New Solution For Mi16 Oil Surge

[crf450 0 1 Cars]

Because there are many other engines with oil cooled pistons that don't have the same problem. Nearly everyone on here acknowledges it's a head issue and thats why solid lifters help

OK, plenty of people do think the surge problem on the Mi is caused by the head holding oil but I'm still waiting for someone to explain why this couldn't be overcome simply by putting extra oil in the engine to compensate.

[Doof 11]

martin, wouldn't that depends on the capacity of the head? I've no idea how much it can hold but i'd think its quite a bit.

[petert 550]

OK, plenty of people do think the surge problem on the Mi is caused by the head holding oil but I'm still waiting for someone to explain why this couldn't be overcome simply by putting extra oil in the engine to compensate.

 

Like I do! With an extended sump!

[boombang 2]

You can't simply put extra oil in without extending capacity and pickup as the crank will churn the oil, filling it with bubbles whichs affects oil pressure and pickup.

[nick 3]

What Martin is saying is that if there is (for instance) two litres of oil sitting in the head (with the engine running) then adding an extra two litres of oil to the sump should bring the oil level back to the normal level (below the level of the crank avoiding aeration) and counteract the oil trapped in the head, thus, curing the oil surge. As a lot of people know this isn't the case.

 

Also Martin tried the extended sump/pick-up idea about three years ago and found that it made no difference whatsoever, I'm sure he'll elaborate on this later. As we are finding out, it seems what works for one might not work for another, apparently we just need to build our std engines better.......!

 

Nick

Edited October 2, 2006 by nick

[petert 550]

Also Martin tried the extended sump/pick-up idea about three years ago and found that it made no difference whatsoever, I'm sure he'll elaborate on this later. As we are finding out, it seems what works for one might not work for another, apparently we just need to build our std engines better.......!

 

All I know is that an engine I built two years ago, with an extended pickup and baffled trap door sump, holding 6.5L of racing oil, has been the winner of it's class for the last two years. It doesn't get much better than that for recommendations. I'm sure one day he'll eventually spin a shell, but the next rebuild will be a dry sump.

Edited October 2, 2006 by petert

[nick 3]

How often does it get it shells changed though? Being a race engine I would have thought the bottom end is re-built quite often?

 

Martin and C_W both keep them running through loads of track days (with varying amounts of surge) but at the expense of regular shell changes (I'm presuming Chris changes his regularly here)

 

We are experimenting with crank located rods on my soon to be re-built Mi just to see what, if any, effect is has on the oil surge. This is in conjunction with a baffled sump and windage tray from a gti-6 and (maybe) blocked off oil spray bars. It may work, it may not, but we shall soon find out.

 

Nick

Edited October 6, 2006 by nick

[C_W 3 1 Cars]

Martin and C_W both keep them running through loads of track days (with varying amounts of surge) but at the expense of regular shell changes (I'm presuming Chris changes his regularly here)

 

Nick

 

Not once

 

What I have done with mine though is an oil change almost every trackday, and always warmed it up before thrashing it.

[KRISKARRERA 2 1 Cars]

Not once

Blooooody hell!!!! That's more than lucky.

[nick 3]

Sorry Chris, I thought you did regular changes. Thats pretty amazing then!!

 

Nick

[petert 550]

How often does it get it shells changed though? Being a race engine I would have thought the bottom end is re-built quite often?

 

After two seasons it's still on its original shells. I also forgot to mention it has a Hillclimb record to its name as well. It really does take a pounding but has shown no signs of giving up. It gets fed a diet of Motul.

[jacobs53 0]

Reply regarding CRF's presumptions.

 

If the piston spray bars and fully floating pistons were the reason to the oil surge, surely the 2.0l turbo (8 valve) would be also effected. It doesn't have the fully floating pistons but it does have spray bars.

 

I have worked with the Ryton employee team building cars for the 2005 season and they agreed the oil surge was due to the cylinder head. With every race engine they ran it always had a drilling and external plumbing to allow the oil to return to the sump. Never happened again

 

lee

[welshpug 1,622]

So if the factory boys are drilling and plumbing externally surely thats what should be done

[niklas 1]

Some time ago I spoke to a local enginetuner about the problem. He's not Peugeot-specifik and I got the understanding that in general it's quite common to drill and plumb externally.

So maybe it's common with DOHC design that oil gets trapped in the head!?

[Dazza 4]

Nice read guy's with wealth's of actual experience and no doubt ££££££££ ''' of rebuild's

I do know of the orogin of this thread ,i havent seen him drive but he is a decent guy ,his mi engine is a serious piece of kit iam informed, a mega buck's build and ive heard whispers of big bhp ,i dont know any more than that or in fact wether its all true any more than anyone else ?

However as iam entering the MI powered 205 brigade iam considering the oil surge option's .

I do build all my own cars and engines ,i only farm out machine work .i have a self built and modified 1905 cc running 45' s + lots of other stuff and it regulary shows a soild 140 bhp road power when set up recently, iam really happy with it and its goes really really well trouble free.

Initially iam not interested in baffle trays as imo there not doing anything 100% proven here ,its the external rear oil plumbing lines iam intending to do to my Mi's as imo this will be the most effective way of solving these issue's ,if you put and keep sufficient oil around the pump / sump thats the problem solved imo .The 8v never surges or should i say the guage never budges even on slick's .The XU 9J4 does differ in design with the spray bar set up around the little ends and also the bigger head capacity and hydraulic followers all taking there little capacity's (has anyone ever calculated this amount of supply requirements campared to the XU9JA).However the pump / sump should work if re-supplied sufficiently even if its a poor design ,i do wish that the sump pickup was slightly deeper like the BMW design with a well type profile ....

Has anyone any info and pics of the external pipework and pick-up location's before i start to proceed with this .

Thanks Dazza H www.teamdenbo.com

Edited October 7, 2006 by Dazza

[crf450 0 1 Cars]

Reply regarding CRF's presumptions.

 

If the piston spray bars and fully floating pistons were the reason to the oil surge, surely the 2.0l turbo (8 valve) would be also effected. It doesn't have the fully floating pistons but it does have spray bars.

 

I have worked with the Ryton employee team building cars for the 2005 season and they agreed the oil surge was due to the cylinder head. With every race engine they ran it always had a drilling and external plumbing to allow the oil to return to the sump. Never happened again

 

lee

I'm not saying the surge problem is deffinatly down to the bottom end design and I know that plenty of people fit external drains to the Mi head but I'm trying to understand the head drainage theory and for the life of me I can not understand how the head holding oil can't be overcome by overfilling the sump. Please anyone that understands the head drainage theory join the thread and convince me I'm wrong.

[Rippthrough 98]

I'm not saying the surge problem is deffinatly down to the bottom end design and I know that plenty of people fit external drains to the Mi head but I'm trying to understand the head drainage theory and for the life of me I can not understand how the head holding oil can't be overcome by overfilling the sump. Please anyone that understands the head drainage theory join the thread and convince me I'm wrong.

 

 

probably because you can't overfill the sump enough to fill the head up without causing damage from overfilling?

[welshpug 1,622]

overfilling will not work on many counts, firstly you will get air in the oil due to the crank whipping it all up (can remember the correct term for it)

 

but also if there is penty of oil in the sump as the head is filling up, instead of a pint or two you'll get however much extra you put in there in the first place if the corner is long enough!

 

basically if its the head filling up more oil wont stop it from filling up, itll just put more oil up there!

 

and if the factory engine builders and many french rally builders are doing said plumbing why should we ignore this mod and search elsewhere?

[Rippthrough 98]

overfilling will not work on many counts, firstly you will get air in the oil due to the crank whipping it all up (can remember the correct term for it)

 

Foaming

 

I have lots to do today as you can see...

[nick 3]

How can it "just put more oil up there"?

If that was the case the sump would empty and you would have a gallon of oil in the head!

 

If it take one litre of oil to fill the head under normal running conditions why doesn't putting on litre of extra oil in the sump cure surge?

 

You wouldn't get aeration from the crank running in the extra oil because the oil level would be at the normal level (1 litre in the head, replace that litre with more oil in the sump, back to the std level)

 

Nick

[Rippthrough 98]

How can it "just put more oil up there"?

If that was the case the sump would empty and you would have a gallon of oil in the head!

 

If it take one litre of oil to fill the head under normal running conditions why doesn't putting on litre of extra oil in the sump cure surge?

 

You wouldn't get aeration from the crank running in the extra oil because the oil level would be at the normal level (1 litre in the head, replace that litre with more oil in the sump, back to the std level)

 

Nick

 

Not when you aren't cornering and its returning ok!

Besides, I have a feeling the head would contain much more than 1 litre.

[nick 3]

So how does cornering effect how the oil returns?

 

Nick

[Rippthrough 98]

So how does cornering effect how the oil returns?

 

Nick

 

Moves the oil away from the return/s at one side and overwhelms the others?

Edited October 9, 2006 by Rippthrough

[KRISKARRERA 2 1 Cars]

Never had oil surge in my 405, determined to get it now. When it stops raining.

[nick 3]

I've been reading an old thread That said that the pump flowed approx' 16 litres per minute, so to get a true reading on this a test bench needs to be set up to see if the head can drain the same amount.

 

The head is coming off mine in the next couple of weeks, so it looks like there could be some oil flow testing going on!!

 

Nick

 

p.s. Has the 8v got similar sized returns?