Ok perfect! I thought I did something wrong with the lifters. When I took them out I couldn't push them down at all. Out of curiosity how do they release the pressure? Or are they always pressurized. And yes I will only use the block. I am gonna take SAI heads to the shop to change seals and clean valves and resell. Is it true that u can use those on a non SAI if u plug them?
Thanks again

 

The piston was fatigued from miles, When you tightened up the top end, the rod disconnected itself from the piston,(probably cracked around wrist pin) punched up through the cam, then punched a hole in the block, seen it before. Nothing you could do, it was just old and worn out. Has nothing to do with the lifters or the cam.

 

Chris that makes a whole lot of sense and seems like a very probable cause. Because all of the damage was around cyl 6 that had no compression which I am starting to believe had to do with the piston rod. I did the head job thinking they were leaking. But if the piston rod was loose then it was causing the bad compression then eventually it got loose and broke cam shaft and threw a hole in the bottom.
I am working on rebuilding a new block, do u know where I can get the set of rings and gaskets etc... For it
Thanks again that was very helpful

 

Chris,

Do you see a lot of fatigue failures and destruction at 150k? This failure is interesting to me as my Rover has 99k on it right now. I was under the impression that if the weak block castings held and my cooling system/maintenance was kept in check, I could get 200k out of the motor.

If this is an unlucky and fairly uncommon problem then that is one thing, but if Rover V8s like to throw rods around 150k, I might have to rethink my dreams of modding the Disco and just enjoy it as is, nearly stock with 2" OME lift, and save the money for something else when the 4.0 eventually gives up the ghost..

 

I had or almost similar happened to me on my 4ag motor, in my case my exhaust cams broke i figured the torque spec of the camshaft bolts was not all even. good thing is it sounds like you know your way around a disco so not worried hope you get your disco back in the road.

 

Did you not read my information regarding never installing used lifters on an old Rover cam??????????????
I see you are hanging onto another set of used ones which really concerns me.

 

Don't freak out. Just keep the cooling system in check and make sure it has oil in it. She'll go.

 

So Mike, what do you recommend. If i can't use new ones? also could you please give me some info concerning remanufacturing and installinganother block?
thank You

 

The block is out. As you will see in the pictures below, Cyl 6 piston rod broke and tore everything apart.
but what has me wondering is I did find a freeze plug in the block that was all bent out of shape. i am not sure were it came from but now i am wondering if it had anything to do with the loss of compression and if it was the cause for everything jamming and causing the damage, or did the plug fall after the rod broke and tore the block.
the block i bought from the yard is int eh machine shop, all comments and suggestions are appreciated.
Thank you, you guys are awesome.



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