Hi all, I'm fairly new to the classic car scene, I currently have possession of my late grandfather's S Type, I think it's a mk2, but not 100%. (I need to check the reg no.) It's a 3.4, which I think is a V6? (Again not 100%). I managed to get the fuel pumps running, and get her started after 5 or so years of being sat in a barn, but she developed a misfire. I feel for the good of the engine in the long term, a top end rebuild would be a good starting point. I'm a diesel engineer for John Deere, so I've done a fair amount of headgasket jobs, and valve lapping and reselealing etc. But I just wanted to know if there's any particular do's and don'ts I should be aware of? And any advice for resealing/cleaning the carbs? Thank you in advance!

 

if it ain't broke don't fix it !!

whether 3.4 liter, or 3.8 liter, the original Jaguar XK engines are 6-in-line, not V6.

the same engines were used in the MK-2 and the S type.

the MK-2 has the exhaust pipes on one side, a single fuel tank / single fuel pump;

the S type has twin exhaust pipes, twin fuel tanks / twin fuel pumps.

 

The first thing to do is to remove the plugs and do a compression test, bear in mind that the compression on petrol engines is a lot less than the diesel engines your used to.

I would expect at least 130PSI minimum and all readings to be within 10-15PSI of each other. Others might have a different opinion. If its low on one or more cylinders put a small amount of engine oil down the bore and try the test again, if the compression improves then its bore wear or rings, if it doesn't then its valves or head gasket.

Once this is done I would check the valve clearances, from memory these are 4 thou inlet and 6 thou exhaust, I would allow 1 thou tollerance on this (i.e. inlet 3-5 thou and exhaust 5-7 thou.

Do you know what the oil pressue on the engine is? 30-40PSI running hot (i.e. while driving along or reving at around 3000RPM would be great, the hot oil pressure isn't so critical, anything above about 15PSI at idle hot is ok. My engine is 50PSI hot running and 30PSI hot idle and its just been fully rebuilt, also worth connecting a mechnical gauge as the electrical ones arn't very accurate.

I wouldn't take the head off unless there is a problem with it. Most running problems on these cars are electrical and the quality of some repro bits like points and condensors is highly suspect so just because you gave changed something doesn't mean that this is not the problem.

 

Post some pictures of the car and the engine bay so we all know what you have and you will get more accurate advice, Homer has given some good guidance to start, and Jose is correct and is also an S Type guy.

Misfiring could also be fuel, so once we know what you have that may depend on the advice, you may have Strombergs or SU carbs, probably SU, but if you think you have a V engine and not an in-line you may have a Daimler, you are probably confusing the 2 cam covers as a V, the straight 6 looks like the picture below in my signature area.

Post the details on the plate in the engine bay, chassis no engine no etc.

Welcome to the forum George