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See Homepage. This page: Re-grind a car engine's crankshaft big-end/crankpin journals, without removing the engine or crank.

The Winona "InTheBlok" in-situ crank journal grinder.

Idly flicking through a garage supplies catalogue from 1948, turned up the following handy piece of portable garage equipment. The Winona "InTheBlok" crankshaft grinding machine was designed to save both time and money when it came to fixing up a worn old engine, one that had knocking big-end crankshaft bearings. Given that in the late 1940s, many weary old crocks were being dragged out of long-term storage following the war, and kept running when long past their sell-by date, any gadget such as this that could offer a cost-effective route to wringing out more life from a tired engine, was likely to find a receptive audience.
Typically, knocking big-end bearings left the unfortunate car's owner with a short list of options. Scrap the car and buy a replacement. Remove the engine and fix it yourself. Find a replacement engine. Or entrust the car to a local garage or engineering shop, and task them with removing the engine, dismantling it, and then performing the necessary machining work before re-installing the overhauled unit. Choosing any of these options was likely to lead to inconvenience while the car was out of action, and likely a hefty bill at the end of it all. This is where the portable Winona "InTheBlok", made in the USA, came into service. For with this tool, it was now possible to re-grind the crankshaft main bearing(s) in-situ from below the car, without the need to remove the engine from the car and dismantle it. The illustration featured below shows how this was possible, once the oil had been drained and the sump removed.
Winona InTheBlok crankshaft main bearing grinder
The "InTheBlok" is described as follows in the catalogue ...
"The InTheBlok Crankshaft Grinder is a fast Precision tool, and can give results comparable to those obtained from large bed-type machines costing hundreds of pounds."
"It is simple in design and operation. The Adjustable Hook Head, together with a Sliding Stabilizer, enables crank pins to be reground, all to size and in-line with the mains without removing crankshaft from engine, as illustrated."
"For grinding in-situ the InTheBlok can be used with electricity-driven rear wheel drive unit, the crankshaft being rotated through the transmission."
"Lathe attachment enables both main journals and crankpins to be reground as shown on the illustration on right [not shown here], depicting the grinder and attachment in operation on a lathe."
As it states above, the engine would be turned over during the regrind process by one of the car's rear wheels, which would be sat upon a purpose-built motor roller that operated the crankshaft at approximately 12 rpm, depending on the rear axle ratio of the car. This is shown below.
Motor driven rear wheels
The list price for an InTheBlok grinder was 130 GBP, plus another 47 for the motor roller. The attachment which enabled the InTheBlok to be used on a traditional lathe, to enable work to be undertaken on both main and big-end bearings, would cost the garage owner a further 14 GBP.
The catalogue in which the InTheBlok is featured dates to over 70 years ago, yet this nifty gadget is still available on sale today. A Youtube video, details below, shows the key components of a surviving early example. Interestingly, this example includes an attachment that would take the place of the starter motor, engaging with the flywheel ring gear to spin the engine over.
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