Compression test results SE engine

Hi All
What do you suspect from these results ? I did the test twice with the carbs removed . Cold engine , not run for many years . No oil down the bores , although I had dosed it with WD40 over the past few days .
Cyl … 1st test… 2nd test
1…60 …65
2…137…140
3…140…145
4…112…115
5…125…126
6…125… 130

Comments appreciated .
Jim

No. 1 strongly suggests a stuck or burnt valve.

you have forgotten more than I know, but I usually found a stuck, or even worn valve gives very low compression, but a ring stuck in the groove gave low-mid psi…in any case it is likely the head will need to come off, unless (any possible stuck valve) miraculously frees up

a couple of times I took out a piston, and freed the rings, and this was due to moisture entering that cyl

being that a leakdown kit is so inexpensive, I would try that next, help pinpoint before dismantle

Given the engine has not run “for many years,” and assuming those years were not under optimal storage conditions, were it me, I would, at a minimum, remove the head.

Old gas can stick intake valve guides, among possible causes. This will also allow a peek at the piston crowns, to see what story they tell, plus, renew the highly-corrodable steel head gasket.

Mine had a bad valve when I got it, not sure if bent, burnt, stuck, or what. My readings looked very much like this, except I thing my offending one was closer to 85. It ran sooooo badly, but it ran. The rebuild was a full head job, rings, bearings and timing stuff, and it got me 160-165 on all again.

take a look in the cylinders with a bore scope

Interesting info Jim. BUT the engine needs to come apart if you want any kind of ‘piece of mind’. You might try some oil down the bores to determine if its head or rings but …

Best regards

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Thanks for the replies.
A squirt of oil down no 1 doubled the compression , so looks like it could be rings .It’s just nice to have an idea what I have to look forward to .
Jim

If it doubled it, you likely have broken rings.

Might be best not to drive it, till fixed.

TEST IN JUNE … TEST TODAY
1…60 …65 … … … 110
2…137…140 … … 125
3…140…145 … … 130
4…112…115 … … 120
5…125…126 … … 120
6…125… 130 … … 125
I have been dosing number 1 cylinder with paraffin and giving it a flick on the starter over the past week .I now get a much better result on no1 .Do you think it may have been a gummed up ring before ?
I am sending off my carbs for a rebuild so I have 6 weeks on thinking about trying to start it .

Hmmm. I get a little thoughtful when people put a lot of effort into starting an engine that has been left for a long time or that is pat of a full rebuild. to have piece of mind when the car is returned to the road especially with the cooling system and suchlike it is necessary to strip and inspect it.
Water pump (bearing impeller etc) Oil pump, Hydraulic chain tensioner, main and big end bearing, crankshaft seals etc etc etc will all need to be carefully examined. In addition a though flushing of all oil and water galleries including core plug and crankshaft sludge traps should all be removed. so why not get on with it?

This is just my humble opinion of course.

Thanks for the reply Phil
I can’t disagree ,in a perfect world, but this car will never be a show winner and being probably the least desirable XK (140FHC) , I have to manage the budget. I know if this car was restored professionally it would make no commercial sense .
I don’t know if I have enough confidence to strip it my self and if it goes away to be done there will be many items that come under the heading "while its apart lets do this " then there is another few thousand gone . This is a not for profit car , and I intend to keep it (if I ever finish it ! ) but I don’t want to spend more on it than it is worth .
Glad of more comments either way.
Jim

The change in your #1 would make me want to take it apart.

With an unknown engine (i.e. you don’t know why it was taken off the road) there’s not much point in taking just the head off.

It’s a “Hail Mary” moment. Sometimes it works, sometimes it doesn’t.

Hard to say, but possible, on a gummed-up ring.

If it has good oul pressure, and other stuff seems to be decent…start it up.

Listen. See if it smokes excessively (once warmed up and all your loosening oul is burnt off).

If the engine runs smoothly, with no odd or excessive noise, then recheck compression, check valve clearances.

I had checked the valves and they where bang on ,which is encouraging .

Run it!! If after a while, all seems good, yer golden!

The way I see it if it has broken rings you’ll have to strip it anyway so attempting to run in this condition won’t make things worse from that point of view. And if the rings are OK and it will start, running it for a minute will give you an idea of its condition and might bring the compressions back to normal. Either way, if it was mine I’d be itching to fire it up.

Quite possibly it last stopped with one of the valves on #1 open and you have a bit of corrosion on valve and seat. If it will start you may get rid of that.

That’s my 10ps worth if an engine rebuild isn’t in your budget.

Eric

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fresh oil, filter…if cam covers off some new cam lube on lobes…turn by hand first…plus out…then with plus in…turn by starter…but disconnected so it wont fire…all ok? you/ve said valve clearances ok, timing ok…fire it up…with fresh fuel. Nick