308 Head fused to block

Mark E made a cool head puller....mark, post some pics!

 

If you don't mind me asking why are you removing the heads? Does it have a headgasket leak or valve issue? If it is an hg leak did it overheat a lot or mix fluids? Thanks.

 

i had same problem had to make up a puller even then it was still slow goin.. good luck mate !!
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I have been very lucky so far to have found engines that popped apart quite easily. Some of these pictures of others cars engines look downright scarey.

 

Don't forget the trusty 2x4 and 3lb hammer.
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hey chris mate ... how you goin with ur engine kicked it in the guts yet!!!

 

A QV is a whole different animal than a 2v to get apart because the tops of the studs are not exposed so there is nothing to push on easily.

I haven't built a QV head puller, it's got more parts than a 2v puller, but it's not that much harder. You need a plat or series of plates like on a 2v, but then you need a series of bars that reach from the top stud to the bottom stud and don't hit the head in the center. Then you drive the pusher bolts down to hit the bars which in turn push on the studs and will pop the head up about 1/2". After that you have to pry it I think but it should come easily after you get it moving and can get some oil in around the studs.

 

It's caused by corrosion around the studs. A little coolant leaks and gets into the stud hole in the heads and corrodes the alumium causing it to expand and lock the head on. Once I got the heads off the couple I've worked on I drill the hole in the heads 1/32" larger, coated the studs with never seize and used a little on the head gasket right next to the studs. Maybe overkill, but the one I took back apart 6 years later came apart with no hint of a problem.

 

I have seen Ferrari shops destroy heads that didn't come off by simply hammering it to pieces or however else they can destroy it.
My mechanic when taking the engine from my 78 308 apart had a similar problem. He made a gadget which put significant pressure on the head and let it sit for days continuously squirting some special German made penetrating solution on it which he swears by. Of course you can also suspend the engine held by the head but it may not get as much pull as you would like to have.
No amount of hitting will do anything, time seems to be the key in this situation.

Helmut

 

On the 4 valves I have found that the only non destructive way is to heat the head to 300 degress through and through. Once that is done there is a pretty good sized overhang on each end of the head, with the edge of a 1/2 inch or thicker plate of aluminum up against the bottom of that overhang hit it with a few pretty good raps with a 4 or so pound hammer. That will slightly raise the head. Slide some sheet metal shims in the gap. Cheap rain gutter flashing from the home builder store works well for this. Go to the other end and repeat. Reheat the head and do it all over again. Keep building up the shims at each end, constantly hose the studs down with penetrant, work slow and be patient. I know of no one who has found a really good way or built an effective puller for the 4 valve heads with their shrouded studs

One thing to remember, the head needs to be really hot. Don't chicken out, it will take 300 to 350 degrees and not just surface temp. The whole head needs to be that hot.

I too put them together with anti sieze on the studs but I doubt 20+ years of heat and water will care about that. And that corrosion will fill an 1/8 inch gap. I have taken apart 6 year old motors built with no precautions and once the nuts are removed turn it over and the heads will fall on the floor.

 

Key to avoid this from happening is use of proper anti-corrosive anti-freeze, and renew every year/2 years. Of course this doesn't do anything for an exisitng problem/condition.

 

Anyone ever painted the holes in the heads and the block studs with zinc chromate while you had them apart?

 

here's my puller but bummer you can't use it on the 4v .. .makes the job easy on the 2v

cheers
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Kroil Penetrating Oil. I've used this over the years to free up frozen parts. Spray it on the head bolts and let it sit. With one engine, I sprayed the head bolts and tapped the head with a hammer just to set up a vibration each time I walked pass it. After a week of doing this the head come off without much effort.

 

This is typical of aluminum heads and blocks with studs. I ran into this with my Aston Martin engine project and nothing other than a couple of shots with a hammer on a block of wood would get it to move. There are probably areas of the head that extend beyond the block; you want to position a piece of wood (like a 2x4) under them and give it a couple of good whacks with a hand held sledge hammer. Forget using carpenters' hammers, or the ones used on knock-offs, etc. You need a hammer that has at least a 5lb. head IMO. Give it a shot on one end of the head and then move to the other. They fit very tightly over the studs so you can't expect one end of the head to move very far without making a corresponding move on the other end of the head. Good luck.

 

Iy took me 4 days to take off one head and 3 days for the other on my 2v motor.

Listen to Brians suggestion about heating the head then hitting the overhang up on each end of the head. I'm pretty sure you can use a propane flame blower to heat it up to the required temp.
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Robert,
Rifledriver is a VERY long term Factory trained Ferrari technician. Go with his advise.

It's important to heat things up evenly to minimize the risk of anything warping, so I wouldn't reccommend the propane weed burner.

A powdercoating oven will nicely warm that engine up to the necessary temperature.

Or make a plywood box with an open bottom large enough to go over the engine & engine stand with plenty of clearance. Line the box with foil faced insulation & put it over the engine in with a couple of 500W Halogen work or driveway lights under the engine. Keep a good eye on the temperature so nothing gets too hot.

 

If you can get your hands on a type-k thermocouple and a digital temperature gauge readout you can precisely measure your air temp. Perhaps a couple of well placed thermomemters for measuring food temps might work too. I'm not sure if they read that high a temp or are long enough to reach the required area you need to be.

 

But don't you want to heat just the heads and not the block?

 

That would be pretty hard to do. The block would draw the heat away from the heads unless they were at the same temperature.

Heating the assembly will cause the aluminum parts to expand a bit more that the steel parts (studs) and should make it easier to separate.

 

I would believe the head gasket would act as a pretty good insulator. If you could heat the head by itself, the main heat loss would be primarily into the studs where the block would suck it away, might actually shrink the studs relative to the head? Hard to say really, just glad all mine popped right off without any fuss.

Might be best to yank the heads off every 10 years instead of letting them get bonded on so tight. The fact you cant push against the studs on a QV, I could forsee a head becoming so stuck you may not be able to remove it without cutting it off.

I also seem to recall a post somewhere of someone removing stuck heads on a 2V, he made some hole saws out of thin wall tubing that just barely slipped over the studs and cut down through the head past the studs to break it loose. I dont know how that worked out, but someone raised the question of what would happen if the saw broke apart down inside the hole. That would be a mess.

 

Am still not really clear on where the water is coming from to cause the corrosion?
In all the pics I've seen some studs are corroded and some not but many of the corroded studs its only part of their length. All these partial length corroded studs appear to show corrosion reaching down from the top, often mainly the threaded section of the studs.
Is this water entering from above or leaking past the head gasket from internal water ways? The pics seem to suggest penetrating from above.
Any thoughts?