heat cycling
- Thread starter Doc Brown
- Start date
Zman
Platinum Level Site Supporter
If I remember correctly, you do three heat cycles of bringing the engine up to normal operating temperature at medium load for 15 to 20 min then let it cool completely. I thought it had something to do with annealing / reducing internal stresses in new engine components.
Although that is directly opposite of what I have been told by engine builders for break in of 2 stroke engines with plated cylinders that have the correct build clearances. Warm it up and ride it like you stole it because you need heat and engine loading to properly break in the rings.
Although that is directly opposite of what I have been told by engine builders for break in of 2 stroke engines with plated cylinders that have the correct build clearances. Warm it up and ride it like you stole it because you need heat and engine loading to properly break in the rings.
Thank you.
I have been told that some people let the engine run two minutes and blipping the throttle, then ride it 10 minutes and let it cool down 24 hours. Then they repeat that twice to have three cycles altogether.
It has been said the only reason is to reduce internal tensions (hope that's the correct term) in the material structure.
The ride it like you stole it theory, we all have heard about Moto Man brake in procedure, has a different reason. As you say it has to do with the rings and how they bed in...
I have been told that some people let the engine run two minutes and blipping the throttle, then ride it 10 minutes and let it cool down 24 hours. Then they repeat that twice to have three cycles altogether.
It has been said the only reason is to reduce internal tensions (hope that's the correct term) in the material structure.
The ride it like you stole it theory, we all have heard about Moto Man brake in procedure, has a different reason. As you say it has to do with the rings and how they bed in...
Jacob 'Berg
Member
My practice has always been to warm the bike to operating temps, shut it down and check for any leaks and check cylinder bolts are still tight. Then ride for 5-10 minutes on flat ground, varying the throttle position, no constant throttle, or high rpms, and no heavy loads. After that I will take to the trail and ride it as I normally would. I've done this for several top ends on various 2t bikes with no issues.
swazi_matt
Active member
the method i have always used (and posted here numerous times with all the backup info) is to warm the bike up and then slowly run through the gears changing at 1/4 of max revs and then using the engine braking to go back down the gears, then repeat at 1/2, 3/4 and full and you're done
SS109
Active member
Heat cycling is way overblown. Been rebuilding engines forever and complicated heat cycling procedures are not needed.
Fire up bike, do not blip the throttle at all (don't risk a cold seizure), let idle until up to full operating temperature, shut off, let cool to ambient temperature, check for leaks, check and re-torque head/cylinder bolts if necessary, heat cycling is done.
Fire up bike, do not blip the throttle at all (don't risk a cold seizure), let idle until up to full operating temperature, shut off, let cool to ambient temperature, check for leaks, check and re-torque head/cylinder bolts if necessary, heat cycling is done.
SS109
Active member
Exactly! If something is going to fail with today's metallurgy then it was just going to fail no matter what you do. Plus, we aren't dealing with brand new engines anyway. Almost every part inside has already been heat cycled 100's of times.
SS109
Active member
Not trying to be combative at all so sorry Doc. However, I do disagree. Your original question asked...
What I and gasgasman replied was relevant to the discussion. I explained how I understood heat cycling after my 30+ years of building car and motorcycle engines and to what extent I do heat cycle and he agreed and said why. Of course, heat cycling an engine surely won't hurt anything!
Also, it is here as reference for future members who search about heat cycling. The discussion can be useful showing all points including those that say it is completely unnecessary. Remember, keep an open mind! <cough>ATF<cough>
What I and gasgasman replied was relevant to the discussion. I explained how I understood heat cycling after my 30+ years of building car and motorcycle engines and to what extent I do heat cycle and he agreed and said why. Of course, heat cycling an engine surely won't hurt anything!
Also, it is here as reference for future members who search about heat cycling. The discussion can be useful showing all points including those that say it is completely unnecessary. Remember, keep an open mind! <cough>ATF<cough>
rodent
Member
SS109
Active member
That's nice but I see no heat
I'd say I see more heat here
https://www.youtube.com/watch?v=ieVDfnUKN9s
I could give an exhausting answer, but sorry don't feel like it. For me it's not a question if it makes sense or not, I was interested how others do it.
Is it allowed to assume that if others do it, they think it makes sense?
Not trying to be combative at all so sorry Doc. However, I do disagree. Your original question asked...
What I and gasgasman replied was relevant to the discussion. I explained how I understood heat cycling after my 30+ years of building car and motorcycle engines and to what extent I do heat cycle and he agreed and said why. Of course, heat cycling an engine surely won't hurt anything!
Also, it is here as reference for future members who search about heat cycling. The discussion can be useful showing all points including those that say it is completely unnecessary. Remember, keep an open mind! <cough>ATF<cough>
If you took my answer down the wrong pipe, sorry. Wasn't my intention to annoy you.
Maybe it makes you happy that I work on engines since 40+ years, started at the age of 15 and spent a lot of time with somebody working as tribology expert in the oil and automotive industry. Unfortunately my English isn't good enough to explain some scientific aspects, especially molecular structures and how they change in a heat, cool, heat cycle versus the materials they inevitably touch or get in contact with. Especially in two stroke engines with their rather old-fashioned pistons.
I accept all opinions and if you say it's completely unnecessary that is perfectly fine for me.
SS109
Active member
Sorry Doc. Wasn't trying to upset you or anyone else. I think maybe a little was lost in how I worded things. That said, we cool!
Jakobi
Super Moderator
https://www.youtube.com/watch?v=c2eWHNSaSZU pSSST!!! the barra!
What do you think on the matter Doc?
I like to keep things simple..
Buy quality parts, measure tolerances on assembly, throw it together.
Run to test for leaks, etc. Short test ride using some load on acceleration and deceleration to start bedding rings, and then ride it as per normal.
What do you think on the matter Doc?
I like to keep things simple..
Buy quality parts, measure tolerances on assembly, throw it together.
Run to test for leaks, etc. Short test ride using some load on acceleration and deceleration to start bedding rings, and then ride it as per normal.
rodent
Member
^^^Is that yours?
I have a customer I deliver to had a Barra in his ute making around 1200hp, he pulled it last year and built a new one not quite so slow(allegedly)
He hasn't dyno'd it yet though.
Jakobi
Super Moderator
^^^Is that yours?
I have a customer I deliver to had a Barra in his ute making around 1200hp, he pulled it last year and built a new one not quite so slow(allegedly)
He hasn't dyno'd it yet though.
I have a Barra 245T.. 2005 model running the stock single Garrett GT35/40r turbo. Conrods were the weak link until 06 where they beefed them up after a couple reports of people bending them.
I've kept mine stock as a rock as it's my daily drive and I don't have the coin to spare (not only tuning but also maintaining).. Relatively easy to get some decent figures with a fuel pump, injectors, valve springs, cat convertor, intercooler and a tune.. but most people then overlook the added wear and tear on the drivetrain. Especially if the tune is more on the aggressive side or the driver lacks mechanical sympathy.
I think if I were going to do one up, I'd probably look at buying HP tuners, throwing in a couple of sensors and tuning it myself. Shame they've stopped building the falcons here
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