Temperature / Compression ???

[sporty982000]

Does anyone know what the ave temperature is for the blaster ? cylinder temp or max temp ?

I did not know, if anyone has done some real engine temp testing or not.



Compression, Man I tell ya, I can't find the compression recommendation in my manual, what page, is it on ? cuz I must be ray charles, cant find it.

Now I see 6:6:1 ratio.

Is there anyone, out there that boosted there compression ratio, with tighter specs for the cylinder / piston wall clearance and piston ring gap ??

I was looking at maybe buying a temp gauge for aorund $40, but would not really know, what the average temp is or max temp before it locked. was hoping for some type of baseline.

Sporty

 

[joeak47]

Does anyone know what the ave temperature is for the blaster ? cylinder temp or max temp ?

I did not know, if anyone has done some real engine temp testing or not.



Compression, Man I tell ya, I can't find the compression recommendation in my manual, what page, is it on ? cuz I must be ray charles, cant find it.

Now I see 6:6:1 ratio.

Is there anyone, out there that boosted there compression ratio, with tighter specs for the cylinder / piston wall clearance and piston ring gap ??

I was looking at maybe buying a temp gauge for aorund $40, but would not really know, what the average temp is or max temp before it locked. was hoping for some type of baseline.

Sporty

I've been averaging 300 to 340 degrees in the 98 to 105 degree ambient tempuratures here in Nevada.

I've been testing engine tempuratures in this thread here >>>

http://www.blasterforum.com/engine-13/joeak47s-thread-cast-piston-vs-wiseco-forged-piston-49255/

Some folks think that might be high,but its not. I believe that humidity also has a factor in running tempuratures too.

I looked into other "Air Cooled" engine temperatures,both non-forced air and forced air cooled engines. Both two stroke and four stroke.

The blaster temperatures you see in the thread above ar way low compared to the temperatures that the gokart guys run,and....the gokart guys run them for long periods of time under "probably" heavier loads than us blaster guys do.

The gokart guys running the two stroke Yamaha KT-100 engines are running temperatures "as high as" 500+ degrees!!!
However,...they have no issues unless the engines are getting detonation,and the engines put out the power at the higher temperatures!

This is a Yamaha KT-100 engine...

What I found very interesting is the gokart guys that run in the "clone class",which is the class that runs the,for the most part,a "chinese copy" of the honda gx200 lawn mower engine. These forced air cooled (fan cooled) engines are four strokes with valves and springs to worry about keeping cool. These clone engine guys run right about 400 degrees!

Here's a link to a very short read on the clone tempuratures...

4 Cycle Karting Forums - Clone Racing Temp


This one is from harbor freight...they look like this...

if you have this manual here...its on page 87 top left corner 140 -160 psi ...

DON'T FOR GET THIS... you have to compensate for altitude when doing a compression test! Add 3.4% for every 1000 ft increase in altitude above sea level.

Your not going to get a big increase in power with an increase in compression on a two stroke. It helps a bit,but makes a bigger difference on a four stroke engine.

Don't get too tight on your piston to cylinder clearance,or you'll run into problems. Cast pistons run tighter tolerances than forged pistons,so be careful,especially with a forged piston. A forged piston needs more room to expand as it warms up.

Closing up the ring gap won't do much for compression,and can get you in trouble if its too tight when things get hot. They need room to expand too.

Also don't get stuck on the 6.6 to 1 compression ratio as being low. Thats just the static compression ratio.

Hope this helps you out. Joe

 

[bummer981]

Good information Joe have some GREEN.

 

[sporty982000]

Joe,


Awesome info. Thanks.

I dont have that manual. I bought one on e-bay, just a pdf one and plus I downloaded a free one.

 

[best]

Joe,
I recall reading stuff on aircraft and VW engines, and talking with a co-worker about his aircooled Porsche about 350 degree cruising temps, 450 max power temps. Aircooled snowmobiles used to run in the same ranges. Plug tip temp goal is to run at 500 degrees that I recall. All of this is from my shady memory, so take it for what it is. Sill looking for Triplecrown to show up so we can take some FLIR photos of his engine.

 

[slickerthanyou]

Where are we talking taking a temp reading from? And with a heat gun or a probe?

I take readings on my head between the fins at the spark plug base and again right above the exhaust port.

With My right bend pipe running rich i was at 220 head, 300 exhaust port this was after a two hour run in summer about 85 degree 60% humidity, light breeze-

With the left bend toomey, my head temp was 191 degrees, and exhaust was 240 this is after a 40 minute run.

I swear I read that 400 is borderline. I can't find that info.

 

[best]

The Porsche guy said the 911 has a temp sensor built into the head. Sleds and small aircraft have a thermocouple washer under the spark plug. Some of the aircraft also have EGT Exhaust gas temperature sensors in the header too. Read out with a different needle on the same gauge. The EGT reacts faster than the cylinder head temperature. The pilot used the head temp to adjust mixture during cruise and watched EGT on takeoff. Temps on sleds and aircraft dropped off fast when the load was taken off.

There are washer type temperature gauge kits sold for snowmobiles. It might be worth buying one to watch head temp to protect engine.
I believe they run about $50.


Edit; did a quick look for internet souces:
Bus Boys Inc - VDO Products Mentions ave VW temps of 275-375
eBay Guides - CHT Gauges for Air Cooled Engines More info, max temp 400 suggested
Bob Hoover's Blog: Another 100hp VW Conversion VW on aircraft thread, 450 max temp
Homemade VW Beetle Head Temperature Gage for the Air-cooled Bug. 320 degrees VW cruising temp
Head Rebuilding Suggests running temps for VW heads at 350 degrees
High cylinder head temperature in Lycoming or Continental aircraft engine Suggests sparkplug tip must run at +800F
The Savvy Aviator #59: EGT, CHT and Leaning Excellent aviation article, 350-380F cruise temp
http://www.costaricaaviation.com/flightschool/LycomingEnginesOperations_rev1.pdf Lycoming manual, min teps 150F, max life under 400F, 435F in climb Pg10

Well, it seems under 400F is best for long life, +400 acceptable for short periods, if you can believe these sources.

 

[joeak47]

Seeing all these higher temperatures makes me feel better about my tempuratures.

 

[sporty982000]

I found these:

TTO Digital Gauges at Trail Tech Home

E-bay has them for around $40.00.

I thought down the road, I would get one. I see this as a plus to watch temp.

http://www.ebay.com/itm/TRAIL-TECH-...Parts_Accessories&hash=item2c66aa7a4c&vxp=mtr

 

[79 bronco]

We were removing a 200cc big bore sleeve from a Yamaha ty 175 trials bike cylinder, and at about 500 degrees the sleeve fell out... BUTT we were removing the Big bore sleeve from the cylinder because the sleeve was moving around in the cylinder, and we think the people over bored that cylinder..

 

[best]

We were removing a 200cc big bore sleeve from a Yamaha ty 175 trials bike cylinder, and at about 500 degrees the sleeve fell out... BUTT we were removing the Big bore sleeve from the cylinder because the sleeve was moving around in the cylinder, and we think the people over bored that cylinder..

That makes sense. Depending on the amount of grip something has in a press fit, especially of an aluminum over iron fit, it may take very little heat to make it come loose. First of all most of the heat in an engine is generated up in the cylinder head and first couple mm's of the cylinder. Secondly the heat is generated inside the iron cylinder and the cooling is taking place on the aluminum body. At no time while running should the entire cylinder get to 500F. If the inside of the cylinder head was 500F the liner might be 400 and the aluminum body perhaps 350F. Make sense?

I keep promising to get some heat pictures of a hard working Blaster engine, but my engines are all water cooled, and trying to get Triplecrown, myself, and the FLIR camera all together at the same time has proved difficult.

Hey those links to the TTO meter look interesting. I have had an issue with a Trail Tech product in the past, but for $35 I'll take another gamble with them. Temp, tach, and hour meter looks good. A word of warning, many thermocouples need to be calibrated so the number value indicated may not be entirely accurate, but they will indicate when you are overheating.