props for a 38'

[Ed Donnelly]

My friend just picked up an older 38' Cigarette. Has twin 588C.I. B.B. chevies. 4.560 bore 4.5 stroke 9.5 compression. Merlin heads ,dominator 1050 carbs. Dyno'd at 650 hp at 5600 rpm. He is running trs drives 1.58( should be 1.5 or 1.38?)
4 blade 17.5x29 props. He is only running 4400 rpm.WOT. What should he do with these props....Ed

[BUIZILLA]

Ed, you sure about that 17.5" ???

J :pimp:

[MR MAGOO]

Are you sure he has TRS drives? 17.5 diameter props would be Speedmaster props.

If it is a TRS boat, the gear ratio would be 1.5:1 (thats the only ratio offered) and the 29 pitch would be way too much for that hp.

I've been playing with TRS boats for years and have blown up many of them. Here's some advice from someone who learned the hard way :yes:

Stay away from 4 blade props on a heavy boat like the older Cigarettes. They load up the drives more than the pinion gears can handle.

Under prop it a bit and spin the motors a little higher than normal. It will reduce strain on the weak link (pinion gear)

The right hand TRS will break way before the left will. (left hand TRS drives have a better supported drive gear, in the front of the lower gear case)

Keep an eye on the gear lube. If you see metal on the magnet change out the gears or they will change themselves :puke:

I've had pretty good luck with cryo-treated gears. They lasted the longest.

My suggestion would be a pair of 25p Mirage Plus props. They will allow the motors to spin about 5600 or so

I had it with exploding TRS drives and recently converted my '89 Top Gun to the Konrad 540 drives. They are bullet proof and we picked up 5 mph to boot!

Check it out at www.konradmarine.com

[Mr X]

I would try cutting down the diameter to 17.0 first and try them.

[Ed Donnelly]

Thanks for the speedy replys . I won't be able to check the boat out until this weekend, then I will have first hand knowledge. If any of the info changes, I will repost...Ed

[MR MAGOO]

I thought that a 16" diameter prop was the max for a TRS.