Nigel Clark Posted March 26, 2020 Report Share Posted March 26, 2020 I've just removed the sump on my Spit Mk3 to fit a new gasket and been surprised to see there's no wire mesh strainer on the oil pump pickup pipe. It's an early Mk3 from 1967. Should it have a strainer on the oil pump? I'm more familiar with the internals of Triumph sixes and those always have a strainer. I've seen an early Herald 1200 engine without a strainer but that had a mesh screen inside the sump to catch coarse debris. Rimmers online catalogue shows a Spitfire Mk1/2/3 oil pump with a strainer: https://rimmerbros.com/Item--i-GLP145 Does it matter that there's no strainer? Seems to me any sizeable debris will go straight into the pump and cause wear that would have been avoided with a mesh strainer. Nigel Link to comment Share on other sites More sharing options...
johny Posted March 26, 2020 Report Share Posted March 26, 2020 My original pump on a MK1 Vit had no strainer only a grill across the top of the sump to stop any large debris falling in. I wonder if a strainer could get blocked with gunk and cause oil starvation.... Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 26, 2020 Author Report Share Posted March 26, 2020 22 minutes ago, johny said: My original pump on a MK1 Vit had no strainer only a grill across the top of the sump to stop any large debris falling in. I wonder if a strainer could get blocked with gunk and cause oil starvation.... Thank you, I've always found strainers inside 2 litre Mk2 and 2.5 litre sixes. If there's enough debris to totally block the strainer, I would imagine the engine is already in serious trouble! Nigel Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 26, 2020 Report Share Posted March 26, 2020 C/O Canley the mk3 parts list shows a no strainer straight entry pump like your's Nigel, not available but shows 217058 now used across the range rimmers show a straight entry filtered pump GLP145 used across all but late 1500 4cyls so i guess the debris trap was an evolution pete Link to comment Share on other sites More sharing options...
NonMember Posted March 26, 2020 Report Share Posted March 26, 2020 The only engine I've seen where the oil pump had ingested serious chunks (fragments of broken timing chain shells) was my GT6 Mk3, which does have a strainer on the pump. I'm not sure they make all that much difference. Link to comment Share on other sites More sharing options...
johny Posted March 26, 2020 Report Share Posted March 26, 2020 18 minutes ago, Nigel Clark said: Thank you, I've always found strainers inside 2 litre Mk2 and 2.5 litre sixes. If there's enough debris to totally block the strainer, I would imagine the engine is already in serious trouble! Nigel It's not really totally blocking that could happen but restriction of flow so at high revs there less oil for adequate cooling of bearings. Anyway I'm talking about prolonged lack of oil changes so there's a large amount of residue which is unlikely to happen these days.... Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 26, 2020 Author Report Share Posted March 26, 2020 Thank you for the input gents. As it ain't broke, I'm not going to fix it, and will leave the oil pump alone. But I will be changing the oil and filter regularly. I would have done that anyway! Nigel Link to comment Share on other sites More sharing options...
johny Posted March 26, 2020 Report Share Posted March 26, 2020 Not even going to check the clearances on the pump Nigel? Its only 3 bolts or are you really happy with the oil pressure its been giving? Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 26, 2020 Author Report Share Posted March 26, 2020 Hi Johny, Oil pressure is good, about 50psi when hot at 2000 revs, so right in specification. That said, you're right, so I will drop the pump and get the feeler gauges out tomorrow. It's not as if time is in short supply right now! Nigel Link to comment Share on other sites More sharing options...
johny Posted March 26, 2020 Report Share Posted March 26, 2020 It's low revs pressure that seems more problematic and my pump has too much axial clearance which can be rectified by laboriously (unless yours is alloy) grinding down the body on a sheet of glass. Of course main and big end bearing clearances can also be a big drain on oil pressure.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 26, 2020 Report Share Posted March 26, 2020 the spec for all our small chassis cars is 40 to 60psi at 2000 rpm there is no spec for idle or hot or cold all you have for a minimum is the low pressure switch setting of around 6 to 8 psi. so 50 at 2000 is spot on . Pete Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 26, 2020 Author Report Share Posted March 26, 2020 3 minutes ago, Pete Lewis said: the spec for all our small chassis cars is 40 to 60psi at 2000 rpm there is no spec for idle or hot or cold all you have for a minimum is the low pressure switch setting of around 6 to 8 psi. so 50 at 2000 is spot on . Pete Yes, that's why I'm not really worried about the oil pump. Or the crank. I had a look at the big ends and there's no need to replace the shells. I only started this because the sump was leaking. Bit of a can of worms really... New oil pump? Crank grind? Full restoration looms. I don't think so, I'm only fixing an oil leak! Nigel Link to comment Share on other sites More sharing options...
johny Posted March 26, 2020 Report Share Posted March 26, 2020 Trouble is the relief valve is rated at around 45psi so you don't know what the pump is giving or should really give! Certainly a good idea to confirm all tolerances while your there.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 27, 2020 Report Share Posted March 27, 2020 went to sainsbury's and Leeks were on shortage at least refitting the sump on a 4 cly is certainly more appealing than on the 6 cyl Ha ! Pete Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 27, 2020 Author Report Share Posted March 27, 2020 Plenty of leaks here, just depends on the spelling! I've had the oil pump out today and it measures up well, all clearances in specification, so I've bolted it back in. Sump goes on with a new gasket tomorrow. Thank you again for your help. Nigel Link to comment Share on other sites More sharing options...
johny Posted March 27, 2020 Report Share Posted March 27, 2020 Probably sucking eggs here but check the sump seal face and flatten down any raised areas around the bolt holes from previous over tightening. I would also suggest new spring washers unless yours are in very good condition as the correct bolt torque is low so they can loosen.... Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 27, 2020 Author Report Share Posted March 27, 2020 Hi Johny, Yes, thank you. I've run a straight-edge over the sump face and tapped down a few previously over-tightened bolt holes. The face of the block has been scraped clean and it's all ready to go back with a new gasket tomorrow. And the oil pump has been torqued back at 8 lb ft each bolt with new split washers. Currently the oil pump is full of engine reassembly lube, hope it doesn't drip out before the oil goes back in the sump tomorrow. The spark plugs are out and I'll give it a good spin on the starter motor before reconnecting the coil and refitting the plugs. After that, I'm scratching my head to think of an essential reason to take the Spitfire out. We probably need a box of eggs and and some milk... and beer of course! Why go out in the modern when the Spit needs a test run? Nigel Link to comment Share on other sites More sharing options...
NonMember Posted March 27, 2020 Report Share Posted March 27, 2020 35 minutes ago, Nigel Clark said: Why go out in the modern when the Spit needs a test run? I refer the honourable gentleman to my earlier comment in another thread 🙁 Link to comment Share on other sites More sharing options...
Nigel Clark Posted March 27, 2020 Author Report Share Posted March 27, 2020 38 minutes ago, NonMember said: I refer the honourable gentleman to my earlier comment in another thread 🙁 Sorry, I'm being a bit obtuse here, what earlier comment is relevant? Nigel Link to comment Share on other sites More sharing options...
thescrapman Posted March 27, 2020 Report Share Posted March 27, 2020 One about breaking down I think. i gave the TR a run to work today, looked less essential than it was. Link to comment Share on other sites More sharing options...
NonMember Posted March 27, 2020 Report Share Posted March 27, 2020 38 minutes ago, Nigel Clark said: Sorry, I'm being a bit obtuse here, what earlier comment is relevant? 19 minutes ago, thescrapman said: One about breaking down I think. Indeed. My Spitfire "needed a test run" but I went in the modern because the test run lasted ten yards before failing. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now