I was given this power unit and it has been just waiting to be used. I need an engine to put in my 29 Model a project and this fits the bill. I took it apart to see what it looked like and I was pleasantly surprised. It appears to be a 1941 Mercury block according to vanpelts website. It has the raised deck and has round center water jacket holes. There is no numbers cast into the bellhousing other than x8. The block is factory relieved and has a bore of 3.188. There is a slight ridge. The pistons are domed and steel. There are valve seats installed. The water pump on the left has a double pulley. The generator has a 36 style cut out and has a 6 blade fan. The carb is a 94 91-99. Is it possible that I have a standard bore 41 Mercury engine? Why is it relieved and have hardened seats?
Hardened seats were standard for most flathead years. Looks like a typical '41-2, used in trucks and Mercs, also built through the war. Manifold is maybe '37-8, carb would match age of engine, oil filler cap is '32-4! If engine was originally in that machine rig, Ford industrial engines were truck versions with no real differences from Merc. When Ford started reliving some engines (certainly by wartime period), why, and which engines got the relief are all entirely unclear. Your left pump is truck, right p***enger... Some wartime engines (not this one) had a cast boss for third oil port, used for full flow coolers and filters on various military applications. I have one like yours, except with that boss, undrilled like most. The boss stayed there from WWII onward...
Thanks Bruce, is there a way to determine if it is a Ford or Mercury? Any reason I can't clean it up and run it this way? Thanks!
no way to tell really, but being relieved, more likely to be a truck block.some 99 blocks had a "99" cast in front of the right head, and some have it cast into the top of the centre exhaust runner inside the top water jacket hole. its actually irrelevant in terms of rebuilding it. Bore wear looks OK, take the pan off ,clean out the sludge,and check a main bearing, if it looks intact and not too much **** running thru the oil..change the oil and start er up! it might smoke..it may not. worth a try!
Cool, I was going to pull the pan next. Someone put 59ab heads on it. It had two different head gaskets. Some of the studs are too long and had extra washers on them. Should I replace the x-tra long studs or just put in bolts? Does it really matter? What about rust in the block. Should I be concerned with it? I was going to pressure wash the block. I could acid wash the water jacket.
Anything you can do to clean the water jackets will help cooling - a lot. Pressure wash, acid dip, poking with long, sharp objects, rolling it around on plywood, etc. Knock as much **** out of the water jackets as you can.
My guess would be 1941 or 42. The raised intake surface and factory releved lean towards truck or industrial. Bore should be 3 1/16". Check for cracks while the heads are off.
I believe if it's a 99T block the bore should be 3-3/16" and it would be a Merc or truck block and not a Ford with 3-1/16" bore. Jim
Wouldn't the steel pistons indicate an industrial engine? It is quite possible the second belt shive on the "driver's" side water pump could have very possibly been to drive a governor. Ted
Looks to me like it was run on propane/butane -- if that's aregulator in first pix it would be part of such a rig. If so the valve seats being hardened would be part of the "industrial" setup since there was no lead in butane. Good news is that if it was a butane engine the bores & bearings should be in good shape -- steady rpm's and clean fuel means this things can run foever.
Thanks for all the info. I am going to switch to a crab style distributor, clean it up good and put it in. Does anyone know why Ford used steel pistons?
They used both steel and aluminum, steel on replaceable steel sleeve engines only. See Yunick on steel pistons! They are a development of the high tech composites that Ford used on the last Model T's. Ford vs Merc block...all 239 blocks were the same, just heads and accessories differed between trucks and Mercs. 221 Ford blocks were often hotrod bored to 239's...can still be distinguished by center water holes, AND by the MUCH thicker Merc outer diameter on cylinder castings. Look into your Merc at that center t****zoidal holes and see how thick these things are!
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