Head Bolts

[Guest]

I finally had to pull the heads on my Pontiac. I did a tune up and then it started backfiring. I broke three headbolts off (1/2 inch above the block). Other than penetrating oil and patience (I have none) or cutting the bolt off flush and drilling it out does any one have some suggestions???? Since I have now broken three bolts how about just replacing all of them with grade 5 ??? bolts??? Any advice or information would be greatly appreciated but perhaps not used.

By the way the valves seem perfect but there was 3/16" of carbon all over except for an arc on the farthest side of the piston from the valves. There seems to be very little ridge on the cylinders and in fact you can still see some of the hash marks.

[nearchoclatetown]

Tinindian, patience is a virtue. If all else fails try 3 fingers of Wild Turkey.Clean all the crude from around the maating surface of the bolts, spray with your fav spray, and tap the bolts sideways lightly with a small hammer. All you are trying to do is vibrate the juice in place and slightly loosen the threads. Maybe heat with propane, more juice, more time, more patience. Let cool, repeat all the above. When you are sure use a new pair of Vise Grips, not the junk from the flea market you bought for $.25. Carefully work the bolt back and forth, more juice, more patience, maybe more heat. When it moves easily, apply more juice, and remove the bolt. It will probably/maybe pull the threads with it, so you will need heli-coils., no big deal. You may want to do this over a few days, don't be in a hurry!!! When I do this for others,I charge more for owner installed broken drills and easyouts. So if the Wild Turkey doesn't work, seek professional help. BTW, I would recommend Grade 8 bolts or hardened studs and Grade 8 nuts, and resurface the bolt mating area. It's probably dished out, make it flat so the bolt has a good area to push against.

[Matt Harwood]

If you have a welder, I have a technique that I learned from a fellow hobbyist. Basically, you weld a nut to the broken-off stud (and 1/4" is plenty). Between the heat of welding and having a nut on which you can place your wrench, I have yet to find a broken bolt that wouldn't give up its grip. Here's more information from the guy from whom I got the idea (about halfway down the page):

The Bug Shop

[Guest stude8]

All the recipes so far are good ones, the heat is the best tool you can use, I was told by an old timer to heat the broken bolt or stud and hold parafin at the base so it can melt and wick down into the thread area. The parafin works better than the penetrating oil that gets evaporated by the heat. If all else fails there is the "Tap Blaster". I had to use him to get some broken bolts, one broken drill bit and a broken tap stump out of a bad dog block I was rebuilding. It is a reverse welding process that "Sucks" the molten bolt material out of the threaded holes leaving them intact and useable again. It ran $20 a hole for 5 holes and I took the engine to his shop. They sometimes make house calls on their schedule if the engine can't be moved easily. I live in a Chicago suburb so that service is common amongst tool and die shops that have expensive tooling they must preserve. Stude8

[Dave@Moon]

I have a set of Hanson brand extractors ("Easy-Outs") that came with a matched set of <span style="font-style: italic">reverse</span> drill bits. I've had great luck with these. Often the heat from the drilling alone, combined with the tension from the bit spinning reverse to the threads, is enough to break loose the remaining bolt.

(Obviously you need a reversible drill to use them, but nearly all drills are reversible now.)

Reverse threaded drill bits are not easy to find, but I strongly reccommend a set for anybody.

[Bob Kinker]

Using heat & a pipe wrench should get these broken bolts out. Also, liberal dousing with your favorite penetrating won't hurt. I have used the left handed drill bit trick on many occasions with great success.

I would not think of using grade 5 bolts for head bolts. Grade 8 or better!!!

Good luck with your engine!

Bob

[Guest]

Thanks for all your comments. I am trying penetrating oil, a tap and patience but I WANT IT RIGHT NOW . Seriously I am trying to be patient. I read somewhere if you lube the threads in the block you have to adjust your torque????

Thanks Guys

[nearchoclatetown]

Tinindian, that is a whole 'nother ball game, special lubes, no lube, etc.. Refer to a shop manual from when your Poncho was new.

[Guest]

I finally borrowed a mig welder. Welded a nut on the broken bolt and voila. I then decided I should really pull all the valves and grind them. Not enough patience I bent two valves. So now I am looking for 2 of 5841259 valves. I think they were out of a 302 GM engine but the only thing I have less of than patience is memory after 36 years.

Thanks for you input guys.

[Guest stude8]

Now the eternal question will be: Was it the heat from welding or the hex nut that got the stump loosened up and out??? Stude8

[Guest De Soto Frank]

"Yes"...

( Say there was enough bolt sticking-up to thread and put two nuts on, and jam them together...I'd bet you'd be just as likely to wring the bolt off again...

Of course this all depends on whether the original bolt was eroded right under the head, or seized dowm where it threads into the block...)

[Guest]

From the looks of it I would say the heat from the welding was the key. The threads were perfect. They were all black not rusty brown like the others. Obviously the bolt broke because of crystalizing. Now I just need three valves and away we go for another ????? years.

[Guest De Soto Frank]

Have you tried Egge Machine for the valves?

Also try Vintage Auto Parts; they used to have lots of valves...

[Guest]

Egge had three now they are on their way to me. Maybe I should also look for a spare or two. After all I hope to get 25 more years out of my daily driver.

[Guest imported_tigermoth]

hello tinindian, i am glad the bolts came out for you. for what it is worth ...metal doesn't break because of crystallizing. this wives tale started many years ago before metallurgy was the science it is today, probably because of the metal objects appearance in the area of the break. skinned knuckles magazine has written a couple of articles covering this subject over the years. having said all of that..bottom line is you got the bolts out!

[Guest]

I really would be interested in persuing information about metal crystalizing or not. At present however do any of you have specific information about new grade 8 steel bolts being put into 75 year old cast iron. All the bolts go through solid cast iron in the head and all are threaded right through the block into the water jacket. All or any information appreciated.

[Peter J.Heizmann]

Hello, Tinindian...

Quite some time ago, we had a lengthy discussion concerning "bolts" as applicable to the same scenario you are undertaking. Had my metallurgist' and myself delve into it with a report on results of test case bolts. We actually "pulled" them as if a common test bar in the foundry and ran them through the spectrometer.

Go up to the "Search" icon at the top of the page. Enter search word Bolts or Bolt Strength.

If I recall, crystallization was also discussed. My advise, always, always pre-heat before welding so as to avoid thermal shock. Under a microscope, one can easily see the crystallization, or, carbides (white iron for lack of a better word).

Regards,

Peter J. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Guest De Soto Frank]

Tinindian,

Especially where bolts thread into a water jacket, I would strongly advise applying Permatex (or similar) anti-seize compound, liberally, and all the way down to the bottom of the bolt threads...

It will probably make subsequent removal easier for "the next guy" (who might be you ! )

I' m curious...I know you 've mentioned that this Pontiac has been your daily driver for the last 40+ years...do you have another car, or is this one it ?

Good luck getting it under way again!

[Guest]

Thanks Peter and Frank. This car has been my daily driver since 1959. I have had multiple cars at different times. At one time I had a Pontiac of each year from 1926-1932 inclusive licensed at the same time. I also had a 1930 8 cyl dodge, a 26 Studebaker and a 28 Buick all licensed at the same time. Since I have been married (40 years in the fall) my wife has always had a car but my daily driver to work and anything except very long vacation trips has been my Pontiac. I have been in every state west of the Mississippi and most everywhere in Canada west of Fort William/Port Arthur in it.