diesel engin, what size?....

[Guest]

Hi all, back again after a complete brainstorm and a hate for all things electronic.

After spending the last few months aimlesly drifting around the Channel I decided it was time for a bit of speed now and then so, along with the brother, we have bought a 21ft Bayliner. Took it out last week for it's first run and got as far as Maidstone before the temperature went up, the oil pressure went down and smoke started billowing from the engin compartment.

I have had a couple of reasons given, water intake blocked by weed and engin dosn't liked being run at low rev's, it's a V8 petrol lump.

As it has quite a few hours on it I was considering having a new disel engin installed but I have no idea of the hp I should be looking at.

The boat will be used mainly up the Medway and Thames and around to Ramsgate and Eastbourne with the ocasional trip across to France.

So what would you all suggest?...........................

Tim Eades
<P ID="edit"><FONT SIZE=-1>Edited by TimE on 26/08/2002 00:45 (server time).</FONT></P>

 

[petem]

Probably AD31 (150hp) or KAD32 (170hp) would be about right. These engines will set you back about £13k to £16k plus fitting respectively.

Obviously it's going to be a hell of a big job. Have you condsidered a rebuild of your current motor with an LPG conversion?

 

[CJN]

If you are to consider plg, do not forget that a under the 1972 act, a vessel cannot be duel fuel if moored on an inland water way ( boat safety scheme ) it can be petrol or diesel or lpg, but there are no refuel points up stream. Need to look at the condition of your engine, age, hours etc. Is it going to be worth you changing it to duel fuel LPG or re-engine to diesel. Depends on how much you will use the boat. What speeds you may want out of her. You will change to charactoristics of the boat if change to diesel. V8 vers smaller diesel lump!
Engine getting hot at low revs. Have to consider, lazy pump, impella or just flow restriction of the water ways on the block.

 

[MLBURGE]

What sort of speed are you after, assume 25-30 knts.

I would aswell go with the volvo's the AQD31-(150 hp turbo charged) or the KAD32 (170HP turbo and supercharged)

I would go for the 170 hp KAD32 on a duo prop outdrive this would give better acceleration and should give enough power to get around 30 knt's if not more.

I don't no if your existing outdrive will be compatable with the new engine but i doubt it and the duo prop's are exellent outdrives.We have recently re-engined our project 31 with twin AQD31 (130hp) and duo prop outdrives and we get 27-28 knt's
and the total cost including outdrives was just over 20k fitted but we did f/glass the engine bearers and transom ourselves which saved a little bit .We used John hawkins marine at medway bridge marina.

whatever you do make sure you get enough power for what you require, we now wish we would have gone for the more powerfull AQD31 (150hp) because this would have easily given 30 knt's
p.s give me a shout if you need engine bearers glassed or any other GRP work

 

[DavidJ]

You will spend the rest of your life ironing out conversion problems and what you will have left is a very non standard boat which will be difficult to sell on.
I know you have just bought it but my advice is fix it, sell it and buy something a bit more suited to our fuel prices. I don't think you will find many 21ft diesels though, but for the mileage/year that you are likely to do, the economics may only be marginal over petrols.
David

 

[Guest]

Thank you all for the advice. It's certainly given me plenty to think about

 

[BarryH]

Have a look at samurai motors. They do a V8 GM deisel that will be a straight swop for your V8 petrol, or so they say! Now people are going to slag them saying they go pop bang and let you down. So do the V**** everyone else is suggesting. They do a low tune 170hp upto a 250hp turbo job. They dont seem that expensive and you keep the same drive and mounts. Worth a look if nothing else.

OK, to hell with it. Unbolt it and we'll use it as an anchor!

 

[tico]

Forget V**v*s .... Get a FSDTI from Mike at Lansing Marine.
1.... It'll fit the out drive
2..... Its simpler and same power as the AQd31 (140 hp)
3..... It's HALF the cost
4.... Works wonderfully!!!!

 

[neale]

For the record Bayliner fitted 130hp petrol engines to their 21 ft boats as an option. Their figures quite between 25knots (Sunbridge) and 29 knots (Capri) top speeds.

 

[MLBURGE]

The samarai's are worth looking at,we may have considered them but did not have the space in the engine bay for twin engines but you should be ok.

The FSDTI which is basically a marinised 2.5 dti ford transit engine may be ok.We looked at them at the boat show but they have to adapt your existing bell housing which may lower the second hand value of the old engines.The engines may not run as quiet or smooth.

We compared prices and excluding the duo prop outdrives and fitting there is little difference engine to engine between the FSDTI and the AQD31(130 hp)

weve had the AQD31's for a year and no problems at all.

Also check out the fuel figures, you may save money long term.