Scirocco Register

Ok so long story short, I bought a non runner as a project, had not run for a year or so, timing was out so I’ve changed the timing belt and water pump, have double, triple etc checked the timing and it’s spot on, so, the problem.

Tried a first start to no avail, getting fuel to carb and into bores, getting spark, won’t fire, won’t even splutter, the closest I get is a backfire flame out of the carb if I’ve been turning over for some time, so thought I’d check the compression, the results are as follows:-

All wet tests

Cylinder 1 - roughly 70psi
Cylinder 2 - roughly 70psi
Cylinder 3 - barely 10psi
Cylinder 4 - roughly 70psi

Dry test, 1,2 and 3 were around 50psi.

So, there’s clearly something very wrong, but what?

Cylinder 3 appears to be more catastrophic than the others, but the others are all very low, but are all so similar that I find it hard to believe that there’s something wrong with each cylinder individually (except 3 obviously)

So someone mentioned oil pressure for the tappets, would this be a reasonable explanation? And would it prevent the valve seating entirely? If so, how can I check oil pressure as I can’t get the engine to turn over fast enough to extinguish the oil pressure light

Any and all suggestions would be very well received, I’m at the point of taking the head off to see what’s going on but would prefer to exhaust all other options before removing it

Thanks a bunch in advance hero’s!

Are you sure the ignition or valve timing isn't 180 degrees out?

Normally a lot of cranking will extinguish the warning light, so it could be low on oil pressure.

It may have been overheated in the past causing the poor compression. Can you see the condition of the bores with a good torch through the spark plug holes?

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Thanks for the response Blakey!

All timing marks line up perfectly and as the timing marks are on the flywheel and cam shaft, I don’t see how the engine could be 180 degrees out? Although it’s very possible I’ve overlooked something, The distributor also was timed up what I believe to be correct (pointing to the notch in the casing when the cam and cranks were set to TDC)

I’ve also removed the crankshaft pulley to ensure the key was in tact so I know the cam timing mark is in the correct position which I also clarified by inspecting the cam lines in cylinder 1, fully closed

If it was overheated the figures wouldn’t be so even surely?

Any idea how I could test the oil pressure other than waiting in the light to extinguish?

I did have a look in the bores with an inspection camera but I really couldn’t see anything tbh

Oil pressure testers are pretty cheap on eBay but a lot of them aren't metric, so you may also need an adaptor.

Was the throttle valve wide open when you tested the compression? Those values are really low.

If all of the spark plugs are fitted how easy is it to turn the engine over using a socket on the crank pulley? Does it go tight on each compression cycle?

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Maybe il buy one then

Yea throttle wide open mate

Il put the plugs back in tomorrow and double check but I think there was your standard resistance at TDC

Was the car running ok before it was taken off the road?

Dry compression test should be 160 ish psi so if timing etc is all spot on then I would pull the head off and have a look inside, if you don’t know why the car was taken off the road and left.

When I rebuilt my engine I took out the spark plugs and rotor arm and cranked the engine over on the starter to build up oil pressure before starting it, it did only take a minute or so for the oil light to go out.

Might be worth checking everything over once more, and make sure you have fresh fuel getting into the carb, maybe rig up a bottle of fuel to feed the carb, check a good spark and a fully charged car battery.

So I checked the oil pressure first thing, removed the oil pressure sensor and turned over to visually check, the gallery was blocked up with emulsified gunk and nothing came out at all on turnover

So I dropped the sump and the oil was nasty and full of hunk, removed the oil pump and stripped and cleaned it, I tried cleaning the oil galleries I could see by hand with carb cleaner as best I could but there’s almost certainly going to be blocked galleries around the engine.

So how can I best clean the galleries out without stripping the engine (baring in mind it doesn’t currently run so engine flush seems a bit pointless)

And my next question, would the non existant oil pressure cause the lack of compression? I understand the valve tappets are oil fed by my understanding of how they work is limited, so if they don’t have oil pressure will the valves not seat at all?

If the galleries are that bad, either it hasn't had an oil change for far too long or it has been overheated badly, so only a rebuild would resolve that.

Whilst you have the sump off, it may be worth removing a big end and crank bearing cap to see the state of the big end and main bearings. If they scored/burnt/heavily worn, that should confirm the worst case scenario.

Otherwise, if the above turns out to be ok, you may be able to use something such as ATF to begin to clean the internals, by pouring down all the return galleries in the head, but this won't clean the pressure galleries until the engine can be run. To be honest, even if you could begin to get it cleaner this way, it would result in many many oil and filter changes afterwards to catch and get rid of the gunk, still risking blocking the pump.

Very strange the oil being that bad after a year of not running... my current engine sat outside at the end of my brothers garden underneath some tarp for 4 years and the oil was still runny when I drained it and all as ok inside when I took the head and sump off, the sump was very rusty on the outside as it was sat on the floor! He did at pour some oil into the cyinders before it was layed out outside..

Yea the oil looked brand new on the dipstick but deeper in it was emulsified and nasty and that obviously been sucked up into the galleries when I’ve been turning it over, it was significantly full of fuel where they’d been trying to start it over and over too so that didn’t help!

to be honest engines like these are common and arent too pricey
by the sounds of it the engine is probably toast i would be looking for a replacement.
for example a running doner
https://www.autotrader.co.uk/classified ... ars&page=1

even better
http://forum.sciroccoregister.co.uk/vie ... 82#p152782

Ok so, some good news, after stripping and cleaning the sump and oil pump, inspected the big end, crank main, and camshaft bearing, all like new

Cleaned out all galleries and turned over and hey presto, full oil pressure with crystal clear oil coming through everywhere!

Next up, let’s get it ready to test again

Great news, fingers crossed for good compression then! [emoji3]

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The engine are fairly bomb proof so fingers crossed it all good from now on....