Quattrini M244 running hot in 4th

[Svint1]

Hi,

Was on my first tour With my New-built M244-engine this weekend.
Setup;
Pinasco Casing

Quattrini M244 Cylinder kit

Quattrini M244 crank

Pinasco SI26/26 VRX, 2,69 in pilot, BE3, 150HD
Vespatronic With GP-One fan, 24-18'

EFL Gearbox, 64/24

Sip Road 2.0 exhaust.

 

Then engine runs great, very very litle or no vibrations and pulls very Nice.

 

But when cruizing in 4th gir, the temperature on the cylinder head gets very high, 150-160 C.

-just by cruising in 100 on flat road.

 

No matter how hard I push it in first, second or Third gear, it will not get hotter than 140...

Any suggestions to why it gets so hot in fourth gear?

 

Rgrds

Øyvind

[McGregor]

I'd say of course in 4th gear you've got the highest engine load. More than in the lower gears.

Any problems with that? I don't think this head temperature doesn't really matter, what kind of sensor do you use?

 

[Svint1]

Ok, I just thought such a "big" engine would run easier on flat ground...

I'm using the sensor for the SIP speedo.


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[McGregor]

Maybe your pilot setup is a little too lean. Think your throttle won't be opened above 1/4 at this speed, is it?

But in general that SIP-Head temperature won't really tell you that.

Check outside temp with it and get an EGT maybe

[Svint1]

Ok, thanks!

I'll try a bigger pilot jet.

But, even with the carb fully open, it gets hot on flat road.

Approximately 25 degrees hotter than in the other gears with the carb fully open...


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[Han.F]

  Am 12.6.2017 um 06:49 schrieb Svint1:

Pinasco Casing  with this Casing it is very easy to get leak air ... did you control that?

Quattrini M244 Cylinder kit  squish?

Quattrini M244 crank

Pinasco SI26/26 VRX, 2,69 in pilot, BE3, 150HD  ->
1. forget the quotient!!!      
2. HLKD? (maybe 150 or 140 will run better)   
3. Use the MMW 4.2 Slide
4. I can not believe that you need a HD150, but if it is so, you must drill out the channel to the nozzles stock to ~3mm!
5. Fuel tap?
Vespatronic With GP-One fan, 24-18'

EFL Gearbox, 64/24

Sip Road 2.0 exhaust. (maybe a bigger stinger will fix your problem ...)

Aufklappen  

 

[Das _O]

vespatronic starts to decrease pre-ignition (?) at 4000rpm. at 100 km/h, assuming regular px 200 gearratio, your rpm will be around 6000rpm. so at 6000rpm ignition time is just a little later than 24° you got at 4000prm, way earlier than a static 18-19°.

 

[Svint1]

Pinasco Casing  with this Casing it is very easy to get leak air ... did you control that? Yes, Checked and ok

Quattrini M244 Cylinder kit  squish? 1,37

Quattrini M244 crank

Pinasco SI26/26 VRX, 2,69 in pilot, BE3, 150HD  ->
1. forget the quotient!!!      
2. HLKD? (maybe 150 or 140 will run better)   
3. Use the MMW 4.2 Slide To be ordered and tested...
4. I can not believe that you need a HD150, but if it is so, you must drill out the channel to the nozzles stock to ~3mm!
5. Fuel tap? BGM
Vespatronic With GP-One fan, 24-18'

EFL Gearbox, 64/24

Sip Road 2.0 exhaust. (maybe a bigger stinger will fix your problem ...)

Bearbeitet 13. Juni 2017 von Svint1

[Svint1]

  Am 12.6.2017 um 12:53 schrieb Das _O:

vespatronic starts to decrease pre-ignition (?) at 4000rpm. at 100 km/h, assuming regular px 200 gearratio, your rpm will be around 6000rpm. so at 6000rpm ignition time is just a little later than 24° you got at 4000prm, way earlier than a static 18-19°.

 

Aufklappen  

 

Does that mean that I should set the ignition to 22-13??

[Das _O]

at least worth a try. with static ignition i always ran 19-20°. small non-alu polini a little less.

 

i always had problems at 100km/h, even more, runnnig behind cars. almost no throttle, no cooling from carb. even worse with big exhausts. reso kickin in at around 5.500 rpm and carb on "idle". besides ignition, maybe squish, i guess u need a richer mixture just above "idle jet", but i never pushed the si carb to the max, running vhsb atm, preferring the ability to set mixture by needles.