GBMUD Posted August 9, 2006 Share Posted August 9, 2006 Remember that you need oil and not oil pressure to have lubrication. As long as you are using good quality oil then there will still be oil in the bearings even days after the engine was last run. Agreed though, I am not happy running without oil pressure for long. Chris Quote Link to comment Share on other sites More sharing options...
pugwash Posted August 9, 2006 Share Posted August 9, 2006 i'm going to be bring back a pre-lube kit for my engine from the states. stores oil under pressure in a bottle and then releases is into the engine when you turn the ignition on. You should find that the oil pressure light goes out straight away. Costs about £95 for the big engine version- about £120 for the monster engine. Hopefully it will really really help to reduce the wear in the engine. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 9, 2006 Share Posted August 9, 2006 Pugwash - you mean these? Quote Link to comment Share on other sites More sharing options...
Lara Posted August 10, 2006 Share Posted August 10, 2006 Have just scanned a big load of pictures and info etc, PM me your e-mail address and I will send the file over. Lara. Quote Link to comment Share on other sites More sharing options...
Tonk Posted August 10, 2006 Share Posted August 10, 2006 Tonk - I'm glad to see you are already figuring out the best way for you to do this... Al. Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted August 10, 2006 Author Share Posted August 10, 2006 Pm Sent - thanks Lara. I've been doing a little digging (haven't found much) - you know those book references? Apparently... 1. I need to size the tank about 30% bigger capacity than the total oil in the system. 2. I should use a screen filter between any scavenge pickups in the sump and the scavenge pump sections. 3. Lines from the scavenge pump sections to the tank should enter at a tangent to avoid aeration, and the tank should have a couple of mesh 'floors' in. 4. The tank should have 1 input at the top per pump scavenge section. 5. The tank output at it's base needs to be higher than the pressure section of the pump so that it is always gravity primed. That's it so far... Thoughts? Hopefully, it appears, can just buy a scraper for my engine and fab up the sump to incorporate it. Al. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted August 10, 2006 Share Posted August 10, 2006 Does the return to tank discharge below fluid level Al? its best practice with hydraulics but not used with bikes, not sure with cars - Lara, whats you recommendation? Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted August 10, 2006 Author Share Posted August 10, 2006 Does the return to tank discharge below fluid level Al? its best practice with hydraulics but not used with bikes, not sure with cars - Lara, whats you recommendation? That's a good thought - I think the idea is that the inputs at the top of the tank are at a tangent to the curve so the oil kind of flows in along the internal wall and spirals down into the main bulk of the fluid - to get rid of any bubbles. I imagine that if the oil is squirted in at 90 degrees to the tank wall it'll create aeration bubbles as it lands on the rest of the oil. Squirting oil in below the fluid level will mean that any air bubbles picked up by a scavenge section in the sump (a lot) will be injected directly into the main oil reservoir and not go through any 'removal' prcesses like the mesh or swirl or tangential injection at the top. I suppose the difference between this any hydraulics is: one is sealed and the other has a great deal of air put into the system every cycle/loop - which must be removed if oil pressure is to be maintained. So hydro coming in below fluid level makes sense - pure fluid into pure fluid gives no aeration. Dunno. Guessing really. Al. Quote Link to comment Share on other sites More sharing options...
GBMUD Posted August 10, 2006 Share Posted August 10, 2006 As a matter of interest, what sort of volume of flow (litres/minute?) should one expect through an oil system? I guess that wet or dry sump are about the same. Chris Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted August 10, 2006 Author Share Posted August 10, 2006 As a matter of interest, what sort of volume of flow (litres/minute?) should one expect through an oil system? I guess that wet or dry sump are about the same.Chris Good question! I was thinking about that. Each stage of the pump has it's flow rate dictated by it's width (as I understand it), so different width sections give you different flow rates through different oil lines as required, but... As you say - what to aim for?!? Note this is a chevy engine, so I guess it could be a bit different? Probably similar to the RV8? Al. Quote Link to comment Share on other sites More sharing options...
GBMUD Posted August 10, 2006 Share Posted August 10, 2006 Good question! I was thinking about that. Each stage of the pump has it's flow rate dictated by it's width (as I understand it), so different width sections give you different flow rates through different oil lines as required, but... As you say - what to aim for?!?Note this is a chevy engine, so I guess it could be a bit different? Probably similar to the RV8? Al. I guess flow is limited by the oil pressure control valve and viscosity of the oil? Do remote pumps have an internal pressure relief valve? Could one use the original oil pump, being fed from the remote reservoir? Oil can only escape through nozzles/bearings so fast. I was wondering really about what quantity of oil to expect coming back to the reservoir and whether a few bubbles will really be an issue. Does engine oil froth or will the bubbles surface readily and burst? One never has trouble with oil bubbling in a traditional sump. Chris Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted August 10, 2006 Author Share Posted August 10, 2006 No. You need a multi-stage pump - for scavenge points and a pressure feed. A single pump isn't enough. People have used a single remote pump on the Rover V8 being fed from a wet sump, but that is to avoid the distributor drive wear by driving the pump directly with a pulley, it's still a wet sump single pump system. With multiple pickups in the sump and effectively very little oil in there you are sucking up vast quantities of air, it's much more that with the regular wet sump. Al. Quote Link to comment Share on other sites More sharing options...
Daan Posted August 10, 2006 Share Posted August 10, 2006 you have a multistage pump, so you can suck oil from different strategic places- the whole point of a dry sump- so there is always one stage pumping oil. But this means loads of air from the others. Also, you try to create a vacuum in the sump to reduce losses, but together with the blowby past the pistons, you will have loads of gas regardless. Daan Quote Link to comment Share on other sites More sharing options...
02GF74 Posted August 10, 2006 Share Posted August 10, 2006 I guess flow is limited by the oil pressure control valve and viscosity of the oil? Do remote pumps have an internal pressure relief valve? Could one use the original oil pump, being fed from the remote reservoir? Oil can only escape through nozzles/bearings so fast.I was wondering really about what quantity of oil to expect coming back to the reservoir and whether a few bubbles will really be an issue. Does engine oil froth or will the bubbles surface readily and burst? One never has trouble with oil bubbling in a traditional sump. Chris first parano, oil pressure valve limits the pressure; the flow is dependant on the oil pump volum, its design and speed it rotates at. I don't think viscosity of the oil will affect the flow significantly; the pressure is achieved by the resistance to oil flow by the gaps in the bearings. Thinner oil will be affected less; so that is why oil pressure is lower when engine is hot (oil thinner and gaps expanded) and also when an engine is worn (gaps bigger). I am not sure if the original oil pump could by use to feed oil into the engine, can't see why not though since it would provide the same flow as the original wet sump set up, but you need the additional scavange pumps that pick up oil from different parts of the sump. second para. the frothing, by what has been said, is due to the scavenge pumps picking up air - in a wet sump the oil flows down into the sump via gravity and was not whisked by any gears. Quote Link to comment Share on other sites More sharing options...
Lara Posted August 10, 2006 Share Posted August 10, 2006 Well it's all been said really, 30% at least for air volume in oil tank, Oil entering tangentally to the tank wall to create swirl, Gauze separators, Oil entering above oil level because it is a white frothy mess after being mixed with loads of air, Oil pickup or at least oil "head" above pump level, (you have to watch for drain down when the engine is off with this as the sump can fill with oil over night on occasion and if you just fire up the engine without thinking you get neat oil being pumped by up to four big pump sections and if you have an oil cooler in one of the return lines then you will split it apart instantly) (done that at the race track and did not laugh) More oil capacity the better, Big breather and catch tank on oil tank, Good strong scrapers, Well designed oil path after scraper and directed back to pickups, As few 90 degree bends and cast type fittings as possible in oil lines, Most pumps have built in oil pressure valves and a SBC needs about 60psi to live at high RPM and big power, or 10 - 12psi per 1000 rpm up to 60psi max so no need to over do it. The scavenge sections are usually about 60% larger than the pressure section because of the oil and air mix, and the fact that they "Must" remove more oil than the pump pumps in, and this is harder than it sounds! When finished, run the engine at about half max revs and measure the difference in tank oil level, you want to aim for about 1 to 1.5 Litres max of oil floating around your engine as a guide to a good system. Good luck. Lara. I will send you the ISBN numbers for the books Al. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.