Heads or not?

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From experience with Triumph Stag head bolts (which are absolute shockers for seizing solid) try tightening the bolts up so as to break the seal other than that we would use a mig welder to form a dome on top of the bolt so as top transfer heat down its length. Sounds like someone has over tightened the bolts to bodge the coolant leak.

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My first thought was "oh ****!" someone has used locktite instead of GM thread sealant. The sealant is only there to stop corrosion as there are no intrusions into the waterways.

BUT the remedy would be the same, some heat if locktite or even that freeze release stuff. And maybe hit them with a decent hammer. They won't break. I pity you getting the LH rear out!
Regards Philip A

Thanks for the quick responses. I don't have access to a welder, is there a cheap way to heat the bolts? What is the freeze release stuff? I don't think it is locktite, would have thought my impact wrench with its 360nm of torque would be enough to break locktite. Plus there wasn't anything on the exhaust bolts, so I'm guessing the head bolts went in dry.

My engine number starts with 56D.

Shell

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Originally Posted by PhilipA

"Blocks with a daub of RED paint or numbers in the range of 2.8, 2.9 or 3.0 written on them are clearly the most desirable(4.6 litre ones)." 3MM is the thickness when the sleeve is centred.

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with apologies to Dozer,,

If the wall thickness of the "best" 4.6 is supposed to be 3mm,,, maybe the 2.8, 2.9 etc are also written in red down in the valley ??,,


also Dozer, your 56D, while in the vicinty of other V8's is in the wrong listing below,,

and missing entirely from this one!
Rover V8 Engine Numbers

Thanks Pedro. Not sure what to make of that, perhaps the engine has been replaced at some stage. It has automatic transmission. Will see if I can find any other numbers or marks on the block later today.

Shell

Hard to believe a 18" breaker bar cant shift a head bolt.

It may be time for a pipe on the breaker bar,, I really cant see heat or cold travelling down a bolt that long with any success ( anyone?? ),, you cant get much more than 100nm on them before the alloy threads strip... you out there Dave?

did you say it was suspiously cheap? [wink11][tonguewink]

Most likely you are up against galvanic corrosion because thread lube was not applied appropriately,

Go grab a fire blanket and an old school induction heater or a couple of 1000W halogen lamps.


you can try this without removing the sump first but it doing so does get the heat up to the block faster.

Drop the oil, pull the filters, degrease the inside of the block at the bottom.
Place your heater facing up towards the block or the lights under neath.
put the fire blanket over the top of the engine and drape it downwards.
Turn on the heat and wait. you need a couple of hours. Dont let insulation get to melting.
Go the head bolts, you wont be reusing these ones so... With a Big drift and an FBH, smack the head of the bolt in towards the thread. 5 or 6 very hard blows.
put your 12point socket on swing to tighten first and then to loosen long slow application of torque is what you need here. your going to need about 5 foot of bar on it

IF that doesnt work...

using a small butane torch (I usually use the one that goes onto those disposable butane gas bottles for camp stoves) heat the head of the bolt and do the do up undo thing again.

If that doesnt work, AND assuming you have high quality sockets, try a rattle gun.

IF that doesnt work, since you wont be reusing these bolts again.........

grab a center punch a 3, 6 8 and 10mm drill bit and a good drill, it helps to have a bench grinder or a wetstone grinder to resharpen the bits....

Center mark the bolts, drill into the center of the head in 3,6,8 mm down to about 3mm past the shoulder of the bolt (about 13mm) total depth heat the head of the bolt again, and try to undo it, it should either undo OR fracture off if it wont, go the 10mm bit. Then it will BUT, you dont have a lot of margin of error with the 10mm bit.

With the ones that snap off, one you have the head lifted off, grab them with vice grips and undo them, if that wont work, heat them up with the torch and try again, if that doesnt work try an easy out, if that doesnt work, use a stud extractor, if that doesnt work weld a nut onto it and go again.

only turn the bolts about 1/6th of a turn at a time and do them in the reverse sequence of tightening. Then progress about 1/4 then 1/2 a turn and then spin them out.

IF the bolts closer to center are significantly harder or easier then the ones further out you need to check the deck and the heads for square.

Dozer - you have a 4.0 Low Comp RV8 - your number starting with 56D is the correct prefix. You will note that the two engine number lists posted do not actually have numbers for the D2 (they RR numbers) and the lists on the internet are the same. I have asked Rimmer Bros who have the main list that people go to include D2 numbers.

I have a 4.0 V8 and it starts with 55D so is a little earlier than yours.

Talk of information for a 4.6 is off track just a little as for all intention, the 4.0 and 4.6 are the same engines just different cranks, conrods and pistons - all other hardware is basically the same for the two Thor engines.

The blocks are the same but when built and tested, the ones that were at the minimum standard went into the 4.0. The ones that were the highest standard went into the 4.6 and those whose quality was in the middle went into either engine. As mentioned the valleys of the engine blocks were given a coloured dot to indicate which quality the block was - I dont know what the colours are but the 4.0 I have does not have a coloured dot and the bare 4.6 block I have does not have a dot on it.

All this is a side show to the issue you have - it will either be a simple failed head gasket, warped heads or a more complex block issue such as a slipped liner or stripped threads or cracks. My 4.0 was leaking at the back drivers side and it was a stripped head bolt hole and a crack between the the head bolt hole and the nearby water jacket.

Thinks should be clear once you have the heads off.

Garry

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Originally Posted by Dozer2

Have tried breaker bars and impact wrenches, normal hex sockets, impact hex sockets, bolt extractor sockets, kincrome's lok on sockets, lots of penetrating spray and tapping with a rubber mallet. Have broken several extension bars. The head bolts won't move, and are becoming damaged on the corners but not rounded yet. If I can't get the bolts out I will have to put it back together without replacing the head gaskets and hope that the coolant seal stuff will work. Any ideas anyone?

Shell

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Ok, I'm a pretty light chap (72 kg). I used an impact hex socket, breaker bar and the jack handle extension (good pipe extension) from the D2 to break mine.

Are all the bolts tight AF?

They are meant to go in with a very small amount of oil unless they have used ARP Studs (ARP I think have an epoxy).

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Originally Posted by Blknight.aus

Most likely you are up against galvanic corrosion because thread lube was not applied appropriately

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Thanks Dave for the epic list of steps. Will save for all future stuck bolts. I hammered, applied rattle gun, and used a 1.5m fence post over my breaker bar, and now the passenger side head is off. Interestingly though there was a lot of pressure behind the head, was hissing and releasing stale engine smells as I removed the bolts. Once the bolts moved a turn they came out easily.

Thanks Garry for the information on my engine, I hadn't been able to find my engine prefix online. There's a few more green marks in other places on the block too. Good to hear from another Canberran!

Pedro, Andrew, the long pipe did it. Andrew, I'm even smaller than you at 55kg 1.65m so maybe that's why I had trouble getting the bolts out.

Photos showing the worn water jackets on the gasket on the passenger side. No breaks in gaskets but it explains the leaks at the ends.

Attachment 148766Attachment 148767

Will do the other side tomorrow.

Shell