Help! Cam Housing Removal

[triplesn8s]

Well I dove into this motor for a mechanical challenge (I have rebuilt / modified many motors by many manufacturers) & I got one, but not the one I was looking for.

I had wondered what kind of ham-fisted mechanic would be careless enogh to break a cylinder cooling fin, now I know. My kind.

I swear these cam towers are welded to the cylinder heads. I have removed 12 bolts & counted them 10 times to be sure. I have wacked this thing all around about as hard as I dare (breaking a fin with a misplaced blow) and it just rings like a bell, hasn't budged a micron. I did not intend to take the cylinder heads off.

Is cylinder head removal my only option at this point? How do I separate the heads & cam cover once it is off the engine? At least now it is tightly held when I wack it. How hard can I wack it without disturbing the cylinders / heads? It is a magnesioum case '72 motor.

If I knew it was going to be this hard to get them off I would have done the cam change on the motor. I wanted to reseal the tubes & o-ring the rocker shafts. Serves me right for trying to be meticulous & perfectionist.

I am loathe to try driving a blade between the surfaces but I am getting pissed & desperate. I need some solid been-there-done-that advice ASAP.

Thanks,

Bill

[69911e]

Do you mean you removed 12 nuts? If so I think there are 18 per bank, 6 per head.

[john walker's workshop]

you removed the head nuts from the sounds of it. that doesn't separate the cam towers from the heads. if you haven't already removed the chain housings, do that, then remove the heads and towers as a unit, and finish disassembly on the bench. remove rockers, rocker shafts and cams, then all the 8mm fasteners that hold the cam towers to the heads. a light pry with a screwdriver on each side of the head will pop them free of the tower. mark the heads so they go back on the same cylinders.

[john walker's workshop]

and get wayne's book. it would have helped.

[triplesn8s]

I was following Waynes book. Fortunately I have learned at the cost of the corner of one cylinder fin that Wayne's book is far from a comprehensive reference or "How-To" manual. Purchasers of this book be warned. I am going to proceed with much greater caution, book or no.

I was following his book with the exception that I did not want to remove the heads. Nowhere in the head removal instructions did it mention 18 bolts holding the cam housing on the cylinder heads with 6 hidden under the rocker arms. His head disassembly instructions amounted to "take it to a shop".

I found the other 6 bolts in the torque diagram of the assembly area of the book.

I strongly recommend that Wayne add the following sentence to the "Head Removal" section in the next printing of his book, "If you remove the cam housings only from the cylinder heads there are 18 bolts holding the cam housing to the head, 6 of them under the rocker arms."

I will bet my paycheck I am not the only guy to fall into this one.

Thanks for the backup guys. You would have saved me.

Bill

[Tricky D]

Bill,

Did you see the section titled CAMSHAFT HOUSING AND HEAD DISASSEMBLY? It starts on page 41. On page 43, after you've removed the rocker arms it states, "Now, remove all of the 13mm nuts that attach the heads to the camshaft housing."

Since I just finished this disassembly 5 minutes ago, I contend Wayne didn't miss a thing.

I believe you owe him an apology.

[john walker's workshop]

if you weren't going to remove the heads, why did you remove the head nuts? where in the book did it say those nuts held the cam tower on?

[briankeithsmith]

More than likely if you were pulling the cam towers you would pull the heads also because the cam head/cam tower mating areas will have to be cleaned and I can't imagine you'd want to do that with the heads on the engine.

Brian

[Wayne 962]

Originally posted by triplesn8s
I was following Waynes book.

Obviously, you need to read more carefully. On Page 41, I detail the procedure step-by-step, beginning with the removal of the rocker arms and then the camshafts.

Originally posted by triplesn8s
I will bet my paycheck I am not the only guy to fall into this one.

I'll take that bet - you're the only one I've ever heard about having this problem. Read the book more carefully before you start complaining about it!

-Wayne

[triplesn8s]

Apparently I am being appropriately flayed. But in response:

I never touched the head nuts.

When you can spin the engine with heads down on a stand it is quite easy to clean things up.

Somtimes we all get tunnel vision when working on something.

I was following step by step. I did not want to remove the heads, instead attempting to remove the cam towers. The head / tower separation is several pages later, "off the motor". I was working "on the motor". The nearest reference to the total number of nuts (18) holding them together doesn't appear till the assembly section. In the lighting I was working with I never detected the nuts under the rockers. Nor did I pick up on the reason the rockers had to come off first. What I saw looked like what in my experience would be a typical bolt pattern (the obvious 12) for cam towers.

A clear mention of 18 bolts and the requirement of rocker removal to access them in the head removal section might save a few folks like me from ourselves. I still would find it difficult to believe that I am the only person who ever made this mistake. But I am willing to admit it and make a constructive suggestion if it will save someone else the trouble in the future.

'Nuff said.

[Tricky D]

Fair enough, Bill.

I certainly can't say I've never had tunnel vision on a project like this...or not known when to quit, etc. I've ruined many a project and made much more work for myself over the years.

My $0.02 - take a deep breath, relax, and move just a little slower. This little bit of advice has served me well in those instances that I actually listened to it - the previous paragraph describes those times I didn't listen.



Good luck on the rest of your project!

[triplesn8s]

Thanks, Tricky.

Upon further reflection if the phrase "all the nuts" was "all 18 nuts" it would have tipped me off immediately because I did leaf forward to that section.

And yes, I was definitely trying to work too fast.

Bill

[Shuie]

Ok, sounds like you found the bolts under the rockers.

I dont think any of the books out there are comprehensive 'how to' manuals that provide a complete literal description of every bolt that needs to be removed (Wayne's Engine book is real close). They are more like guides that provide a good explanation of the process.

Read and familiarize yourself with the entire process before touching your tools. Re-read the section that deals specifically with the task at hand before performing it.

I've never rebuilt any engine before and Waynes book helped me get my engine apart without breaking anything. It was the only reference I used during disassembly.

I read the book at least half a dozen times before I ever put my engine on the stand. The entire disassembly section of my book is covered in grease and oily fingerprints (sorry Wayne) from me flipping through and re-reading things as I moved along.

[Wayne 962]

Don't worry - I'm over it.

There is no real good reason to remove the cam towers from the heads with the engine still in the car. There is a delicate surface (see the assembly section) that needs to be properly cleaned and prepared. If you need to work on this, you should remove the heads and the cam towers as an assembly only. The reason why no one else has had this problem is that it's generally not a smart idea to remove the cam towers from the heads without removing the assembly from the car.

I will add the statement: "To remove the cam towers from the heads, you must remove the rocker arms, camshafts, and 18 nuts, in that order" to the 101projects.com website...

-Wayne

[Wayne 962]

Originally posted by Shuie
The entire disassembly section of my book is covered in grease and oily fingerprints (sorry Wayne) from me flipping through and re-reading things as I moved along.

Ha, the exact opposite - the book is supposed to get dirty. I hate to see them pristine and preserved - that means they aren't being used properly. Besides, if it gets too dirty, you need an additional copy for inside the house!

-Wayne

[Rot 911]

I would recommend reading the book in its entirety at least twice before starting any tearing down of the engine!

[nreed]

I agree...I read Wayne's book (which I could not have been successful without) about 4 times, then I still went slow, used my head, and prayed a lot. I had very good results!!!

[DonE]

Speaking of taking it slow, I am now have all my parts for my 930 rebuild. If I work on it over the weekends and a couple evenings during the week, how long should I budget to complete the rebuild (not including the machine work)??

[Tricky D]

As I recall, somewhere between 40 and 80 hours of work time.

It's probably closer to 40, but I've budgeted 80 because 1) it will be my first rebuild, and 2) I will be going very, very slowly and rechecking everything I do.

[Wayne 962]

80 hours for the first timer, not including the cleaning and prep work.

-Wayne