Jump to content
Ultimate Subaru Message Board

Blown threads on cam seal cover


kmpdx
 Share

Recommended Posts

Hi guys,

I am finally doing the front seals, timing belts, water pump, etc. Reassembling yesterday and the upper bolt on the passenger cam seal cover kept turning. I backed it out and there was a helicoil stuck to the bolt from a previous repair! I was careful but had I known I would have babied it more. Anyway, it still held a little torque (3 lbs maybe?) and I put blue threadlocker. I still need to get the belts on tomorrow and get it all back together. I am thinking even more of not putting the timing belt covers back on to keep an eye on the seal and all the new work.

What do you guys think? should I attempt a different repair or just hope it stays together? The bolt tightened  fine on the bottom and the design of the rear of the seal holder seems to offer support but there is a lot of vibration there I would think. Should I try another helicoil or some other adhesive? Maybe tap an M8 hole with an M8 bolt of the same length?

Thanks,

kmpdx

Link to comment
Share on other sites

Heli coils obviously worked fine , and there’s options too. In certain situations you may prefer something like I use - Timeserts. They are a bit pricey but you get what you pay for. That said you can also find simple heli coils on multi million dollar machinery. 

An insert allows you to bolt up and be able to remove that bold as well without any coil coming out with it.

There are others but I found Timeserts to be great. 

 

Covers on , covers off - the great debate ! Lol

I prefer they be on. Just spent good money on a couple New covers and seals because I expext longevity on our cars. 

  • Thanks 1
Link to comment
Share on other sites


IF the Helicoil doesn't seem secure, move up to Timserts or similar.  I would not go to a bigger bolt.

I followed the timing belt cover debate while it was hot a few years back.  I've been running them without the front covers for a long time now with no problems.  I don't do anything crazy, like rally cross or bashing through snow drifts though.  It is a lot easier to monitor condition and tension and idler bearings with them open.

  • Like 1
Link to comment
Share on other sites

If you anticipate possibly having to fix something else, or in your case, need to monitor whether something needs fixed or not, I couldn't imagine going through the trouble of putting the covers back on. 

Even if it shortens the life of the belts by a few thousand miles, the difference in effort involved to change them (or anything else) is exponentially worthwhile in my opinion. I've had open belts for a few years now, BUT like DaveT, I don't offroad much. 

Dan

Link to comment
Share on other sites

I use black cable ties when repair is not possible. For those in good condition I use rubber washer or oring as mechanicalthrrad locker yet gentle on ancient fastening principles so not using mating faces to bind stuck

Link to comment
Share on other sites

If the thread is into the plastic baking plate I use cheap cable ties. 

If into the block, it'll be trickier to sort out as the cable tie trick won't work and I doubt you'll have much wiggle room for a timesert repair depending on which bolt is the issue.

If we're talking cam covers then that's a whole other game!

Cheers

Bennie

Link to comment
Share on other sites

On 9/7/2018 at 6:30 PM, kmpdx said:

What do you guys think? should I attempt a different repair or just hope it stays together?

Yes you should:

1. chase the threads with a tap (M6x1.0)
2. get a longer bolt which will then reach deeper threads that have never been used before.  You can insert a coat hanger, etc and measure how deep the hole is so you know how long of a bolt to get.  make sure the bolt is long enough to fill the hole. 
I prefer subaru bolts due to quality but i'm sure you can get a high grade bolt from a parts store, low grade average bolts will rust
Have a few washers in hand in case the bolt is too long, to use as spacers under the bolt head.

 

On 9/7/2018 at 6:30 PM, kmpdx said:

 I backed it out and there was a helicoil stuck to the bolt from a previous repair!

***My guess is the threads just came out in one big hunk and they looked like a helicoil.  That happens all the time and is more likely than a helicoil backing out. Are you 100% absolutely positive you saw a "helicoil"? 

Also - if the helicoil "came out" it's unlikely the bolt would hold any torque at all...it'd just hang there completely unloaded. 

Link to comment
Share on other sites

Sorry for the late reply. I was busy putting this thing back together! You are right, I had the cover slightly misaligned and ended up stripping the threads on the top and bottom. I used a thread repair kit for the auto parts store and it seems to be working fine. The hardest part was getting the right-angle drill to fit in that space. I had to cut the shank off the drill bit to make space.

I did out the timing covers back on. Hope I don't regret it too soon.

Thanks for all the great advise.

Two things I learned in this. Paint can openers work great for removing seals. Like no effort, seal out in 15 seconds. To make a fast seal for the thermostat housing, Right Stuff Grey. I was struggling to get the seal and that stuff is not cheap but totally worth it

Link to comment
Share on other sites

First real stress test. Drove 300 miles to southern Oregon. I cannot BELIEVE the difference that the new seals on the oil pump made! The motor maintained real pressure for the first time since I bought it. Also no oil leaks on the front like before. No tick for now but I will have to see if that holds up after the oil breaks down a bit. I wish I had time to get in and do all the rest of the motor. Anyway, I am thinking this motor might go another 50k as is. Thanks to everybody for the advice and I am sure I will be back.

Thanks,

kmpdx

Link to comment
Share on other sites

It is satisfying! I cannot believe the difference that the oil pump reseal made in performance. This car still needs stuff. I wish I could pull the motor and reseal the whole thing including head gaskets  and check the valves. That really will probably never happen. I need to flush new brake fluid and probably replace the brakes. Would love to drain and  fill the tranny and rear diff. Also, Would like to replace struts and bushings all around. Lol, I think brakes will be next.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...