nath 131 Report post Posted March 21, 2014 I'm in a bit of a pickle. One of my boats has a Perkins Prima M50 50hp diesel. It was left to sit for a long time (I have recently pried it off the old owner) with salt water in the bilge and anodes non- existent. Long story of discovery short, the alloy sump and bellhousing are TOAST. Each is 30% corroded to mush. NLA from Perkins dealers (1989 motor wtf??) and no parts in NZ. I am a design engineer but a fresh one. I can get a new sump made by profile cutting to drawing, and welding a box to it. The bellhousing however is more challenging as it is dished. Does anyone have experience in making/ designing bellhousings? I do not have access to a 5 million dollar CNC machine but have access to most else. Any magical resources for bolt patterns of engines perhaps? Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 21, 2014 (edited) Go fishing, pull the plug, get into a dinghy, have a beer and put a line over the side and catch a cold. Works all the time and gets rid of an old piece of sh*t.. (Perkins) Edited March 21, 2014 by *Glenn* 1 Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 21, 2014 Back on topic What brand, model and history on the boat ???... Engine & trans configuration, launch, motor sailor, yacht etc ??? Quote Share this post Link to post Share on other sites
allan 295 Report post Posted March 21, 2014 have a look at this lot any help http://firesales.co.nz/Perkins%20Prima?p=gcb&gclid=CPm-zsjior0CFQJxvAodOZcARQ http://www.marineengine.com/boat-forum/showthread.php?2719-Perkins-Prima-50-hp http://www.parts4engines.com/index.php?main_page=index&cPath=55 If you wanted to replace the motor complete http://www.boatsandoutboards.co.uk/inboard-engines/perkins-prima-m50-50hp-marine-diesel-engine-112-hrs-only-matched-pair-avail-PAA90171 PRM 80 gearbox if required http://www.prm-marine.com/shop.php?sec=prod∏=5&product=prm80 Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 21, 2014 Hey most perkins are good! This one however wasn't the best model. Used in Austin/ MG cars around 1990. 28 ft 1930 Hard chine, stepped sheer bridgedecker. I don't boat to fish although nice to do to get lunch when cruising. Here are my babies Quote Share this post Link to post Share on other sites
elmarco 56 Report post Posted March 21, 2014 Hey most perkins are good! This one however wasn't the best model. Used in Austin/ MG cars around 1990. Are you mad?... Seriously. I'd be replacing it with something more reliable. Like a 50 year old hand grenade.... 1 Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 21, 2014 20k would have me a new motor in it..... But this is a project and I have good connections service wise, just not to magic up a bell housing :s Sent from my GT-I8190N using Tapatalk Quote Share this post Link to post Share on other sites
Allanw 1053 Report post Posted March 21, 2014 Just buy a chevy V8 petrol. It'll be a shitload faster, a shitload cheaper, and you'll probably never spend the difference in fuel costs running it. 40 knots should be sufficient 1 Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 21, 2014 I'm talking to the wrong people about classic boats.... sigh! Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted March 21, 2014 Is it possible to machine whats left flat then tap studs in and just make a deperate bottom section out of plate steel. Or stainless? Would have as much strength as thick cast alloy. Just depends if stuff like starters are mounted in them. Sent from my GT-I8160L using Tapatalk 2 Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 21, 2014 (edited) Just buy a chevy V8 petrol. It'll be a shitload faster, a shitload cheaper, and you'll probably never spend the difference in fuel costs running it. 40 knots should be sufficient Speed in a displacement type boat is restricted by hull design. You can fit double the design HP in a displacement launch or yacht and it will still only do it's maximum displacement speed due to hull design. You'll probably just end up sinking it as the prop will push the stern down, not forward . Motor / prop / hull design is a drawing board calculation with a lot of experience included. The MS is a Solar isn't it Nath ??. Edited March 21, 2014 by *Glenn* 1 Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 21, 2014 Someone might have second hand lying around . You tried these guys ?? http://www.nzmarine.com/directory/business/transdiesel Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 21, 2014 Transdiesel are my resource as one of their managers is part of a separate classic yacht trust we have. She isn't a Salar 40 but looks similar. In fact is the sister ship to an English boat designed as a sport fisherman for the head of then BOAC (British Airways) but with aft cabin where the cockpit would be. Her 120 ford shits all over a Perkins. Currently chasing a lead in picton of a Perkins for parts Sent from my GT-I8190N using Tapatalk Quote Share this post Link to post Share on other sites
elmarco 56 Report post Posted March 21, 2014 I'm talking to the wrong people about classic boats.... sigh! Guess so - my definition of classic boat is a mid 80's Apache or Cigarette.... Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 22, 2014 Ok so may be do-able after all. The axial length is only about 100mm so I can get away with cylindrical, as I was remaking the engine box cover anyway so will modify to fit. The engine bolt pattern (although it's just a plate anyway) is SAE, and the trans end is standard Borg- Warner so I reckon it's not such a difficulty. I'll just not include the redundant holes etc. Quote Share this post Link to post Share on other sites
hybrid 1040 Report post Posted March 22, 2014 You are probably looking at sand and casting one up. There is an outfit in Glenfield who have a foundry who can do such things. Its not cheap however and would will still need to get the rough cast milled to spec. Still a lot cheaper than CNC. I have a friend who makes parts for race cars and he produces stuff through these guys for the race market. Quote Share this post Link to post Share on other sites
elmarco 56 Report post Posted March 22, 2014 There is also an outfit in Otahuhu that can do castings - Supreme Steel from memory. Maybe cheaper to replace the engine than a one off bellhousing though.... 1 Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 22, 2014 You are probably looking at sand and casting one up. There is an outfit in Glenfield who have a foundry who can do such things. Its not cheap however and would will still need to get the rough cast milled to spec. Still a lot cheaper than CNC. I have a friend who makes parts for race cars and he produces stuff through these guys for the race market. Cast would work, but yep big cost getting it right. My idea is draw up 2 plates on solidworks once I have the exact bolt patterns, give the .dxf to Profile Cutting Services to make up, then to another firm beside my work in East Tamaki to form sheet steel into a c.314 diam x 100 long cylinder then weld the plates to each end. With cutout and guard for starter obviously. Quote Share this post Link to post Share on other sites
aja540i 1905 Report post Posted March 24, 2014 Cast would work, but yep big cost getting it right. My idea is draw up 2 plates on solidworks once I have the exact bolt patterns, give the .dxf to Profile Cutting Services to make up, then to another firm beside my work in East Tamaki to form sheet steel into a c.314 diam x 100 long cylinder then weld the plates to each end. With cutout and guard for starter obviously. The trick is getting the two shafts (engine and gearbox) lined up EXACTLY. You may need to make a special jig that holds the 2 shafts in place while you weld the bits together, or a dummy shaft that locates the centres of both plates. I dont think the sand casting is as expensive as it sounds, remember with sand casting they cant reuse the mold, so every casting is a "one off". If you make the pattern the casting might be quite cheap, it will be the machining afterwards that is expensive! Good luck! Quote Share this post Link to post Share on other sites
nath 131 Report post Posted March 25, 2014 Have gotten the bellhousing off a 4-108 which has mostly the same holes, may need to tap some new. Starter looks like it will line up but must test fit. Will also need to make a new mount for it on one side. Will update here with the sump build. Quote Share this post Link to post Share on other sites
nath 131 Report post Posted May 8, 2014 Boring update, I have adapted an old (old doesn't mean cheap with marine parts sadly ) Perkins 4108 50hp bellhousing with Borg Warner adapter plate for the velvet drive. Luckily these are roughly SAE so have standardised diameters and concentric input/output. The sump which was also fried is being remade in steel then galvanised for extra protection before painting on the outside. Costing an arm and a leg, and disappointingly taking a very long time too. Quote Share this post Link to post Share on other sites
