Cord 810-812 Head bolts

Stroker, I want to remind you that I said the TEST torque was 55 foot lbs. & the INSTALLATION torque was 45 foot lbs.. Also I said that the thread engagement should be 5/8" in length. Any thread that passes that test should be O.K. when the head is installed. Henry

A magnetic base drill press can drill a perfectly straight hole in anything magnetic. Many rental yards have them for rent too. McMaster Carr would be a great place to buy one. These are great drills that can be used most anywhere. You just place it where you want to dril and flip on the mag switch. Then its stuck to whatever you want to drill a hole in. Shop around because some of these mag base drills are very expensive... Maybe this could be a club tool that is shared around. Ebay would be a good place to have a look see...

Hi Peter, You can go to a competent machine shop, tell the machinist that you want him to make a drill bushing for you with a enough beef to use your hand held electric drill.Bring him the head so that he can figure the dimensions with two cap screws to hold the bushing to the block. Cast iron is real soft. I suppose you will do all the bolt holes or just the one. Never use a regular tap, use a thread chaser for the rest and make a bushing to check the rest of the threads as Henry suggests, your friend Carlton I am sure will work along with you on this.

Gents- You may be wondering what happened to me since our last postings- we're tryng to finish the @#$%& front fenders and shoveling @#$%& snow! Massachusetts- 30" on the roofs and driveway.

It's warmer now (50 deg.) so I'm once again thinking CORDally. On the head bolt problem I think the conservative way is the way to go- thanks Henry for the suggestion of Keenserts and using a 5/8" sleeve to test the other bolts to 45 Ft.Lbs. while the head is off.
Has anyone used one of those drill guides for a hand held drill motor? About $35, but in the picture they look kinda frail.
I could buy one of these and attach a 1/8" plate with various holes to attach this rig to the engine. Any thoughts?

I think, Jim and Henry have fully explained there thoughts on the matter. I've done this insertion before with either method and they work well, I like Henry's idea for the sallow bolt holes and Jim's for the longer ones. My only thought, if it's only one thread that is bad, I was sucsessful using a heli coil with the head in place. Fortunately it is easy to get to. In as much as you have the fence off and it is real easy to get to all of the bolts on the passenger side take the head off and do all or check all as Henry suggested with the sleve method, and replace the one's that are soft.

---

JUST A THOUGHT, remember on the driver's side the one head bolt behind the steering shaft is IMPOSSIBLE to fix when the car is together, think about that !

Pete, I guess I might as well put in my $.02 worth! Jim & others are correct! Do it CORRECTLY NOW & you will not regret it later. Here are some things that I found in 62 years of Cord Madness. Use only Keen-serts or equal in the upper row of threads. The block thickness in that area was thin to start with & with rust & erosion over the years has made it become less. Heli-coils do not work well here due to their short length (my opinion , you can only use ones about 3/8" long) . Design practice over the years has been to have a minimum thread engagement of at least one thread diameter; in this case 7/16", however 1.5 x .437 = .655 would be preferred. I check ALL of the threads with a new 7/16-20 bolt (grade 8 ) using a heavy steel sleeve on the bolt that allows 5/8" extension from the sleeve. Screw this into each hole & torque to 55 foot pounds, if any do not pass this test , I use Keen-serts as above. Longer Heli-coils seem to work well in the lower longer holes . Final torque for the head installation 45 ft. lbs. It has worked for me!javascript:emoticon('') Henry

Heads off also permits you to look at the almost certainly corroded water passage holes on the block side of the head. I've seen heads that looked great cosmetically but were just a hair away from starting to leak out of the edges of the head.

Sorry to add to your fears, but as has been pointed out these are things best investigated in your garage.

Pete,

I have to agree, now is the time to pull the head and do it right. While you have the head off take a very good look at all the other threads and put inserts in any that are questionable.

Jim

Mike's drilling guide idea is a MUST -DO if you do decide to pull your head !

His post popped-up just as I was still typing my above thread post !

The problem I see is how are you going to control your hand operated electric drill to be sure that your new enlarged & tapped bolt hole is dead-on straight with the cylinder head still on the car ?
If you are off just a few degrees you will be stuck when it comes time to insert this bolt through your cylinder head & into the new thread insert !
Now if you use the Helicoil method with the cylinder still on the engine the head itself will become a pilot guide so you are sure that you get a perfectly dead stright-on bolt hole.
It's really easy & safe to drill through the existing head bolt hole.
You should probe the existing hole first with a wooden dowel rod and mark the exact hole depth on this stick to the topsurface of your cylinder head.. Also measure the exact thickness of the cylinder head only & mark that on your guide stick.
Now you will have a guide rod to work by.
Before you start to drill wrap some masking tape slightly less than the old tapped bolt hole depth. This will be your maximum drilling depth stop.
Use a slow variable speed drill with the new drill supplied with your new Heli-coil kit. The old tapped hole will center your new drill for you. Hold your electric drill so the side drill flutes just miss the guide hole in your cylinder head.
When finished clean-out the hole chips & de-grease the hole with laquer thinner or acetone.
Get your new heli-coil and put some locktite 242 threadlocker on it's outside only.
Put the heli-coli on the supplied isertion tool and follow the directions for insertion !
Use care when you finally break-off the Hli-coil insertion tang inside at the end.
It's OK if the tang drops in the engine water jacket .
Let the locktite 242 cure for a few hours then insert your old, or new head bolt if the old bolt's threads were damaged.. Coat the threads of this new bolt with Permatex #2
gasket sealer & slowly bring this bolt up to proper torque spec.
Re-torque all head bolts in the proper sequence and to the proper ft lbs of torque.
Run engine and later re-torque all head bolts !

You should now have a new leak-proof tapped head bolt hole that is stronger than when the engine was new !

I wish you lived near my home shop garage~~~ I would do this repair for you !

It's really very easy !

Good Luck !

Pull the head and do it right. If you don't it will come back to bite you at the most inoportune time. I would use a insert as you are thinking of and not a heilicoil. I would be suspect of the other holes also. I would go to the trouble and make a drill guide to make sure the hole gets drilled straight. Bolt the guide to one of the other bolt holes and make it adjustable so you can us it for other holes if need be. I would agree with Jim and do all of them.
CORDially Mike

Gents- Wow, I must hit a vein of knowledge! One thing I forgot to mention besides the "weeping", as I tightened the head bolts in a rotational path to first 30 ft.lbs. then 45 ft.lbs. the weeper started to feel "soft"on the second pass so I stopped. My experience with such things told me I was starting to strip threads, so I stopped and hoped (hence, my present dilemma). The bolt is above #8 and I'm scared that I might not have enough pressure to hold in the compression and/or the antifreeze. I'm sure of the bolt lengths and their placement and think someone before me put a middle length bolt in this teer and tried to tighten it before he realized it wasn't bottoming.

I'm thinking of pulling the head and drilling and inserting a 1/2" insert from Mcmaster-Carr, which requires a 9/16" O.D. hole and has a seal/vibration stop midway up the shank on the I.D. 7/16"-20 hole. Waddia think?

Are you sure that the bolt isn't too long. If it is it will bottom out in the block. Whatever you do make sure it is the right length.

Pete,

Because your weeping hole is along the top teer of head bolts, I don't agree with all the advice posted. I think you will find that the maximum thread depth (or thread engagement) along the top teer is about 1/2", depending on which threaded hole you measure and if your block has ever been decked. Not too far deeper, you will hit an adjacent portion of the block. Since the depth is so shallow and there is absolutely no visibility with the head in place, I would not attempt drilling or installing anything with the head in place. Others may differ, but my rationale is that the value of a head gasket is not greater than the risks involved.

With the head off, you can also measure the thread depth of each hole and then ensure that your head bolts are the optimal lengths to give you the optimal thread engagement (not too long, not too short).

PETE:
The above repair methods explained by Jim pretty much cover this repair subject.
He did a fine job ~~~

Since you only have one offending "weeper" bolt ~~~

I would first try permatex #2 gasket sealer on the threads of the "weaping" bolt's threads ; Also put a bit of this same sealer on a very slim screwdriver or nail and coat the threaded female hole in your engine block before replacing the head bolt. Permatex # 2 is much thicker than the much thinner aviation sealer. It fills problem gaps that cause water & antifreeze "Weeping" much better than much thinner aviation sealers.
I always use Permatex #2 on all head bolts & suds that are not installed in blind tapped holes on engine blocks.~~~ ALWAYS !
This does not really alter your later headbolt torque-wrench readings very much when you finally torque your cylinder head to proper specs.

Another old mechanics trick my Father taught me for very loose fitting threads is to wind a thin string or thread on the leaking bolt's threads before you insert it.
The thread needs to fit in the bolt's theads very tightly. The object here is to take-up extra space between the bolt threads and the female threaded hole.
Glue the thread or string end to the blunt end of the bolt with superglue; then wind it around the threads. This string method acts like packing to fill the gap between the bolt threads and the threaded female hole in the engine block. This tightens the overall fit and stops the weeping water or antifreeze.
To me this is really a Band-Aid approach and it's better to use a Heli-coil thread repair.

The Heli-coil repair method with the head still in place would be my very next move if the single bolt thread sealer method fails .
You can buy a complete single bolt Heli-coil installation kit at many automotive parts stores for under $20. They consist of a heli-coil, proper oversize drill bit , and a special plastic heli-coil insertion tool. I use locktite #242 thread-locker on all my new heli-coil installations. Be sure to clean te block's threaded hole & new Heli-coil with laquer thinner or acetone to remove any oil and grease before putting the locktite thread-locker on the new tread repair coil. This locktite application on the new coil seems to prevent them from twisting-out. I have had great success with heli-coils.
Heli-coils are the best thing, for one or two stripped or worn threads, since sliced bread !
I have been using them since the early 1970s !
Work quickly inserting the heli-coil as the locktite #242 thread-locker you put on them can set-up very quickly.
DO NOT use this same locktite #242 threadlocker on the head bolt itself !

I too~~~am not a fan of using fine threads in this sort of application !

Studs used on cylinder heads instead of head bolts causes some tough future head removal issues~~~especially with aluminum heads !
Ever try to remove an aluminum head with corroded aluminum casting holes & studs ? What a tough job indeed !

If you do decide to pull the head~~~go for all new thread inserts as stated above.
Installing all new thread inserets is not an easy job as these all need to be perfectly perpendicular drilled holes with exact right angles and square with the engine block surface. You could easily get into big trouble if any are drilled , tapped, and installed at a slight angle off of being perfectly square . A very tough job for the home mechanic with only an electric hand operated drill; especially with the engine still in the car's engine bay !

Good Luck~~~I hope you do not need to pull your head !
This should be a simple & easy repair fix !

Hi Pete,
Sorry to hear about your problem. You have a couple of options to attempt a repair. One is as Mike suggested pull the bolt and apply a sealer to it and put it back in. If the threads are good this will work.

Second is ot put a helicoil in. This can usually be done with the head on (be carefull). Personnally I don't like using helicoils because I've had problems with them leaking and pulling out. (I'm sure I'll hear about this thought).

Third is to put a full threaded insert in. To do this you have to pull the head off. The good part of this repair is you drill and tap to a standard size so you don't need special drills and taps. I use EZ-Lok ( www.ezlok.com ) inserts. These have loctite on the external threads to hold them in place and to seal the insert.

When I rebuild an engine I put the inserts on all the head bolt holes. After 75 years I don't trust the fine threads. Also too many people may have runa tap thru the holes to clean up the threads. This usually removes some metal in the process and weakens the treads. You should only use a rethreading tap to clean out the holes.

Good luck with which ever way you go with the reapiar and let us know how it works out.

Also hurry up and get the car done and too Auburn this year for the 75 birthday of the CORD. If you are really feeling bold you can caravan out with us.

Jim

Pete,

Have you tried permatex aviation thread sealer on the threads ?

If you need a thread insert, the head must come off. I suggest that you start by measuring the thread depth or projection of the subject hole. Threaded inserts provide for full thread projection, which is only one reason why I prefer them. The McMaster Carr catalogue might help with your selection of a threaded insert based on the hole depth of thread projection you measure. Your correct the threads are 7/16 x 20

www.mcmaster.com/#threaded-inserts/=aymaqd

Hi Pete,

I'll bet my Cord has been "under restoration" longer than yours...

Anyway, when my dad bought the Cord as a junker in 1950, he found that most, if not all, of the threaded bolt-holes in the block were stripped or damaged. His cure, which as a boy I helped to accomplish, was to drill out the damaged holes, re-thread to the next-larger standard size, and then make studs on the lathe to fit the newly-oversized and -threaded holes in the block on one end of each stud, and to fit through the holes in the heads at the other end. Attachment of the heads is now by nuts, not bolts.

Hope this helps. If not helpful, well, at least it's of interest.

--Tom 1509A Westchester

Gents- 2241H is slowly coming along- engine and transmission are really great, body and rear fenders done and painted, but I have a "weeper" head bolt along the top teer. Several guys have suggested putting in "Keenserts" in the block to recreate the original threads so I can use original size head bolts.
My question is has anyone had success with this, and if so what drills and insertion tools are required? Does the head have to come off to drill and insert the insert? The car is not here so I'm remembering the bolt size is 7/16"-20 NF(?).

Any help will be greatly appreciated!

Pete Rhoads