Hi all, I live in France and own a MK2 2.4litre 1967 since 1980 , it was my student car :-) and I drove it daily during 5 years then it has been stored for about 35 years.
restored it myself "nuts and bolts" during the last 2 years.
After the first break-in tests (600km) I realized that the oil consumption was 2 litre / 500km and heavy blue smoke followed me , I have to say that original pistons stayed inside and only the piston rings have been changed as the honed cylinders showed only 2/100 mm ovalisation and pistons seemed to be in good shape, valve guides and valves have been replaced and the cylinder head machined . I dismantled the engine again and noticed that the piston ring clearance was 0.15mm instead of .02 to .07 mm.! So I am looking for NEW pistons 8/1 CR and original bore size....with no success ;-(
Have you a source for the 2.4 litre pistons?
Sorry for my bad English :-)

 

I'm looking for some for my 2.4 engine and I spoke to David Manners Jaguar Spares in Oldbury England and they can get them, I think they said they were £375+VAT and they can get +020 +040 and +060, there is also a +030 but they are difficult to get apparently.

 

Hi,
you might find them in USA. Terry's Jaguar found me new 9/1 Mahle pistons at .020 for my 3.8 litre when nobody else had them.
Good luck!

​​​​​​

 

The pistons for the 2.4 are different to the 3.4 and 3.8 and i'm not sure how many 2.4's were ever sold in the USA or if they were even available?

 

Welcome!

The best thing you can do is check the bores for size, taper & ovality & rebore to the first standard size that corrects this & you can get spares for (Hopefully +020). Home honing is not recommended for the XK. You usually do more harm than good. David Manners is a gent & reliable supplier.

 

It looks a lovely car. I'll second on David Manners. I've been buying from him for 40 years. If you are a JEC member, remember to ask for the club discount.

 

Why not just go get some forged pistons made ?

 

Would having a set made cost less than the £375+VAT to buy a set?

 

The last time I had a set made was for my Mark VI Bentley at Ross Racing pistons for 600 US dollars, but that was 20 years ago.
I think it would be worth checking into.

 

Hi , I checked the bore for scratches, ovality , conicity and all is in specs so I do not want to rebore as the engine didn't smoke and consume oil when I stopped it 35 years ago. But I cleaned the pistons , their grooves (perhaps this was the error :-)) and fitted new rings...and then the smoke and oil consumption began....

 

Personally I wouldn't fit new pistons to old bores, the cost of a rebore isn't huge and the cost of new pistons is a fair bit so it wouldn't make sense to do that. If you fit new pistons and it still smokes then you will then have to rebore it and buy another set of new pistons in an oversize.

 

David Manners is such a decent man. Goes beyond the call of duty to help. He found me some NOS items I thought I would never find. Some from as far away as Cyprus.

After expat assignment & serious attempt to to finish the restoration. I stopped off in the UK & went to personally meet all the suppliers I intended to use like Manners, Jon Skinner etc. Good to know who you are talking to on the other end of the phone from the Southern tip of Africa.

 

I agree, why waste this opportunity to improve the internals for performance and reliability, forged pistons would be the way to go and then bore as needed. Rebuilding the engine is the best time to improve the performance and worth the extra money to do so. Remember you are already doing all of the labor to put it back in, etc. I would also recommend getting a forged crank and porting the heads with larger intake/exhaust with a 3 angle radius and mild cam; getting it all balanced and blue-printed will be worth it with a good performance local engine builder..

 

Why not use forged pistons


Because I do not know where to find them :-)

 

I think it is worthwhile to go back to basics.
It sounds as if the " new" rings fitted were incorrect. Even a fairly worn bore/piston will accommodate new rings for some time. Were the oil scraper rings put in correctly?
Actually most of the wear in a motor tends to be in the bore and not in the pistons.
This was quoted to me by a professional engine re-builder whom I have known for 40 years.

I would have someone measure the current pistons for wear before embarking on new pistons. I think it might be worthwhile to talk to a professional engine rebuilder

On another point about getting more performance out of a 2.4
I recommend the Jaguar sponsored modification of getting rid of the downdraft Solex carbies and manifold and fitting a 3.4/3.8 manifold and SU HD6 carbies as was done on the 240.
I have done this to a MK1 and a MK2 and it changes the engine characteristics from a "slug" to a get up and go.
Bill Mac
MK1
MK2
XJ6S3
X300
15 previous Jags MK5 to X308

 

Hi Bill Mac
the wear in the piston grooves for the 3 first rings is largely out of specs as the play is about 15/100 mm instead 3 to max 6/100 and YES the oil scrappers were put in correctly as the 3 top rings were (respective positions and shift ) :-)
Valves and guides are new and lapped
Max bore ovality is about 3/100 mm
Oil was absolutely BLACK after only 600 km :-(
After the 600 km I checked the compressions (WOT) and found 9 bar on the 6 cylinders instead 11...

This is why I think the pistons have to be replaced...but perhaps I am wrong :-)

 

This is a more general question. Primaz suggested a forged crank. I thought that the original cranks in the XK6 were forged from EN16 steel. Did Jaguar switch to cast at some point?

If you are swapping cranks and machining the bores, why not go big and make the engine a 2.8 or 3 litre?

 

I want to keep the engine as original as possible, so no swap of any kind

 

And of course the very obvious. Ensure that the ring gaps don't line up with one another.

 

Of course , that is the basis of the technique :-)