AWM Posted March 23, 2008 Share Posted March 23, 2008 Hi ALL.... Maybe a daft question, but I am putting an Irvine 46 on to a Black Horse ARTF, but have lost the mounting bolts. The engine is mounted inverted on some sort of plastic engine mount. I need to drill the holes for the engine on the mount. What sort of bolts should I use? I was thinking about standard 3 mm bolts, secured with Nylocs and threadlock. Should that suffice? Cheers.. Alan Quote Link to comment Share on other sites More sharing options...
Helidel Posted March 23, 2008 Share Posted March 23, 2008 If engine holes are large enough use 4mm socket head bolts, and 2 std nuts on each or use threadlok, some types of Nylocs are affected by heat and can come loose! Quote Link to comment Share on other sites More sharing options...
AWM Posted March 24, 2008 Author Share Posted March 24, 2008 I can't get 4mm bolts into it, so will use the same arrangement with 3 or 3.5 mm bolts. Thanks for the info Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted March 24, 2008 Share Posted March 24, 2008 I wouldnt worry AWM .On the full size Islanders I've worked on, the 6 cyl Lycomings are held by 4 X 6 mm setscrews each .Make you think about over engineering Eh ? Quote Link to comment Share on other sites More sharing options...
AWM Posted March 24, 2008 Author Share Posted March 24, 2008 Haha.. nice one, the mind boggles.. or under engineering? Quote Link to comment Share on other sites More sharing options...
Ernie Posted March 24, 2008 Share Posted March 24, 2008 Suppose I'm a peasant, but, on small engines (40 etc) I use self tappers with a locking spring washer below the head..Self tappers with allen heads are very nice. but no problems in many yearsernie Quote Link to comment Share on other sites More sharing options...
AWM Posted March 24, 2008 Author Share Posted March 24, 2008 Thanks Ernie.. good info. So I can just drill the mount out to accept a 3.5 mm self tapper, with a spring washer at the head as you say. That is fine for mounting the engine onto the mount? Just clarifying that you don't mean the self tappers for the mount itself onto the firewall. Quote Link to comment Share on other sites More sharing options...
Ernie Posted March 24, 2008 Share Posted March 24, 2008 Hi Alan, No No...... Not self tappers into the firewall..Most common are spiked nuts from behind the firewall, with bolts into them...But, much better look at the just engines website ( a wonderful place) they supply bolts with a rubber sleeve that you insert from the front of the firewall, and lock when you tighten them up..Also good for keeping the decibels downernie Quote Link to comment Share on other sites More sharing options...
flytilbroke Posted March 24, 2008 Share Posted March 24, 2008 3mm set screws although strong enough for the job are a loose fit in Irvine mount holes as the holes are 3.5 mm. Not a major problem, can muck up the engine offset a little. For self tappers mind not to drill the pilot holes in the GRP mount too large though, the self tapper screws need to "bite".I do not like the poor bolts sold by many dealers as "engine mounting bolts" as the heads on them are often rather small. Quote Link to comment Share on other sites More sharing options...
Andy Green Posted March 25, 2008 Share Posted March 25, 2008 M3 or M4 what ever fits the engine, but I alway tap the nylon mounts (well all mounts really) , and use a lock nut.Andy Quote Link to comment Share on other sites More sharing options...
Snorbitz Posted March 26, 2008 Share Posted March 26, 2008 I had to laugh when i read this article.....i've just spent days trying to find 3.5mm screws for my Irvine 53 and couldn't get any anywhwere. Then somebody suggested "4BA" screws and nuts....PERFECT...they are about 3.5mm and do just nicely thankyou. I'd rather not drill out an engine mount to 4mm unless really ness and like flytilbroke said 3mm could leave you with a strange engine offset. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted March 26, 2008 Share Posted March 26, 2008 Yeh & 6 BA is a perfect fit in an 1/8" hole & 8 BA in a 3/32" hole .Bring it all on back ! No problems then ! Grumpy Myron for lots of reasons .Now my new digital TV doent work cos there was a power cut !! re - installed the old system .Worked for many many years Not two days! Quote Link to comment Share on other sites More sharing options...
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