8CM Flathead help

So, I'm starting a trip down nostalgia lane with my Dad...I’m 51, he’s 74. We're going to build a flatty. It'll finish up at 286", 4 1/8 X 3 5/16. What we're starting with is a 8CM. Frozen, of course. The cylinders are soaking away, I'll push the pistons out next weekend. The crank is in great shape and resting in a cradle of it's own. The big question of the day is how does the idler gear between the cam and oil pump come out? Is it pressed, threaded?

Thanks for the help,
Pat

 

Pressed.

 

Best of luck with your build! Since you have an original MERC 4" crankshaft, you're going to be offset grinding it to the early 39-42 rod journal size for the extra 1/8" of stroke. Are you going to be running the early full-floater rods (like they did back in the day)? I hope so - would be nice to see somebody build a stroker like they used to build them . . . 91A/21A rods, full-floater bearings, etc..

If you need any information/help, let me know. Also, if you go the full-floater route, you'll be looking for STD bearings (81A - 221 Flathead size) - as once you offset grind the crank, you'll be back to STD for the early rods. The early full-floater bearings are expensive, but they work really well if you correctly setup the engine.

 

The idler gear rides on a shaft that is pressed in the block. There is a threaded hole in it that you can insert a bolt (3/8 as I remember) and use a slide hammer to pull it out.

 

Let me know if you are looking for std brngs.
I know where some NORS std parts are. Not sure what bearings but can find out or put you in touch.

 

The easiest way to remove the idler gear is to thread a piece of all thread in the shaft and a steel bar with a hole drilled in it to lay across the back of the block. Run a nut down on the bar and tighten. This will pull the shaft and gear out smooth and easy. I just did it last night after scratching my head for a bit. P.S. space the bar out from the block to allow room for shaft to be fully removed.
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i use a puller for a power steering pulley and a couple blocks of wood. seen guys use a drift and hammer from inside,also.

 

A 3 3/8" X 4" is an easier way to get to 286". You have to replace the pistons either way but you can avoid the problems of replacing the rods, fitting full floating bearings and doing an expensive rework of the crank.

 

I agree with dale. That is how I did mine, and contrary to what a lot of people think-no overheating.

 

Here's how the 49-51 Mercury Manual shows it's removal. You could do the same with a big socket, a long bolt and a washer.