Sunday, July 27, 2014


 Here is a FIAT twin cam cylinder head, from a 2-litre [1995cc] carbureted engine. The owner wanted more performance, so in addition to adding a Weber 32/36 DGV-5A carburetor and a set of headers and better exhaust, I put in a set of camshafts from an earlier, 1438cc FIAT twin cam engine. They are an exact interchange, BUT the earlier cams have more lift and will give a big bump in the horsepower curve.
 The valves, when pushed open, extend below the level of the cylinder head so a holding jig is necessary to avoid bending one or more valves in the process of doing the camshaft interchange and subsequent valve adjustment. I built this one some years back and it will support several different types of cylinder heads, even a GEO Metro head. [GEO metro....?] 
 Here are the exhaust camshafts for both engines. Note that the 2-litre cam has big, lazy lobes. You can't see it in the photo but the lift and duration are different between the two camshafts.  The cam followers are all in a row at the top of the picture. The actual valve adjustment shims fit in the TOP of each of the followers, not inside.
 This shows the exhaust camshaft housing, with the cam and drive gear for the notched belt in place. At this point the housing with the cam followers [not installed here] is ready to be installed on the head.
 I build a lot of special tools. The stud with the screwdriver slot in it is one of two. They serve to hold the cam housing-to-head gasket in place and as a guide while I set the cam housing onto the head. All the bolt holes line up--no fudging around. Neat.
 Now the fun begins--getting in the correct shims to give proper valve clearance. The tools are FIAT items. Here is how they work: With the camshaft turned so the lobe is angled up, away from the lifter, you use a feeler gauge and measure the clearance [between the camshaft and the follower]. Spec for exhaust valves is 0.018" to 0.021"--I like to set them at 0.020". If you do not have the correct clearance, you push the spade ended black handled gizzmo in between the camshaft and the hardened shim, which is sitting on top of the cam follower "bucket". Then you rotate the little tool [which I have in my hand] around the cam and situate it so its fingers sit on each side of the "bucket". Then you use a shot of compressed air and the shim will pop out of its place on the top of the "bucket". 
Measure the thickness of the shim. I use the micrometer to check that my digital caliper is reading accurately today. If the clearance is too tight, you install a thinner shim. Then remove the tool and recheck the clearance. Repeat as required.  [Note--spec for the INTAKE valves is 0.015" to 0.019"--I set them at 0.018"]. 

Note the cam followers ["buckets"] next to the digital caliper. Four of the followers are turned "right side up". Two of them have shims set on them so you can see where the shims fit into the recessed area at the top of the follower.

It is nice to have a full set of shims, separated by thickness sizes.

And here's the finished head, ready to set on the engine.  If YOU are doing this, some things to remember: The camshafts MUST be in the correct position, the engine timing mark on the front pulley MUST be on Zero, and you MUST use a NEW timing belt. It is also a really good idea to install a NEW belt tensioner--the bearings in the old one are probably shot. READ THE SERVICE MANUAL!

Thursday, July 3, 2014


 Contrary to contemporary Germanic myth, even BMW speedometers screw up. GASP! I know that's difficult to believe, but what you see here--on the left in the instrument module--is a dead one.  At least, the odometer is dead.
 So let's see vas ist kapoot.  This is the back of the module. Simple, eh? [That row of lights across the bottom is a sequential warning system tied to increasing speed, to tell a Bimmer pilot how close he/she is to going to jail].
 Well yes, simple so far. Remove 8 screws and lift off the plastic outer housing. We're not there yet....
 Take out some more screws and whaddaya know? A speedometer! And that little gauge at the base of the tachometer? It is fuel mileage gauge, but in litres per 100 kilometers. See, Bimmer drivers have to have SOMEthing to wow the drivers of LESSOR cars that happen to ride with them [and they explain how it works while speaking German, of course].
 This speedometer was built when--apparently--neither BMW or VDO had figured out if they wanted to fish or cut bait. Mechanical operation or electrical? GOSH! I don't know---let's do BOTH.  So they did. The speedometer is electric, much like a tachometer. The odometer is driven by a wee electric motor, through a fairly complex gear train.Obviously, they did it because the COULD, not necessarily because it made good sense.  So what screws up? Those gears are plastic [of course] and one or more of them get tired of it all and spit off a tooth or two.  In this case, TWO gears spit teeth. You can see the dark brown gear [bottom center] that's missing a couple of teeth. Harder to see is a WEE LITTLE shit of a gear just at the bottom of the other brown gear, still in the speedometer apparatus.  It's minus a couple of teeth too. The more or less clear plastic housing to the left of the speedo body supports the gear train shafts and keeps the gears in place.
 The three new gears are at the lower left. The only fly in the ointment is removing the chewed up WEE gear [that is still on the shaft in this photo]. That shaft is pressed into the wee electric odo drive motor. If you reef on the wee gear to get it off, you'll pull the guts out of the drive motor and that will turn your whole day very dark brown. I used one of my special pullers to remove the little shit.  The two new larger gears just drop onto their respective shafts [in the correct order and location--they do not have the same number of teeth]. The new WEE gear has to be carefully pressed onto the motor drive shaft--to the correct depth.  Oh yeah, it's great fun repairing something that was a crap design in the first place.
But, here it is--ready to rip once again, and log many happy miles at speeds well above any posted speed limit. Anywhere.


 What you see is the familiar Monte Carlo or Saab Deluxe instrument panel.  But wait! Take a closer look---this is from a VERY rusty car. In fact the steel instrument panel itself was rusted through in a number of places. I wanted to see what I could salvage from this mess....
 The back of the panel didn't look so hot either. Almost all the bolts are rusted beyond any hope of unscrewing. In fact, the clamps for the speedometer and tach have been removed, and the retaining bolts broke off.  THAT didn't bode well....
 Rust never sleeps, as you can see. At this point I wasn't feeling good about this....
 The speedometer case is toast.  But...hold on! The "innards" don't look too bad...maybe SOMEthing can be salvaged here, yet....
 Well, I'll be...! The innards look better than some I've seen that weren't rusted! The little tool is one [of 50 or more little speedo tools] that I've built. I use this one to operate the speedometer by hand. Turns out I was able to do a normal reconditioning of the speedometer--including replacing the odometer drive gear [which is normal]--and the sucker works like a champ!
 My spares stash yielded a good outer housing that cleaned up nicely....
And even the chrome ring and the glass cleaned up just fine. So a word to the wise--don't throw away a Saab speedometer or tachometer just because it has a bit of rust on the outside. It's what's INSIDE that counts! And if you have one you don't want---I DO!