I got my special running- brilliant, a quick jig around the garage, and took a video on my phone.
But then noticed water bubbling from the head on the valve side. Turned off sharpish.
The oil had turned to emulsion.
I had been told the engine was ready to run, so didn't check the torque settings on the head, but had done a quick check and they were down tight.
So off with the head, which is a Cambridge finned type- checked that first, and and it isn't flat.
Then noted water in 2 and 3, and immediately saw these cracks- they're on both centre studs, and radiate to the (linered) bores.
I texted Zeto about this, and he fears the block is destined for the scrap bin.
I'm attaching a couple of images.
Drat! I put a lot of work into getting ready to fire it up, back to the drawing board.
I have never seen one do that before,
It appears the top surface has not been ground as you can still see the diamond stamping marks.
I would check the roundness of the bores ajacent to the cracks.
It should be possible to grind the cracks out enough to fill with JB Weld which will keep it running for a short while. ( the crack might well go a long way down the bore under the cylinder liners )
If all the studs will come out it will be worth having a go at a repair then get the top surface skimmed just enough to make it flat. fit all the studs back in with blue loctite which will hold then and stop leaks coming up the studs.
The above is a bodge fix which will get you running till you can find another block to build up preferably a non sleeved block.
if you can find another block easily then do not waste time on this block.
I have run a block like that for several thousand miles.
High temperature silicon on the gasket, Radweld or similar in the water, careful tightening of the head nuts over several days using a low range torque wrench, going easy on the centre stud.
Run it, check how much water is in 2 & 3 before starting.
If the oil is a lot emulsified there may be another source of water somewhere.
The bores have liners? What can happen is that the outer walls of the cylinders rust through and the top and bottom of the block become effectively "disconnected". Net result is that the studs pull the top surface about and it becomes becomes very "wavy" and constant head gasket problems and cracks ensue.
Dave Williams at The Austineers in Bradford-on-Avon had a block that had been so afflicted. He'd cut it in half to demonstrate the problem. Made a pretty graphic exhibition.....
Cracks around there are very common though they are usually just visible as hairlines, I wonder how tight that stud was done up.
They seem to have already progressed as far as they are able to.
Where exactly was the water coming from? Sounds like your head is also not flat.
I'm not a big fan of skimming but I'd certainly check it and if necessary lap it flat and only skim it if that's not enough.
With alloy heads it's important not only to follow the correct nut tightening sequence / torque but also to re-tighten them (COLD) after the engine has first run up to temperature.
Rather as I feared then gents.
Would you have a go at sealing it with a good gasket seal Tony, as you suggest, or might it only last a short time, and possibly do further damage to the bottom end with water pressure in the bores when it fails?
I might be better rebuilding the engine properly maybe?
Unless of course anyone out there has a tuned engine for sale
Thanks for the replies
Steve
03-01-2021, 11:51 PM (This post was last modified: 03-01-2021, 11:52 PM by Tony Betts.)
like chris sed,
for my money, i wouldnt use the block. id rather do it properly.
its not about splashing money about, it just that i dont get enough spare time to do things twice.
normally i just smear a thin grease, but i think you will need a good gasket paste for that.
i dont like grinding aluminium heads, but if you have to. make sure the company leaves it to cool properly. and i mean properly. then give it a finish grind.
quality aluminium heads are heat treated when new before grinding or cutting. it makes the machine work easier, and the aluminium doesnt stick or clock the cutters or grinding wheel. however on a regrind you will get some areas that will cool and relaxe more that others. so a finish cut is needed when done.
ive not used my J&S 540 for a long wile, but i would always clean a true the wheel with a diamond, and leave the head or block for at least 30 mins. before i done the finish cut.
(03-01-2021, 11:51 PM)Tony Bett Wrote: ive not used my J&S 540 for a long wile, but i would always clean a true the wheel with a diamond, and leave the head or block for at least 30 mins. before i done the finish cut.
