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MG TD TF 1500 - No Oil Pressure
|Battery arrived today so thought I would crank, newly rebuilt, engine over with ignition diasbled. Temprorary oil pressure gauge fitted, filter filled with oil via screwed plug, pump gears loaded with vasaline during rebuild but absolutely no oil pressure. Union to gauge opened but dry, banjo loosend but also dry, screwed plug to oil pump removed and filled with oil - two squirts from oil can - engine turned over with oil pump plug out - absolutely nothing. I am now wondering if I have forgotten a woodruf key in the oil pump and the gears are not turning or I have left out a gasket in the oil pick up and I have an air leak. Any advice GREATLY appreciated. This has been the worst day since I bought the TF.|
Calm down...it's going to be something simple.
First, how long did you crank the engine over? Oil pressure does not always immediately pop up when the engine is first cranked over. Give it several tries, just wait a few minutes to let these starter motor cool.
If that doesn't work buy a cheap garden sprayer, drain a few quarts of oil from the sump (you did fill the sump, didnt you?) and put them in the sprayer. Attach the hose from the sprayer to the oil pressure connection and pump the oil into the engine. This will fill all the oil galleries in the engine and backfill the pump. Try cranking the engine again and pressure should build almost immediately.
|Some cars very hard to prime, search the archives for many methods. I have had best luck removing top oil line (early separate filter systems) or brass plug later, filling with oil, then turn engine backwards to suck oil in, repeat several times. Then try it. George|
|There is oil in the sump, yes? Regards, Tom|
|I despaired too when I failed to get pressure on my rebuilt engine until I read that you had to start for 30 seconds.|
On the count of 29 the oil flowed through the rockers and tears of happiness from my eyes.....
|Willem van der Veer|
|Very poetic Willem, and I'm being very sincere, not sarcastic. |
|I seem to recall that I was estatic when the engine of 'the53' came in at 28 seconds. |
Jan, is yours an engine with the late horizontal oil filter or an early vertical one? Bud
|Pull the spark plugs until pressure shows up.|
"filter filled with oil via screwed plug," You then are trying to pump oil downstream of the pump with air in the pump. That can make it difficult to prime. Removing the priming plug on the oil pump does eliminate all that downstream resistance. Priming the pump and rolling over backwards will wet the gears and housing plus put a little in the pickup. Dry gears may not draw enough of a vacuum.
Priming the pump will also give you a good clue that gears are spinning if it spits up a bit of air out the primer plug hole.
On initial startup, I've removed a plug in the oil gallery, squirted in shots of oil and used an air gun to blast it throughout.
Ann Arbor Hydraulics
|JIM NORTHRUP SR|
|Mine was very reluctant to prime so I tried a trick that I've used on hydraulic pumps:|
I lightly plugged the draft tube and rocker cover vent with paper towel and applied air pressure through the dipstick tube while cranking with the spark plugs out - instant prime! It just doesn't take much pressure to push oil up the pickup tube and the paper towels will pop out if you apply too much.
|J E Carroll|
|Hi JE -sorry but don't know your name. If you lived a little closer I would be round with a bottle of malt whisky. One five second blast down the dip stick tube and instant pressure!!! Thank you very much|
|pull the spark plugs and crank her a bit. Easier on the starter. It will eventually pump up I'd bet. Mine had sat for 20 some years, plus I had converted to a spin on filter so that all takes time to fill up.|
|Great, Jan! Can't say as how I'd ever heard of Jim's technique before, but even old dog's can learn something new. Bud|
|I'm not a big fan of the buzz-it-over-until-you-get-oil-pressure school. A friend had his engine rebuilt and was not able to get it into the car for a couple of years. The shop had correctly used red assembly lube throughout. When he tried to start it my friend had trouble getting oil pressure, and buzzed it around with no plugs on and off over the course of a few days. He discovered he had a bent chassis right by the side of the block, and soon thereafter pulled the engine to have the chassis straightened. The tappet chamber - and therefore the cam and followers, rockers, etc. - were all completely dry and un-lubricated, and friction had already caused scuffing to the cam. The red assembly lube had run off all the vertical internal parts over those two years.|
Pressurizing the system really is the best way.
|JE...great idea...1st time I've ever heard of it!|
|Old dog just learned a new trick.|
Reminds me of time, working on a dump truck, the old pump was much higher than the oil tank and couldn't prime. I detached the pressure hose from the pump, started the engine, sucked on the hose until I could feel it catch, stuck the hose in a pail and ran to shut the engine off. Of course the hose popped out of the pail and ran a bit of oil on the ground, but it was worth it.
|JIM NORTHRUP SR|
Glad to hear it worked for you!
I figured it out because many aircraft have their hydraulic pumps mounted quite a bit higher than the reservoirs. To keep them from cavitating, reduced engine bleed air pressure is routed to the reservoir to provide a head pressure and keep a positive inlet pressure to the pump. It's only a few psi. Only once will you install a new pump and fail to pressurize the tank. It will really howl until some bleed pressure forces it to prime. It can't be too good for the pump either. I've since applied the knowledge to some hydraulic equipment.
I often get in to Luton airport using airport transfers tunbridge wells, usually a very short layover but occasionally an extra day. Anywhere near?
|J E Carroll|
|Hi Jim |
After seeing oil pressure via starter, fitted up temporary fuel tank and hot wired the engine. It started immediately and purrs like a well fed cat. Pressure when cold 75psi - but don't know accuracy of the tep gauge I am using.
I live in Scotland to the north of Glasgow and Luton is a day's journey away but if ever venture further north let me know - I owe you big time.
|Good job! |
This thread was discussed between 10/09/2013 and 11/09/2013
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