Stripped head

[dmich2]

Well I went and stripped one of the holes out on my 2.8 head when I was mounting the valve covers. I saw my mechanic rethread some stuff but want to be sure I do this right. ( My mechanic no longer does this sort of stuff... ) I purchased a tap set and just wanted to know if there's anything special about rethreading a hole. i know you need the tapping oil. Since its aluminum I guess the magnet for the shavings won't work, so how do I collect those? Or do I just take it somewhere and pay for it? I'd like to tackle it on my own though.

Dennis

 

[PaulK]

Dennis
The best fix is installing a helicoil. This is an insert that is made like a spring wire that is wound out of wire in a diamond Cross section. A helicoil kit can be purchased from most good auto stores and comes with drill, tap and insert. the best lube for drilling and tapping aluminum is lard.
Paul

 

[Bill Blue]

The 2.8 head is aluminum? I had always thought it was cast iron. Well, they say you learn something new everyday. Here it is only 9:15 A.M. and the days work is done!

Bill

 

[alpine_64]

The 2.8 head is aluminum? I had always thought it was cast iron. Well, they say you learn something new everyday. Here it is only 9:15 A.M. and the days work is done!

Bill

Bill, i'm almost sure you are right that the 2.8 heads are not alloy. I think there are aftermarket alloy heads for the essex V6, but not the cologne. The only alloy heads i have heard of for the cologne were special racing ones Joe told me about.. but they are all raw castings

 

[Rsgwynn1]

I've used helicoils on outboard heads and have found them to be totally reliable and easy to install. Inexpensive too.

 

[V6 JOSE]

Hi Dennis,

Are the holes you are wanting to put threads into, in the intake manifold? The intake manifold has four threaded holes for the rocker cover. I guess you don't want to remove the manifold to do this job, right? If you want to catch all the aluminum chips the Helicoil tap will make, just put plenty of axle grease into the tap, and the aluminum will stick to the tap and not fall into the engine.

I would recommend removing the intake manifold and helicoil all the holes in the manifold base at the same time, because if some of the holes are stripped, you can bet the others won't be very far behind, and you surely don't want to have to do it again. It will take a bit of work to R and R the manifold, but I think it is worth it.

You'll be able to do it yourself with a helicoil kit. It isn't very hard. The tap will make a threaded hole with special threads to accept the helicoil. Once the hole is threaded, just place the helicoil onto the special tool you need to screw it into the hole. When the helicoil is down to where it is slightly below the surface, unscrew the tool and use a small drift to knock off the little tang at the bottom. Now you'll have a hole that will never strip again, unless you have some animal work on it.

Jose

 

[volvoguys]

Methinx I must be missing something here. Have the threads been stripped or crossthreaded? Since this is merely holding a valve cover on, is it really necessary to go to the trouble of dropping a Helicoil as opposed to tapping a coarser thread. After all, rocker covers only require a pound or two torque and get removed, well, almost never.

Mark

 

[V6 JOSE]

Hi Mark,

These little engines oil so well up top, that if you don't have all the bolts working to hold the rocker cover on, it will leak like a sieve. The holes for the rocker cover aren't the only holes that should be helicoiled. There are six threaded holes for the bolts that hold the top portion of the manifold on. The Offenhouser four barrel manifold is a two piece design, so requires the six extra bolts. The aluminum that the manifold is made from, isn't very strong, so stripped holes are very common, and is the reason I recommend helicoiling all the holes even when new.

Jose

 

[dmich2]

Thanks everyone for all the great responses. I feel like such a Homer. dohhh!!! Jose, you are correct. It is one of the top bolts securing the valve cover to the intake manifold that is stripped.

Back to the ol' bank account...... I better do them all.


Dennis

 

[Nickodell]

My 20c worth. If you're dealing with aluminum I would agree that Helicoil is the way to go, especially where bolts/studs have to be removed and replaced several times, as the insert offers a much more robust means of cinching everything down. With alloy, there is so little margin between too loose and sod it! now look what I've done! I did my first Helicoil insert in 1954 when I stripped the threads out of the spark plug hole in my Triumph T100 m/cycle.

However, with steel or cast iron my first choice is to drill oversize - just enough to remove the remains of the original threads - and retap. Much simpler, quicker and cheaper (no need to buy a kit that you might only use once or twice).

 

[bmohr]

Be sure to drill straight

When using helicoils be very careful to make sure you're drilling perpendicular to the surface. Probably easier to do in steel or iron, but it's easy to drill a slightly crooked hole in aluminum. Don't ask me how i know...

That being said I echo what the others say about how good they are.

 

[dmich2]

I went back to this thread.. No I haven't fixed the problem yet. Anyway. In searching for the helicoils I found these two examples. Have any of you had experience with the thread insert pictured below?

http://www.timesert.com/

I wonder how it compares to these which I think most refer to.

http://www.emhart.com/products/helicoil.asp

Thanks.

Dennis

 

[V6 JOSE]

Hi Dennis,

The problem with the threaded insert, in your application, is that the rocker cover rail you are wanting to thread, is too narrow to fit the insert. The Heli Coil is just a bit wider than the original threads, so will not break out of the rail.

Jose