cam bolts sheared/stripped. Easy out o.k.? Reuse head gasket?

[paulivan]

1996 2.5L.

When bolting on the cam shaft caps I first stripped one hole before reaching 14.4 lbs. Fixed that no problem with heli coil. Back to bolting cam on again and sheared a bolt in another hole, also felt like I stripped another thread but not sure yet.

 

Has anyone got one of these 6mm bolts out with an easy out? Should I take it to a machine shop or try to get it out myself with the heads bolted? That's my preference but I don't want to do any more damage to this head. Any advice would be appreciated.

 

Inspected all the Cam bolts and found lots of degredation like it was disolving around the upper threads where the bolt hole is not threaded but only on some of the bolts. I found one that had a pin hole going straight through the bolt. Does anyone know why this happens? Is this normal? Would putting sealant around the cam cap mating surfaces help prevent this?

 

And after all this is resolved is it o.k. to reuse the new head gasket that has just been torqued if I have to remove the head for a machinist to get out the sheared bolt?

 

Thanks

 

PT

[idosubaru]

i would not use an easy out, they suck. i've broken dozens of them and they probably work about %10 of the time (on easy stuff, they never work on the difficult things).

 

use a left handed drill bit to try and extract it. if you're familiar with helicoil, then keep using that on any stripped or bad threads. get a right angle drill (you can rent one if you don't have one) to help drill if you can't get to the bolt. be very careful drilling into the head, go at an angle or too deep and you may hit a water jacket.

 

a machine shop would be nice. if you're down this far and having these issues, might want to make sure it's done right if you run into any trouble.

 

i would not reuse the head gasket. that's just my oppinion which is precautionary, i certainly don't have any experience with that though. if the car hasn't been heated up then i bet you could get away with it, but i'd hate to try it myself.

[dxrflyboy]

  grossgary said:

i would not use an easy out, they suck. i've broken dozens of them and they probably work about %10 of the time (on easy stuff, they never work on the difficult things).

 

use a left handed drill bit to try and extract it. if you're familiar with helicoil, then keep using that on any stripped or bad threads. get a right angle drill (you can rent one if you don't have one) to help drill if you can't get to the bolt. be very careful drilling into the head, go at an angle or too deep and you may hit a water jacket.

 

a machine shop would be nice. if you're down this far and having these issues, might want to make sure it's done right if you run into any trouble.

 

i would not reuse the head gasket. that's just my oppinion which is precautionary, i certainly don't have any experience with that though. if the car hasn't been heated up then i bet you could get away with it, but i'd hate to try it myself.

HGs are NOT reusable. Whenever you reinstall a cylinder head, a new gasket MUST be used. Also check the head surface for flatness. As far as broken cam cap bolts go, a machine shop is your best bet. Another option is a set of reman heads. Unless you have the equipment and training to make precision repairs such as this, your best bet is to send it to one who does.

[paulivan]

So just to clarify this. You are sying that even if the engine has not been fired up yet and the gaskets were only bolted up for a day in the shop I need to get new gaskets?

 

PT

[2X2KOB]

I'd advise a new gasket. For sure.

[dxrflyboy]

  paulivan said:

So just to clarify this. You are sying that even if the engine has not been fired up yet and the gaskets were only bolted up for a day in the shop I need to get new gaskets?

 

PT

Yes. The gaskets are only made to be torqued down once. If you R&R the heads again, you will need new gaskets.

[a97obw]

This happened to me just the other day! Was it one of the bolts that secure the front bearing cap that you later put the cam seal in? That's the one I broke. I wound up drilling it and using an easy-out (screw extractor) to get the broken part out. Take your time, use a punch or small nail and a hammer with light tapping to put a punch mark in the center of the screw and then start out with a very small drill bit. Follow that up with a slighty larger bit. I did it this way and then tried the extractor and it came right out. This was with the head still on the engine, and the engine on a pallet.

Wound up ordering 8 new bolts to replace them all. The larger ones that hold the center and rear camshaft caps had no problem getting to the 14.5 ft. lbs torque, but the front ones I settled on about 10 or 11.

Sounds like you've got a lot of trash in the threads. If you had the heads machined, I would suggest at least hosing them down with a can of carb cleaner and then follow that with WD-40 and the straw to blast out all the oil passages to the cam bearings. You can't use enough compressed air to clean the heads after the machine shop does their thing.

 

http://www.ultimatesubaru.org/forum/showthread.php?t=52424

[ShawnW]

These holes are made with insufficient metal surrounding the hole but on top of that when the head and engine are severely overheated I have seen the holes all degrade badly in multiple engines. A guy ran his 98 EJ25 for 30 minutes with the temp gauge pegged and the heads were almost unusable.

 

Re-use of the head gasket when the engine has never been fired isn't a perfect situation but if its the metal multi layer gasket and you are going to put it back on the same cyl head and block surface I say go for it.

[paulivan]

Thanks everyone.

 

I got the bolt out with a craftsman extractor set no problems so did not pull the head.

 

A mechanical engineer friend of mine said the bolts probably started coroding because of steam from a leaking head gasket so maybe my blown gasket was a long time coming. He also said I should not have re-used the head bolts but since it's all bolted up to just carry on and more than likely it will be fine.

 

I'm thinking about playing it safe and changing them out while I still have a chance. Especially since I already torqued them twice now due to an apparent error in the Chilton manual. They give a different numerical sequence than the factory (posting found on USMB) for the same text instructions. I backed off the bolts to change sequence to factory specs.

 

Chilton calls #1 Top R., #2 bottom L., #3 bottom R., #4 top L., #5 top middle , #6 bottom middle. The factory goes: Top Middle, Bottom Middle, Top L., Bottom R., Bottom L., Top R.

 

Could I have damaged the gaskets by using the wrong torque sequence and retuorquing with different sequence?

 

thanks.

[paulivan]

  a97obw said:

This happened to me just the other day! Was it one of the bolts that secure the front bearing cap that you later put the cam seal in? That's the one I broke. I wound up drilling it and using an easy-out (screw extractor) to get the broken part out. Take your time, use a punch or small nail and a hammer with light tapping to put a punch mark in the center of the screw and then start out with a very small drill bit. Follow that up with a slighty larger bit. I did it this way and then tried the extractor and it came right out. This was with the head still on the engine, and the engine on a pallet.

Wound up ordering 8 new bolts to replace them all. The larger ones that hold the center and rear camshaft caps had no problem getting to the 14.5 ft. lbs torque, but the front ones I settled on about 10 or 11.

Sounds like you've got a lot of trash in the threads. If you had the heads machined, I would suggest at least hosing them down with a can of carb cleaner and then follow that with WD-40 and the straw to blast out all the oil passages to the cam bearings. You can't use enough compressed air to clean the heads after the machine shop does their thing.

 

http://www.ultimatesubaru.org/forum/showthread.php?t=52424

My stripped thread was in the #3 intake valve cam shaft cap, lower bolt.

[a97obw]

The procedure in the Haynes manual is the same as the Subaru factory manual, which includes tightening the upper and lower center bolts first. Then on to the outside corners.

In your case, I'd definitely use new head gaskets, but as far as the head bolts go, I'm in the camp of using them again....simply because I've never seen the head studs replaced "by procedure" in an air cooled volkswagen or Porsche, sure the torque is probably much lower but these studs get much hotter and I would bet they stretch much further than the ones in your Subaru. They'll pull out the threads in the case before they exceed the modulus of elasticity of the bolts. By far.

 

But do what you feel comfortable with and take your time. I've been along the same road you are going for the past 3 weeks, and it is a LOT of work! Good Luck!