Monday, January 17, 2011

Engine Rebuild - Head Disassembly

Got the head disassembled and cleaned up.  It'll be going into the machine shop tomorrow morning to get hot tanked and inspected.  After that I need to start making some decisions about what to do regarding port work and cam selection.

Also listed a ton of parts from the engine (and some suspension parts) on Ebay to raise funds for the project.

First two valves out

All 8 valves pulled out

Valve seats appear to be in not-terrible shape, but will likely get replaced with hardened seats

Small valve train parts oiled and bagged

Wednesday, January 12, 2011

Engine Rebuild - Stripping Parts

Spent some time last weekend stripping engine parts, including the block (now that I know it's good). Also started chasing out threaded holes in the block that were full of paint and rust.

Still putting together a shopping list of parts to rebuild the engine, and changing my mind every 12 hours about what to do with the cam and head.

Block after quick pass with the wire wheel to knock off the loose stuff

Sprayed with aircraft remover, which will remove just about anything from just about anything

After one application of aircraft remover and another pass with the wire wheel in a grinder

Bin of parts before stripping

Bin of parts that have been pretty well cleaned up.  Still more to do before paint.

Chasing out threads in the block

Tuesday, January 4, 2011

Engine Rebuild - Inspection Results

I took the block, crank, and pistons into the machine shop yesterday morning to have them inspect and evaluate everything. No sense in buying parts and having machine work done until I know the bones are good.

I got a call back from them this morning with some good news. The cylinder bores are well within spec for +.040" and should be perfectly serviceable with a hone job. No cracks in the block. The crank journals are all to spec and will only need a polish before reassembly. After inspecting the dropped #3 piston they said it was probably usable with some light cleanup work, but I might still err on the side of caution and replace it.

Now that I know most of the major components are in good shape, I need to start planning (and saving) for the next steps.

Basic engine build will likely look something like the following:

  • Hone cylinder bores
  • Deck block to get to a better compression ratio with the F head
  • Block vatted out
  • Replace freeze plugs
  • Mahle +.040" pistons with new rings
  • Repaint block
  • New cam bearings
  • New (std) main bearings
  • New (std) rod bearings
  • Oil pump reinforcing ring
  • Chase threads for accessories
  • Hone gasket surfaces

  • Mild port work on the exhaust ports
  • Clean up mounting surfaces
  • Heat vatted out
  • Replace freeze plugs
  • Install hardened valve seats
  • Reuse valves if possible
  • New manifold studs

Cam is still TBD. Would really prefer to stay running the dual SU's. May stick with a stock volvo grind and stock valve train.

Engine Rebuild - Teardown

I don't own a truck or an engine hoist.  To buy an engine and transmission in south Georgia, I needed both, so I rented them.  This meant I was "on the clock" the whole time, and had to get the engine and transmission picked up, separated, and mount the engine in the stand in one day.  It took some planning and luck, but it all worked out.

The seller said he was told " the engine was rebuilt" by the previous owner.  This seems to be the second most common line (right behind "driven by a little old lady on sundays") in the old-car-and-parts marketplace.  The actual running condition of the engine and transmission was unknown, so I just had to cross my fingers.

The engine is a B20F (8.7:1 compression) and was originally fuel injected, but has been converted to a downdraft Weber carb. This is my first time taking apart an engine, so I've got no real first-hand expereince to rely on, but for the most part things inside the engine look pretty good.   Well, at least they LOOKED pretty good, until I dropped the #3 piston while removing it.  A rookie error, and one that will likely cost more than I have invested in the entire engine and transmission to correct.

The cylinder bores will be checked out by the machine shop to see if they can simply be honed.  There is no real ridges or scoring, so I've got my fingers crossed.  All the bearings are standard size, don't show tons of wear, and the crank journals look decent as well.  Hoping to avoid anything more than a polish on the crank.

M41 dismounted
Pistons are +.040" Mahle
Pistons out
Damage from dropping #3 piston
Rod bearing wear (standard size)
Main bearing wear (standard size)
Piston skirts all look pretty good (except for the one I dropped)
Work area
Bin of parts to clean up
Block and crank ready to go to the machine shop to get checked out

Engine Rebuild - Purchase

Towards the end of 2010 I had pretty much gone through all the major safety and reliability systems on the car.  It's nice to have a 43 year old car that stops, goes, steers, and shifts like it should.  

Around this time I started thinking about longer term goals for the car, including rebuilding the engine and converting to a manual transmission.  The car currently has the original engine and automatic transmission, neither of which has had significant internal work since new.  They get the job done, but one or the other (or both)  will probably act up before too long.  

Converting from an automatic to a manual with sting some originality purists, but it's a modification in the name of future parts and service availability.  It'll probably keep the car on the road longer, while making for more driving enjoyment in the process.  

B18 and B20 engines seem to grow on trees in the Pacific Northwest. Down here in the south they are significantly tougher to come across.  When a B20 and M41 (4 speed with overdrive) showed up on Ebay a couple hours away for cheap, I snatched it up.  Plan is to rebuild both as time and money allows.  It'll be a slow process, but since the current equipment seems to work well at the moment that isn't really a concern.

Previous Work - Second Half of 2010

I'd been hoarding parts to re-do the rear end of the car for several months.  New brakes, new suspension bushings, new shocks, new seals and gaskets, etc.  Of course I picked the hottest part of the year to start the work.  Lots and lots of time spent wire-wheeling and sandblasting parts to clean them up for paint.  Having access to a sandblaster makes projects like this much more tolerable; it's so much faster and cleaner than wire wheels, and gives a better result to boot.

The Lockheed booster is still waiting to be reinstalled.  I've gotten used to driving the car without it, but I'll probably appreciate having it back in the car once it's done. 

  • August 2010
    • Rear springs sandblasted and painted
    • Rebushed and repainted rear suspension arms installed with new hardware
    • Rebushed and repainted panhard bar installed with new hardware
    • Rear brake backing plates and drums sandblasted and painted
    • Rear axle removed from car and repainted
    • New rear brake shoes installed
    • New rear brake cylinders installed with speed bleeders
    • New rear brake adjusters installed
    • New rear brake hardware installed
    • New rear axle felt seals installed
    • New rear axle inspection cover gasket 
    • New rear axle limiting straps installed 
    • New rear brake hardlines installed
  • November 2010
    • 1968 break-away steering box installe
    • Replaced steering box bushings, oil seals, gaskets
    • New IPD polyurethane steering bushings installed
    • Center link sandblasted and repainted
    • New tie rod ends installed 
    • New steering arms installed
    • Pitman arm sandblasted and repainted
    • Idler arm sandblasted and repainted
    • New idler arm bushing installed
    • Idler arm bracket sandblasted
    • Driveshaft support bearing replaced
    • Driveshaft support bearing carrier replaced
  • December 2010
    • Lockheed brake booster disassembled, inspected, painted, and rebuilt

New bushings and new paint on the breakaway steering joint

Rear brakes as-found

Mid-project with the new and refinished suspension parts hung

Start of brake reassembly

Rear brakes complete

Inside of the Lockheed Booster

New Lockheed diaphragm
Brake booster reassembled and ready to reinstall