Changing the schrader valve in the end may help. Napa has them . It doesnt use a regular schrader valve
True. I would expect it to leak off though if something was bad? I didn't let it sit this time, but when I tried it last week (or whenever it was) it held for several minutes.
So, Is my old big block F350 going to be faster than your brand new F150 raptor? probably not. stoplight to stop light, the newer, smaller engine and efficiency of power and lighter weight will make that raptor faster. Or possibly about even, if I get the jump. Now, lets put 12K lbs on the azz end of them and see who wins. I betcha that old big block will out pull it. So, stop light to stoplight empty they are about even, except I'll use more fuel doing it. Load them down like they were designed and then it will clearly show. 12K lbs is similar to a 28-36" bar for this comparison. Now put a 28-36" on that stock 372 and you will clearly see the 660 grunts away. Does that make sense? your 359 probably had a catalytic converter. they are choked up pigs in stock form that don't have the power to pull a 20" bar. So you went from that to huskys top performing saw for the midrange pro market. the 372 is the Do it all saw. So yeah, there was a big difference. now, if you would have had that 359 ported, it would run better than a stock 372. The 066 should have a 7 pin on it the way you are trying to force it. They are 5 bucks at a stihl or husky dealer. You were leaning on the saw hard. I could see the av mounts bottomed out against the tank. take the one off your 372 and put on the 066. Then put the 8t on your 372 and see how it acts while you are trying to run it the same way. people don't realize how much torque you give up running a 8T over a 7T. Dawgs are not meant to use to pry on a saw. Take them off and see how it cuts. but as others have said, open the damm muffler up. a muffler mod on a newer 066/660 is night and day difference. The good running 066's had a dual port cover and the outlet on the side by the chain brake. the original outlets on the side were about 1/2" in diameter, and the opening on the front cover was 1/2 x 1.5". your only opening is 3/8. you will gain almost a full horsepower by doing a simple muffler mod.
Make sense? I see where you're coming from. But it's really a comparison. Big block has less HP and torque then the smaller Raptor motor, so in order for it to compare my 72cc would need to have more power and torque. If you're willing to place a bet on towing 12k# I'll drive the Raptor
I think better better example between the Raptor and the F350 would be if you said, "oh, and you have to shift at 2,500 RPM".
ok, I didn't want to go there, but how about an eco-turd-boost. My big block is older and has more HP and Tq... seriously, take the 8 pin off your 660 and put the 7pin off your 372 on it. larger rim with a lot longer dawgs will kill the strongest of saws when leaned on hard.
I think it was even well under 6hp according to Chad's dyno sheet. The dual port put it back up to roughly 6.5 or so and the factory HP spec is listed at 7.0. Oh yeah, here it is... http://firewoodhoardersclub.com/for...orted-660-vs-stock-660-vs-dual-port-660.6007/ Also, the problem isn't just in the restrictive mufflers and lean tunes. There is a reason the early cylinders are sought after items by guys building these saw's.
For us less than mechanical guys, does anyone know or sell modded mufflers? I'd rather not fool with it, since I'm not sure. Back on topic, I agree that the sprocket change is noticeable. I have run a 25" 8 pin set-up on my biggest saw and it still cuts quick if you don't put too much pressure. I would be happy to take the 660 for a fair price if O.P. doesn't want it anymore. I'm sure I can find a use for it.
chads dyno doesn't do tq readings does it? Torque is what makes the chain cut, Hp is what keeps the chain spinning, it would be interesting to see the tq curves between those same saws. that chart is deceiving to people that don't understand how hp is derived from torque and some people would look at that and think dawging a saw in would be faster than letting it cut based on HP/RPM on that chart, but we all know that isn't the case.
I'm not looking to feel better. Making you aware of other things to consider. Also compression testers don't leak off if they are not accurate. Put a 36" bar on that 372. Then put about 1000 hours run time on it and then you'll know what the 660 was intended for.
You can buy an aftermarket dual-port muffler for under $30. Some are treating HP and torque as two separate things in this discussion. (Steve, I know you understand ) HP is simply a mathematical conversion of a torque reading at any given RPM. Chad's dyno outputs a torque reading from a load cell (scale) which he then converts to HP to compare against factory specs. (To clarify for those that are learning right along with me) Torque is a measure of (rotational) force. Horsepower is a measure of work. Go to the nearest wall and push on it as hard as you can. You have exerted force on the wall. If the wall is still standing, you have made 0 HP. If you had a different result, please post pictures.
It had never crossed my mind till you asked. Glad you did. 372 is a 7pin. I'll have to swap it over and try it if it ever stops raining.
To make it simple, the 372 (or just about any modern 70 cc saw) will take a 660 in wood under 20" . As a few have stated earlier, put a 36" bar on that 660 and let it eat at it'd own pace (not rocking and digging in the dogs), then put that 36" bar on your 372 in the same log.. Oh and make sure you have a 7 pin with that 36" bar. Looks and sounds fine to me. Maybe a tad off tune still, but seems to cut fine for what a 660 is stock (in small wood). My (old) 441 and 460 both steal the 660's lunch money in wood under 25". They are big saws.. Yes. But that doesn't make them faster. Just stronger in the wood that it was meant to cut.