Leathl_WS6

Biggus! Do you stuill have B&M Pulleys? If so what sizes?

Thanks
Rob

JFletch

Im looking for pulleys to boost up my 600sc if you still have any .Thanks Jeff

Leathl_WS6

Jeff, I bought smaller pulleys from Teague. They have any size you want..

http://teaguecustommarine.com/em0011...e-pulleys.html

They are 16 rib instead of 8... and the offset is about a 1/4 off from your stock pulleys, but they have been on my motors for a full season with no issues... I did not even notice any excessive belt wear... I also have the 600SC's with the BM 420s...

If you wanted them perfect you could just have the backside of the pulley machined a little, so they lined up perfect and have the extra 8 ribs removed... I am planning on doing this to mine before summer... I put them on last year just to test and never actually had them machined to fit perfect.

Rob

MILD THUNDER

I bought a 3 groove vee pulley that guys use on say like 871 setup. I then installed a 600sc top pulley, on the bottom. Works nicely. Takes it from stock .93:1 ratio to 1:1. Should be roughly 1.5-2psi gain.

JFletch

Thanks for the info guys. I was wondering if the 16 rib would align or not . Do either of you know where I would be at with the 4.4 upper.I think that will get me just about where I want to be. I am trying to go up approx 2psi.What was your gains Leathl ? I wouldn't mind going to a full 16 rib setup. I put a crossover on it and I threw a 10 rib belt out on the Saginaw bay last summer. I need to secure the lower mounting point better since the wide circulation pump is no longer there.Or go to the 16 rib tensioner and lower. Probably get the 16 rib upper and see how it performs first just need to figure out the best size for me..Really appreciate your input fellas.

Leathl_WS6

Jeff, I'm pretty Sure 4.4 will be way too small. My situation was a little different, I made cam, head and piston changes which lowered my boost with the stock pulleys. So I was sitting at around 3.5 with my stock setup. I went with the 4.7 pulleys and it took me back up to around 6PSI. If you're sitting at 5 now. the 4.7 will likely get you 2 PSI or a little more. I would be careful running any more than 7psi with a 420 blower unless you add an intercooler.. They aren't the best at higher boost levels... I'm sure Mild Thunder could provide you more detailed information on this..

MILD THUNDER

I dont think youll see heat problems with that blower until you start really spinning it. The 800sc was 18% overdriven with no intercooler. On a 600sc, stock is 7% underdriven. The stock 600sc bottom pulley is 4.600. A 4.4 top pulley would put it at 4% over, would should be about 3 more psi. A 4.7 top pulley would be 3% under. , and should net about 1psi, maybe 2. Alot depends on if you modify the engines. A cam and head change can really change things.

I dont care for the way mercury set up the tensioner on the 600/800sc. It swings outwards when the belt stretches. I been thinking of a new setup with a tensioner that swings inwards, keeeping the belt wrapped better around the upper pulley, as well as adding an idler. The 10 rib belts can work really well, if they are routed properly. Nice thing about the 10 rib belts is i been getting the Gates belts for 20 bucks a piece. I toss them out after 1 summer .

JFletch

You guys rock. Im a newb here so not wanting to jack this thread any more than I have . I ran it all last summer and it runs out nice (less than 150 hrs on the motor) in my Checkmate but am having a rare vaporlock type situation maybe 4 or 5 times all summer long. It runs extremely cool but although I put all new electric fuel system, pickup and lines, I have to prime the filter when this happens. never loose fuel pressure while running. Only at restart very rarely. Thanks guys for all the advise and knowledge. Jeff

Leathl_WS6

I agree Joe that tensioner really sucks, Every time I look at my motors I seem to have jumped a rib on the pulley. It's weird now with the new 16 rib pulleys that has not happened yet. But I did re adjust the tensioners as best I could when I had the motors apart. Let me know if you come up with something, I would love to get rid of that setup, without breaking the bank..

Leathl_WS6

Jeff, don't worry about Hijacking this thread it's a million years old.. LOL
Vapor lock may be the wrong term in your situation, vapor lock means the fuel gets so hot it turns into vapor. This is caused from fuel lines running too close to a heat source.. The motor will not start because it needs liquid fuel for combustion. It's not a problem when the engine is running because the fuel moving through the lines keeps things cool. But once you shut off the engine that's when the fuel can vaporize...

What you are describing seems more like a leak down or bleed off of pressure.
If I understand you correctly, you're saying your fuel bleeds down and you loose fuel pressure? and your filters are actually empty?

My setup has a check valve on the fuel lines where the fuel can only pass through one way. So once the fuel is in the lines, it's not possible to drain back into the tank. If your fuel filter is empty, I would suggest adding something like this.

http://www.jegs.com/p/Earls/Earls-Fu...61341/10002/-1