The crankshaft came back at .010" under for both rods and mains. All bearing clearances had to be checked again and the main caps were shimmed to achieve .002" clearance. The new Sealed Power chrome rings were all identical and I checked ring end gap for ALL cylinders this time for both the top and 2nd rings. The short block went back together without incident.
Before we left for Florida, I spotted an ad on Craigslist for old Chevy 216 and 235 parts. I emailed the seller and learned he had a 235 head but didn't know the casting number as it was covered in snow. He thought he already had a buyer for the head and some other parts but promised to stay in touch if that deal fell through. When we got back from Florida, I contacted the seller again and learned that his original buyer had not come through and he would get me the casting number asap. He was located about an hour and a half north of me and his area hadn't received the massive amount of snow we had during the Groundhog Day blizzard (Feb 2). Of all the cylinder head castings used on the 216 - 235 -261 eingines, I kept reading that the most desireable head was the one with a casting number that ended with 848. The 848 head has a smaller combustion chamber which allows a compression ratio of about 8.5:1 instead of the 7:1 with other heads. I figured it was worth searching a bit for an 848 before being forced to run that 53 head again. Luckily, the wait was worth it. Turns out the seller was a 15 year old computer savy kid teaming up with his not-so-computer-savy dad to sell off an accumulation of old parts. Josh (the 15 year old) got back to me around Feb 16th with the casting number off the head. Pay dirt!! Buy a lotto ticket!! It was an 848 head. Seems his dad had rebuilt the 235 engine this head had been on many years ago but used a different head that had been already prepped. This one was off a 1961 Chevy. I drove to Ludington on Sat, Feb 18th and met Josh and his dad in a Meijer gas station. Both were a couple of gearheads. Josh has his own car that he races in demolition events and would rather tinker with that car than play sports. Kind of amazing cuz he's built like a line backer - and only 15! Nice folks.
The 848 head was REALLY grimy and rusty so it was disassembled and sent out for better cleaning than More Power's equipment could do. It came back on Thursday looking much better. The best news was not finding any cracks during magnafluxing! We were heading down the right road this time.
New exhaust seats were installed and #1 cylinder was prepped for a pre-assembly valve to piston clearance check. The .080" clearance on the intake valve was nearly identical to the original 54 head so the 848 would be machined the same way. We had followed the recommedations of Clifford Engineering to prep the 54 head. .100" was removed from the head surface and the intake valves were sunk a compensating .100". The intake stems were cut down .100". That was Clifford's standard method for a 235. However, we had discovered some other things to do to maximize the valve lift and restore proper valve train geometry. We added .100" shims, cut from steel stock, under the rocker arm stands and added .080" lash caps that had been shortened to the exhaust valves. These two items allowed for use of the stock length pushrods and gave us the maximum valve lift. This way we were able to make full use of the Comp Cams camshaft. I'll add pictures of the head once the 848 is ready for installation.
I had originally planned to hold off on any parts removal from the 41 until I was sure the engine project was completed. However, once the engine was originally run on the dyno, I needed to pull some parts so I went ahead with removing the rear end and getting the 57 rear end ready for installation. That's the next chapter that needs updating.
No comments:
Post a Comment