Heat Seize

[Storkfoot]

Several years back, I had a cylinder head temperature guide on a mildly tuned SR (remember them?) 193cc. I go through one of the Mersey Tunnels to work each day. This has a steep hill.

If I let the scoot labour up the hill in 4th, the temperature gauge went through the roof. If I slammed it into 3rd and let it really rev highly, it would scream like a banshee but the temperature would shoot down.

If I hadn't have seen this, I'd never have appreciated the effect of fan speed on engine cooling.

[ToBoldlyGo]

Good point that.

[Fast n Furious]

Several years back, I had a cylinder head temperature guide on a mildly tuned SR (remember them?) 193cc. I go through one of the Mersey Tunnels to work each day. This has a steep hill.

If I let the scoot labour up the hill in 4th, the temperature gauge went through the roof. If I slammed it into 3rd and let it really rev highly, it would scream like a banshee but the temperature would shoot down.

If I hadn't have seen this, I'd never have appreciated the effect of fan speed on engine cooling.

Excellent piece of observation.
This doesn't happen with a properly engineered cowling solution I can assure you.(assuming all other engine properties are in order)
I would post some photos of my solution but the devil is in the detail, which would mean stripping it to photo it properly, which isn't gonna happen until next winter with luck.

[corrado]

This doesn't happen with a properly engineered cowling solution I can assure you.(assuming all other engine properties are in order)
I would post some photos of my solution but the devil is in the detail, which would mean stripping it to photo it properly, which isn't gonna happen until next winter with luck.

You tease.

[Warkton Tornado No.1]

Re: Heat Seize
Post by corrado » Wed Feb 01, 2017 12:24 am

Fast n Furious wrote:
This doesn't happen with a properly engineered cowling solution I can assure you.(assuming all other engine properties are in order)
I would post some photos of my solution but the devil is in the detail, which would mean stripping it to photo it properly, which isn't gonna happen until next winter with luck.


You tease.

You can say that again...

Re: Head cowling improvements
Postby Fast n Furious » Mon Jan 16, 2017 7:37 pm

Photographs mmmmm.
My camera makes pictures that are 5+Mb jpeg which are too big for posting I think. I need to find a way of condensing these into something more manageable. When I've figured that out I post some pics.

[EddieStone]

Squeaking? That could be an air leak somewhere. The only time I've heard an engine squeak was when the head needed torqueing down.

Could also be the plug needs tightening.

[Fast n Furious]

This doesn't happen with a properly engineered cowling solution I can assure you.(assuming all other engine properties are in order)
I would post some photos of my solution but the devil is in the detail, which would mean stripping it to photo it properly, which isn't gonna happen until next winter with luck.

You tease.

I know. Sorry about that, but if all goes well this year, then the report I will eventually make will offer time and mileage tested justification.
Then maybe it will be worth having some parts batch produced so others can reap the benefit affordably. Ideally, this is something every lammy owner who rides with gusto can benefit from.

All good things come to he who waits.

[Adam_Winstone]

Squeaking? That could be an air leak somewhere. The only time I've heard an engine squeak was when the head needed torqueing down.

Could also be the plug needs tightening.

^... I agree that an engine with a blowing head gasket can sound like a bird cheeping or a mouse squeaking.

[ToBoldlyGo]

That's funny you should say that. The head gasket blew previously and had been replaced. Perhaps I should be asking what causes a head gasket to blow?

[CHRIS in MARGATE]

Mating surfaces not true.
Reassembled with poorly cleaned surfaces.
Poor quality gasket.
Not torqued correctly
Not retorqued.
Studs working loose.
Compression excessively higH.
Squish too small.

[holty]

ive blown a head gasket before and can comfirm it can give a squeeking type of noise, also a big reduction in performance as well, i managed to limp home just going slowly. i know some people would prefer not to use a head gasket and set their cylinder and head and squish so no gasket is needed, studlock makes a good seal, but not too much, you dont want any on the bore, ive got an engine stand that rotates so i put the barrel facing downwards once the nuts are on, and the torque up, so any leakage runs into the head then leave overnight.

[ToBoldlyGo]

Oh well, I'll have to bite the bullet I think. Sounds like there is nothing else for it but a complete rebuild, essentially.

[ToBoldlyGo]

Just as an after note, the engine is apart now and there is quite a bit of scuffing from the seize. But what is telling is the build up of coke around the crown of the piston and the ports. And yes, a ring was gummed up. It reminds me of the problems some have said they experienced with Exol fully synth oil. Which is what I was running on, funnily enough.

[Fast n Furious]

Just as an after note, the engine is apart now and there is quite a bit of scuffing from the seize. But what is telling is the build up of coke around the crown of the piston and the ports. And yes, a ring was gummed up. It reminds me of the problems some have said they experienced with Exol fully synth oil. Which is what I was running on, funnily enough.

Actually, if you trawl through the forum, people have reported similar issues with other makes of fully synthetic oils as well. EXOL may just be getting a bashing here cos it is a popular choice on cost?

[ToBoldlyGo]

Have they? That's quite possible. I think fully synth is probably overkill for most people's scooters.