peterunwin

Hi All,
We are in the process of installing higher powered engines and to enable the drives to cope with the extra power i have changed some of the bearings to minimise shaft deflection and also installed a PTFE hose into the lower unit this will be connected through the transom into a micro hydraulic pump through a filter and returned to the top bearing in the upper, this will allow me to run a much lower oil level this along with circulating the oil should keep the temperatures much lower.The drives have completed almost 1000 hours of use as wet sumps still on the original gears but the bearings have required changing every 250 hours and the oil every 50 hours.

Peter

C_Spray

iTrader: (2)

You're blazing a new trail here. I have not seen these drives on any applications in the US other than D6 diesel engines on cruisers. I have DPX-A drives (no longer made) on my 38 Formula behind 600 hp per side, and have thought about converting to DPR's, but it seemed to be too big a job to be worthwhile.

Did you make your own shorty lower units, or are those standard ones with nosecones?

JJONES

http://www.weismann.net
knows alot about them

peterunwin

Hi C_Spray,
The engines are modified D6'S running at around 400HP and 900 NM of torque, we are doing some further modifications to the engines which will increase their power to around 500HP with the torque deliberately kept below 1000 NM, we are also increasing the RPM to 3800. The lower units are Volvo castings which i have cut the skegs down and made nosecones for. Apart from running very hot the drives seem to be quite reliable unfortunately due to lack of demand Volvo will cease production in March and i don't think they have any plans to produce a replacement highspeed drive.

Peter

C_Spray

iTrader: (2)

By "lack of demand", I assume that you are talking about the "-R" version, not the DP-H version that shares the samne gimbal and upper. There are lots of diesel stern drive packages being sold over here.

JJones - I saw Weismann's Hammerhead drive, but nothing about modified Volvos...

peterunwin

Hi C_Spray,
When volvo introduced their 400HP stern drive package in July last year they also re engineered the DPH outdrive it has stronger castings, uprated gears and bearings but it only has gear ratios and propellers suited to heavy boats with a top speed of around 45knotts. I think the DPR lower unit will still fit the new upper, i will be trying this in the future. The reason for discontinuing the DPR leg is because they only managed to sell around 20 worldwide in the whole of last year.

Peter

whatta life

could you tell me what modifications you have done on your d6's i have the d6-350's in my formula 400ss and would like to get more hp out of them. my dealer wants me to swap out for the new d6-400 and drives. way to much money for what i want to do. would like to know what can be done and well the drives survive 400hp ?

C_Spray

iTrader: (2)

From what I understand about the D6/400 versus the D6/350 and the old DPH's versus the new ones, the differences go beyond simple tuneups. Your best bet may be to look into trading up to a newer 400SS with the 400's.

whatta life

i want to know what peterunwin did to "modify" his d6's to 400hp and what further mods he is doing to get them to 500hp. i'm going to run the current outdrives until they go boom then upgrade to the newer ones.

i've heard they run very hot on the top, wonder if a drive shower would help.

FIXX

iTrader: (2)

cone clutch drives converted to semi dry sumps ??
i dont think they will last long with out any oil keeping the cones from welding themselfs together..