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Gunboat engine rebuild (again)


Guest catweazle (Banned Member)

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Thanks for your comments,it helps to know people are interested.I dont know why they went for pre combustion chambers,in smaller engines it does make them a bit quieter,hardly relevent in this case.when you look at the design for 1968 it was complicated.I think it turned out too sophisticated and expensive for the application.They went back to simple push rod V8s after that.I think what they do have is masses of bottom end compaired to what else was available at the time.Just one engine in a scrapper was all that was needed.The Oshcosh 8 wheel foam tender had two engines but twin turbos ,it did 100mph.If this engine was made today

and electronicaly controlled it would make 800hp easily.The top revs are 2.200 high i supose compaired to the 1.200rpm of other engines at the time,but not by todays standard.The remarkable thing is it does 15 knts at 1.500rpm,the turbo is only just coming on song ,the last 700 rpm then

more than doubles the boat speed.:cool2:cheers CW.

 

Thanks for the interesting information, and I bet it sounds luvverly when it's wound up. Drool drool............sorry but I just love the sound of big engines. One of my favourites being the big Gardener single cylinder diesel that is often on display at vintage shows. I think the one I'm thinking of is about 90 hp. I stood beside it at Ardingly for about twenty minutes, completely hypnotized by the sight and sound of it.

 

It amazes me the power they can extract from engines now. Eeee when I were a lad 14 litre Cummins engines produced about 220 :shocked: hp and that was a lot in those days. As years went by turbos were added and power went up and they reached their limit in haulage use at about 420 hp, mainly because that was about the limit of the fuel injection equipment. They were years ahead of everything else......four valves per cylinder, common rail fuel system and individual rocker operated injectors. The V8's they used in Ford trucks were the same set up. They also had a similar head gasket arrangement to the Cat engine in your boat. It had a plain steel head gasket (Like 20g), waterways were sealed with silicone 'O' rings and the head gasket sealed on what Cummins called a 'Fire ring' which was a raised lip on the liner. They were real screamers and revved to about 2800 -3000 rpm.

We have a Foden with a Cat C10 (340) in it and that is all electronic. Sadly the installation and electrics don't work too well together. Injectors are about six hundred quid a piece.

I also think that without the quality of modern oils and cleaner fuels, the life expectancy of many of the modern engines would be somewhat limited. 420 hp out of eleven litres is more normal now. Unthinkable in the good old days. Look at the early Mini's ...........40,000 and they were just about clapped out. Take a Metro, twenty years later; almost identical engine, modern fuel and oil and it will go 200,000 + without too much attention.

Sorry I'm rambling again............I do this when something really interests me. :coffee::yawn:

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hi gent, i used to drive a 35 ton cat excovator, and use a mobile concrete crusher, all powered by cat engines, the crusher would run at about 2800rpm any more she would over heat, but the first cat i drove was a 20ton and she used to overheat,. that was put down to oil pressure.???after the fitter had spent a few days cursing and throwing spanners around, you could run her flat out. just a thought.

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Guest catweazle (Banned Member)
attention.

Sorry I'm rambling again............I do this when something really interests me. :coffee::yawn:

You can allways join Andy and get a ride,Sound i would say Lancaster droan.I find the electronic injectors dont last long,its the electric bit that fails.you only need a leak back which lowers the rail pressure and it wont start.

libaryone011.jpg

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Guest catweazle (Banned Member)
a few days cursing and throwing spanners around, you could run her flat out. just a thought.

In my case make that a few weeks,oil pressure is one thing we have never been short of:-Dcheers cw.

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You can allways join Andy and get a ride,Sound i would say Lancaster droan.I find the electronic injectors dont last long,its the electric bit that fails.you only need a leak back which lowers the rail pressure and it wont start.

libaryone011.jpg

 

I would rather listen to the sound of the engines from the shore. Never been too good as a passenger, and worse still on anything that floats. :nut::-X

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The V8's they used in Ford trucks were the same set up. They also had a similar head gasket arrangement to the Cat engine in your boat. It had a plain steel head gasket (Like 20g), waterways were sealed with silicone 'O' rings and the head gasket sealed on what Cummins called a 'Fire ring' which was a raised lip on the liner. They were real screamers and revved to about 2800 -3000 rpm.

 

 

Will, I believe they were not too successful in trucks due to inadequate cooling capacity - in construction equipment with bigger radiators they would go a good 15,000 hours without being touched at all (V555).

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Guest catweazle (Banned Member)

We had a previous pilot boat same hull as mine,it had twin v8 cummins 185 hp cant remember the type no.they were 2.800 rpm.but it was a slow boat only 16 knts,which in 1968 was ok i supose.it had four exhausts and sounded great at speed.It was the standard engine trinity house used for the pilot boats.I was impressed with a coolant conditioner filter,never heard of it before.

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Guest catweazle (Banned Member)
I would rather listen to the sound of the engines from the shore. Never been too good as a passenger, and worse still on anything that floats. :nut::-X

All you can hear on the shore is the cam gears /balancers rattling away.:rofl:

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  • 2 weeks later...
Guest catweazle (Banned Member)

The start up went ok but lots of smoke.no pictures as i was concentrating on the job,it was all very worrying as we had not found the cause.Weather was good for the trial.Andy spent the first hour in the engine room i bet his ears are still ringing.one small sea water leak,oil leak at speed from rocker cover on the other engine from a bolt gone missing,it squirted on to the turbo of the port engine.i could of bought a sherman with the insurance money.Bugger.another leak from a bolt hole that never had a bolt in it but never leaked before,how do these things happen,is there people up above having a laugh,if there is and i get there cant wait to play.I varied the speed quite a lot never went faster than 24knts and not for long.all in all encouraging.had no water temp/rev counter/oil light due to the wiring getting a bit of abuse when we were working on that side.more work,now it needs its new props and a bundle of money for this years moorings which i aint got.maybe i should start a friends of Horatia charity.

As theres no footage,heres some old stuff from happier days,a race to selsey bill from Bembridge home of the Nelson.They made me start at the back.

th_bembridge2007.jpg

Afraid theres a bit missing got timed out .i won of course.:yay::yay::yay:

Edited by catweazle (Banned Member)
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Guest catweazle (Banned Member)
The oil leaks and missing bolts......Sods Law:cool2: How fast were you going in that race and whats the fuel consumption? or is that something you don't want to think about:-D

Well Deryck it was before the engine rebuild the 1st time so we had low compression on 4 pots,about 32 knts 0.75 of a mile to the gallon at max revs.We also had a race round the island one year ,i can cobble up some video of that if you like,still got more from the quarry.and AWDC to come

better retire now so much to do work gets in the way.:-D

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Guest catweazle (Banned Member)
Like the commentary on the video. :-)

 

Glad it's all working well after the rebuild. Time to start enjoying it again.

So am i mate,but it will be a while before i stop worrying about the cause i think.Only all the painting that didnt get done last year and the gauges to get working .and the radio that wont transmit.and,and.and getting a headache allready. :-D

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I thought you were combining a boat ride with the duties of an engine test mechanic Andy! Please ignore all the scribble then. I was all envious there for a moment! Can you explain your latest avatar? Looks like something in grey primer but can't see where it would fit on an Explorer.....

 

Oh heck it's the jib isn't it!!!

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