Topic: Loss of Spark
in Forum: C3 Engines

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It would be unusual to have opposing cylinders w/bad gaskets, especially on a blown engine(as far as the lower comp. readings). Did you do the comp. test with the throttle all the way open? That would effect the two cyls. if you have a dual-plane mnfld, which you probably do not.

My guess would be the valves maybe not adjusted correctly on those two, or, the cam could be bad. The # 5 & 6 cyl. lobes would be next to each other. If nothing else pops up to explain it, you may need to check the actual lift/duration on these two(four, actually) cam lobes. A bad grind, or flat lobes would not be unheard of.

As far as the loss of coolant, a pressure test would be a good place to start. I would suggest you do that while the engine is hot/warm. If it is a cracked/damaged head, it will show up easier that way. You can also use an ultraviolet dye in the coolant, and see if you can locate a leak that way.
Good luck! That's a sweet ride ya got there, Scott!

Joel Adams
C3VR Lifetime Member #56
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In reality a range of 148 to 160 is acceptable by anyones specs. I don't see any problem there at all. The lowest is less than 10%, and that's just fine.
As far as the water loss problems goes, that's another story. You can have good compression and still have a seeping head gasket causing some loss. Start with a pressure check and see if anything shows up that way.
Then go to the local parts store and see if you can rent/borrow/buy a chemical block tester. This fits in the top of the radiator and you add a detection fluid that's blue in color. All the air from the radiator goes through an air stone and up throught the fluid. If there is any combustion leakage into the coolant the fluid will change from blue to green to yellow. Any color change is bad, and you have a leak. If there is no color change, the seal is fine, at least from combustion to coolant.
You may also check for something like a leaking freeze plug or weeping from the water pump. Dont' overlook something as simple as a leaking radiator cap. Often leaks can be so small that the coolant evaporates and leaves no wet spot. Usually a trace pattern can be found. If not, there is a dye that can be added to the coolant. Then use a black light on the engine, radiator, etc. The dye will glow yellow or green under the light, and show where the leak is located.
Ken's about covered the compression problem, here's me .02 about the ignition. I use to work for Mallory, was the head of the tech and customer service department. The little black box is there to protect the electronics in the distributor from transient voltage spikes from destroying the electronics in the distributor. If you have a Unilite or Magnetic pickup, the switching transistor in the distributor is the weak link. Both of these styles of distributor need to run a ballast resistor to keep them from burning out, but if you have a high powered stereo or any other electronics that draws high current and drops off rapidly, the little black box is supposed to help in that case. If you are running a capacitor discharge ignition box, the ballast resistor is not needed. If you are runing a points distributor it is still needed. If it quits again, I can tell you how to check the rest of the system, but it's gonna be a long post.
Dave
Anybody have any lighter fluid and a match.


Ken's about covered the compression problem, here's me .02 about the ignition. I use to work for Mallory, was the head of the tech and customer service department. The little black box is there to protect the electronics in the distributor from transient voltage spikes from destroying the electronics in the distributor. If you have a Unilite or Magnetic pickup, the switching transistor in the distributor is the weak link. Both of these styles of distributor need to run a ballast resistor to keep them from burning out, but if you have a high powered stereo or any other electronics that draws high current and drops off rapidly, the little black box is supposed to help in that case. If you are running a capacitor discharge ignition box, the ballast resistor is not needed. If you are runing a points distributor it is still needed. If it quits again, I can tell you how to check the rest of the system, but it's gonna be a long post.
Dave
[/QUOTE]Dave-
I've got a Mallory Unilite with the tach hook up. What does the ignition ballast resistor look like?
Thanks

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MICK - C3VR Lifetime Member #113
Car is running ok now ?? Must have a bad ground or short that is intermittant.
Changed wires,plugs, checked the compression all good. Can't go to a real mech until the problem pops up again.
