Cam cap bolts stripped

When doing one (or 16 as it were) of these thread repairs be very careful to drill and tap the hole straight. If the head is off the bike using a drill press can help. It's quite easy to install the insert crooked so please take your time.

LarryC wrote: See this all the time..... Just had to repair all 16 holes in a head. All got helicoils. You can't easily use time-certs on cam tower bolt holes. Helicoils are much easier for that application and will suffice.

Have had heads come in with broken off drill bits and broke off taps in the same hole. Those are always fun.

It's always the 4 bolt caps you see this with. Rarely do you see a 2 bolt cap with stripped out holes. THAT ought to tell you that dowel pins located on opposing corners of a 4 bolt cap require a little bit of attention when installing the caps. The problem that causes this is almost always binding on the dowel pins because of improper tightening and not paying attention to checking the pins for burrs, the cap for burrs and making sure the pin is in the head with the tapered end up.....and last but not least.... apply some oil to the dowel pins, the caps and the bolt threads.

As long as these motors are around there will be stripped cam tower bolt holes. That's as certain as the sun rising in the east.

Larry don't forget to mention the idiots that should not ever have a wrench in hand ! :evil:

So I went with the helicoils. A previous contributor pointed out there's a special tap timeserts use to get the insert below the bolting surface and it doesn't seem to work for this application.

I think I saw someone mention using locktite to secure the coil in place, any opinions? I've got about a week and a half to think about it with my thumb up my bum. I guess I'll continue degreasing and other bits of maintinence from my factory service manual.

I'll be sure to post pictures and such on how it went and how I feel about the product.

Cheers!

DFIGPZ wrote:

LarryC wrote: See this all the time..... Just had to repair all 16 holes in a head. All got helicoils. You can't easily use time-certs on cam tower bolt holes. Helicoils are much easier for that application and will suffice.

Have had heads come in with broken off drill bits and broke off taps in the same hole. Those are always fun.

It's always the 4 bolt caps you see this with. Rarely do you see a 2 bolt cap with stripped out holes. THAT ought to tell you that dowel pins located on opposing corners of a 4 bolt cap require a little bit of attention when installing the caps. The problem that causes this is almost always binding on the dowel pins because of improper tightening and not paying attention to checking the pins for burrs, the cap for burrs and making sure the pin is in the head with the tapered end up.....and last but not least.... apply some oil to the dowel pins, the caps and the bolt threads.

As long as these motors are around there will be stripped cam tower bolt holes. That's as certain as the sun rising in the east.

Larry don't forget to mention the idiots that should not ever have a wrench in hand ! :evil:

Let's not forget that good judgement is learned from bad judgement, and sometimes bad judgement is catestrophic, and that shouldn't stop us from mentoring the ignorant.

Ignorance is treatable. There's no cure for stupid. :lol:
Steve

Kz_Café wrote: I think I saw someone mention using locktite to secure the coil in place, any opinions? .
Cheers!

Don't bother with Loctite as it is "Anaerobic" which means it only cures in the ABSENCE of air and therefore not suitable with the inserts open coil design.
The locking action of the insert expanding once installed is sufficient.
Do not use Loctite on a Helicoil/Wire coiled insert repaired hole as the Loctite can bond the insert to the bolt which can then lead to the insert winding out with the bolt on removal at a later date.

I followed these instructions and have had no issue in doing so....

Helicoil Instructions/procedure

Rather than just relying on the HeliCoil spring tension to retain the insert, is there any way to positively lock the insert into the housing threads?
The following methods are recommended to help secure an insert into the housing...


Apply a light coating of Loctite Thread-Locker compound to the external portion of the coils of the insert prior to threading it into the housing. If this method is used, be sure not to apply too much Loctite and be sure to wipe the internal threads of the HeliCoil insert clean after it is installed so that the fastener does not bond to the insert.

Interesting, I see both sides of the coin. Kinda seems like risky business applying locktite to the coil, how about a light coating in the outer thread the coil inserts to. Seems like a viable option to mitigate any excess thread locker getting on the bolt and binding everything up.

I haven't needed it and never had one come out.
Steve

I have installed dozens of helicoils in cam cap bolt holes, never had any that came back out and I installed all of them dry.

I would also vote dry. Imagine the headache if some Loctite ends up on the bolt. Loctite can stay liquid a long time in open air.

BTW, 550's have all two-bolt caps. No four-bolt caps.

Had 2 I trust outta 4 say to use it and 2 not......... Jay from APE was the 5th and deciding vote with another no on the locktite. (After driving 50 miles for a high temp special red too). :S