There is a first time for everything updated three fouled plugs

[92Rustang]

I was doing some more checking today on why I did not have compression on the #8 cylinder. I was watching the rockers as I turned the motor over. Something was not right. I pulled the rocker off and I found a broken valve spring?

I called summit and they are sending me a new one. I'm running somewhere around .538 lift. The spring is rated at .560 is this to close? I have heard of broken springs ,but have never known anyone that broke one. I don't think I'm runnnig any crazy lift.

Just wanted to let you guys know I found the problem. Thanks for the help everyone.

[DRASTiK]

As far as broken springs, I've never had it happen to me personally, but if it says 560, then it seems to me 538 should've been fine. Maybe a little close, but still okay. I'm just glad to hear that a spring was your problem and not something worse.

[PKRWUD]

What about the other two fouled plugs?

Take care,
-Chris

[92Rustang]

I have been thinking about that. This started as a miss. I drove another 8 miles to make it home. The miss got progressivly worse. I'm hoping this caused the problems with the other cylinders since they are all right together. Hopefully this is not just wish and something else is wrong. Do you have any ideas? I will be pulling the spring off monday and inspecting the heads more carefully. Thanks

[PKRWUD]

You've got two fouled plugs on one side, and one on the other. One was due to a valve hanging open. Hmmmm. This may sound silly, but how well are your plug wires separated from each other? What were the compression readings again?

[92Rustang]

I have never had a problem before. The only place the wires are close is the cap. The compression readings when like this . 1-3(23-26lbs or 110)4 was a little lower.5-7 (23-26). The more I have been thinking about the more I think something else could be wrong. The only change I made as the A/F gauge that can't be it. Thanks for the help. I really don't won't to pull the motor apart again.

[PKRWUD]

I'm sorry, but I don't understand your compression numbers ("23-26lbs or 110"???). I would recommend replacing the bad spring, installing a set of cheap, new copper plugs, and drive it for a day or two. Then check the plugs, and see how they look. Also, I would re-do the compression test, but after you test them dry, test them wet.

Take care,
-Chris

[92Rustang]

I forgot the other value on the gauge. It started with a K. 23-25 lbs was the other value ,but I did think that was the one used for automotive compression. I thought the numbers were always higher like 100-120 when talking about a motor. The main thing is that they are all close right?

I have a new spring coming Monday. Should be on Tuesday or Wednesday. Do you think I still have a problem? Thanks again for your help Chris.

Chris I checked out your site that is a pretty sweet olds motor. My first car was a 81 grand prix that I put a olds 403 into. The motor did not rev high ,but it did put you in the seat, even with the 2.29 single track once it hooked. God I miss the good old days. Timing and carb what else was there.

[PKRWUD]

Okay, I'm concerned. 23-25lbs. is not enough cylinder compression to run, so somethings up. How many engine rotations are you allowing when checking the compression? Describe how you're checking it.

[92Rustang]

I rotated the engine maybe three times(compression strokes) at the most only on a couple of cylinders because it did not seem like the gauge was moving up anymore. I get off at 3:00 today I will go home and do it again. How should I do it. I have a twenty dollar gauge that holds air when I put it on the air compressor so I know it works, correctly or not is another story. It is a compression test gauge with all the fittings.

[PKRWUD]

Dry compression test:
With the engine warm:
1) Remove all spark plugs.
2) Unplug the coil.
3) Wedge the throttle at WOT, either under the hood or with a brick on the gas pedal.
4) Install the tester into a cylinder.
5) Either with a remote starter switch or with the key, crank the engine over for five (5) revolutions.
6) Read the gauge and write down the reading.
7) Release the pressure from the gauge, and move the tester to the next cylinder.
8) Repeat 5-7 until all cylinders are done.

Also, make sure there is an O-ring on the spark plug hole adapter! You will need a squirting oil can for the wet compression test. Post the results from the dry test, and let me know if you have a squirting oil can.

Take care,
-Chris

[92Rustang]

OK I've got. One problem the upper intake is off and the valve spring is broke on the number 8 cylinder. How much of a difference does it make if the motor is not warm. I do have a oil can and will do both tests and post the results. Thanks again for all the help. Wish me lick. Should be posted by 5 CST tonight.

[PKRWUD]

Skip #8. I'll remember that the engine is cold when I read the numbers. To do a wet test:
After you have completed the dry test, repeat all of the steps, except just before you attach the tester to a cylinder, add 3 squirts of motor oil into the cylinder through the spark plug hole. Don't oil all the cylinders at the same time, just do each cylinder prior to testing that particular cylinder. Post these numbers separately from the dry numbers.

Take care,
-Chris

[92Rustang]

Sorry for the delay I had some crap around the house to get done. I did the test today not good.

DRY WET

1 160 150 makes no since
2 175
3 175
4 175

5 145 160
6 150 160
7 150 175
8 valve pring broke could not test


I was unhappy with the results kind of wierd though. Looks like the passenger side is wore more than the drivers. I went back and tested 3 again and got 175. So I think the test is right. I have heard bad things about the valve seals on these heads could this be a problem? I did not really want to rebuild the short block yet. The motor seemd to run ok before the valve spring broke. If I had the rocker arms adjusted wrong on the passenger side could this give my a low compression reading? Thanks for ther help guys.