Triumph Repair: engine performance, flapper valve, jerky movements

Question
QUESTION: Scott,
Thanks for your input on my '79 Spitfire. I just found out (the hard way) that the noise which I thought was a bad timing chain was in fact a bad air pump! Luckily, I'd intended to replace it anyway and had the new one on hand.

I also discovered that the EGR pipe which connects the exhaust manifold to the intake manifold was completely clogged on the intake side. I also discovered that the check valve from the air pump seems to be malfunctioning. You can both suck and blow air without any impedance at all. Would these things be helping to cause the rough idle after warm up and the pulsing of the engine? Also, the jerky movements after warm-up?

Also, if you wanted to sell the 150CD you mentioned I could convert it over to the auto choke system(California insists!). Otherwise, I'm going to send my carb off to 'Micropolishing' to have it completely overhauled! I appreciate your offer of assistance. Let me know what you think about all this. Whatever you decide is fine. I really appreciate your help.

Thanks, Jeff

ANSWER: EGR Pipe/Air Pump: I don't believe there is a check valve on the pump; I believe the flapper valve was part of the pipes that fed into the head itself; looks sort of like the vacuum retard on a distributor, but a larger pipe.  I don't think either should affect the idle.  You could always test by removing the air pipes from the head, or blocking the air pipe feeds.

Its common to remove these two bits to get a better running car.  If you are running full smog, I would look there for bad hoses or problems; the 1980 I had only ran better when I took all the emissions out.

CD150:   If you are going to send it off for an overhaul, then go that route; that way if there is a problem, they can help you trouble shoot or send it back to them.

Hope that helps...

---------- FOLLOW-UP ----------

QUESTION: Scott,

Thanks for your answer.

Yes, there is a check valve in the line from the air-pump to the air-rail. I discovered that it was jammed up with bits of metal from the 'blown' air-pump. I managed to clear it al;l out and now it functions fine!

I discovered that the EGR valve DOES in fact have a vacuum leak and am getting another one. There was also an exhaust leak at the #4 cylinder air injection rail.

I'm taking the carburetor apart to check all its functions (float level, etc.). I'm hoping to get it passed for smog by this week-end.

Say, one question: The CALIFORNIA ZS 150CD carburetor has an internal Temperature Compensator. Do those go bad, or are they sealed? If it goes bad is it time to replace the entire carburetor?

Thanks, Scott. I'll keep you posted on everything I'm finding.

I'm hoping to get a 1965 VOLVO 1800E. I've got my eye on one. I love those cars...I have ever since I first saw one when I was about 10 years old or so (not sure exactly when it was. I was in Canada at the time).

Later, Jeff

Answer
The temp compensators were supposed to be sealed; some early ones are actually adjustable.  You can pick them easily.  The temp compensator isn't really internal, it mounts to the outside of the carb.  Inside that part is a bimetallic valve, so you could clean the plunger that makes the seal, but that would be the only maintenance you could do.  Most of the ZS books say don't touch it, as they were somehow set from the factory.  

There are not really any "new" carbs, all you can reasonably do is rebuild them.  The only part that really wears is the throttle shaft bushings (radial play if you pull up or down the brass shaft).  They can be replaced and reamed out to size, just find another used body that is in good shape.  Used CD150 carbs are a dime a dozen, and you can swap out your choke mech onto any CD150 and be OK.