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Tech Session - Engine Rebuild by Barry Rosenberg

The subject engine had been previously prepped and made ready for assembly, as I knew time would not allow an entire rebuild in one session.

The engine had been bored .030” over and the rings fitted to the bores and pistons. However, the set of rings that came with the .030” pistons must have been for a set of .020” pistons because the ring gap was over .037” -- Correct gap is .012” to .017”. New rings had been ordered and installed although one was left off the piston to explain how to gap a ring. Cam bearings had also been installed as they are the first thing to go into an engine and their installation is very critical. If you get them in wrong, the rocker arm on the MGB engine will not get oil. I have seen this before.

I first installed the crank using petroleum jelly as my lubricant, explaining that it will stay on the bearings as long as the owner wants to let the engine sit. Then, a normally simple job, to install the crank thrust washers. I start off with standard size and measure end play. Knowing the end play I want is .004” to .006”, an easy calculation tells me how much oversize I need to go on thrust washers. Unfortunately, I could not get the standard set in.  45 minutes was wasted sanding new thrust washers to fit the engine and allow the crank to rotate freely. 

Next was piston fitment and a showing of different ring compressors. Again, petroleum jelly lubricated my bearings and the entire piston sides. Next came the camshaft, stock for an early MG engine with mechanical tach drive, but put into this later engine. Then the cam timing was set with the gears, timing chain and tensioner.

A new water pump was to be installed; but, first, I wanted everyone to see that the new water pumps are not like to original ones. The flange for the pump pulley to bolt to is in the wrong location in comparison to the old pump. Craig showed and fixed the pump to match the original unit. So far in this rebuild we had wrong rings with right pistons; incorrectly made thrust washers and a poorly assembled water pump.

One of the things I talked about is that I do not install my oil pump until the head is on and valves adjusted the first time. So, we installed the already assembled head. Two valves were left out for demonstration and pointing out the incorrectly installed hardened seats (set too deeply in the head). Then the lifters were coated with the proper cam lube and petroleum jelly then installed in the bores. They had been previously test fitted. The head was torqued and the valves adjusted.

Then, I talked about the modification I make to the oil pumps for better pressure, packed it with my jelly and installed it. We did not get the pan on that Saturday due to time management on my part. There had been too much talking and answering questions and not enough work being done. But it was supposed to be a teaching process and that requires me to answer all questions.

Sometimes during the day, Tom Nadelhoffer and Larry Norton became cooks and servers and made lunch of burgers, dogs, buns, beans and chips. Thank you for your help. Tom Bosko did a video of the session and after the second time doing so; I am still not comfortable working in front of the camera. I have no fear of the camera, but I fail to remember it is there and that it can show great detail when I am pointing out something small but important, such as the dot indicating the top side of the rings. Maybe by the time I do another tech session next year I will get better.

Ron Human, whose engine it was, came by Monday to finish the assembly and paint it. That went without any problems. The engine was painted a Damask red as original and left overnight to dry. And I must say, it looked great; pictures included I hope. You may not be ready to build your own engine but at least now, you know somewhat of what it takes to do. You can understand how long it takes to do it right. And there is never any reason not to do it right.

We pull the engine, take it apart, measure everything necessary, clean the parts not going to the machine shop, order the parts, take all items to the machine shop and make a return trip to get them when done, assemble the parts with the new pieces, assemble the engine, paint it pretty with a hardened acrylic enamel, install it, get it running, and then tune it. And, we only bill for 35 hours on a four cylinder engine. Sixes are slightly more. Those of you that came Saturday, know what I am talking about.


The monthly ORF today was another chilly one -- 18 degrees near Suches, where we stopped to join with Tim Gaffney and take a break -- but, the sun shone brightly and the view of the snow covered mountain tops was exquisite!  Unfortunately, at 60 MPH while running the mountain "twisties", it's difficult to manage a cell phone camera to capture the moment -- so nobody did.  We had 11 cars running the excellent route -- thanks again to Tom Nadelhoffer.  Additional ORFs were: Larry Norton, Mike Cook, Jim Doran, Jay Franklin, Jeff Adams, Manny Gil, Jim Unger, Wally Carlisle, and Steve Ratcliffe Our morning target was the Cajun Depot Grill in Ellijay, GA, where Paul Van de Walker joined us for lunch.. The Cajun Depot Grill is inexpensive and the food is good. It's definitely a "do again" place. With the temperature all the way up to about 38 degrees and the wind at 10 knots, we headed home at about 2PM through Dawsonville. Fun trip, good time!