Flywheel & Ring Gear Replacement
Thursday, July 25, 2013
The day started early with anticipation of completing the job in 8 hours. Replacing a flywheel and ring gear in Sue Stealey’s white 1975 MGB was a fairly straightforward procedure – remove engine with transmission, break apart the engine from the transmission, install new flywheel and reassemble. We would add a new starter also since the pinion gear was in poor shape. Our estimate was roughly 2 hours to pull, 3 hours sorting out the bits and 3 hours to refit. Even though Steve Skegg’s spacious garage has heat & air conditioned, we opted to open the garage door allowing the pleasant air outside in.
Bill Hedrick and Steve Skegg started on disconnecting the various components required in removing the engine while Kim Tonry, John Schroeder and Bob Simon gathered the necessary tools and hoist equipment required. Victor L’Heureux arrived a short time later after battling ‘rush hour’ traffic on the expressways. Steve’s 4-post lift really simplified the process of removing the components under the car. The engine/transmission was out in two hours – right on schedule. The ‘blind’ diagnosis was correct. The old ring gear was shot, very badly chewed up. What’s more the clutch plate had probably less than 5,000 miles left on it. So we would have been pulling the engine in the next few months anyway.
The unexpected always occurs with a job of this magnitude. While removing the various components, we noticed the water pump bracket was broken – and had been for some time since the broken edge was not shiny – and one engine mount bracket was cracked. We had difficulty in removing one nut from the exhaust headpipe. It finally broke loose—well, the stud broke before the nut released. No problem—just drill out the broken stud and remove. Still, it added time to the project that was unaccounted for.
The clutch slave cylinder fell apart in our hands and needed replacing. Bob found a local supply for these which saved the day. The throttle cable was badly frayed at the Carb. We were able to obtain a replacement from spare parts from a previous project. With the new flywheel/ring gear installed and new clutch plate in place the transmission was again mated to the engine. We were about an hour behind schedule at this point.
Reassembly was another story. The engine/transmission went in easily enough until we attempted to reconnect the transmission cross member – the bolts would not line up. Various attempts were made in resolving the problem – loosening adjacent bolts, jacking up the transmission tail, using pin punches to start the alignment, cleaning the bolt threads of grime – until finally one bolt started. The other three followed suit in short order. Nearly two hours were expended in this effort. Luckily we had the car up on the lift or this task would still be in progress. Kim had to leave early around 4:30 but the rest of the ‘A-Team’ saw it through.
Finally we finished connecting all the electrical connections and hose fittings, replaced the engine coolant and crankcase oil, and turned the ignition key. The engine started immediately. What a glorious sound! No more nasty grinding from the starter motor.