Mi16 With 8 Valve Rods

[Cameron 16]

I know you're technically right, but if you say oil starvation then not many people know what you're talking about.. call it surge and everybody seems to understand.

 

You've got to question what causes the oil starvation in these engines, and it's pretty much accepted that it's due to A - the oil surging away from the pump pickup during cornering, and B - a large volume of oil being accumulated in the cylinder head due to the large volume and location of the drain hole. These two factors cause the pump pickup to suck air instead of oil, causing oil starvation to the bearings and general carnage.

 

The thing that never convinced me about this was that the clearance at the side of the con-rod is still relatively large as bearing clearances go, so I could never see it affecting the "oil consumption" of that bearing a significant amount. I know the speculative theory was that it could help to keep oil in the bearing for a valuable few revolutions in the event of the pickup running out of oil, but that fact is - give it a slightly longer corner and you will still come to the point where the bearing has run out of oil. Further, the oil consumption theory was never actually tested, the guys just fitted it to an engine and said yep, no surge (yet), it must work.

 

I know we argued a lot about this in the original thread, as the guys thought I was just another newbie who had "jumped on the surge bandwagon" and wasn't trying to make the same efforts to overcome the problem. However, the hybrid engine theory was aimed at the root cause of the oil starvation: surge in the sump - thanks to the GTi6 baffled sump, and accumulation in the head - thanks to the smaller volume and better oil drain.

 

As I've said though, I'm not marketing this as THE answer. As Welshpug has said any wet sumped engine can be made to surge, and I'm sure there are conditions where my engine could run dry, especially as it doesn't have a windage tray. Hopefully I won't be putting up a thread like this next summer, but we'll see.

[crf450 0 1 Cars]

I know you're technically right, but if you say oil starvation then not many people know what you're talking about.. call it surge and everybody seems to understand.

 

You've got to question what causes the oil starvation in these engines, and it's pretty much accepted that it's due to A - the oil surging away from the pump pickup during cornering, and B - a large volume of oil being accumulated in the cylinder head due to the large volume and location of the drain hole. These two factors cause the pump pickup to suck air instead of oil, causing oil starvation to the bearings and general carnage.

 

The thing that never convinced me about this was that the clearance at the side of the con-rod is still relatively large as bearing clearances go, so I could never see it affecting the "oil consumption" of that bearing a significant amount. I know the speculative theory was that it could help to keep oil in the bearing for a valuable few revolutions in the event of the pickup running out of oil, but that fact is - give it a slightly longer corner and you will still come to the point where the bearing has run out of oil. Further, the oil consumption theory was never actually tested, the guys just fitted it to an engine and said yep, no surge (yet), it must work.

 

I know we argued a lot about this in the original thread, as the guys thought I was just another newbie who had "jumped on the surge bandwagon" and wasn't trying to make the same efforts to overcome the problem. However, the hybrid engine theory was aimed at the root cause of the oil starvation: surge in the sump - thanks to the GTi6 baffled sump, and accumulation in the head - thanks to the smaller volume and better oil drain.

 

As I've said though, I'm not marketing this as THE answer. As Welshpug has said any wet sumped engine can be made to surge, and I'm sure there are conditions where my engine could run dry, especially as it doesn't have a windage tray. Hopefully I won't be putting up a thread like this next summer, but we'll see.

 

I'll except the blame lies with the Mi head if someone can tell me why this cant be overcome by overfilling the sump the amount the Mi head holds over the GTi6/8valve head.

This theories been around for years and in my eyes it makes no sense.

[Cameron 16]

I don't think it's down to the oil capacity alone though, that's the point. The GTi6 head has better oil drains so not only is less held in there in the first place, the rate of oil being returned to the sump is higher.

[allanallen 528 2 Cars]

I don't think it's down to the oil capacity alone though, that's the point. The GTi6 head has better oil drains so not only is less held in there in the first place, the rate of oil being returned to the sump is higher.

 

So why hasn't it been overcome with the external oil drains that I believe several people have tried?

[Tom Fenton 1,542]

I've not seen any evidence either way with the external head drains, an idea I had was to try and modify a diesel or GTI6 vac pump driven off the end of the cam, used as a scavenger pump to collect oil out of the back of the head and pump return it to sump rather than relying on gravity.

[Cameron 16]

You tell me. I haven't examined any external oil drains so I can't comment.

 

Let me explain again, before I get any more "Oh yeah? Well why hasn't xxxxxxx done xxxxxxx then Mr Smarty Pants?" replies, that I'm not marketing my solution to be the end to oil starvation. What I am saying is that in my opinion it is a more positive step than the crank located rods were, and that it has a better supporting theory behind it. I have tested my engine on track and it's stood up very well so far.

[Tom Fenton 1,542]

Oh put the handbag down, this thread to me is a discussion between folk about the possibilities, but you seem to be taking it to heart?

[Cameron 16]

It's not about the handbag, I just don't want this to turn into the Spanish Inquisition with me having to explain my way around a whole host of "what if's" and "why not's". I'm just trying to state it as clearly as I can so people don't end up with the wrong idea.

[welshpug 1,661]

What else could it be other than oil drain/usage problems in the head? possibly contributed to by lack of windage tray in most bar the later 2.0 Mi16's?

 

Sandy's comment here;

 

We've never known any problems with our customer's solid lifter engines.

 

 

Solid lifters would dramatically reduce the amount of oil going up to the head wouldn't it?

[Batfink 201]

I dont think anyone on this site has tried an external head drain, gravity fed or scavenged drain so its something that would need investigating and testing.

Has anyone calculated the volume of the head to find how much oil it can hold or how much oil needs to be taken out of the sump before the oil pickup point is exposed?

 

Heres another maybe stupid solution. What about an external oil surge tank and pump solution like what we use for fuel? Using a small diameter tank so the pickup can never be exposed to air?, maybe use an electric pump so its constantly fed oil no matter what rpm, with an overflow drain back into the main sump, then the standard pump feeds off the small tank. I dont know how costs would pan out but i doubt it would cost more than £400

[Batfink 201]

Solid lifters would dramatically reduce the amount of oil going up to the head wouldn't it?

 

Yes. But its the expense that I think puts people off.

[James_m 0]

Has anyone extensively tracked a XU10J4 with the full windage tray etc? surely this is the answer as it would conclusively prove or disprove the head retaining oill theory, and if not perhaps point the blame at insufficient oil drainage of the alloy block oil ways in combination with the head retaining a large amount of oil.

[stefan 4]

ohhh they do Rich they do!

 

its why my ZX doesn't run an RFY any more! long tight left hander, needle dropped right down, 20 miles later and it was rattling its tits off.

 

Mine was a very early 2.0 from 1992 and didn't have a windage tray.

 

RFS now installed.

 

What's RFY and RFS?

[crf450 0 1 Cars]

When I first got bored of changing shells in my Mi I started making a twin pick up set up with oil pick ups at each side of the sump and a valve that switched between the two that was sprung into the middle. This would mean they drew oil from both pick ups when you weren't cornering but then had a weighted paddle that would operate the simple valve and switch to the pick up with the oil on cornering,this all hung off the side of a standard pump.

Might go and see if I've still got the bits knocking around .

[welshpug 1,661]

That sounds pretty damn ingenious

 

What's RFY and RFS?

 

 

RFY is a 2.0 iron block Mi16, S16, ZX16v, Xantia VSX engine.

 

RFS is a 306 gti6 (S16 BV6 in france and europe) Xsara VTS, and ZX Dakar egnine.

[brumster 135 1 Cars]

Has anyone extensively tracked a XU10J4 with the full windage tray etc? surely this is the answer as it would conclusively prove or disprove the head retaining oill theory, and if not perhaps point the blame at insufficient oil drainage of the alloy block oil ways in combination with the head retaining a large amount of oil.

 

My XU9J4 never had a problem on sticky tyres and high-grip surfaces with long, sustained corners.

My XU10J4 doesn't either.

 

XU9 was standard apart from a cam swap, PTS sump baffle, high pressure spring, ARP bolts and otherwise a thorough rebuild, including head, and a small skim.

The XU10 is a proper Longman-built jobbie, though - rods, pistons, solid lifters and so on - along with the PTS baffle again, gti6 pump and the usual stuff.

 

No mods on either in terms of fancy oil draining solutions/etc... just how Peugeot intended them, apart from a 19-row oil-to-air cooler, fwiw.

[Baz 421]

At the risk of repeating myself to add to brumster's post, aswel as many others in previous years, i've been competing in a standard (but properly rebuilt) Mi for the last 5mths on A048's, and Anthony and I also thrashed the crap out of it at Cadwell on almost-bald/slick Parada's in september and it must be said, we're both barely sedate drivers!.

 

Yes you can watch the pressure guage wagging it's needle around (mechanical and standard), but it's simply not an issue like some people seem to make out.

 

Ohh, and the most recent one (mentionned above) has no baffling to the sump at all...

Edited October 11, 2010 by Baz

[crf450 0 1 Cars]

You tell me. I haven't examined any external oil drains so I can't comment.

 

Let me explain again, before I get any more "Oh yeah? Well why hasn't xxxxxxx done xxxxxxx then Mr Smarty Pants?" replies, that I'm not marketing my solution to be the end to oil starvation. What I am saying is that in my opinion it is a more positive step than the crank located rods were, and that it has a better supporting theory behind it. I have tested my engine on track and it's stood up very well so far.

 

I'm willing to except the Gti6 head drains better and it holds less oil but I'll ask again "why cant all this be overcome by simply putting whatever the Mi head holds extra in the sump before you start the engine".

 

The idea that blame lies with the Mi head design was being banded around this forum before I came on here so its nothing new but just I dont get the theory.

 

The problem we've got is all Mi engines surge but not all die on track. CW's car has the oil light on on occasions but the old dog survives (I mean the cars the old dog not Chris). In my experience I reckon its about 75% will die in the first session with sticky tyres.

We've also got the question of how Nicks car was being driven, when it died at Spar that same w/end it had survived an evening at the Nurburgring GP circuit and about 20laps of the North Loop at 8.30 pace and was being driven by Andy Harvey who is a racing driver with championship wins under his belt.

We all like to think we can drive but I did a track day a few months ago with a forum member who is well respected for doing loads of track days and having a s*it hot car but on track my mate was lapping about 10seconds a lap quicker than him in a standard GTI6 so he's never gonna have oil surge issues.

I think as starting point you need to know if your engine is one of the those engine that will die on track before you try and solve the problem. Do you know the history of your engine Cameron?

[C_W 3 1 Cars]

The problem we've got is all Mi engines surge but not all die on track. CW's car has the oil light on on occasions but the old dog survives (I mean the cars the old dog not Chris).

 

 

Lol

 

The oil light actually only came on maybe 2 or 3 times on my first few trackdays (a coned chicane at Elvington and the tight complex to the hairpin at Croft), each time I was looking out for the pressure drop and would drop it into neutral and wait for the pressure to come back up; this probably made the difference as the engine was never under load when the pressure dropped off/light came on. Obviously this was not good as being in neutral slowed me down and let other cars pass which was completely unacceptable.

 

So I then bought the horrendously complex PTS sump baffle and fitted that (though I did admittedly modify it a bit to make it fit an alloy vaned sump; this probably reduced its effectiveness marginally). I didn't really notice it being much better with this.

 

I removed that shortly after, and had a full height plate welded into the sump (vanes ground flat where necessary) that sits as close to the pickup as possible with a small gap at the bottom for oil to flow under from the other half/3rd (this may have a trap door facing the pickup, I can't remember now). There's also the small XU10 oil pump baffle fitted, then lastly I made a "top plate", kind of like a windage tray but it's welded on the top of the sump itself. This covers as much of the sump top as I could with a hole drilled for the dipstick. Not much attention was paid to how oil would drain back in to it, however I found this all worked better that the PTS baffle and I never had a red oil light ever on track after that (50+ trackdays/maybe 6000track miles). The gauge would fluctate but never drop to nothing or even down past half normal .

 

Is it worthwhile asking what oil people are using in their Mi16s that have and haven't suffered failures? I always used Castrol 10/40 Magnatec from 2000-2007, then Mobil Super S 10/40.

[Anthony 1,003]

but I'll ask again "why cant all this be overcome by simply putting whatever the Mi head holds extra in the sump before you start the engine

In effect, this is the theory that Petert's extended sump/pickup works on, which certainly appears to atleast help (but not cure) the issue

 

Ignoring the ground clearance issues you'd get for a moment, I'm willing to hazard a guess that if you put say three of these extended pickup/sump setups together to make a monsterously deep sump that holds say 9-10 litres of oil, that the surge issues would no longer be an issue purely down to the amount of oil that would have to "disappear" for the pickup to run dry.

[C_W 3 1 Cars]

I think baffling gets it half way there, but couldn't you make a "big winged" sump so instead of making it deeper, go outwards for extra capacity? Maybe drop the pickup down a little so it's in a "well" on it's own though.

[rallysteve 22]

I did see once on another engine, all be it on a rover V8 in a range rover the sump had been modified to help prevent surge resulting in oil starvation. It had a plate put in that sloped the oil heavily towards the pick up and had diagonal fins with several trapdoors in to keep the oil around the pickup. Although i realise this was to help stop surge as a result of vehicle angle rather than g-force. It might be a bit complicated to explain, but in theory was very simple.

 

I was thinking a heavy slope towards the pickup with a winged section around the pickup area with a trapdoor maybe effective. I will try and do a quick sketch if i can. Might be complete sh!t but just my idea.

 

Steve

[Cameron 16]

I only know about half of the history, I got the engine when it had covered about 60K and I ran it for a year or so before rebuilding it. The car at that point was only slightly uprated from road spec and although I never managed to get the oil light on, it did dip worryingly low a few times on my first 'ring trip. I rebuilt it as the hybrid shortly after that.

 

I have pretty limited track experience at the moment but I was driving it pretty hard at Oulton Park, there's a few corners there that would give it a hard time! I'm planning to get a lot of track time in next year so we'll see how it gets on then. I'm pretty certain that it'll be dry sumped as soon as I can afford to do so, that'll be the only thing that stops me checking the pressure gauge!

[Baz 421]

Agree with this 100%- it just seems that some do and some do not.

 

Personally I've been lucky- an alloy Mi16 used for 6 years of trackdays on semi slicks and full slicks, with 2 different cylinder heads on it, and apart from getting a little tired now due to use and abuse, still shows good oil pressure.

[pug_ham 244 3 Cars]

Ade (PVFC pug) doesn't have surge issues as he's on a dry sump !

Yeah, forgot about that one.

 

Is it dry sump or just accusump? I know his res is in the boot he has a DES engine doesn't he & only fitted this as extra protection even though he hadn't had any issues with the DES engine alone, simply after blowing the previous engine up(not a DES lump).

 

Graham.