Clutch Removal On A 2.5 OHV

Greetings All,

I’m an SS1 owner. Before I found a correct Flathead I purchased a 3.5 and then a 2.5 OHV engine just in case I never found one. Well, I found a Standard 20 HP engine but the front and rear engine mounting plates are not correct since the engine was originally in a Standard, not an SS.

The 2.5 has the correct spacing for the starter, but not the same mounts. My plan is to remove the rear plate from the 2.5 and fill in the rest with Autocad when doing the template.

Enclosed is a picture of the rear of my 2.5 OHV. I have nothing on this era engine for a manual.

Is clutch removal pretty straightforward? Any hints?

Otherwise, I’m just disassembling anything that looks like its in my way.

Not my first rodeo, but thought some of you might have some tips to make it easier?

Sorry about the focus?

No different to any other clutch, does the Standard engine have a crank? the 2 1/2 flywheel should fit. If the Standard engine has a front mount plate fitted it should fit the SS1, post a photo.

Just loosen the cover plate bolts in sequence.

In an X pattern, times 6…

Straightforward Borg & Beck clutch.

Four bolts on the flywheel with locking tabs.

TDC alignment arrow on the flywheel, lines up with a mark on the bell housing.

Balance marks 0 0 on pressure plate.

and flywheel; they were balanced together at the Standard factory, note extra holes drilled and then an extra piece welded on for weight. Suggests this is probably the original pressure plate.

Not sure what the L5 and these other marks mean, but the engine number is L205.

Balance check on the pressure plate, it’s good!

It was originally blue and I happened to have this spray can of blue…
I noticed the six BSF bolts were very short. I’d be curious to hear what you find on the length of your bolts, measured under the hex head.

So long as there is at least 1.5 X dia of thread then its fine.

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Greetings Rob,

My bolts appeared to be a little over an inch measured under the head.
Broke one, missing one.
I’ll post a pic tomorrow. The pressure plate had some blue paint remnants, will wipe down to see if it presents better.

Greetings All,

Clutch and pressure plate came off fine…see picture of bolt length.

The flywheel bolts removed with little issue.

The flywheel, another story. Anything special I should know. I am guessing the flywheel is being held by corrosion. Liberal amounts of PB Blaster applied will attempt tomorrow, may grap a puller as the oak block I usually use did nothing.

Thanks for the help so far!

Penetrating oil, patience, pounding with a rubber mallet. Looks like flywheel had four bolts, are there any alignment pins lining up crankshaft and flywheel that could be corroded slightly? Any chance bush in end of crankshaft for gearbox primary shaft is holding it together?

Greetings All and Roger,

No, looks most likely like corrosion. Everything else looks good.

I’ll break out the aluminum drifts and get the puller readied.

Do the reverse sledge trick: take a hardwood stump, or BF brass drift, and pound inwards with a BFH at the flywheel flange face.

We’re two strip tab washers fitted with the flywheel bolts ? Check for two dowels retained by them.

Just lever it off against the back plate. If you have oxyacetylene then heat it.


Thanks for the confirmation on bolt length. Mine were 5/16-BSF x 1/2" long, and I could not tell if they were original or replacements. They had blue paint on them.
What with subtracting the thickness of the pressure plate flange and lock washer, I felt there was not enough thread engagement in the flywheel, so I substituted 3/4" length bolts, all matching heads so there should be no adverse affect on balance.

Greetings All/PeterJB

Yes, they were present and dowel pins in place.

Plan on a little heat tomorrow as it has been liberally soaked with PB Blaster multiple times.

Tomorrow is another day.

Just to be redundant in communication, there may be alignment dowel pins for the clutch assembly to the flywheel and also alignment dowel pins for flywheel to crankshaft. There may be two alignment dowel pins for flywheel to crankshaft. Working a flywheel up those pins to freedom from the crankshaft can take a while. Good luck and patience to you.