ORIGINAL: T3beatz
No prob, do you think i would have problems with the grade 3 bolts on there. the're either 10/24 or 1/4 size bolts i have to check? I can't find an other type thats long engough. I get my standoffs from PSP Mfg, they don't carry a 4 inch bolt and that is whatz needed to get the clerance from the cow... these seem strong, I don't think they would break unless I was to go down and even then I think the firewall would break first....
If that was my airplane, I wouldn't use metal standoffs of any kind! The mounting lugs on the engine don't appear to be very large and I would be affraid that any twisting or rough handling would remove (break) them from the engine case! To prevent twisting, I would use some kind of wood standoff. Or better yet, build out the motor box and add another firewall that you could mount the engine to with shorter bolts, fender washers or very short standoffs. Then you will have no problems getting good bolts of the proper length. I would believe that any bolt will be stronger than those tiny cast aluminum lugs and I would do everything I could to keep them attached to the engine case.