Before I strip it apart, what other things might I have to replace? I presume the head gasket at least?
Can I get the piston out by moving the cylinder as would probably be easier than taking the crank case apart? (Think that's what T was suggesting) If I can i would need the base gasket?
Are the gaskets special? Can I use stock cardboard gasket material?
There are a few pistons and rings up for sale here so might be OK finding one.
Can't find the UK Victa parts seller I've recommended before via Google - will have to run a search on my old ODK posts.
The head gasket is made from a special material; the later PowerTorque 160cc head gasket will fit, IIRC.
The base gasket is nothing special; gasket paper, or even cereal packet cardboard, will work just fine.
Originally Posted by Tyler
Poppet could be complicated by how they used different styles (black or white) which apparently aren't compatible
Tyler, the 'poppet valve' we refer to here, is the one in the deco valve, not the one used in the G4/LM carby.
Originally Posted by NormK
Tyler, you obviously need a good rattle gun, makes it so easy
Yep, these nuts often only respond to impact. Which can also be applied by using a long ring spanner and a 2lb hammer, as we had to do in the old days...
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
Hi Tyler, when I said rattle I meant air impact mine is a 1050nm and it has never let me down on a crank nut or bolt. My old 320nm just wouldn't cut the mustard on the Victa nuts. Only downside is with the big one is you can destroy sockets easily
I have only ever used anything up to 340 ish, so that makes sense. My regular one doesn't normally have significant issues, but sometimes just won't touch it
Thanks, that helps a lot. Think I can get hold of a new piston and rings fairly easy but the gasket was illuding me so good to know I can use a powertorque one.
Took the piston off as picture and gave it a bit of a clean but presume that this is too far gone?
Bit confused what the shim is and why it's there, was underneath one of the rings. Is this normal?
Problem seems to have been at least partially caused by coking round the exhaust port.
Now looking at honing tools, and excuse to buy new tools. What kind of grit do you use and presume it just needs a light going over to avoid oversizing it.
Also, what size are the engine nuts? Might as well take the engine off the body, will be easier and can give it a good clean.
Made some progress today, cleaned up head and cylinder ready to reassemble.
An impact gun would have been nice but working with limited set of tools although this has now expanded to some long angled needle nose pliers!
Thanks, that helps a lot. Think I can get hold of a new piston and rings fairly easy but the gasket was illuding me so good to know I can use a powertorque one.
Took the piston off as picture and gave it a bit of a clean but presume that this is too far gone?
Yup, that one's 'had the Richard'. The Powertorque piston kits fit the earlier full-crank motors like yours, but not vice versa.
Quote
Bit confused what the shim is and why it's there, was underneath one of the rings. Is this normal?
Yes; it's an 'expander ring'; which is no longer used, due to improvements in piston ring technology since the 1970s.
Quote
Problem seems to have been at least partially caused by coking round the exhaust port.
Now looking at honing tools, and excuse to buy new tools. What kind of grit do you use and presume it just needs a light going over to avoid oversizing it.
If you can find a local motorcycle workshop, chances are they'll have [or can refer you to someone who does] a suitable cylinder hone for this job. Good hones aren't cheap!
Quote
Also, what size are the engine nuts? Might as well take the engine off the body, will be easier and can give it a good clean.
These nuts are [as are all on that mower] Imperial AF/SAE system fractional inch sizes.
Quote
Made some progress today, cleaned up head and cylinder ready to reassemble.
An impact gun would have been nice but working with limited set of tools although this has now expanded to some long angled needle nose pliers!
For sure; but none of this advanced technology was available, back in the early days of Victa mowers.
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
Hi Gadge, A few years ago I was rebuilding a 1948 350 Enfield motor and somebody had fitted a Toyota piston to it, was all good till they tried to rotate the crank and the piston skirt came down and hit the crank. Believe it or not, instead of removing the piston to shorten it they cut the skirts back on each side with a hacksaw insitu. How did I know they used a hacksaw, the cuts were how it ended up cutting and I could see the teeth marks and I would say it was an 18 tpi blade. The motor was running because we went on several club rides before it gave up the ghost. Moral of the story is sometimes you can get away with murder regarding pistons
As far as the crankshaft bearing condition is concerned, the critical bearing is the 'big end' rollers in the connecting rod. The crankshaft main bearings are standard radial ball types, and quite easily replaced. Not so with the big end.
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
Moral of the story is sometimes you can get away with murder regarding pistons
That's for sure! A well known expedient during WW2, when replacement motorbike/stationary engine pistons just weren't available, was to make a new piston out of hardwood - apparently red gum was the best timber...
Here's a vid of a Briggs running - with an Oak piston crown installed!
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
Hone tools seem to be cheap compared to paying for it to be done by someone else. Plus, would much rather learn a new skill and have the satisfaction of doing it myself. What kind of hone tool do you have NK? A ball hone or a 3 pronged one? Do you do it wet or dry? What grit?
Morning Shedrummager, I'd use that piston, as compression comes from the rings and bore.I collected rings from old PTs and other Victas and swap them , long as they are not worn so thin..... cheers speedy.
........................Keep your blades sharp......................
Hi SR, I use a 3 leg hone with 100mm long stones because you have to travel over the transfer ports and 100mm does it easily. Grit not sure, either 220 or 180, whatever was the cheapest on ebay at the time. I use oil on the stones and give it a good clean especially in the transfer ports one I have finished honing it.
Morning Shedrummager, I'd use that piston, as compression comes from the rings and bore.I collected rings from old PTs and other Victas and swap them , long as they are not worn so thin..... cheers speedy.
Thanks speedy, gives me hope that the block is not completely unsalvageable!
Originally Posted by NormK
Hi SR, I use a 3 leg hone with 100mm long stones because you have to travel over the transfer ports and 100mm does it easily. Grit not sure, either 220 or 180, whatever was the cheapest on ebay at the time. I use oil on the stones and give it a good clean especially in the transfer ports one I have finished honing it.
Thanks NK, good to reaffirm what I've been looking at. Think the longer stones required to stop the snagging on the ports.
Have taken the crankcase off the body to give it a proper clean. Rust on the cranks looks worse than previously observed. Will concentrate on getting that to a reasonable state before getting into honing/replacement parts.
Thanks to all who have replied to my constant questions, it's been a great help! I am quietly optimistic that this will turn into a fair runner but will take some time.
Sorry for not posting.. She's getting better (I hope). Decided the right thing to do was strip the bottom end and see how bad the rust on the cranks was. It was not good but buffed them with a wire wheel to get the loose stuff off, washed throughly now partially reassembled.
Got a honing tool and gave that a go, got the glaze off, not perfected the cross hatching but I think it'll be good.
Bearings were good, seals too. Reassembled with 2 stroke oil and crank seems smooth.
Gave blower housing a bit of wire wheel treatment and just painted it with rust converter for now.
Made new base gasket and now waiting for delivery of piston, rings and head gasket for final assembly, depending on the postman, maybe this weekend it'll be back together..
Picture of crank is before rust removal, looks bad but it's mostly surface rust.
You've been a busy bee. Progress looks very encouraging. Wish I had table space like that. I can make some if I an determined enough. That looks on track to becoming operational real soon.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!