Cyl valve stuck after loong sleep- SOLVED

Post by **Bluesman** » Mon Sep 03, 2007 11:04 am

Hi folks - next issue: our Minor 1000 -60 has been garaged for 15+ years. We are bringing it back to life (see various "electrical" threads

) and now it´s running. Sort of. 3 cans fire properly, number 3 does not. I suspect a stuck valve, since the sparkplugs for cans 2+3 showed rust. If the valve stem has rust on it...it wont close. My hopes are that it will sort itself out with time, oil and engine heat doing the work. I have had the engine running for about 5 minutes in total since first started, but still only 3 cans.

a) Will it sort itself, ever?
b) can I help in any way (without ripping the cylinder head off), i e by lifting the rocker cover and tapping on the valve side of the rockers for cyl 3 (gently, with a blunt, heavy object (lead mallet etc))?
c) would it help to idle the engine for , say, 20 minutes, to really get the heat effect?

The engine had a big overhaul before being garaged. New pistons, bearings etc. This problem is therefore not likely to have been there when it was garaged. I´d rather not split the engine if I can avoid it.

Cheers /Richard, Sweden

Post by **chickenjohn** » Mon Sep 03, 2007 11:14 am

Do a compression test on all 4 cylinders. Unbolt the rocker cover and turn the engine over by hand (using starting handle, ignition off) to see if all valves are opening/ closing properly, you can then see the condition of the rocker gear, valve springs and push rods.

Post by **bmcecosse** » Mon Sep 03, 2007 12:09 pm

As above - off with the rocker cover and inspect the valve movements. You may be lucky and it resolves itself - don't rev it hard meantime - and see if heat does the job. If you 'tap' it - it's only going to go further down and may eventually be whacked by the piston - which will certainly jush it back up!
Sure it's not just dirty spark plug/leads in wrong order - something simple like that ?

Post by **chickenjohn** » Mon Sep 03, 2007 12:42 pm

Or having seen the distributor cap in the other thread- maybe a new cap and rotor arm will get the car firing on all 4. Go for the simple things first! ;-)

Post by **Bluesman** » Mon Sep 03, 2007 9:43 pm

Distributor fires on all 4, especially after I changed the coil to a new one. The old one died - as predicted - when hot. New one (hi-performance) gives huge sparks, so something to be happy about.

Still no life in #3. Compression tests follow tomorrow, along with a sanity check of the ignition timing (cyl 1=proper timing).

After that, I will decide whether I want to lift the head off and do a valve job or not. That of course means expenses and waiting time (cyl head gasket kit)...cud have lived without both.

Cheers/Richard

Post by **rayofleamington** » Mon Sep 03, 2007 10:46 pm

does the missfire go away at higher revs? If yes, that is more indicative of a 'small' leak (eg valve nearly closed / badly leaking rings). If it missfires also at high engine speed then there's something seriously wrong.

When you do a compression test, they should all be within approx 10% of each other. I can't remember figures for a 948 engine but anything less than 100psi is probably bad. anything like 180 psi and something isn't standard!
If you repeat the test putting some oil in the bores the results should be a bit higher (better sealing on the piston rings). If the results (e.g. for a low cylinder) improve a lot with oil then it's a sign of faulty rings. If the results only change a little (or not at all) then any problem is likely to be valve related.

Post by **Bluesman** » Mon Sep 03, 2007 11:25 pm

Ray - it *feels* like the engine runs on all 4 when on half throttle, but I can´t prove it. The plug says no, and the engine definitely feels weak.
I can´t take it out on the street, I have sub-zero brakes right now.

Thing is that this engine is supposed to have had most innards renewed right before being garaged 15+ years back. New pistons, bearings - the works. I talked to the owner, but he has forgotten a) why he renovated it and b) what exactly was done. I have a rough idea, but....It feels sound, it sounds wonderful, but it looks like it has an partially open valve or two due to long storage in wet climate. I also don´t know if the cylinder head was renovated, but I guess the comp test will tell if things are fishy/leaky.

For tomorrow´s sanity check: is there a cyliner #1 TDC marking on the distributor, or a verified place where the rotor *should* be when the engine is at #1 TDC?? I failed to find any marks on the distributor rim (Bosch has one, but Lucas...?)

Thanks to all for the compression tips. Will do.

Post by **chickenjohn** » Tue Sep 04, 2007 7:36 am

Take the rocker cover off and have a look- its only two bolts, then you can see if all the valves are opening/ closing as they should when you turn the engine over by hand.

Post by **Bluesman** » Tue Sep 04, 2007 8:36 am

Will do, John, will do. Later today/tonight. My daytime employer probably won´t allow me working from the garage even if I could...patience required.

Cheers /R

Post by **Orkney** » Tue Sep 04, 2007 9:14 am

My daytime employer probably won´t allow me working from the garage even if I could..

Thats what wireless laptops are for

Post by **bmcecosse** » Tue Sep 04, 2007 10:46 am

Just get a Mini 998 head gasket (no need for a kit) from a local auto parts place, and if you turn the engine over on the starting handle you should be able to feel 4 equal compressions - if there are 3 good ones and one 'easy' (perhaps with sucking/blowing noise) it's a guide to what's wrong!

Post by **downsey** » Tue Sep 04, 2007 2:40 pm

We are bringing it back to life (see various "electrical" threads )

It amazes me that i've never had an electrical problem. Before i got the car in '05, it hadnt been on the road since 1965. Put the 1275 in and she fired right up with all the stock wiring harness!

Post by **Bluesman** » Tue Sep 04, 2007 4:57 pm

Well - compression results:

Cyl 1 cyl 2 cyl 3 cyl 4
Dry: 100 110 <30 110
Wet: 120 110 <30 120

Confirms a stuck valve, IMHO.

I am in the garage now, have lifted valve cover.
Which valves are inlets?

I need to see if valve clearances are OK-ish and I want to release the valves for cyl 3.

Clearances? I have both inch and mm gauges

so feel free to tell me either way

And yes, I have no manual. That´s why I ask you friendly people for help

Cheers /Richard, @garage, Sweden

Post by **Bluesman** » Tue Sep 04, 2007 5:23 pm

OK...SORTED!
Previous owner had "adjusted" no 3 to have both valves hanging in free air at all times.
Now she runs on all 4...110 psi on nr 2!
Phew....thanks anyway!

Post by **rayofleamington** » Tue Sep 04, 2007 7:15 pm

It's possible that the rockers had not been adjusted since BEFORE the engine rebuild. If the head has been reconned or even changed, then this kind of problem can occur.
The downside is always not having a clue to what has been done and what hasn't.

In the short, medium and long term I would recommend getting a manual - and a Morris owners manual that shows the servicing requirements. A lot of teething trouble on a new Minor can be solved by working through the service procedures from beginning to end!
[I rarely take that advice and as a result I get to find the problems by breaking down instead

]

Post by **bmcecosse** » Tue Sep 04, 2007 7:40 pm

Well done - now torque the head down and reset the valves again. I use 0.012" on inlets and 0.015" on exhausts to allow for the greater expansion of the exhaust valve stem when running. It's very important that the gaps never close up - or the seats will be burned.

Post by **bigginger** » Tue Sep 04, 2007 8:29 pm

Just the customary comment that the maker reckoned 0.012 for all - since you don't have a manual.

Post by **Bluesman** » Tue Sep 04, 2007 8:51 pm

Abt the manual: it´s on its way. Got myself a Haynes + a Morris renovation guide from Alibris. The driver/owner manual should arrive tomorrow from another source. Patience is just not my big virtue in life, I *had* to get this (and the other stuff) sorted before I take on the big task(s)...I need a complete new brake system plus a welding job (torsion bar junctions to frame etc) but the welding job comes later. First we need a running engine and some brakes to get it out of the owners garage (steep uphill driveway!)

In any case - all tips duly noted and hereby thanked for.

Cheers /Richard (soon on a different thread near you

)

(Ah...I actually have a Haynes already. It spent 15+ years in that same garage. Trust me - it´s only 1% readable..mould, insects and mice have taken their toll - good thing the owner didn´t stash his paper money there....it would have rotted away)

Post by **bmcecosse** » Tue Sep 04, 2007 9:45 pm

When the 'manual' was written there was lead in the petrol! It's the use of unleaded petrol that makes it wise to open up these exhaust valve gaps slightly.

Post by **bigginger** » Tue Sep 04, 2007 10:16 pm

I know, you've said so often before. Sorry to give the factory figures again, but the OP had said that he doesn't have a manual, and better that he can decide for himself what gap to choose