1997 Felicia 1.3 Carburetor

About a year ago I started noticing the oil pressure warning light go off at idle. Changed the oil pressure switch, still the same. The engine has 275,000 km (cca 170,000 miles) on it and it was never opened: it still has its factory head gasket. But it still works really good.

I upgraded to 10W-50 engine oil as a temporary fix, but it still has oil pressure issues at idle on a really hot day after a highway drive. No clicking or ticking noises from the engine, at least no more than usual for a pushrod Skoda ;)

I'm preparing to drop the oil pan because of its gasket leak (that is still factory too). While the pan is down, I might as well check for wear in main and big end bearings or other wear points.

 

Now, my Haynes manual describes doing this with the engine on a mount. Is it possible to use standard measuring tools and maybe Plastigauge to check the crankshaft bearing clearances with the engine still in the car? Has anyone done this? Are there any other things to check while the pan is off, related to the oil pressure issue?

 

4 minutes ago, SaltySkoda said:

there any other things to check while the pan is off,

The pick-up strainer that takes the oil up to the oil pump. That may be all that needs doing, if it's significantly blocked up by solids that have accumulated over the years/kms.

Clean or replace, depending on replacement cost/availability.

Edited 1 August, 20205 yr by Wino

I agree with Wino. It could be oil starvation rather than low oil pressure. On the other hand, since the issue shows up in extreme hot weather, I would replace the thermostat and the radiator fan thermocontact wih slightly lower temperature ones (like for tropical countries Felicia). You know, back 20 years ago, when winter was winter and nobody played God with the weather, Felicia didn't need such modifications in Europe. But now...

 

I assume the engine maintenance was OK during its life, right?

 

PS

As for the Plastigauge question, read their recommendation.

 

Edited 1 August, 20205 yr by RicardoM

I'm not 100% convinced re strainer although clearly it needs checking when off and when driving at speed it could be partially blocked with things that drop off when the engine is stopped.  I myself think it is something worse though - I've experienced this in the past with worn main / possiby big end bearings that loose oil pressure past the worn bearings especially when the oil is hot/thin. On very early smaller Ford engines that had a three main bearing crank (mid 60's) they suffered wear in the main bearings (especially the middle one) that caused exactly the same hot oil low pressure issue at idle. The 5 bearing crank engines (pre crossflow ) that were introduced when the MKII Cortina was introduced were bullet proof. 

 

PS it is very hard to check for main bearing wear in situ

 

The reason I mention it is I think the Felicia has a three bearing crank. It might be enough to sort this with a new set of shells but this is still an engine out job. Probably better to replace with a better engine from a scrapyard though as the rest of the engine will still have a lot of wear (sump gasket leak might be a clue - increased crankcase pressure due to bore/ring/piston wear!)

 

 

 

 

Edited 1 August, 20205 yr by bigjohn

@SaltySkoda

Start simple. Disregard panic mode advice if the engine had good maintenance.

Thank you all for a constructive discussion.

I couldn't find a new strainer or oil pump gears at my favorite Czech parts dealers, but decided to renew the sump altogether because the plug threads are shot. And I imagine the old sump is covered with gunk. I intend to remove the oil strainer and give it a good wash. Then check for flatness at the mating surfaces between the strainer and the engine block, and try to check the pump gears for wear. Also give the bearings a shake to check for excessive clearance, but without unbolting any of them, at least at this stage.

My father was the first owner of the car, and he has kept good care of it. I took over the maintenance about 10 years ago. There were really no serious problems with the engine, only repairs that were done to it apart from regular maintenance was a coolant pump replacement and I switched the carburetor for a manual choke Weber.

The plan for this car is to keep her going as long as possible, using a generous budget but trying to do everything myself. I think of it as a hobby: there's always something to do with the car especially at this age, while using it as an almost daily driver. Replacing the engine would be an interesting project, but knowing the full history of the car I don't really believe it would be necessary in this case.

Keep us posted about the cause of oil pressure drop so that other users learn from your experience.

On 05/08/2020 at 22:00, SaltySkoda said:

Also give the bearings a shake to check for excessive clearance, but without unbolting any of them, at least at this stage.

 

 

Sorry I didn't want to scare the horses - just feeding back previous experience of low oil pressure at tickover! 

 

However I agree with start simple.

 

The only bearings to shake will be the big end bearings - and they can seem fine even if they are not if the engine has recently run due to retained oil. Rotating the engine first a few times by hand can help (sump removed so no oil pickup)

 

Smell the old oil - if the bottom end is serious distress it will smell "cream crackered" - I've found oil after a failed engine due to big ends/mains etc has a distinctive smell. I suspect this isn't the case here.

 

Actually you have given a useful snippet of info in that your father was the first owner and you know its history from new - so it still has the original standard sized big and main bearing shells installed.  If there isn't an oil starvation issue and as you say if the engine is running fine then it could just be the bit of leakage past worn (but not broken!) bearings is enough to give lowish oil pressure at tickover with thin (hot) oil then there coud be a couple of "simple (ish)" options:-

1. Do nothing(presuming no starvation issue as above!) - Borderline pressure at tickover may be ok - seems ok in use as the revs rise. Temporarily connecting an oil pressure gauge may be a useful diagnostic - It could last for years like this!
2. Whilst the sump is off it could be possible to change the big end shell for replacement "standard" ones, this will reduce oil pressure loss past some worn shells - obviously it wont fix main bearings or any crank issues but it could be enough to keep the engine running ok for years without removing it. NB I once did this to a Viva 1256 engine - the big end bearings had worn down to the copper backing and the crank was ok ish, the new bearings gave the car a new lease of life and it was still running ok with them when it expired due to terminal rust!  PS You'll need to run the engine in a bit if new shells are fitted. A Haynes manual or equiv would be useful but remember to keep big end caps in the same order and orientation and examine old shells and how they are installed as there can be oil holes in them etc,

 

 

 

 

 

 

 

 

 

Edited 7 August, 20205 yr by bigjohn

2 hours ago, bigjohn said:

A Haynes manual or equiv would be useful

I doubt it very much.

This weekend I finally found the time to take a look what's going on.

It seems the pump is fairly worn. The strainer assembly is heavily scuffed by the gears. The pump casing is not as worn, as you can see, but it also shows some concentric scuff marks. I forgot to take a photo of the gears, but they seem badly worn at the strainer side.

So the pump is definitely up for a change. The problem is, as is seems, nobody is manufacturing these pumps anymore.

Any suggestions, beside trying to find a good used one?

I haven't seen oil pumps for Felicia 1.3 sold as a whole. Try searching by components: gears, cover.

More worrying is the cause for the scuffing and wear of the metal parts. The pump didn't have enough axial play.

Edited 14 September, 20205 yr by RicardoM

4 hours ago, RicardoM said:

I haven't seen oil pumps for Felicia 1.3 sold as a whole. Try searching by components: gears, cover.

More worrying is the cause for the scuffing and wear of the metal parts. The pump didn't have enough axial play.

 

Yeah, well, the timing chain was replaced by an authorized Skoda service shop some 10 years ago. Nobody else had any need to touch the oil pump. The pump should be factory original as far as I know. Keep in mind that the pump runs on unfiltered oil: any debris could have caused the scuffing.

Only the strainer assembly is available as a new spare, not the pump gears. I can only buy a pump backplate (as a part of the strainer assembly). I called several parts distributors today.

 

So, should I just resurface the pump backplate (or buy a new one) and hope for the best? There doesn't seem to be much alternatives.

 

 

3 hours ago, SaltySkoda said:

any debris could have caused the scuffing

Debris from where? Do you have evidence for that? I mean an oil pan is not exactly a recycle bin if the car has been serviced well.

10 hours ago, SaltySkoda said:

I forgot to take a photo of the gears, but they seem badly worn at the strainer side.

The oil pressure builds using the teeth, not the sides of the gears.

You can try resurfacing the cover of the pump using fine sandpaper fixed on a flat, hard surface (a sheet of glass will do too). Start with 120-grit then go up to 400-grit. The idea is to have a maximum axial play of 0.1 mm.

 

Resurface the backplate, check the rotor clearances with feeler blades, while you have the sump off you would be crazy not to remove one big end cap at a time followed by the main bearing caps to inspect the bearings, just keep them clean and retorque them and they wont know that they have seen the light of day, they can be replaced in situ if required.

 

Beyond that and what you have already done there is little that can affect the oil pressure with the noticable exception of the pressure release valve, check its operation, spring tension and the seating area.

 

 

On 14/09/2020 at 20:09, RicardoM said:

Debris from where? Do you have evidence for that? I mean an oil pan is not exactly a recycle bin if the car has been serviced well.

The oil pressure builds using the teeth, not the sides of the gears.

 

You can try resurfacing the cover of the pump using fine sandpaper fixed on a flat, hard surface (a sheet of glass will do too). Start with 120-grit then go up to 400-grit. The idea is to have a maximum axial play of 0.1 mm.

 

In real life, it is impossible to keep the crankcase 100% clean of small hard particles that may come from outside or as a result of normal engine wear. It may be a very small amount here and there, but in this particular case the damage had a chance to accumulate over 23 years and nearly 300,000 km of almost daily driving in all possible conditions.

The pump needs all its clearances to be within range, in order to provide pressure. Otherwise, surface tension can't keep the oil from running around the gears, effectively reducing pressure and output flow.

 

After a lot of searching, I managed to find a Belarus-based merchant that still has a new set of gears for this pump. I'll take the backplate to a machinist.

 

On 14/09/2020 at 22:15, J.R. said:

Resurface the backplate, check the rotor clearances with feeler blades, while you have the sump off you would be crazy not to remove one big end cap at a time followed by the main bearing caps to inspect the bearings, just keep them clean and retorque them and they wont know that they have seen the light of day, they can be replaced in situ if required.

 

Beyond that and what you have already done there is little that can affect the oil pressure with the noticable exception of the pressure release valve, check its operation, spring tension and the seating area.

 

That seems to be a good advice, I'll check that for sure.

The pressure valve spring was strong and I didn't notice any problems with the mechanism.