Joined
·
5,299 Posts
Crank pulleys and such
I'd been running a stock, single groove crank pulley on my 1.9 SSD40 engine and was always somewhat aggravated by a bit of fanbelt squeal, even though I use a clutch fan '75 WP. This engine built RPMs so quickly that there was really no cure for it without putting excessive force on the WP shaft bearings with too much tension on the belt . . . it's a new, "external mass" belt, BTW, so I know it's not the belt.
Then I aggravated this problem even further by installing my blueprinted, ported, big valve HC 2.15 SSD48 in it's place . . . gobs of torque and it builds RPMs even quicker than my 1.9 did. HAD to resolve that squeal problem somehow. New engine idles at about 1150 RPM with a slight "rump, rump", 1.9 idled at about 900 RPM.
Did a few calculations and, taking the ever present Texas heat into consideration, came up with the idea (thanks, R-Bob) to reduce the crank pulley diameter by ~15%. While I was fabricating this (Toyota crank pulleys), I also changed it to a dual groove type for a future project. Now for every 1000 RPMs of crank speed, the WP and alternator drive belt speed is reduced to an equivalent effective speed of 850 RPM.
Squeal's now gone and have tested combo during hottest part of the day with temp gauge never exceeding a half mark left of center. "Seat of pants" tells me that it accelerates somewhat smoother through the gears too. All in all, a VERY worthwhile undertaking and perhaps an idea to consider for other members' "Hot Rod" engines.
I'd been running a stock, single groove crank pulley on my 1.9 SSD40 engine and was always somewhat aggravated by a bit of fanbelt squeal, even though I use a clutch fan '75 WP. This engine built RPMs so quickly that there was really no cure for it without putting excessive force on the WP shaft bearings with too much tension on the belt . . . it's a new, "external mass" belt, BTW, so I know it's not the belt.
Then I aggravated this problem even further by installing my blueprinted, ported, big valve HC 2.15 SSD48 in it's place . . . gobs of torque and it builds RPMs even quicker than my 1.9 did. HAD to resolve that squeal problem somehow. New engine idles at about 1150 RPM with a slight "rump, rump", 1.9 idled at about 900 RPM.
Did a few calculations and, taking the ever present Texas heat into consideration, came up with the idea (thanks, R-Bob) to reduce the crank pulley diameter by ~15%. While I was fabricating this (Toyota crank pulleys), I also changed it to a dual groove type for a future project. Now for every 1000 RPMs of crank speed, the WP and alternator drive belt speed is reduced to an equivalent effective speed of 850 RPM.
Squeal's now gone and have tested combo during hottest part of the day with temp gauge never exceeding a half mark left of center. "Seat of pants" tells me that it accelerates somewhat smoother through the gears too. All in all, a VERY worthwhile undertaking and perhaps an idea to consider for other members' "Hot Rod" engines.
