Sunday, March 31, 2013

Tranny Rebuild

One of the very odd problems with this car was the transmission.  It's a 4-speed with an electrically controlled overdrive - another standard feature unique to the '71 142E - and the 4th gear clashes when engaged.  It's not uncommon for a car with 350k miles to have a worn synchro ring or two (they are the clutch-like things that bring the gears to the same speed before engaging so you don't get a clash), but it's almost always 2nd or 3rd gear since they get the most shifts.  I've never heard of a 4th gear synchro failing.  So, apart came the transmission to see what's up.

Here's the whole assembly on the bench.  The red part is the transmission, and the alloy part is the Laycock overdrive unit.  The first step is to separate the two main parts.

Transmission and Overdrive together
Next,  the guts of the transmission are removed leaving just the case.  The overdrive is fine and records show it was recently rebuilt so I'm not going to touch it.

Gutted transmission case

Transmission entrails
Oh look, there's the problem.  There is nothing more satisfying than finding a clear cause of a problem, and this was one of the more satisfying.  The 4th gear synchro was cracked!  As a result, when pressed against the mating cone, rather than acting as a clutch and bringing the two parts to the same speed, the ring just splayed out and did nothing.  Problem solved with one $40 part.

Cracked synchro ring
While the box was apart I checked the various bearings and found the input shaft bearing was a little worn so I replaced it and the needle bearings where it rides on the main shaft.  The counter shaft thrust washers were also worn a bit more than I'd like so I went ahead and replaced them as well.  Then back together it all went along with a nice new clutch fork boot and clutch release bearing.

Transmission and overdrive reassembled and ready to go back in the car

Friday, March 15, 2013

Engine compartment cleaning

The engine compartment on this car was filthy when I first got it.  Last fall we gave it a first scrub with engine degreaser and got the first layer of grime off.

Now that the engine is out I've really gone after it.  First step was scraping off the 1/4" layer of grease+dirt+oil.  Next was a bucket of degreaser, followed by rolls of shop towels and Simple Green.  Then rubbing compound to get off the really tough stuff, followed by wax.

Looks much better now, doesn't it?  And it will look even better with that spankin' clean engine in there.

Thursday, March 14, 2013

More engine assembly

Another day spent further assembling the engine.  First the cam went in, followed by the thrust plate and timing gear.  The gear is a semi press fit and there is great temptation to tap it on to the cam end until it's seated.  But there is nothing but a freeze plug to hold the cam in place, and more than one unsuspecting shade-tree mechanic has inadvertently knocked out that freeze plug.  Once out, then only way to gain access to fit a new one is to pull the engine - a very costly mistake.

Anyway, having been warned of this before, I found a spot where I could fit a bar to hold the cam in place and not bank up any critical machined surfaces.  Then, with everything lined up - the key on the cam with the key way on the gear, and the timing marks on the crank and cam gears - I heated the cam gear with a torch to expand it to make fitting easier.  A little heat and a little tap tap tapping with the butt of a hammer handle and on it went.  Torques the nut to specs, and she's good to go.

Next were the piston assemblies, which needed to be assembled into assemblies.  Basically the new pistons need to be attached to the connecting rods with the wrist pin.  Other engines I've worked on require a bit of a press fit and typically require heating the pistons much like the timing gear, but these were a smooth hand press fit so assembly was easy.  It did take a little sleuthing to figure out which face of the rods was forward.  The pistons are marked, but with the rods separated from the old pistons, that orientation was lost.  Pictures to the rescue!  I shot a few when I disassembled the engine and was able to identify some unique casing marks on one which revealed the correct orientation.  Problem solved - almost.

The first piston/pin/rod assembly went together easily, but on the second piston I was having a heck of a time getting the retaining snap ring into place.  I finally went and looked at the little package that they came in and discovered that the packaging, and the size marked on the package, was different for that one piston.  Crap.  But fortunately I had the old pistons still kicking around and was able to salvage and reuse a couple of clips from the old ones.

With all pistons installed and rods torques, I once again checked to be sure the engine rotated freely, and it's smooth as silk.

Next installed was the new oil pump, followed by a new rear crank seal and seal housing.
Then moving to the front of the engine I wen to install the timing gear cover only to find the new gasket was broken into 3 pieces.  Must have been some sort of shipping damage with all the gaskets just loose in a box.  No problem, that can go on later after I get another gasket.

Water pump next.  But wait, where's that gasket?  And what about all the O-rings to seal the pipes and heat joint?  All missing.  My guess is that they assume you are installing a new water pump on  a rebuild, and that the pump will include all the gaskets.  Not me.  I just put in a new pump a year ago, so now I need a pump gasket set.

OK, all is not lost, so I went to install the head.  Gasket fits - check.  Installed new cam lifters, fit the head, torqued all the bolts.  Done.  Cleaned up all the push rods, dropped them in place, then bolted down the rocker assembly.  Head complete.  Oh, and along the way I removed all the masking from the paint job which was a bit of a tedious process.

Now we are just down to accessories and external components like manifolds, motor mounts, water pump, timing cover, water pipes, alternator, etc.

Tuesday, March 12, 2013

Engine painting and reassembly

I got the engine back from the machine shop the other day, and now it's time for painting and reassembly.  Here are the "before" pictures.

Before painting, lots of different areas need to be masked off.  This took over an hour to get everything covered.  Don't worry, the timing gear cover is a junker so I just used it to mask off that area.  That black thing is the holder for the engine stand.

And here it is on the engine stand with the masking removed and assembly about to begin.

First thing in is the crankshaft.  But before installing, I had to pull off the old timing gear from the front and install a new one, plus install a new pilot bearing in the back end where the transmission couples up.  And finally, here's the crank installed, oiled up, and the bearing caps torqued down tight.

The end play checks out between .003" and .004", and the crank turns freely.  I love it when a plan comes together.