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-   -   Broken Valve Spring (http://www.clubcobra.com/forums/other-upcoming-events/145256-broken-valve-spring.html)

splenderleith 10-14-2021 06:05 PM

Still no luck getting the head to budge enough to get a plastic spackel knife under it. I am starting to lose confidence that I will ever get it off. I will try to get some thin hex nuts to get the studs out.

eschaider 10-14-2021 07:36 PM

OP,

The studs in your head seem to have a close fit to their associated stud holes in the head. Attempting to get the head off by prying on any edge will just jamb the head with the studs and you won't get anywhere. You need to find a way to get the studs out and the head will likely just lift off. Your idea of thin jam nuts might be a good solution.

My suggestion would be to pull the engine, put it on an engine stand and the job will become much easier. When you do get it apart consider buying some broached ARP studs for the new engine so you can easily install and remove the studs with an allen wrench.


Ed

bobcowan 10-14-2021 08:45 PM

I dropped a valve on the race track one day. Since it was a Dart block, it only took a week to get it running again.

https://i.imgur.com/CV8DdWI.jpg

eschaider 10-15-2021 09:09 AM

Very thorough component failure there, Bob. ;)


Ed

Jerry Clayton 10-16-2021 07:52 AM

Pi x R squared equals the piston area for fiquring the lifting pressure -------example--------a 4 inch bore size would be R = 2------ soooo 2 x2 x 3.14 = 1256 x 100 psi = 125600 lbs total force------


The aluminum heads -the washers under the nuts have squeased the alum head material into the threaded area of the stud which will keep the head tight against the block----There are step washers available that do require clearancing but will prevent that------

patrickt 10-16-2021 08:49 AM

Quote:

Originally Posted by Jerry Clayton (Post 1498209)
Pi x R squared equals the piston area for fiquring the lifting pressure -------example--------a 4 inch bore size would be R = 2------ soooo 2 x2 x 3.14 = 1256 x 100 psi = 125600 lbs total force------

Gaz doesn't believe you. He says that anyone old enough to have raced back when you did has to have at least two toes in dementia now.:p

patty442 10-16-2021 08:56 AM

jerry check your math. 2 x 2 x 3.14. = not 1256

Jerry Clayton 10-16-2021 09:45 AM

OK guys-I did that specificatly so some of you would get in here with the idea of what and how it works out----yes, it is 12.56 square inches on a 4 inch bore and then multiply by the PSI gives you the total force of 1256 lbs------
Now maybe you'll get the idea that maybe 15 to 1 compression can cause bent rods?????

sunman 10-16-2021 10:01 AM

Connect the rocker studs with a metal piece with a 3ed hole over the stud. Use an nut and bolt with bolt head over stud and push the head off like a balancer puller. Put the threads up thru the hole, put the bolt head on stud and turn the nut to apply pressure.
Edit: If you have a puller that fits studs use it

Jerry Clayton 10-16-2021 10:53 AM

BHJ products ( makers of torque plates) have a product line of "T washers" they are for aluminum heads and you use a stepped relief cutter that counter bores the top of the bolt hole in the heads for the relief for the T----this keeps the washer from squeesing the alum into the threads of the stud-------

NROTOXIN 10-16-2021 02:07 PM

Quote:

Originally Posted by splenderleith (Post 1498124)
Still no luck getting the head to budge enough to get a plastic spackel knife under it. I am starting to lose confidence that I will ever get it off. I will try to get some thin hex nuts to get the studs out.

I'm looking at my car and without removing the 9/16 studs the heads cannot be removed due to foot box interference. Removing the 9/16 studs on the lower/back deck of the engine in the car appears very difficult to impossible.

Gaz64 10-16-2021 02:58 PM

Quote:

Originally Posted by cycleguy55 (Post 1498045)
You might try using air. Make sure all the head bolts are loose or removed. Put a fitting in one of the spark plug holes in an end cylinder (not the one with the broken valve) and pressurize it. Area of a 4.36" bore is 4.75 sq inches, so 100 PSI is 475 lbs pressure pushing up on the cylinder head.

I'll say my interpretation of Brian's statement lead to some confusion.

I read it as 100 psi is 475 psi, as in 100 psi becomes 475 psi, which is impossible while you have a shop line connected to the cylinder.

100 psi would create 475 lbs of force, not pressure.

The theoretical force output of a cylinder is the usable piston area multiplied by the applied air pressure (F = PA). For example, a cylinder with a 11⁄2-in. bore and an extend force of 80 psi generates 141 lb of force (1.767 × 80 = 141).

LG57 10-16-2021 03:57 PM

Seems like you have no choice but to pull the engine to complete the teardown. You'll have to have the engine out in order to repair the damage anyway. Time to bite the bullet pull it out of there!

cycleguy55 10-17-2021 09:30 AM

Quote:

Originally Posted by Jerry Clayton (Post 1498209)
Pi x R squared equals the piston area for fiquring the lifting pressure -------example--------a 4 inch bore size would be R = 2------ soooo 2 x2 x 3.14 = 1256 x 100 psi = 125600 lbs total force------


The aluminum heads -the washers under the nuts have squeased the alum head material into the threaded area of the stud which will keep the head tight against the block----There are step washers available that do require clearancing but will prevent that------

Uh, that would be 12.56 in², not 1,256 - so 1,256 lbs. force @ 100 PSI.

460 CID standard bore is 4.36", so (4.36 ÷ 2)² x 3.14159 = 4.7524 x 3.14159 = 14.93 in² x 100 PSI = 1,493 lbs.

My earlier numbers were incorrect.

Gaz64 10-17-2021 04:01 PM

I would now get a borescope camera to look at the piston top.

If the bore or piston is damaged, then that negates the need to try and pull the head in situ.

Jerry Clayton 10-17-2021 05:26 PM

The washers for the block studs need to be a bigger diameter so as to have more contact area with the aluminum -----

jknich 10-18-2021 11:53 AM

Maybe without the washers you can use two jam nuts and remove the studs?

Jerry Clayton 10-18-2021 04:10 PM

Snap on has a stud removal/install kit-CG-500 Stud remover------

767Jockey 10-18-2021 04:34 PM

This Gear Wrench stud removal kit is only $50.

https://www.amazon.com/GEARWRENCH-41.../dp/B000K1KHB6

splenderleith 10-18-2021 06:59 PM

1 Attachment(s)
Quick update: I got the head loose. It was just the dowels holding it in place. Once I got it wiggling, it came (almost) off pretty easily. The biggest issue I am facing is the head hits the passengers toe box before it clears the studs. I broke the stud loose that is closest to the interference area. I can’t unthread the stud far enough to remove it. I am considering backing it out as far as possible, then cutting it off and threading it back in far enough to remove the head. The other option would be to try to get the motor up a couple inches.

I would love to lift the engine a little? But I am not sure if I can do it without any kind of cherry pucker. I think 1” may be enough.


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