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Discussion Starter · #1 ·
Can I rig up an engine (A series in this case) to check compression ratio with the engine out of the car. Just using a battery to the starter. No fuel or carb. Thanks
 

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yes ,remove all plugs ,make sure the batteries fully charged or better still jump leads off a running engine to your power battery(so you get consistent results) then do a dry test andthen a wet test,with a teaspoon of oil or something thinner(wd40 or oil and diesel?)
you didn't say if it was all running ok before but if not check tappets if readings all over the place on your first try ....
write it all down
neil
 

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TechnicalTom
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Can I rig up an engine (A series in this case) to check compression ratio with the engine out of the car. Just using a battery to the starter. No fuel or carb. Thanks
To get the best results the engine needs to be at operating temperature, but a compression test on a cold engine would give a very basic idea of the engine condition, if all the cylinders read the same pressure . having no carb. will just add to the poor results.I have run A series engines on the floor and I recommend you look at doing this.
 

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Discussion Starter · #4 ·
Ok thanks, picking the engine up tomorrow. I'll let you know how I get on :tup:
 

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Discussion Starter · #5 ·
Not sure if I'm doing it right or not able to. I'm not getting any compression from the cylinders as air is coming out of the exhaust port.
 

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I'm Not Jed Clampett
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Hmm, did you get these results "wet" with a shot of thin oil down the bores? If so, could be exhaust valves knackered/exhaust valves not closing; or if the engine's not been run since being worked on, cam timing way out.
 

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Heavy Oiler
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How are you cranking it? I don't see a starter
 

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Discussion Starter · #8 ·
I've managed to turn it several times on each cylinder using my foot on the flywheel cog, got each cylinder upto 10psi
 

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your wasting your time doing it that way mate, you need to get the engine spinning over much quicker. it needs a starter fitting, the exhaust not fitted shouldn't make any difference
 

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Discussion Starter · #10 ·
Ok I'll get battery & starter motor sorted & try again. Should I make sure there's good oil in there if I'm gonna be spinning the engine over faster?
 

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Discussion Starter · #12 ·
Put some oil in, fitted rocker cover & starter motor. Turned engine over with battery results are from the front 30/70/50/70
 

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starting to crawl back up
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get a carb on it and run it and youlle find them figures improve
 

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Can I rig up an engine (A series in this case) to check compression ratio with the engine out of the car. ? you may be getting mixed up a little, you'll have to dismantle the engine to measure the "compression ratio" it's the combustion volume divided into total swept volume per cylinder and combustion volume.

One way to the general condition of your engine out of the car maybe go for a "cylinder leakage test"

cant post a picture for some reason???????????
Got it, compression testing in the title.:mooooh:

http://www.wcengineering.com/articles/ill/leakdown.jpg
 

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If it was me and as its an engine you seem to know little history of - I'd clean it all off externally, drain the oil, strip the engine carefully noting any defects and cleaning, photographing, checking, measuring and bagging/boxing as you go. Keep all the original nuts and bolts in their respective box. Rebuild or get someone who knows to build it and then you know where you stand. Objective - many miles of trouble free driving and not having to work on it every time you start it up.
I would never use an engine that had been standing for years without at least having the head and sump off for inspection and cleaning etc. If its a good engine you will have minimal work to get it running well - if its a turkey it will save you wasting valuable time.
 

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As Prefect say strip and check. From the figures sounds like a complete rebuild job. Get yourself a Manual cheap enough on ebay or I have a brand new one you can have for a £5. I will be at the Mersea Sunday if that helps.
 

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My'a gives about 150 psi on 8:1 compression. Rebuilding one is straight forward,and this certainly needs it.
 
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