Tune up to isolate a Low Power problem

[Patton]

Tomorrow, I am going to spend most of my day off tuning up the 100-6 to find why it lacks "umph". The motor seems to run very smooth in the garage, but it accelerates weakly and tops out at 50 MPH.

Please look over my plan and validate that I am going through he right steps.

According to the Workshop manual, low power should be caused by one of these things.

Possible Causes of Low Power
------------------------------
A - 3. Dirty, pitted, or incorrectly set contact breaker points
- 10. Defective Fuel Pump
- 11. Over-choking
- 13. Choked petrol filter or jets
- 14. Valves leaking
- 15. Sticking Valves
- 16. Valve timing incorrect

B - 1. Plugs defective or incorrect gap
- 2. Retarded ignition
- 3. Mixture too weak
- 6. Incorrect valve clearance

C - 6. Worn piston rings
- 7. Worn valve stems or guides

D - 1. Weak or broken valve springs

E - 1. Overheating

G - 1. Leaking joint washers
- 2. Fouled spark plugs
- 3. Automatic advance not functioning

I am planning on following the tune-up steps in Norman Nock's book (it says that Reid collaborated). Hopefully this will isolate the problem and it will be a non mechanical issue.

Thanks
Patton

[ 12-30-2003: Message edited by: Patton ]</p>

 

[Pete Haburt]

Patton;
That list just about covers it. I would check points, plugs, and distributor cap/rotor first and then start it and see what that gets you. Change condensor also, although car usually dies when they go bad.Check timing as well.
Since you state it runs smoothly, I'll presume your ignition wires are ok, otherwise it would be missing.
If still down on power, check color of spark- bright blue is good. If orange, could be bad coil. Had this happen on my MGB many years ago.
If ignition seems ok, you could have one carb with blocked fuel inlet. I had this happen in Duluth returning from 2001 conclave. Cleaned out the needle valve, and away it went. I have since installed an inline fuel filter right before the carbs, no problems since.
Let us know what you find!

 

[Patton]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Pete Haburt:

Let us know what you find!

<hr></blockquote>

Thanks Pete,

I was most worried that I would find out that it is a problem with the motor. Specifically the heads or worn cylinders. I just finished the compression test and it came out pretty good so I think I can elimiate the motor

Here is what my compression test results are. The test was done with the engine cold, all plugs removed.

#1 - 142 psi
#2 - 145 psi
#3 - 140 psi
#4 - 138 psi
#5 - 138 psi
#6 - 141 psi

Avg - 141 psi
Variance 5%