308 Head fused to block

Some years ago I had the same problem with an E-jag cylinder head - corroded to the studs. I used the method others here have mentioned - put some cord into one of the end cylinders and then applied lots of torque to the crankshaft nut. Got a tiny bit of lifting and then moved the cord to the other end cylinder and did the same thing. After several such "lifts" alternating ends, the bond was sufficiently broken (lots of penetrant as well) to lift the head by hand.

I'd at least try that first - it costs nothing, takes little time and you can't hurt anything.

 

I am going to try all methods of removing the QV heads on my '85 308 this weekend. I will start with the heat and alloy block tapping, will also try the rope trip and if necessary, will make the puller as noted above. I think I understand what is being explained but if possible, can you sketch out the QV head puller design? Below is what I have - Thank you

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Good luck man. I had one stud stuck on a 355 engine and it took all day of beating with a stick and wedges. One stud, one day.

 

Feel your pain. Removing the water pump manifold on my "early" 308 can only be done after removing all four studs Seemed simple - wasn't. Just like with your experience, it took one full day, most of which was to remove the very last one.

 

Isnt there a steel plate with bolts contraption most guys have used? Or some rope trick in the cylinder? IIRC

 

The practice of compressing cord on the dome of the piston would be much more practical if someone were to publish the number of ft/lbs of torque to stay below. Without that, I would be afraid of causing a weakening of the piston or the beginning of a twist in the rod.

 

Re: the rope trick. A great mechanic friend explained that as pressure is applied the rope will splay out to the perimeter of the cylinder and apply the force to the outside edges of the piston, not the center. I used this trick using braided line, (a retired Genoa sheet from my sailboat, available in any length at West Marine). The head was seized on the studs, not the head-to-block interface, and worked slowly: using the two cylinders coming to TDC, then remove the rope, rotate the crank and use the other two cylinders. Used a 4' breaker bar on the front crankshaft nut. I estimate 50 lbs of force on a 4' bar = 200 ft lbs. There are some picts here: https://www.ferrarichat.com/forum/threads/observations-on-a-gt4-engine-pull.458208/

When I reassembled the engine I used a very light coating of ceramic anti-seize on the studs (not on the threads!!) after cleaning the bores of the stud holes in the head. Hopefully the head will never need to be removed again, but if it does...

 

That sounds viable though I would still be hesitant to use much force.

I would think that the head studs were plated when new. If not replacing the head studs, it would be a good step to replate those studs to prevent corrosion. It took 30-40 years to build up corrosion from new but a set of freshly wirewheeled or glass beaded studs might rust within a very short time.

 

Easy fix,
Just use my head gaskets, no more leaks.
Murray

 

I tried everything and even hung my transaxle from a head for a while with lots of PB Blaster. Eventually used a scissor jack and an axe handle (check out Derek’s 308.)

 

Here is the tool I made which worked perfectly.
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THat was the plate i was referring to.

 

Thanks for the picture of the puller plate. However, this looks like a two valve engine and my engine is a QV - am I incorrect? There are no accessible head studs to push on with the QV

 

Correct.

 

Thanks for all the suggestions - Both heads are off using bottle jacks and 4x4s

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How did you do it that way?

 

short bottle jacks lots of wood and rubber at the top and bottom and worked very slowly back and forth. Then turned it upside down and used 4X4s

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Can I unbolt this front cover with the cam drives? Will it come off if I don't remove the ring nuts from the cam drive sprockets? Does anyone know the size of those ring nuts? Thanks as always - very helpful to get input from others who have been down this road rather than learning the hard way....

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Yes, you can, but why? This is the time to replace the cam drive seals and bearings, all of them.

 

yelcab - thank you. At this point I want to pull off the front cover so I can remove the pistons and crank - Then, I will change the seals and bearings...

I was just trying to determine if I can unbolt that cover from the front without having to remove the ring nuts on the cam drives??

Also, if anyone knows the size of those ring nuts so i can purchase the correct tool the first time...

 

28mm is the size

 

You’re welcome! The Derek method