jmcowart

Does anyone know for sure about the compatability of CA with the standard new Glass Filled Nylon Engine Mount as found with the GP Big Stik?

My question stems from my installing a four stroke (O.S. FS-95V) engine on a Big STik .60 using the provided engine mount. I understnad that is glass filled nylon. I ended up using the Dubro 4-stroke throttle linkage which required drilling and tapping into the side of the mount for the lingage arm.

Idid all that, then had to take it back off to hook up the throttle arm, etc. Point is, the 4-40 socket head bolt seems to now be a little loose in the hole. I am concerned about it not holding.

Question is - would there be a problem using medium or thick CA to lock the bolt into the nylon mount? Or would there be some kind of compatability issued between the CA and the glass filled nylon?

Or am I just making problems where there are none?

If any of you have been there and done that, I would sure appreciate your thoughts and advice. Maybe there is something Ishould do that I'm not seeing..... Thanks much. Mike.

big max 1935

My Feedback: (9)

4-40 seems small. Use a bolt or screw that fits the engine beam holes or drill all the way through & use a lock nut . Max

Charlie P.

Probably compatable, they ship CA in Nalgene type polymer bottles.  Nylon being a ploymer as well.

But some day you will want to remove that engine bolt.

I'd use hard/long cure time epoxy and re-drill a pilot hole.  You can get fancy and mix flocked glass in with the epoxy for added strength.

Gray Beard

My Feedback: (-1)

Next time try using a tap and cut the threads into the mount. No problem with CA. I cut the threads then float in some CA then cut the threads again. It just hardens the threads just like with wood.

jaka

Hi!
Why have the throttle linkage routed like that???? The easiest way is to just drill a hole in the firewall and attach the linkage (Sullivan thinnest wire)direktly to the trottle arm!

landeck

My Feedback: (1)

CA is compatible with GP glass filled engine mounts. I use it to tack glue the two halfs together when fiting an engine.

Bruce

JohnBuckner

My Feedback: (1)

If I read correctly I suspect what is loose is the Dubro pivot bolt which is threaded into the side of the engine mount with that type of linkage, not the engine beam bolts and 4-40 is the size used.

JM yes what you suggested is an appropriate solution that is likely to work. If it were me I would use instead blue locktite but thats just me.

Since you already have the linkage set installed and functioning great but perhaps on your next ship try what Jaka mentioned. What I do is similar and involves where the throttle is too close to the fire wall I simply make a much larger hole in the firewall and somewhat differently I make most all my throttle pushrods out of thin piano wire around thirty thousanths and that provides even better flexability than the stranded cable and often does not require any outer housing at all.


John

jmcowart

What great, thoughtful, responses. Thanks very much guys. The ideas help a great deal.  In response:

4-40 was recommended and furnished by Dubro as part of their four cycle engine throttle linkage kit.

Can't put nyloc inside the mount arm as it is too close to the engine when installed.

Good thought on the epoxy.

I did cut threads into the mount side. First drilled with #43 pilot drill, then cut with 4-40 tap. After taking the bolt out twice, it seems to have wallowed-out the hole and threads and I wanted to eigher reinforce the threads and/or just glue the bolt in place.  I would hate to have it fall out....

I installed the Dubro 4-stroke linkage as the tank and the portion of the mount against the firewall block the direct line.  Also, as the tank and eveything was already installed there was no easy way to work around it.   I had a U-shaped bend in a 4-40 rod from the servo, but do to my ineptitude, I had locktited (is there such a word?) the rod to the fitting on the engine throttle arm and could no longer adjust is as needed - so I just took it off and started over with the Dubro linkage.......

There is an off-set from the engine throttle arm ( nearer to the centerline of the engine) to the servo rod and linkage (on the outside of the engine mount arm), so I could not come straight to it from the firewall, given the position of the mount frame and the fuel tank.  I kind of had to use the pre-drilled hole for the pushrod which is offset to the side from the throttle arm centerline location.

As it is, i had to make two 45 degree bends in the linkage to line up with the engine throrrle arm..

Thanks, Bruce for the confirmation of compatability of CA and glass filled nylon.  I'm ging to toss and turn tonight, fret and dither some more and use either med CA or epoxy - The linkage may never come off wihout use of a dremel, but at least it won't fall off (I hope).

Many thanks for the discussion and ideas.  It really helps to have this forum and access to people who know what they are doing..

MIke.

blvdbuzzard

CA the hole and re tap. I use thin for fresh threads and CA+ for worn threads then re-tap. CA will not melt of harm the motor mount.

You might have crossed the threads and that is what augured out the hole a little.

I use CA on the threads for the engine mounting bolts.


Buzz.

jester_s1

I'd suspect it was cross threaded too. I have threaded screws in and out half a dozen times before and not even felt them get looser in the holes, let alone wallow it out to the point where I was worried about losing them.

GREG DOE

John, About 30 years ago an acquaintance actually glued a broken Kraft fiber filled nylon engine mount back together with thin CA glue. It was long enough ago that he probably used Sattelite City "Hot Stuff". As I recall it was a .40 size, and he flew it after the repair. CA works great on glass filled nylon.