Sunday, June 28, 2020

Engine (Re)assembly

I hope the second time is the charm with my engine.  I've got everything back together and I think she's about ready to be mated with the five speed.

I installed the new piston rings and rod bearings and got the pistons in place.  I ended up buying a new piston ring compressor as the one I have wouldn't cinch up well (probably from being compressed in the drawer for too long).  I measured all the gaps at .008-.009", right on target.  It was a struggle, but everything did go together properly.  With the pistons installed and the rod caps torqued down, things are tight but turn smoothly.

Then it was on with the sump cover and oil pickup, install and torque down the head and do a cold set of the rocker clearances, and all done.

I still have to relocate the clutch slave cylinder and measure clearances as recommended by the install guide. To do the latter, I have to bring the hoist into play and mount the flywheel and clutch.  There are specific tolerances for the clutch and throwout bearing to work together.  Then the starter goes on, the trans mates to the engine, and the whole thing goes in the car.  Exciting times are ahead!
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Sunday, June 7, 2020

Installing the Rear Plate

While I waited for parts, I tackled the next step in preparing for the conversion: installing the rear engine plate.

This wasn't hard.  The custom machined plate that comes with the Rivergate kit both fits well and looks good, with all required hardware provided.  It also comes with a custom rear main seal mount.

The first step is to install the oil pump cover.  This has to be sealed with silicone, and must be flush to ensure the plate fits properly.  The instructions suggest using a heavy weight, but in my case it was easier to just clamp the cover in place after ensuring it was flush by using a straightedge.

Once that's done, the rear of the block was cleaned and silicone sealant (handily provided in the kit) applied in a thin layer in place of the gasket and where the oil pump cover seals to the block.  Apparently, the gaskets add too much variation in thickness and ironically can cause leaks in this setup.  Once applied, the plate is installed and tightened with the supplied bolts.

Finally, the rear seal was installed by filling any gaps between the plate and the block with silicone, running a thin bead of silicone around and between the bolt holes, and installing the mount.  The seal has lithium grease applied to provide for lubrication.

And that's it.

With the rear plate installed, I moved the assembly to the engine stand in preparation for final assembly.  I'm waiting on rings, and afterward I found I am on an enforced vacation from car things due to some elbow problems.

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Pressing F5

In the computer world, F5 means 'refresh'.  After pulling the engine out of Gidget, I figured I should take a quick look inside both to find that oil leak and see how the engine was holding up.

I'm glad I did.  I had problems.

First, I had a head gasket failure-in-progress between cylinders 2 and 3.  I could see the gray crusty residue of coolant being burned. It turns out the brass plug between 2 and 3 had receded enough to open the gap.  So a trip to the machine shop (Morrison Auto Machine, awesome!) fixed things right up by threading a new brass plug into the head and planing it off flush.

I also had lots of carbon buildup in all cylinders, and it wasn't until I pulled the head apart that I found out why.  This is embarrassing to write, but I had installed the oil seals on the exhaust valves and not the intake valves, so it was just sucking oil into the cylinders.  I hadn't noticed significant oil consumption, but I did see a couple of puffs of smoke every so often... now I see why they were happening.

The valves and guides are in fine shape after a bit of wire brush to remove the carbon.

After all that, I now have a rebuilt cylinder head with properly installed Viton valve stem seals on the intake valves.  I left the seals on the exhaust too--while not absolutely required, I have not found anything that says it is bad to leave them.  And if they degrade, no big deal.

With the cylinder head sorted, I looked over the remainder of the engine.  I mean, why not?  It's apart... and I had to pull the rear plate and rear main seal (Gerard's) to install the Rivergate plate.  Again, I am glad I did... I had some less-serious problems.

I pulled the pistons and rods.  The bearings were worn more than I liked, but the journals were clean.  These were the bi-metal bearings.  I have tri-metal King bearings to Vandervell specs waiting to go in.  The main bearings looked pretty good, but I replaced them (again, tri-metal) since it's a "false economy" to leave them alone.

The camshaft didn't turn smoothly, either.  I had noticed this when I first assembled the engine, and got things lined up pretty well.  It seems that the middle bearing was eating itself up.  These were 'split' bearings, which apparently weren't honed for fit.  The camshaft itself is fine; the bearing surfaces are clean and none of the lobes show unusual wear, all specing out within .001" of each other.  Dan took care of the bearing problem for me by sourcing 'solid' bearings and installing them, and checking the fit.  The cam now turns smoothly and easily.  I replaced the lifters with lighter ones that have an oiling hole as I wanted to eliminate any possibility that the lifters were the cause of my tapping noise.  Everything is clean, smooth and moves easily.

The rest looked ok.  The cylinder bores were not worn, so they got a light hone to allow the new piston rings I have on order to seat properly.  The block is clean inside and there's no metal residue in the pan.

I could not trace down the root cause of my oil leak, though.  Everything seemed tight, though there was a light trace of oil at the oil pump cover (but not enough to cause me to suspect it).  The rear main seal was clean with no signs of a leak.  I suppose it is possible that a slight gap at the cover could have pushed a little oil out, but that was a lot of oil I saw under the car after a short run.  Something was pushing it out under pressure.  Maybe the seal at the block side of the rear main was faulty, but I don't think so.  Anyhow, it will all get sealed up tightly again when I install the new rear plate.  Since I am converting to the Rivergate seal, I installed the original rear scroll seal cap with a new gasket and a light coat of silicone sealant.

Having gotten the block back from Morrison Auto, I installed the crank, lifters, cam, and oil pump.  I had the rotating assembly balanced, and it was indeed a bit off, which could explain the light vibration at 3500RPM.  The pistons and rod assemblies were all within a few grams.

The front plate, timing gears, oil thrower and timing cover went back on with new gaskets (that I happened to have, thankfully).  I checked the timing cover for straightness and made it nice and flat.  I installed a new front seal as well, though the one that was there was still ok.  Finally, the water pump went on with a new gasket.  Everything is nice and clean and properly torqued.

This is apparently a 'refresh', though to me it's a 'rebuild' since I replaced pretty much everything.


I also made new timing marks at a location that I could actually get to with a timing light.  It's accurate enough.  I didn't need all the marks, but it was simple to do.

I'll get this back on the stand (it's all I can do to deadlift it off the bench as it is) and install the pistons with new rings and bearings, and the head.  Then it's on to what I originally set out to do--install the new transmission!
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