Alfa Romeo Valve Adjustment, Part 2

As you read in “Alfa Romeo Valve Adjustment, Part 1” (or if you skipped your reading assignment, you can find it here), the valve gaps on my 1300 engine were out of whack, especially on the intake side. With cams temporarily removed, I measured all the existing shims, did the algebra to calculate the sizes of the needed shims, and placed my order with Classic Alfa in the UK. I was not the least bit surprised when the order I placed at 10 p.m. on a Saturday night landed on my front stoop before I got home from work on Tuesday. (I need to email them and enquire what happens after Brexit, presuming that Brexit happens.)

This magnet was very helpful in encouraging the slippery follower to come out

The following weekend, all the old shims came out, and the new shims went in, again following the “one cylinder at a time” rule I established so as not to cross-install the followers which must remain with their original cylinders. When reinstalling the cams, I could not get the timing marks between the cams and front bearing caps to line up. It made me nervous enough that I removed and reinstalled the cams a second time (remember that the timing chain remained attached to the sprockets). I finally convinced myself that once I released the bolt holding back the spring tension in the timing chain tensioner, all would return to sync, and that is exactly what happened. With the tensioner pressing against the chain, I rotated the crank and cams through two complete revolutions, and then tightened the bolt in the spring tensioner. The marks were still aligned, thankfully.

I double-checked and wrote down all the new valve clearances, and all seemed good (but read on). Since I had the spark plugs out, a new set of NGK B7ES plugs, which are in stock at my local Advance Auto Parts store, went in. With plug wires, intake plenum, and air filter hose back in place, it was time to attempt to start this baby, remembering that the engine had not been run since the car went to sleep the previous autumn. The engine started on the second try, however, there was an unhealthy miss at idle. I shut it down, and made plans for a complete tune-up, which was next on the Alfa’s to-do list anyway.

 

Never-seize coating on plug threads
Postscript: I jotted down all the “new” valve clearances, and really didn’t give them a second glance, undoubtedly presuming that everything was done correctly. Today, while composing this blog post, I noticed that my spec for intake valve #3, .450mm, was unchanged from its original measurement, yet I have no doubt that the 2.15mm shim which had been in there was replaced with a 2.10mm shim, which means that the new measurement should have been .500mm. For now, I’m leaving this alone for several reasons: valve #3 was the closest to spec of all the intake valves during the original check; testing the thicknesses of the new shims revealed that how tightly I cranked on my micrometer made a difference in the measurement (including the effect of residual oil on the shim); and I’m not yanking that cam again for 0.05mm!

 

All photographs and video recordings copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

 

3 thoughts on “Alfa Romeo Valve Adjustment, Part 2

  1. What’s.05mm unless you’re at 8000 RPM and the valve float causes the valves to kiss the tops of those hot pistons? (It’ll never happen, don’t loose any sleep.) 🙂

    Like

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