115 Crossflow Stripped Important Bolt

[Fisher29]

So when I rebuilt my 97’ 115 crossflow I forgot to put one of the hooks that holds the wiring harness behind a bolt, last summer I took the bolt out and put the hook behind it when I tightened it I stripped the threads accidentally, the motor lost 500rpm off WOT from this (guess it had a important job), As a short term fix I put a wire between the threads and bolts and it held for a bit but not anymore (no matter how thick of a wire), Should I drill it out, thread and helicoil it or what can I do to fix it, Threads are on the case half, the bolt mates the intake manifold to case, have included it in a diagram, the bolt is number 40, any help would be appreciated.

 

[Chris1956]

See if you can use a slightly longer bolt. There may be enough threads to hold.

If not you will need to drill and retap for a solid or helicoil insert.

 

[stresspoint]

do it once and be done , helecoil should hold ok there , if the hole is now too big which it probably is being a course thread ,,option, B time sert .

 

[Fisher29]

See if you can use a slightly longer bolt. There may be enough threads to hold.

If not you will need to drill and retap for a solid or helicoil insert.

I did find one a bit longer but it had different threads, I jammed it in there (stupid me) and it seemed like it got tight but I think it was just the threads cross-threading, I don’t think it tightened the intake manifold to the case properly as it was running the same as withought the bolt. And after that the threads were just F’ed. So dont know how that will effect the helicoil size if at all, another thing with the helicoil is I don’t know where the tab will fall in the block (if at all) when I punch it out.

 

[racerone]

That hole may go straight into the #1 crankcase.--I can confirm later when looking at a block.-----You are loosing crankcase compression and suction. -----Do not run this motor until you sort it out.

 

[saltchuckmatt]

Yes, only fix is to do it right. If the motor was affected then you have a problem. Remove intake, fix bolt hole, clean and inspect everything....re-install.

You may want to do a compression check first to see if you burned anything up.

I wish you well.

 

[Crosbyman]

another thing with the helicoil is I don’t know where the tab will fall in the block (if at all) when I punch it out.

maybe you can just leave it in place and install a bolt that will not extend beyond the back threads ... leaving the tab in place. In any event its rather small and worse come to worse it may not cause any problems lying at the botton of the cc.

any chance it could go in backwards & installed with red loctite. you could snap the pin with long nose pliers ???

otherwise install it properly and use tiny long nose pliers to snap the back pin.. Crafts stores have very small long nose pliers for delicate work.

Amazon.ca

 

[racerone]

Just install a helicoil and do not worry about the wee tab.-----The hole does NOT go into the crankcase.---Just checked.----And it would not cause a loss in performance.---I would say do some trouble shooting and do not run the motor until you sort this out.

 

[Fisher29]

Just install a helicoil and do not worry about the wee tab.-----The hole does NOT go into the crankcase.---Just checked.----And it would not cause a loss in performance.---I would say do some trouble shooting and do not run the motor until you sort this out.

Yeah it didn’t seem like it was too important but when it effected my WOT RPM by 500 got a bit worried. Compression is still 130psi in each after rebuild, My #1 plug looks a bit black so thought maybe the carb wasn’t feeding it gas because it wasn’t tight, leaking the fuel elsewhere rather than in the cylinder. Which might make sense because that’s the only bolt mating the top half of the manifold and it’s that top cylinder.

 

[racerone]

That missing bolt does not cause compression issues in the crankcase.---And it cannot cause fuel to leak elsewhere in my opinion.----Find the real issue.

 

[Fisher29]

That missing bolt does not cause compression issues in the crankcase.---And it cannot cause fuel to leak elsewhere in my opinion.----Find the real issue.

Can you check on your block where this other bolt goes into, as this one also stripped on me but I put in a different bolt of same length but cross thread, it’s tight but might not actually be tightening anything, I’m gonna be repairing this one too. Number 14 in diagram,

 

[racerone]

Hard to believe these issues of stripped / damaged threads.

 

[Fisher29]

Hard to believe these issues of stripped / damaged threads.

Was likely not the first time it had been opened up. Any idea if that second bolt has anything regarding its performance, or where it goes too/what’s behind it?

 

[racerone]

I believe it is a blind hole.----Do some real trouble shooting as to reduction of RPM.

 

[jimmbo]

People need to realize, that Aluminium is NOT a Hard Metal, and very easy to Damage. I expect the threads in any Aluminium casting to shear every time I unscrew a Fastener from them

 

[racerone]

I use an impact to take motors apart.----No impact driver when putting a motor together !

 

[jimmbo]

In the late 70s, early 80s there allegedly was a Mechanic, at a St. Albert AB Dealership who assembled Powerheads with an Impact. Apparently it had a lot of Warranty Claims, long after they fired him

 

[havoc_squad]

In the late 70s, early 80s there allegedly was a Mechanic, at a St. Albert AB Dealership who assembled Powerheads with an Impact. Apparently it had a lot of Warranty Claims, long after they fired him

Oh brother, someone's residual disasters floating around with the uga duga gun.

Sounds like the typical retail hiring mess where people get fired/leave after a couple of days of just giving zero cares. Not a matter of dishonest job listing, nor a bad employer.

 

[Fisher29]

I just stripped em out tightening by hand. Was bound to happen I guess. Only 2 out off all of them, and I didn’t think they were too important otherwise I would have fixed them right then and there before installing back on boat.

 

[racerone]

What torque value did you use ?