Low vacuum and compression 2.25L ???

[Regan]

I have just completed my work projects (for the time being) of fixing leaks, etc. but continue to develope news ones - guessing that is good as oil is still in the transfer case and engine! I suppose that's why I have a oil drip pad.

My question and needed guidance is as follows: I took my '67 Series IIA in for a compression & valve check, along with a good engine overview at a respected local mechanic. $250 + later, I am told that I have very low vacuum ( only 7 pounds), low compression at 100 lbs. and the mechanic believes the piston rings need to be replaced. All in all, he suggested a rebuild (by LR professional), swap out to a rebuilt engine or install a turbo diesel as he says that would be "Really Cool"! That's the Bad news. The good news is that all cylinders have the same pressure, not one high/low, no smoke and the engine runs really smooth, i.e. just not producing much power (somehow I did know that!).

I am open for suggestions to find a cure for my 2.25L. Of course, cost/expense is a factor, so $ from high to low or vise versus. I would like some suggesions as I do plan to use this Series over fairly long highway stretches in the future. Now I plan to go only about 1 - 4 hours. I understand that the engine may stay the same, loose more power (as time goes on) or just give out one day, somewhere out west or something. Appreciate your comment/suggestions. Speedo shows 92K, probably 2nd go around. Thanks!
Regan - Lafayette, LA

[Tim Smith]

From your description, I have to agree that it sounds like the rings are worn.

Now I may get crucified for this but I had some good luck with Marvel Mystery Oil. First I used the vacuum line to suck in a jar of the stuff while revving it every so often. Lots of smoke should come out the tail pipe but that is fine so long as your neighbors don't call the fire department.

The engine should be up to operating temps to make the most difference. This cleans carbon from the top end with the cold MMO hitting the hot carbon and if you are lucky, this might help seal the valves. However, I don't think this is really your problem.

Then, and I waited until about 500 miles before my next oil change, I dropped a quart of MMO into the crank case and went for a trip. This will help free up the carbon from the rings. To be honest though, in my case I was getting too much blow by and I'm pretty sure it was just the oil rings that were carboned up. This did give me great results but YMMV.

Just don't hydraulic the engine by dumping too much MMO in the carb through the throat and you'll have no worries. It's cheap and if nothing else will tell you if it is indeed wear or if it's just carbon build up.

[KevinNY]

Frankly I'd leave it alone, it works doesn't it?

[jac04]

Usually the compression test will be done again with a squirt of engine oil in each cylinder. If the pressure goes up significantly, the piston rings are usually the culprit.

I had almost the same issue with my 63 before I had the engine rebuilt. It ran great - smooth, no burning of oil. But, it lacked power. The compression test indicated about 85 psi across the board. These numbers increased a lot when oil was added to the cylinders. Pulled the head and all the cylinders had a big wear ledge at the top. No doubt it could have been driven a lot more miles the way it was, but a rebuild made a huge difference.

[mongoswede]

What are the healthy numbers for compression on a 2.25L...keeping in mind that these engines are either 8:1 or 7:1 compression which is pretty low. Is the engine blowing excessive amounts of blue smoke out the tail pipe?

[yorker]

CRANKING COMPRESSION:
NOTE: Inexpensive compression test gauges are not known for accuracy and your readings will be affected by the temperature of the engine. Use the number you read as a guideline only. Differences between cylinders are more important than the overall number. More than 20 lbs variation between the highest cylinder and the lowest cylinder warrants head removal.

Compression values provided in the manual were taken with the engine at full operating temperature. Metal contracts as it cools so expect your readings to be lower. The difference between a reading taken at full operating temperature and cold can easily be in the 20 to 40 pound range. Compression for a hot engine is approximately 145 PSI for 7:1 heads and 160 to 170 PSI for 8:1 heads


http://www.britishpacific.com/BPSite/seriesLandRover/LandRovertech.html#petrol

[I Leak Oil]

Frankly I'd leave it alone, it works doesn't it?

Ditto......
It'll probably run for a very long time as is. Besides, you hope the mechanic did the compression test the right way but you don't know for sure. Did he say why he thought it was the rings or did he just say it needs them? Drive it and enjoy the thing....

[Regan]

Thanks for the info. The mechanic I used did the valve and compression check by turning the engine by hand and measuring the valve clearance, etc. I gave him all the papers for this forum and tech. data sheets I had for performing this, which he followed to a T. I have noticed, while operating, low vacuum and the compression "feel" seems low as he found or justified for me.
In the end, I will add some additives for the short term to assist in low compression and rings. I do believe this will help some but will eventually need a rebuild, which I will undertake over the winter. In the meantime, I'll enjoy it as is, jut a little bit slower.

[4flattires]

The mechanic I used did the valve and compression check by turning the engine by hand

Huh?

I'll guarantee you get different readings when using the starter and cranking at normal speed. Using the vehicle's starter is the definitive standard for performing an accurate compression test.

[daveb]

To the OP.

This is how a compression test is supposed to be carried out:

You must acquire a compression gauge with a screw fitting that fits the spark plug threads on your engine. Most decent compression gauges will come with adapters to fit the two most common spark plug threads (14mm and 18mm)

Once you have acquired your gauge, you can begin preparing for your test.

Make sure you have a pen and paper to write down the results of your tests.

Run the engine until it is completely up to full normal running temperature.

Disconnect the HT lead (large spark plug wire from the coil), so that the engine will not start.

Remove the spark plug from the number one cylinder (the one closest to the front of the engine)

Screw the fitting of the compression gauge into the spark plug hole until it is snug. You shouldn't need a wrench, just get it down until the o-ring is seated and smushed down a little bit.

Sit in the car.
Depress the acclerator pedal all the way to the floor and hold it down. This ensures the throttle is all the way open and that the engine can draw in as much air fuel mixture as possible, and thus achieve the highest possible compression pressure.

Crank the engine over about 6 or 7 times using the starter.

Get out of the car and go check the gauge. It should hold the highest reading until you depress the button on the side that relieves the pressure.

Record that reading for the number one cylinder

Remove the gauge and replace the spark plug and its wire.

Repeat for cylinders two through four, recording your results as you go.

When you finish all four, repeat the test but add a tablespoon or so of oil to each cylinder as you go. Again, record your readings for each cylinder.

Your results page should look like this

DRY
1- xxx
2- xxx
3- xxx
4- xxx

WET
1- xxx
2- xxx
3- xxx
4- xxx

Get back to us with your results.

rgrds
Dave in DC

[4flattires]

...no mention of beer in this well documented test procedure?

[cgalpin]

Yes particularly with that level of detail I think beer drinking points should be clearly detailed. It would be different if Dave had said "Remove plug wire from coil and turn engine over 6-7 times for each cylinder with the gauge in place. Repeat the procedure with a teaspoon of oil in each cylinder". In this case I'd say it was surely implied.

[daveb]

Well alot of posts in this thread left doubt that correct procedures were followed. And so I thought I would try to help with that. There was never any doubt that y'all had the beer aspect well in hand.

:gulp:



Yes particularly with that level of detail I think beer drinking points should be clearly detailed. It would be different if Dave had said "Remove plug wire from coil and turn engine over 6-7 times for each cylinder with the gauge in place. Repeat the procedure with a teaspoon of oil in each cylinder". In this case I'd say it was surely implied.

[LaneRover]

Well alot of posts in this thread left doubt that correct procedures were followed. And so I thought I would try to help with that. There was never any doubt that y'all had the beer aspect well in hand.

:gulp:

I think you'd have to be drinking said beer - otherwise you might pour a tablespoon or so of that into the cylinder instead of the oil. Though the Rover might like that a celebratory glass of oil just wouldn't cut the mustard.

[scott]

ok, we have established that said or not said beer is supposed to be there. but i do compression test just a bit different than daveb. i remove all spark plugs and from daveb instructions i get the impression he has the 3 non testing at the time cylinders' spark plugs in

so is it all out or just one out at a time?

[mongoswede]

ok, we have established that said or not said beer is supposed to be there. but i do compression test just a bit different than daveb. i remove all spark plugs and from daveb instructions i get the impression he has the 3 non testing at the time cylinders' spark plugs in

so is it all out or just one out at a time?

pull one spark plug at a time. The readings should be similar in either scenario but I have always left the plugs in.

[4flattires]

...with plugs removed.

Primarily due to keeping the cranking speed up for the duration of the test (battery drain). Remember some cars on the road are V8's.

Secondarily due to keeping the cranking RPMs higher without plugs vs with plugs.

Thirdly because it is too dang tiresome pulling, replacing, pulling, replacing, etc. Pull 'em all at once. Replace 'em all at once.

Most importantly, keep one hand handy for the tester, the other hand firmly on the pint when yelling....crank it!

[bkreutz]

If you want a really accurate test, do a leakdown test (or have someone do it) That way if you have excessive leakdown it will pinpoint where the loss is (intake/exhaust/rings) That's the method I use if I have a concern about compression.

[daveb]

Plugs in or out shouldn't matter too much unless you have a weak battery or starter circuit. In which case you should sort that as well. For the less mechanically inlcined removing the plugs one at a time will save hassle getting the wires back on in the correct order. Hence my decision to suggest that method.

I usually pull them all too, FWIW.