Crank repair

[paulbaker1954]

Just after a bit of advice. I volunteer at the RSPCA and we have an old ride on mower with a vertical crank engine that managed to seize solid the crank in the upper housing due to oil pump failure.

The crank runs just in an alloy journal and I suspect that it has just welded itself to the casing.

It is currently in my local machine shop but they are not optimistic as they think that if try to press it out it will just smash up the alloy block.

Sadly this is an old Tecumseh engine and can not get parts.

Just wondering if the whole project is doomed or is there any hope for repair.

Of course cost is a factor here and it may just not be economic in the end

[Moorey]

Which engine is it. A bit more info needed.

[Orcade-Ian]

If Springfield Mowers are still in business in Hill St Southport, they might be able to help - Pete and Mike never throw anything away so might have secondhand parts and both into Bikes too!

Ian

[paulbaker1954]

Which engine is it. A bit more info needed.

Tecumseh Centura 65 engine

[martyn916]

Springfield Mowers are still there, phone no. is 01704 537580, address is 15A Hill St, Southport PR9 0NW

Don't if this is the one but there is this on ebay

https://www.ebay.co.uk/itm/324384110655?hash=item4b86ccb83f:g:0uQAAOSwVztfrvuQ

Good luck

Martyn

[Moorey]

They are listing both half's crank and piston.

[matthewmosse]

I'd just drop the old engine and drop another in. Not even necessarily even the same make or model engine. Same hp or similar. I recently swapped the engine on my mini digger from a Honda 5hp to a teschumench 10hp, basically because I found a tesumench 10hp engine on Ebay for £75 that was new old stock, more power seemed a smart move. Most of these stationary engines are fairly generic and a bit of fettlling to swap engines  can be way cheaper than doing engine work properly. Next up is dropping a diesel onto my grass mower in place of a worn old Kohler. Tesumench seems cheap engine and parts still seem to be around on Ebay, even if theres a wait for them to come from USA.

[paulbaker1954]

I'd just drop the old engine and drop another in. Not even necessarily even the same make or model engine. Same hp or similar. I recently swapped the engine on my mini digger from a Honda 5hp to a teschumench 10hp, basically because I found a tesumench 10hp engine on Ebay for £75 that was new old stock, more power seemed a smart move. Most of these stationary engines are fairly generic and a bit of fettlling to swap engines  can be way cheaper than doing engine work properly. Next up is dropping a diesel onto my grass mower in place of a worn old Kohler. Tesumench seems cheap engine and parts still seem to be around on Ebay, even if theres a wait for them to come from USA.

Sadly not so simple, this is a ride on mower and there is a fairly complex clutch etc that engages the blade. All this sits on the end of the crank so crank diameter, length key way etc are critical and unlikely to be right.

Just hoping a unit will pop up on eBay at some point.

[paulbaker1954]

Ok now I know one of you clever people will help me with my next issue....

I have managed to source a crank (not the right one for this engine) that has the same gear pressed on.

My local shop will be able to press off the gear so I can use it to replace my broken one.

But now I have a conundrum.....

The cam timing on these engines is done by aligning a dimple on crank gear with a dimple on the camshaft gear.  The video here will be a big help explaining

https://youtu.be/aNGT5X6315Q

The problem is because the crank gear is not keyed on just a press fit I have no way of determine where the dimple should go.

So I will have to figure out a way to do the cam timing some other way.

My thought is to install the cam with the lobes furthest away from the valve lifters with the engine at TDC on the compression stroke with the magneto magnets lined up so I know this is the firing positions.

Any thoughts on my approach?

[Bryanj]

Check it visualy, i suspect the dimple lines up with the crank pin I.E TDC

[matthewmosse]

I have made up adapters for a few now, to fit 'wrong' engine outputs to whatever is required, seems most of the cheap engines I tend to pick up are taperd shaft outputs and too short, and what's been needed is parallel shaft with  keyway. It's a bit fiddly cutting the keyways by hand and matching the taper I turn to the taper on the engine but does mean I can use a cheap engine. The digger I re engined needed both hydraulic pump and engine output converting from taper to 1" parallel shaft, keyways inside and out to suit the coupling I had lying around. I reacon it was cheaper and easier than rebuilding an engine.
Sounds like you've got most of the way there with rebuild though. I geuss careful measurement before removing the donor gear and index marking all parts should help alignment on the correct shaft. Seems odd to rely on a push fit for timing, I'd have expected to find some kind of keyway or drill and peg.....