Confused!! Blown Head Gasket or What???

Have you confirmed that you actually have ignition occuring on both banks?

 

Just put a timing light on the spark plug wires to confirm if each cylinder is firing or not. Due to the mechanical architecture of your engine, if all 4 cylinders in one bank are not firing, it will still run perfectly smoothly (but with 1/2 power) -- and the design of your ignition system is such that there are several problems that can cause you to lose the ignition to a whole bank.

 

How about a leak down test?

 

Sounds like it's only running on one bank...if it runs like a honda...check the spark. Also check your digiplex units under the trunk carpet, drivers side. Make sure they are plugged in nice and tight and clean the connectors. Also check the ground. This can be a typical problem with the ignition.

 

Lost power but compression are good on both banks?

Sounds like ignition

 

WTF?
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There is nothing there that would make it run poorly. They dont sound great, but they arent awful. Not yet anyway.

A leakdown test would be a very good starting point and may possibly rule out cylinder to cylinder leakage or perhaps a blown headgasket. When was it serviced last and were the heads ever retorqued? Valve timing, valve clearances, and loads of carbon buildup from poor running, all will effect a compression/leakdown test. I would nail down the ignition first to make sure thats not all your problem is, then start asking the larger questions. Its always best to run a compression test on a hot engine that been running well than one that was run out of tune.

 

The three basics, Spark (existence and timing), Fuel (existence and pressure) , Air (A/F ratios).
Check those FIRST before moving on to possible mechanical defects.

 

It's no secret that the quality of replacement ignition parts (particularly aftermarket) is not great. Just fix it and move on.

 

There is a difference between the carb and injected cars in either the cap or the rotor (but not both?). Contact Ricambi, I believe he will know how to solve your problem. There was a thread about this same problem once before, and I believe the same suspects were involved. Keep us posted.

Part of the problem may also be that T.R. gets a lot of their parts from Superformance, and they list "dual distributor" caps and rotors, with no distiction between carbed or CIS cars. I guess for whats its cost you, added to what its going to cost, dealer prices for genuine OEM would have been a bargain?

 

I'm not sure there would be enough slop to cause this even if they were shot, but are the bearings in the distributor ok, espcially the outboard one?

 

Use our sponsor Ricambi although TRutlands has been around FOREVER and is normally quite adequate on tune up service parts....but IIRC there's a "bad run" of rotors out there that are "that much" too long which certainy does sound like your "cap grooving " problem.......

So as said try to correct the rotors, (Caps are way expensive, you can rebuild them you know...)

Whenn was the last time your distributors were calibrated and rebuilt??

If a bushing was way worn out on the shaft, I suppose it could float around breaking rotor contacts but hard to believe you wouldn't notice some symptoms from THAT!

On the upside your heads are still okay....

 

No, your camshaft will not be floating around, not at all.........

 

I think an OEM cap from ReOriginals is about $425 each.........

Thanks for this thread, I've had a hard day at the office,.....man, folks are so EXCITABLE these days.......

I recall my car "single banking" and blowing the headers apart, the whole thing was on fire.......

 

I would image it is getting cold in Montana, so why not park the car for awhile,pull the distributors off and make sure they're OK, especially the shaft bearing / bushing / housing? Good time to get them calibrated, as well.