs will make the vehicle 'Jump' when you push the throttle,
But they can very easily come back to haunt you with detonation when you are cruising on the highway...

They also make trying to 'Finesse' an obstacle more difficult if the vehicle is going to 'Jump' every time you touch the throttle!

Good throttle response is one thing, but detonation and breaking drive line parts is quite another!

You will have to find your own 'Mediums' by tuning your own Engines for the way you drive...

These are the spring in a V-8 Distributor,



This particular image has a 'Medium' and a 'Light' spring in it, which is usually about right for someone that isn't pulling a trailer or heavily loading the engine while at relatively low RPM and isn't running 2.73:1 gears with 35" tires!

This is a set of spring for the Jeep/Motorcraft distributor.
Mr. Gasket p/n 925D, around $5.



With this kit, you can do about anything you want to combined with the factory 'Heavy' springs that are probably in most of your distributors.
----------------------------------

NOW,
How you GET TO those springs,

It's actually not as hard as all the GM/HEI guys make it out to be.
Once you do it a couple of times, you will have it down pat, and usually two or three times is all you will do it in the life of the distributor, so it's no big deal...

FIRST!
Take off the distributor cap, Rotor, Cap adapter if you have done the large cap upgrade (TeamRush Upgrade)...
IF you haven't done it, DO IT!

Once you have the distributor cap/rotor off, it's going to look like this....



The 'Wagon Wheel' or 'Star Wheel' thing is the 'RELUCTOR', and you need to find the roll pin that secures that reluctor to the advance head it's mounted on.... Mark that roll pin location on the reluctor, since there is more than one place for that roll pin to go!

Once the roll pin slot is marked, pull STRAIGHT UP on the Reluctor.
DO NOT PRY ON THE 'ARMS' of the Reluctor!
If it won't pull off by hand (and some won't), stick a couple of screwdrivers under the base circle ring where the arms mount, and pry up from there.
Bend an arm, and you will need to buy a new Reluctor or have one or two cylinders firing at stupid times!

Reluctor & Roll Pin.


KEEP TRACK OF THE ROLL PIN!
It's VERY small and easy to loose!

Now, it's time to take the vacuum advance off the distributor.
Two screws easy to get to from the top of the vacuum advance/distributor, and the 'C' clip that secures it to the advance plate inside the distributor.

Again, the 'C' clip is VERY small, so be careful not to loose it!



Now, it's time to remove the advance/trigger plate.
Some of you will get lucky and will be able to reach both screws without removing the advance/trigger plate... You will be able to spin it around on it's axis and reach both screws...

The rest of you will be like me and need to remove it to reach the second floor plate screw!

Anyway, There is a Wire 'C' clip thing in the groove indicated by the screwdriver blade...
That is where the Wire Clip is located, and you will need to remove it so you can take the advance/trigger plate off by pulling straight up on it.



And the advance/trigger plate will pull straight up!



*IF*... You have a 23+ year old factory trigger plate...
You might want to take this opportunity to REPLACE IT with a new one!
They are only about $15, and although they live a long time, they DO NOT live forever!
If you replace, look for one with a BRASS center bearing piece instead of steel! They live longer and work smoother!

Now, you are ready to take the floor plate off so you can get to the springs and centrifugal advance head...





THEN YOU WILL HAVE OPEN ACCESS TO THE SPRINGS...

[Ridin' Around]

No, just curious.

[Lawless_Jeep]

[Lawless_Jeep]

Ok, now I have already ordered Mr. Gasket #925D Spring Kit, but it only comes with 2 springs. Is there a better choice of springs out there, or will the two in the kit, plus the two on my distributor be enough?

[John Strenk]

Is there a good way of checking his timing chain without opening upt the engine before he goes through all this.?

[84MSRB]

Sorry, but I'm gonna violate rule #1 right now.
Are you answering in hugo letters to be emphatic, or are you actually screaming these answers?

Just wondered.

[Lawless_Jeep]

Originally Posted by 84MSRB

Sorry, but I'm gonna violate rule #1 right now.
Are you answering in hugo letters to be emphatic, or are you actually screaming these answers?

Just wondered.

Foul!

His keyboard strikes only big fonts for the hard of hearing.