Engine Upgrade - Perkins 4107 to What?

[snowbird30ds]

I rebuilt and marinised a pair of non turbo xud9's and fitted to an rlm31 (same hull) on enfield 130's and it worked well as long as you like 7 knots everywhere, I think it was a company called streamline environmental I got the manifolds from, I made my own first but the weld seams kept cracking.
I have lots of piccies somewhere of the job.

 

[SteveNotlob]

I rebuilt and marinised a pair of non turbo xud9's and fitted to an rlm31 (same hull) on enfield 130's and it worked well as long as you like 7 knots everywhere, I think it was a company called streamline environmental I got the manifolds from, I made my own first but the weld seams kept cracking.
I have lots of piccies somewhere of the job.

I would have thought you would get more than 7knots with a pair of the XUD's ! :-( That's about what I would expect with the old 4107's...
I would appreciate the photos. I think i came across your website but some of the links just came up as blank pages.
Cheers.

 

[snowbird30ds]

It would do a bit more but was mostly going uphill wasting diesel so I stuck to hull speeds.

 

[Restoration man]

I would have thought you would get more than 7knots with a pair of the XUD's ! :-( That's about what I would expect with the old 4107's...
I would appreciate the photos. I think i came across your website but some of the links just came up as blank pages.
Cheers.

My dad had RLM 31 with 4108s we could get more than 7 knots but the problem was you couldn’t see over the dash board the the nose would come right up in the air, about 30 years ago my dad foolishly let my brother and me then aged 13 me and 11 my bro deliver the boat to Upton boat sales from our mooring on the Avon after he had bought a different one under king johns bridge through the lock once on the seven with no personal belongings on board no water not much fuel we tried to get her to plane wouldn’t happen but we had fun washing the fishermen off the bank, ???

 

[snowbird30ds]

I just pm'd you about piccies SteveNotLob.
Mine used to go sky high with the throttle full open but it had trim tabs that could bring the nose back down enough to see, still not enough to plane though, about 8-9 knots absolute max but unrealistic for any distance, 2500rpm was comfortable 7 knots with 14 x 10 props on enfields, would have probably done better on finer props as it would only rev to about 3100 so not getting full hp.

 

[Ferris]

Considering the enfield drives won’t get you more than displacement speeds and you already have the engine bay torn apart would it be an idea to rethink your plan and fit a bigger single engine with a matching drive. The project 31 that princess did did 17kts on a single D3 170.

I’d be thinking a suitable used 4cyl turbodiesel like a Kad32 would do the trick. Would require decent GRP skills also to block up the original drive openings and to glass in new engine bearers.

 

[SteveNotlob]

Considering the enfield drives won’t get you more than displacement speeds and you already have the engine bay torn apart would it be an idea to rethink your plan and fit a bigger single engine with a matching drive. The project 31 that princess did did 17kts on a single D3 170.

I’d be thinking a suitable used 4cyl turbodiesel like a Kad32 would do the trick. Would require decent GRP skills also to block up the original drive openings and to glass in new engine bearers.

My DIY skills are not good enough to do any of those jobs myself so I can imagine employing someone to do it for me is not going to be cheap. Also, I prefer having 2 engines instead of the 1 TBH.
My old MP31 originally had enfield sterndrives fitted but the old Perkins engines had been removed prior to me buying it and they was replaced with IVECO Turbo Diesels that were rev limited (i imagine to keep the torque figures within spec for the sterndrives).
I later replaced the Enfields with Volvo Penta's and had the engines adjusted to achieve their normal RPM range.
I was able to easily achieve 14 knots cruising and could push around 17 knots maxxed out.
With the enfields and derated engines It just about got on the plane if I had less than 1/2 tank of fuel and low fresh water.
I also lightened the vessel where I could, and guess I removed some 200KG of 'stuff' !!

 

[Jim@sea]

Its a shame that in the 1970/80's when the UK was building loads of boats that we only seemed to fit either Volvo or Perkins, and to some degree BMC Diesels (Thornycroft) etc. There was a great range of Italian Engines which were not fitted by any UK manufacturer, i.e. IVECO. (Fiat) (Marinised as AIFO)
I bought a 1986 French Boat (Guy Couch) and it had the IVECO 72 hp Diesel Engine which was fitted into all the IVECO Daily Vans.
If you could get a couple of these engines they would be ideal as they were extremely reliable and parts are available as there are loads of Iveco Dealers.