Damaged bore

[phoenix]

Hi we have found a rust groove caused by the rings about 1/32 deep in a rebuilt engine that was done about 10 yeas ago by someone and probably not turned over since.
It has a new set of +20 pistons fitted. What would you suggest sleeving just the one cylinder and boring it out to +20 or resleeving all 6 and boring to standard and a new set of pistons .
We could not get the engine to tickover well even after playing around with the carbs and timing. We then did a compression test 165 165 45 165 165 165 psi . all valves checked and none sticking .( S1 4.2)

[christopher storey]

I would sleeve the affected cylinder, bore it +.020" and fit new rings all round

[tinworm]

If you want to re-use the parts you have, just replacing the one liner is fine - you do not have to do all of them unless the wear or damage was such that all were a bit suspect - and it made sense to change the lot.

Barrie

[abowie]

I would sleeve the affected cylinder, bore it +.020" and fit new rings all round

[phoenix]

[abowie]

Other things to do..

While the head's off check the valve clearances are correct. This is a lot easier to rectify on the bench.

Since you'll have the crank out anyway, replace the bearings. Even if they're new, sitting in an engine for 10 years can't be good for them.

Get your machine shop to have a look at the crank journals and give them a polish if they think it's warranted. You could also get them to check the balance of the rotating components.

Look at your timing chain tensioner. If it's a Rolon branded one replace it with a genuine Jaguar one.

[phoenix]

Engine now fully striped. Three of the bores have these rust rings an two of the pistons had all their compression rings broken . Also one of the main bearings is slightly scoured . So it's going to be a big bill for the owner on a supposedly a rebuilt engine. Also setting us back probably a month .(we only work part time now plus the engineering shop is busy) while it's apart I may as well balance the rods .

[phoenix]

I am just going to fit new rings to two pistons and I have noticed they have different part numbers .
C 25489 and C 25488 plus oil control ring. Which of the numbered rings is the top one,

[mgcjag]

Hi Bryan...do you have a Jag parts catalogue for your model......if not there is one in the knowledge base section...Steve.

[christopher storey]

Those numbers are not the original part nos, which for 20 thou oversize are C 21707/20,C21708/20 and and C21709/20 in descending order but....

The top ring is chromium plated

The lower ring is plain cast iron

The scraper ring is the usual flexi type

[phoenix]

Thanks for that I can tell them apart now just looking at them. I will be glad when we are going forward instead of taking things apart again . Very frustrating.

[DWW]

I certainly know how that feels, I had to wait nearly 4 years after purchasing a driver that ran to be able to enjoy it again

[phoenix]

All pistons and rods now balanced to within a gram and valves checked just waiting for engineering shop now .