Starting a donor engine (not quite seized)

[badm88n]

Hi all,
I have a Mk1 Golf Gti that came with a donor engine and box that I would like to fit myself. Apart from the previous owners assurances on the condition of the donor engine I have no idea as to its overall condition. As a start I have lifted the engine and box into my garage where I can work on it more easily. I checked the dipstick and it showed a good oil level with the oil a dark brown and no water or mayonnaise. I tried turning the crank pulley using a socket and bar but it did not move, a few attempts later it turned a 1/4 turn and then stopped again. I checked to make sure the attached gearbox was not in gear and it was not. Next I removed the plugs (they looked fine with no signs of oil) and squirted WD40 into each cylinder and also poured a tiny amount of engine oil into each (to help free and lubricate). I also removed the starter motor in case it was sticking and thought what the hell and removed the gear box for good measure. I left the WD40 and oil to soak in the cylinders for a while before trying to turn the crank pulley again. Oh dear it was still stuck and thoughts of a seized engine came to mind. I thought one more try before I give up, so I applied a lot more force AND IT FINALLY TURNED!! It now turns freely using a socket and ratchet (minus the bar), there is some resistance so I guess it must still be a little sticky (rusty?) and am hoping this will clear itself up when in motion.

If I was unable to free the crank pulley I would have dumped the engine. But now its free can I assume its worth carrying on? and how should I proceed with getting this engine up and running? I intend to change the belt and tensioner, remove and clean the rocker cover and what it hides.

Is it worth removing the head to change the head gasket and inspect the innards while i'm in there? Can I inspect the pistons with the head off? What about removing the sump to degunk any oil deposits, can the oil pump be checked?

I guess bottom end problems will only show up once the engine is running or are there any pre checks that can be done?

If you have any advice, suggestions, hints or tips then please let me know.

Cheers & Beers

[deltafox]

Oh dear, i dont like the sound of this at all.

It sounds to me that maybe theres a little piston to valve contact going on, hence the stopping part as you turned it over.
I suspect (but dont quote me here : hehe: ) that you may have bent one of the valves as you turned it over.
Such an occurence could be due to an incorrectly timed cam....which may be why he's let you have the engine.
It shouldnt have needed a lot of force to turn it over, especially with the plugs out.
Do a check on the timing marks and see if they all line up before you go any further.

hth.

[Ren32]

Another possibility, could be that if the engine has stood for a period of time (especially if it's had the manifold/s off) then damp air and moisture gets into the bores and can put a thin film of rust on them (depending on which cylinders had their valves open). This could explain the initial problem of turning the engine over and also explain why you are still encountering some resistance.

The only way to be sure would be to whip the head off and take a look. If there is a thin film of rust in there then you may be able to clean it out in situ but if it has eaten or made any pitting into the bores then you ideally need a re-bore.

[Sam_68]

badm88n said:

It now turns freely using a socket and ratchet (minus the bar), there is some resistance so I guess it must still be a little sticky (rusty?) and am hoping this will clear itself up when in motion.

Rust is an amazingly good abrasive, so if you have slightly rust bores and simply fit the engine in the hope of the problem clearing itself up with use, you'll find it needs new piston rings, at the very least, after about the first 10 miles. If you're really lucky, the rust will score the bores and/or contaminate the oil and wreck cams and bearings, too.

Probably not what you want to hear, but personally I'd be looking at stripping the engine, honing the bores, fitting new main bearings and cleaning the head and re-seating the valves before putting it back together again. Needn't be very expensive, and at lest you'll have some confidence that the engine might run for a few miles before lunching itself.

[badm88n]

Loverly loverly nice to see some useful replies thanxs ren32 & deltafox. Yes indeed the manifolds are off and I stongly suspect damp and rust. When I look into the exhaust manifold and turn the crank I can see the valves moving quite smoothly (are there other valves?). Also in one of the exhaust chambers there was a nice dolop of white mayonnaise, can this collect over time due to damp and condensation or is it more worrying.

I shall check the timing marks to confirm (oh please no!) the bent valve diagnosis. If it helps any when turning the crank I can hear no strange noises. As you say I may as well whip the head off and have look inside to see whats there. Whip is probably not the right word, manual in one hand spanner in the other thats me.

[Sam_68]

badm88n said:

When I look into the exhaust manifold and turn the crank I can see the valves moving quite smoothly (are there other valves?). Also in one of the exhaust chambers there was a nice dolop of white mayonnaise, can this collect over time due to damp and condensation or is it more worrying.

Yes, there are other valves - the ones you can see in the exhaust manifold are the exhaust valves. You also have inlet valves, which should be visible in the inlet ports when you have removed the inlet manifold.

White mayonnaise could well be just due to damp, but there is also a possibility that the engine had blown it's head gasket. Do you have any history on it? If the oil in the sump was not contaminated (coffee coloured, usually) then chances are it is just water/condensation that has found its way into the engine while it has been standing, though...

I still reckon you need a strip down and rebuild to put everything back in order, though. Simply fitting and starting an engine which you strongly suspect to have internal rusting is mechanical suicide.