How do YOU heat your Engine parts?

[nice2day]

It won't be long before I split the ETZ cases (Not literally I hope ). In the past I have been cheeky enough to get away with putting the engine in the oven and heating to about 180 C. I don't think I'll get away with it this time, as well as not liking my food to taste of burning engine oil

You might have seen the Youtube MZ man heating up his engine with 2x blow torches not to mention the fact that he heats up just one area not even spreading the heat. Well I could try that but I was considering submersing my entire engine under boiling water in a BURCO boiler that I have in the shed.

Then again the factory uses a nice electric hot plate so yesterday I bought one of those for about 14 quid.

Another thing is heating the inner main bearing races...The same bloke, as mentioned before, uses a MAP gas torch well I certainly wouldn't do that as its so easy to blue part of the bearing and temper the steel...who wants a brand new bearings fitted with softened balls?

The factory uses a nice metal plug heated on their stove, but I haven't got a lathe to turn one down so I was thinking of heating up engine oil on the new stove in a small tin to about 200 C and submersing the bearing whilst the temperature can be monitored by IR (laser) thermometer. This will ensure safety as far of not overheating the bearing. One snag is that the outer race surface will need to have the oil removed with a rag before fitting to ensure metal to metal contact with its alloy housing. Trapping any oil is very likely to lead to a bearing spinning in the case at some future time.

Anyway these are a few ideas I've had before I start but I wonder how others go about it.
Then again, are there many variations ...Probably not...

Les

[AlanJ]

Hi Les,
I usually heat my parts as you said, in the oven, but to about 120 deg and the bearings go in the freezer for at least a half-hour, they still need a gentle tap in though. One of the most awkward parts I have found with new bearings is the final drive back wheel assy, there are 2 bearings together into the chain sprocket housing and with the small spindle in the middle of them, I didn't find that an easy one. Anyway Les wish you well. Alan.

[AlanJ]

Hi Les,
Just had a thought for heating the center of the bearing, what about sockets, old ones, I have never used that way, but it might work ok Alan

[DAVID THOMPSON]

i got lucky the stepson found a very clean electric stove /oven
and we installed it in the work shop and its plugged in where the welder is

but so far its only been used to redo an r51/3 rear end back in 1986

most often we cook food in it when its way too hot to heat up the House
in the hot summer
dave

[nice2day]

Thanks for your reply and suggestion Alan. The socket idea seems a good one and will try this.

The reason why I suggest a temperature of around 180 C (I've even used 200 C) is that from many previous engine /gearbox restorations on other old bikes is that the suggested 100 c figure is just not hot enough whereas the 200 c figure gives you much more time and provides a more relaxed time frame to do a very precise operation and 9 times out of 10 you won't need to tap the bearing in at all. There is hardly anything worse than having a bearing only go half way go in which can occur where the interference fit is a bit too tight and rapidly heats and expands the bearing and tightens the fit up, leaving you with the option of bashing it home (never do this) or knocking it back out again. With the higher temps and using a mandrel to hold the bearing precisely you can nearly always get the bearing to pop straight in and hit the "end-stop" with a satisfying clink. The mandrel by the way I find is essential to avoid skewing the bearing as once a slightest tilt occurs on the bearing it will lock up. Never again will I attempt to insert the bearing with the fingers as this will nearly always result in a skewed bearing. The mandrel can easily be made from a short piece of broom handle or suchlike with the end made to loosely fit the inner race. This enables you to move the bearing into its housing near perfectly square and also avoids the need for gloves to avoid burning your fingers. How many of us have had to search for the bearing on the workshop floor after flinging it automatically as we burn our fingers on the hot cases.
By the way, leave the bearing to heat up before attempting to remove the tool as you don't want to dislodge the bearing.

Hi Dave, it must be nice to have a kitted out workshop...if it wasn't for all the old junk I keep I could get into my one

Les

[Puffs]

Removed

[Blurredman]

I've never actually heated my engine parts up before engine assembly...

[DAVID THOMPSON]

the shop is nice if i could throw out the junk
but if you throw any thing away.. it will be what you need to fix whats broke next

[nice2day]

I agree David...it's hard to throw anything away as everything looks to have a future use at some time, but the truth is your life will run out before you ever need it. I watch lots of those American Classic car programmes and the amount of times you see projects that have been started only to be left unfinished as the poor owner has sadly passed away. I can see that happening to me so it's a wake up to reality check that life is far too short.

Anyway, I received the electric stove and I'm quite impressed as it heats up fast and the thermostat can be made to operate as low as about 150 C so seems ideal for my needs. Will report on it's usage and hope to come back with a firm recommendation as £14 is a tiny price considering the vast amount we must spend on our hobby.

By the way my post above where I recommended making up and using a "mandrill" to fit your bearings was quickly edited this morning when I found out that a mandrill was in fact a large monkey*
I know some monkeys are quite intelligent but the thought of bringing one home and asking it to fit my main bearings was a vision that had me laughing out loud...
*

Correct spelling is indeed MANDREL.....I bet you ALL knew that but didn't want to let on......


Les

[Puffs]

Well, a few months ago I found myself using a piece of rope (thick 1" or so, 20m) I've kept for more than 30 years... So yes, maybe you won't ever use it - but maybe you will!
Says the man with too much stuff to the man who bought more stuff - is the oven big enough to heat the mandrill to 150°C?

[nice2day]

Hi Puffs...The stove is just a "Hotplate" type

He certainly wouldn't want to sit on it

PS: Regarding the thick rope....hopefully you're not going to end it all Puffs?

[nice2day]

Surprisingly a mandrill was once photographed holding an MZ crankshaft, he told his keepers that his own big end had been playing up and wanted a shiny new one.

Les

[Puffs]

His facial expression suggests he resents sitting on your stove.