Questions about pulling head prior to rebuild

I was hoping to get some hints prior to pulling the head off the block. I was wondering what the best way to keep the timing chains and sprocket From falling down. Also do the pistons have to be at top dead center Prior to pulling the head off?

Best way is to use cable ties or large rubber bands to hold the sprockets together.
Having the 1 and 6 pistons at TDC gives you a reference point if you are removing the dissy but it’s not imperative. However when replacing the head then yes as the cams will be set using the camshaft setting tool that you have(?) and they are set for the engine to be at TDC. There has been quite a discussion recently regarding precisely this subject. Also make sure that you have lint free rags stuffed down the timing cover to save any errant items trying to look inside the sump.

Well you will have to …

Sorry I read 1974.

Sorry forgot to say its a series 1 4.2. I do have 2 cam alignment tools.does antone have a picture to show chains and sprockets tied together?

Just scroll down the list of threads. Nuts for cam gears. Lots of pictures.

This recent thread has some pics: Nut size for cam gear guide pin?

I know that this has been suggested before, but… Why not add your 4.2 Series 1 to your “My Cars” profile? At least then, when you forget to mention which car you are talking about, folks will ask which car, rather than wasting their time describing in detail how to perform an operation on the V12 which you have listed in “My Cars”.

Do you have a workshop manual?

All your questions are covered in any good one.

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I don’t think the crank has to be at any particular position but TDC helps you maintain your frame of reference. Be sure to stuff a rag into the timing cavity before you start trying to disconnect the cams in case you fumble finger something, like tie wire or a bolt. Make lots of reference photos.

Once they’re loose I’d also loosen the cams so the valves are all closed. That way you can set the head down on a towel or something and not bend a valve.

I’ve never heard of any particularly easy way to actually remove it. It’s a bear. If yours is already leaking then you might bet lucky and it won’t be too stuck. It’s heavy though, 2 person job unless you like hernias. Put it up on stands and remove the wheels so you can stand in the wheel well.

The studs are likely rusty so a bit of penetrating oil down the stud holes might help to move easier.

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When all else fails follow the service manual! Clive, I can’t believe the number of folks that apparently don’t have a service manual! How’s the south land treating you!

I tried but couldnt figure out how to changemy vehicle

I can help you there. Click on your own avatar (“C” in a green circle on your case)
A window opens up with your username (Charliek) in the top LH corner. Click on the username…
A window opens up with a list of options. Click on “preferences”
A screen opens with your preferences. Click on “profile” under “Account”
You can now enter lots of details about yourself and your cars. Just edit the text in the “My Cars” box. You could edit the “Location” box too if you want folks to know whereabouts you are located, and/or “National Flag” so we know what country you are in.


Hey Bob, we’re still up north right now and just hoping that no hurricanes hit our place in the south this year.
Yes, I’m amazed at how many folks go-ahead and strip a twin cam engine without looking at a manual. Lots of things could go wrong.

I’d love to see someone try that with a modern BMW engine with variable valve timing and variable valve lift and duration! :slight_smile:

Ray L.

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Those that choose to work with out a manual gives those of us with a manual something to do. We may not be any smarter but we have the directions in front of us. It never hurts to read directions two or three times!

Regards, Joel.

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Actually, i have a manual but sometimes there are helpful hints that arent in the manual. That is what is so great about this forum

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Years ago, I was working as a mechanic in a Lotus/BMW dealer garage. The shop foreman was working on an Aston Martin DB5, just back from having a complete engine rebuild and getting it ready for the customer to pick up that evening.

I had done an Aston DB4 engine myself so knew a little bit about them and watched just too late as the foreman, with the Aston engine idling, tried to quiet the timing chain and turned the adjuster the wrong way.

Of course, the engine quit immediately as the chain jumped the sprockets and instantly bent all the valves. Glad I had nothing to do with that. When the customer arrived to pick up his car, the dealer had a heck of a time explaining why his car wouldn’t be ready for another week or so.

Just a little bit of knowledge would have been a great help in that case.

I just pulled mine and found the Richard Micheal Owen YouTube videos “My Junk EType Engine” very helpful.

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You can even add your car year and model after your name so people don’t have to click on your avatar to find out (see above).

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