I'll be taking the head off soon, that much I know...just wondering if anyone can guess what I might find?
Performance is slightly sluggish, powerwise, but not awful. I WAS getting temperature spikes, but they seem to have stopped. I am not losing coolant, and the coolant seems normal..it does not bubble when i give it throttle. The oil didn't look like it had any water in it, but there is a fair bit of milky oil residue at the filler spout...not sure if this is coming from inside, or outside, with all the rain lately. Compression (cyls. 1-4) is....ugh...60, 60, 60, 63. Last fall they were all 120-125.
Devin
(about to tackle first head job.)
Sick Engine
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roverdevin
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Roverworks
Devin.
Start by doing the compression test again...at those readings the engine would barely run and certainly make no power at all. I suspect your gauge is reading inaccurately or you did not have the throttle open so the engine was working against the closed butterfly.
If you get those readings again put a tablespoon of oil in each cylinder, flip the engine over a few times and then do another compression test. Drastic increase in pressure (20%+) indicates ring wear - no/little increase indicates valves.
It is also possible you have a very badly blown head gasket.
It would be impossible to tune a carb with the compressions you note and your vac advance would not work properly which would cause ignition difficulty etc...
Alan
Rover Works B.C. Ltd
http://roverworks.com/
Start by doing the compression test again...at those readings the engine would barely run and certainly make no power at all. I suspect your gauge is reading inaccurately or you did not have the throttle open so the engine was working against the closed butterfly.
If you get those readings again put a tablespoon of oil in each cylinder, flip the engine over a few times and then do another compression test. Drastic increase in pressure (20%+) indicates ring wear - no/little increase indicates valves.
It is also possible you have a very badly blown head gasket.
It would be impossible to tune a carb with the compressions you note and your vac advance would not work properly which would cause ignition difficulty etc...
Alan
Rover Works B.C. Ltd
http://roverworks.com/
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roverdevin
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Thanks for your response, Alan,
I know those are suspect compression results...I'll try the guage on another vehicle today. There is definately something not right with the engine though...power is way down (though starting and idle seem as good as they have ever been!) I did the compression a few times with similar results. Wet testing did not seem to raise compression.
I did a leak down test last fall, from which I deduced the rings were tight and proper, but I had slight leakage from the exhaust valves.. Is it possible that the head gasket has failed without significant contamination of the oil and coolant? I first suspected head gasket when I was getting temp spikes, but the coolant system seems tight and no bubbles/displacement is visible when the cap is off.
Thanks, Devin
I know those are suspect compression results...I'll try the guage on another vehicle today. There is definately something not right with the engine though...power is way down (though starting and idle seem as good as they have ever been!) I did the compression a few times with similar results. Wet testing did not seem to raise compression.
I did a leak down test last fall, from which I deduced the rings were tight and proper, but I had slight leakage from the exhaust valves.. Is it possible that the head gasket has failed without significant contamination of the oil and coolant? I first suspected head gasket when I was getting temp spikes, but the coolant system seems tight and no bubbles/displacement is visible when the cap is off.
Thanks, Devin
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Roverworks
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Roverworks
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roverdevin
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More diagnostics...Compression guage was misreading. A new compression tester gives me results of 147, 145, 145, 145, 1 thru 4. Is that within specs, or low? The vehicle is still running with a noticable power deficit. I have always suspected I have a timing problem, as it has always been an absolute *&#*&# to tune/get the timing right on. Is there any way of checking the timing belt? I suppose I could easily bring it into my local shop and have them do an enine checkup, but i'm having fun learning.
other things i've noticed: Spark plugs look decent; carbon deposit build up at carb throat; starting, idle and general smoothness of engine are good; power is low;
temperature WAS spiking on hill climbs/long runs, but physical measurement of the water told me it wasn't overly hot...i couldn;t figure out if it was a sender/voltage regualtion problem giving me fautly readings, or hot gas bubbles getting into the water system, but the performance was fine at that time....now the temp gauge seems to read low and doesn't move at all, and I have these power woes. very troubling.
Anyways, I appraciate all the advice and suggestions.
Devin
other things i've noticed: Spark plugs look decent; carbon deposit build up at carb throat; starting, idle and general smoothness of engine are good; power is low;
temperature WAS spiking on hill climbs/long runs, but physical measurement of the water told me it wasn't overly hot...i couldn;t figure out if it was a sender/voltage regualtion problem giving me fautly readings, or hot gas bubbles getting into the water system, but the performance was fine at that time....now the temp gauge seems to read low and doesn't move at all, and I have these power woes. very troubling.
Anyways, I appraciate all the advice and suggestions.
Devin
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derek n
same as post
8) Devin
I may be out in left field on this but if you are running a Zenith or Solex carb, specifically a 36 IV then you may be having carb problems. I had a hell of a time tuning my 2.25 when the carb was buggered. Also I just checked my compression last night. This motor I rebuilt 4000 miles ago and the compression is 170 on all four jugs.
When I rebuilt the motor the compression was 140 in 1,3&4 and 90 in #2.When I pulled the head off there was a real mess. All top rings broken, all exhaust valves burnt, cracked head, blown head gasket, hole in piston, scored cylinder wall, stretched con rod. Funny thing is that it still ran and started well.
Good Luck
Cheers
Derek
'82 Airportable
'56 88"
I may be out in left field on this but if you are running a Zenith or Solex carb, specifically a 36 IV then you may be having carb problems. I had a hell of a time tuning my 2.25 when the carb was buggered. Also I just checked my compression last night. This motor I rebuilt 4000 miles ago and the compression is 170 on all four jugs.
When I rebuilt the motor the compression was 140 in 1,3&4 and 90 in #2.When I pulled the head off there was a real mess. All top rings broken, all exhaust valves burnt, cracked head, blown head gasket, hole in piston, scored cylinder wall, stretched con rod. Funny thing is that it still ran and started well.
Good Luck
Cheers
Derek
'82 Airportable
'56 88"
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roverdevin
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Did another compression check, this time opening up the throttle as I did...got readings of 170, 173, 170, 175 in the cylinders. I keep getting reading all over the place, but this one is with the new guage and the throttle wide open. At least those numbers are a little more reassuring. Going to start looking into valves, carb and timing, though I noticed my ignition componenets all look pretty tired.
Devin
Devin
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DaveB
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Valve lash can make a small difference to performance, but usually not a big deal, unless you can hear them rattling under the cover. Wouldn't hurt to adjust them, though.
Worn points can definitely effect your timing, as they may close sooner or later than they should, and of course timing has a big effect on performance. And the little plastic slider that rides against the distributor shaft can wear out causing your timing to retard as well.
What about carbon buildup? I just had the heads off my Disco, and there was huge amounts of carbon built up around the valves and in the intake, seriously restricting flow, Keith did a fairly extensive cleanup on them while he was in there. While not bad on a V8, this type of carbon buildup can make a big dent in the performance of a 4 cylinder and it generally builds up due to short trips and low, gentle RPMs. You mentioned that you saw creamy buildup on the inside of the oil filler spout. This is usually an indicator that your engine is not being driven hard enough or long enough to evaporate the condensation that happens in all engines. Do you have a breather system that draws the gasses (blowby, and condensed water/oil/fumes) out and into the air cleaner? I know mine has the breather connection for the filler spout about 18" down the tube, so any condensation above that is always going to show as creamy residue. I wouldn't worry about that, but if you're also getting similar residue in the breather on the valve cover, I'd be concerned that you need to exercize the engine more.
Sounds to me like you just might need to "get the gunk out" -- a couple of good high rev runs down the highway often helps with that, or you can use the trick of spritzing water down the carb as you rev it. Since water moelcules don't conpress very well, this does a reasonable job of actually cleaning out deposits within the combustion chamber itself, but you have to be careful to only spray a mist of water, and not dump loads in as your engine would then get hydraulically stuck and you could severely damage it.
While it may help clean out the actual combustion chambers, water will not do much for your intake manifold if its carboned up. You need to purchase a carbon removal product. The one I use was called CarbOut. Works well, creates GOBS of white smoke, and I would shut off the engine while about half way through pouring the stuff in so that the intake manifold gets a good chance to soak and loosen up the carbon in the intake manifold. I usually let it sit for about half an hour before restarting. Sometimes takes a bit of cranking to restart, and if your concerned about hydraulicing it, you can pull the plugs, crank for a few seconds and then reinstall them. Don't have anyone standing on the side where you took the plugs out when you crank it, as it can spew out quite a mess of carbon and chemicals — don't ask me how I know that!
For anyone else reading this, don't try this on a newer computerized vehicle as you will be sure to turn on the engine light, but it does work well for cleaning out older style engines.
Dave
Worn points can definitely effect your timing, as they may close sooner or later than they should, and of course timing has a big effect on performance. And the little plastic slider that rides against the distributor shaft can wear out causing your timing to retard as well.
What about carbon buildup? I just had the heads off my Disco, and there was huge amounts of carbon built up around the valves and in the intake, seriously restricting flow, Keith did a fairly extensive cleanup on them while he was in there. While not bad on a V8, this type of carbon buildup can make a big dent in the performance of a 4 cylinder and it generally builds up due to short trips and low, gentle RPMs. You mentioned that you saw creamy buildup on the inside of the oil filler spout. This is usually an indicator that your engine is not being driven hard enough or long enough to evaporate the condensation that happens in all engines. Do you have a breather system that draws the gasses (blowby, and condensed water/oil/fumes) out and into the air cleaner? I know mine has the breather connection for the filler spout about 18" down the tube, so any condensation above that is always going to show as creamy residue. I wouldn't worry about that, but if you're also getting similar residue in the breather on the valve cover, I'd be concerned that you need to exercize the engine more.
Sounds to me like you just might need to "get the gunk out" -- a couple of good high rev runs down the highway often helps with that, or you can use the trick of spritzing water down the carb as you rev it. Since water moelcules don't conpress very well, this does a reasonable job of actually cleaning out deposits within the combustion chamber itself, but you have to be careful to only spray a mist of water, and not dump loads in as your engine would then get hydraulically stuck and you could severely damage it.
While it may help clean out the actual combustion chambers, water will not do much for your intake manifold if its carboned up. You need to purchase a carbon removal product. The one I use was called CarbOut. Works well, creates GOBS of white smoke, and I would shut off the engine while about half way through pouring the stuff in so that the intake manifold gets a good chance to soak and loosen up the carbon in the intake manifold. I usually let it sit for about half an hour before restarting. Sometimes takes a bit of cranking to restart, and if your concerned about hydraulicing it, you can pull the plugs, crank for a few seconds and then reinstall them. Don't have anyone standing on the side where you took the plugs out when you crank it, as it can spew out quite a mess of carbon and chemicals — don't ask me how I know that!
For anyone else reading this, don't try this on a newer computerized vehicle as you will be sure to turn on the engine light, but it does work well for cleaning out older style engines.
Dave