need a christmas miracle...

[deeb]

So the cooling system is being pressurized in my 97 disco w 108 k . My mechanic buddy just finished doing the headgasdkets and its still showin the vsame symptoms! the job was done right, both heads were magfnafluxed and machined.
Any ideas other than a crack in the block? Please. Thanks, happy holidays!
Chad

 

[Chongo]

need a christmas miracle...

So the cooling system is being pressurized in my 97 disco w 108 k . My mechanic buddy just finished doing the headgasdkets and its still showin the vsame symptoms! the job was done right, both heads were magfnafluxed and machined.
Any ideas other than a crack in the block? Please. Thanks, happy holidays!
Chad

1: is the coolant system pressurizing immediately on a cold engine?, or does it take a few minutes until the engine warms up?

2: if your answer is immediately, pressurize the coolant system with all plugs removed and determine which cylinder is leaking. Remove that cylinder head and investigate and look for cracks only above the piston at BDC, and look for the liner not being flush with the top of the block.

Engine

The engine in the disco 2 is the old buick 215 v-8, with no roller cam, and no rotators on the exhaust valves like US engines. The dry cylinder sleeves, “ these are not wet sleeved engines”, are straight, un - flanged and made of steel, while your block is made of aluminum. This creates a thermal condition of dissimilar materials. Many mechanics blame a blown head gasket on this thermal condition as a, “dropped liner”, but in reality at about 210 degrees operating temperature the cylinder liner actually moves around .004” of an inch away from the head gasket ring , this releases the tension on the head gasket between the liner and the head. This also releases the tension between the head and the head gasket between the liner and the head, and reduces the heat sink value on the head gasket steel ring, {this is why when you remove the old head gaskets on a land rover the steel ring on the head gasket is usually yellowish or has a burnished color}, causing premature head gasket failure. Now note what I said, the head to liner distance is getting larger by .004” not the head separating from the block, but the liner actually grows 50% shorter than the aluminum block walls. And since the stock land rover liners seat at the bottom of the bore, and on the main bearing saddles the expansion ratio starts at where it seats, at the bottom of the bore, not the top.
Expansion ratio of steel is 6 parts per million per degree
Expansion ratio of aluminum is 12 parts per million per degree.
No real such thing as a dropped liner according to popular belief, it is a thermal problem with dissimilar materials. And there is only one bullet proof cure, Top flanged liners, sometimes called top hat liners in the British market.
There just isn’t any other long term substitute for this issue.
Cracked blocks

A rare issue

Land Rover Bosch engine blocks, or the old buick 215 block usually cracks on the main bear saddle bulkheads, just below the liner. This is caused by the straight walled liner. Since the straight walled liner has no lip or flange at the top of the bore to seat against, it must seat against the bottom of the bore. Where the crankshafts main bearing saddle bulkheads hold all the tension from the tightening of the cylinder head bolts. As you tighten the head bolts, the head is pushed towards the block, pushing the steal ring head gasket towards the cylinder liner, forcing the liner to push hard against the bottom of the bore in the block, which is the main bearing saddle bulkhead. Switching to top flanged liners eliminates this issue. This is a rare issue, but I have seen this
several in my lifetime with this engine.

Head Bolts

Head bolts must be replaced every time you remove the head, they are not regular bolts, but a special designed stretch bolt. Their is a tightening sequence principle that must be followed although contrary to popular belief, and the service manual, as long as the principle is adhered to the sequence can be changed. The principle is uniformly and incrementally tightening the head down. The actual order doesn’t matter.
Take a good look
how the head gasket is designed and it comes with a sticky adhesive on the
composite part of the gasket. This will work beautiful if both surfaces are left
perfectly dry, and free of oil, i.e. lacquer thinner. Use NO OIL PERIOD on the head bolts, You’ll regret it if you do. You see the oil you put on the threads, like the book tells us to, will push off the threads as you thread it into the threads of the block and it
gets between the block and head pushing into the gasket areas ruining the effects of
the adhesive on the gasket, Oil and adheasive isn't usually a good combination......

What I did and this works well, I put only 2 layers of Teflon Tape on the threads of the new head bolts and a small amount of grease just under The bolt head. What this does is not let the bolt head gall into the heads and lubes The threads into the block without any oil. I believe this is an area where a lot of people have got themselves into trouble, and they followed the book. This would probably cause gasket failure in a few thousand Miles or so, and would probably be blamed on the mechanic or machinist, when it is A procedure problem. Use the Teflon tape on the bolts, it runs in nicely and life Is good.

In testing the book vs. torque standards I found the service manual, “again” in error as it says to tighten all bolts to 15 ft. lbs. then 90 degrees more in sequence, then a additional 90 degrees for final torque. This is bogus, and utter nonsense. My findings after doing this left the 3 long head bolts at 50 - 58 foot pounds of torque, while the short head bolts read 68 - 72 foot pounds of torque. I found that almost an additional 90 degrees was required on the long bolts for a total of 245 - 270 degrees before the long bolts achieved the 68 - 72 foot pound equivalent to the short bolts. This makes the tension and torque on all bolts even.
Due to the dissimilar materials of the steel bolts and aluminum heads it needs a stretch bolt design. Don’t go buying studs for this engine, you won’t be happy with the long term effects.

Best wishes……..Chongo

 

[deeb]

so does switching to these flanged liners require engine block counter boring to accept the new liner style?

also, will it require a new head gasket set?

thanks for your help
chad

 

[Chongo]

so does switching to these flanged liners require engine block counter boring to accept the new liner style?

also, will it require a new head gasket set?

thanks for your help
chad


Your answer to all questions is yes. Unfortuantly the only permanent cure is a liner rebore and installation of flanged liners. If you are in southern california I recomend Valley head service for the machine work, I've never seen a machine shop do better work, but finding the liners is a little tougher, I pay between # 80.00 to #200.00 per liner depending on who the vendor at the time has them available. I will help you get the vendors for the liners if you are interested, stripping the block completely is necessary for the shops. placing the engine block in an oven to let the liners fall out is not recomended, it may anneal any heat treatment to the block if any.

The process used to do this does matter.

I got all my parts through Brittish pacific, except the liners who I get through
Valley Head Service in Sanfernado Valley California : 1-818-993-7000 You can have them machine the bores to use your old pistons, or they can provide new custom pistons for less than the stock rover pistons, The custom pistons they provided for us performed exceptionally. Stock rover pistons each through Brittish pacific or atlantic brittish are around $200.00 plus each, custom pistons through Valley head service run around $150 each.




http://www.roverparts.com/?source=rangerovers.net


http://www.britishpacific.com/


The liner retrofit costs around $2000.00 plus around $1500.00 for parts. is of corse if you assemble it yourself.


Wishing you the best of luck over the holidays...................

Chongo