Spreader of what ?

[rustyric]

This tool is obviously designed to spread/stretch something open but what ? Its unbranded.

[Lostmind]

valve spring compressor is my guess , for small engine L heads. Lawn mowers , tractors

[oldgoaly]

spring compressor for a flat head or side valve engine

[turnnut]

 if you back off the wing nut, does it close together ?

  maybe a valve lifter so you can remove the keepers ??

[pritch]

It certainly looks like a spring compressor of some kind, but if automotive could you do so with a wingnut?

[Bill Houghton]

It certainly looks like a spring compressor of some kind, but if automotive could you do so with a wingnut?

Oh, sure.  Valve springs are not as strong as their gauge suggests.  This is what the compressors I've seen look like:

This is the first one I've ever seen that's not formed sheet metal - that's one chunky item!

[rustyric]

Side Valve - eh I used to own a BSA M21 motorbike with one of those, when it used to kick back when you started it almost broke your leg !!

[EVILDR235]

I also say it's a valve spring compressor for a flathead / side valve engine. I have one out in the garage and the last time I used it was on a 264 CI Chrysler straight 6 engine in a Wagnermobile scooploader that was converted into a forklift. I had to convert a Chrysler passenger car engine to use in the forklift at work. Decided to lap the valves in while I had the head off. That type of spring compressor will not work on a Ford or Mercury flathead V8 engine. I enjoy working on old engines and dislike working om modern engines.

EvilDr235

[Bill Houghton]

Side Valve - eh I used to own a BSA M21 motorbike with one of those, when it used to kick back when you started it almost broke your leg !!

That's interesting, because side valve motors are inherently mid-to-low-compression motors.  I hadn't realized BSA made side valve motors so late - until 1963!

[Papaw]

Probably wasn't the compression, more likely timing was off.

[Bill Houghton]

My son was over tonight, and suggests this may have been a spreader for a side-valve Cadillac V8, which required a rather specialized shape.

[rustyric]

Still in production (BSA M21) no wonder the british motorcycle industry failed.

[Bill Houghton]

Still in production (BSA M21) no wonder the british motorcycle industry failed.

Harley produced the side-valve/flathead 45 engine from 1929 to 1973 (21 raging horsepower from roughly 750 cc's) - yet Harley's still in business.  That BSA motor's kind of intriguing, but I wouldn't go out of my way to own one.