Hello Skippers hope all is well with you all out there! I'm looking for the answer to a flanged bolt selection for my over 30 bolts that secure my exhaust baffle cover plate to my 1991 Mariner 115hp L4 2 stroke powerhead...can I use the auto parts yellow zinc flanged frame bolts class 10.9?? they are my size and length but will they hold up to the heat and not cause a leak in the gaskets or warp my baffle plate? stock Mercs are 8.8 grade yellow zinc 10.9 is equivalent to grade 8 not 8.8.... I'm not sure if they will hold up with that exhaust heat because they aren't the 8.8 grade.. Anyone know this answer with 100% assurance I do not want to warp my baffle plate and screw up my finally done new powerhead rebuild...Thank you Skippers!! Pond Jumper.....
Overthinking I believe.------I would just use some off the shelf stainless bolts for that.-----That exhaust system is water cooled and does not get really hot !
Thank you racerone you are awesome! I am over thinking yes I am it drove me nuts for over a week on this I could of been on the water days ago! Lol"..... I am very much appreciated for you to reply to this.... Again Thank you very much!
got better then stock bolts and there all coming loose each time I run it happen twice to me my plates are new motor was checked for warp at shop and for leaks ect...I have a great Torque wrench that's dead nut accurate use it on all my motor builds for motorcycles ect ain't my wrench looks like any old bolt won't work for me but mercury ones... I got grade 8 darn bolts also zinc plated same as stock ones went 10mm longer in thread stock are 35mm long I bought 45mm ones from a fastener company not run of the mill stuff..the hole is touch over 50mm deep have plenty of great tight threads.. I get a stronger better flange bolt and there coming loose big-time over half of them twice now crazy!! No water in cylinders thank god...I did use oil on tips of bolts to help my threads stay good after the Re tapping of thread holes and grease on my flange very very little I'm not gonna use lock washers or serrated washer under flange I'll leak at the bolts heads can't use loctite on my aluminum block and strip my threads next time coming out seen that happen to my bike cases and heads when I was younger and greener!! Lol" I'm lost!!
Nope I have 10mm of thread space before bottoming out... My old bolts are from 1990 there missing metal at the top of the shank they are not 8mm thick anymore Mercury discontinued my bolts.. and there 50 mm ones I can cut to size but there over 150 bucks! Crazy.... With untouched threads my new bolts should be locked in place for many runs...my muskie season is weeks away I'm snapping lol" I'm going to sleep on this one I can't afford a new motor to go bad sucks racerone... Pond jumper...
My new bolts are 12mm hex heads and 17mm flange...stock Mercs ones are 10mm head 17mm flange.... I wonder if that's my issue not enough flex in the flange to grab my cover hole raised area of the mounting hole? Maybe I'm thinking only thing I can figure so far lol"...Pond jumper
Lol" One night sleep always gives me my answers to problems purchases and tuff decisions try it sometime lol"...I fixed the loose bolt issue on my exhaust baffle cover plate it's working fantastic! I used thin stainless steel internal tooth locking washers all 35 bolts are very secure and are not backing out for long time I added 20% more torque to the 18lbs torque specified in manual because of the added grip of the internal tooth locking washers throwing the torque off some there grabbing my raised flanged bolt holes on the cover plate Great! ya when the next time I take cover off I'll have tooth imprints in my aluminum flanged holes I don't care I'll be dead in year or two anyway no issue to me....I'm going fishing finally after two years of waiting!! ��
