Mounting a transverse engine in-line - oil system queries
Discussion
Hi all,
I'm in the process of designing and building a kit-car (Sevenesque shape) and am planning to fit the Peugeot XU9J4 engine, or as it's commonly referred to; the Mi16. It's an engine that has only ever been fitted transversely in an original application. Apparently, many rally mk2 Escorts and various kit-cars have used it with success, but I have never actually seen an image of one of these cars, let alone seen one running! Maybe I'm not looking hard enough?
Before anyone questions the choice of engine (as I'm expecting to happen), I'd just like to say that fitting this engine over something conventional like a Zetec is something I'm enthusiastic about. So the choice of engine is pretty-much irrelevant to my query.
The issue I have is in the oil system. Basically I need to educate myself in the laws of oil movement in an engine! It's widely known these particular engines seem to have a slight weakness in the oil flow. In normal transverse applications, they can suffer oil starvation during long, left-handed corners. The oil pickup is positioned at the timing end of the engine, or the O/S of the car. It's believed that during these long corners, the oil in the sump all sloshes to the O/S of the car where the pickup is. During this process, more oil is pumped to the head than is capable of draining back down. Eventually, for a brief time at least, there is nothing left for the pump to scavenge and the big ends get it in the neck.
If my thinking is correct, by turning the engine around 90degrees I'd experience the same issue when braking rather than turning. Seeing as I won't be on the power at 7000rpm while I'm hard on the brakes, coupled to the fact that I'm sure you could generate more G in a corner in something like a 205GTI running this engine as opposed to what you could by standing on the brakes with it mounted in-line, I'm thinking this layout might actually reduce the chances of this starvation happening?
I'm also thinking I'm going to introduce a new issue; the pickup is mounted at what will be the front of the engine. So when I accelerate hard, all my oil is going to roll to the back of the sump. Brilliant! I guess I'm going to have to modify the pickup and position it at the back of the sump as in something like a Pinto. But then I have further issues when I'm braking....see where I'm at!?
I realise that a dry sump is the mother of all cures for everything here. One issue - a dry sump would probably end up costing me £2k! I just couldn't afford that, or justify it if I could. With the cost of an engine around £200 these days, I'd rather buy 3 engines and try different setups - almost sacrificing the engines to find a cure. The remaining spares will be of use in the future no doubt, or I could even make a coffee table from them. It's not true kit-car form to go throwing money around; you have to make stuff!
I'm confident that thinking about increasing the drainage capacity from the head back to the sump, designing some sort of wide sump featuring baffles or trap doors and perhaps even thinning the oil out to 5w30 or something - there's got to be a way! Plenty of Peugeot parts are interchangable, like sumps, oil pumps, cranks....even heads (apparently a GTi-6 head has a smaller oil capacity and better return flow properties), so different combinations are possible.
So basically starting from the beginning - when turning an engine around 90degrees, what basic principles do I need to consider regarding oil flow?
I'm in the process of designing and building a kit-car (Sevenesque shape) and am planning to fit the Peugeot XU9J4 engine, or as it's commonly referred to; the Mi16. It's an engine that has only ever been fitted transversely in an original application. Apparently, many rally mk2 Escorts and various kit-cars have used it with success, but I have never actually seen an image of one of these cars, let alone seen one running! Maybe I'm not looking hard enough?
Before anyone questions the choice of engine (as I'm expecting to happen), I'd just like to say that fitting this engine over something conventional like a Zetec is something I'm enthusiastic about. So the choice of engine is pretty-much irrelevant to my query.
The issue I have is in the oil system. Basically I need to educate myself in the laws of oil movement in an engine! It's widely known these particular engines seem to have a slight weakness in the oil flow. In normal transverse applications, they can suffer oil starvation during long, left-handed corners. The oil pickup is positioned at the timing end of the engine, or the O/S of the car. It's believed that during these long corners, the oil in the sump all sloshes to the O/S of the car where the pickup is. During this process, more oil is pumped to the head than is capable of draining back down. Eventually, for a brief time at least, there is nothing left for the pump to scavenge and the big ends get it in the neck.
If my thinking is correct, by turning the engine around 90degrees I'd experience the same issue when braking rather than turning. Seeing as I won't be on the power at 7000rpm while I'm hard on the brakes, coupled to the fact that I'm sure you could generate more G in a corner in something like a 205GTI running this engine as opposed to what you could by standing on the brakes with it mounted in-line, I'm thinking this layout might actually reduce the chances of this starvation happening?
I'm also thinking I'm going to introduce a new issue; the pickup is mounted at what will be the front of the engine. So when I accelerate hard, all my oil is going to roll to the back of the sump. Brilliant! I guess I'm going to have to modify the pickup and position it at the back of the sump as in something like a Pinto. But then I have further issues when I'm braking....see where I'm at!?
I realise that a dry sump is the mother of all cures for everything here. One issue - a dry sump would probably end up costing me £2k! I just couldn't afford that, or justify it if I could. With the cost of an engine around £200 these days, I'd rather buy 3 engines and try different setups - almost sacrificing the engines to find a cure. The remaining spares will be of use in the future no doubt, or I could even make a coffee table from them. It's not true kit-car form to go throwing money around; you have to make stuff!
I'm confident that thinking about increasing the drainage capacity from the head back to the sump, designing some sort of wide sump featuring baffles or trap doors and perhaps even thinning the oil out to 5w30 or something - there's got to be a way! Plenty of Peugeot parts are interchangable, like sumps, oil pumps, cranks....even heads (apparently a GTi-6 head has a smaller oil capacity and better return flow properties), so different combinations are possible.
So basically starting from the beginning - when turning an engine around 90degrees, what basic principles do I need to consider regarding oil flow?
A nicely baffled sump and an Accusump would be my suggestion. A friend of mine went through about five Mi16 engines due to oil surge in his tarmac rally Pug 205, and that was with the Peugeot Talbot Sport official sump baffles fitted. Then he moved to a dry sump and hasn't suffered from oil surge ever since.
I totally get the appeal of these engines, they are impressively light and can make very good power (friends current engine is around 280bhp, though it wasn't cheap power). What gearbox are you mating it to?
I totally get the appeal of these engines, they are impressively light and can make very good power (friends current engine is around 280bhp, though it wasn't cheap power). What gearbox are you mating it to?
The Black Flash said:
I'd have thought that you can generate far more force by braking than you could by cornering, especially in a kit car?
Either way, as you say probably less important since you'll be off the power then.
It's not the force so much as the length of time that the force is acting when you're going round a corner. I should think a properly baffled sump will do the job in this application.Either way, as you say probably less important since you'll be off the power then.
So is the general consensus that the effects of oil starvation on an engine with these characteristics will probably be less severe in the in-line config rather than transverse?
It seems a dumb question, but knowing the problem in the transverse layout as I do, and having never seen an in-line layout I'm really not sure how it will react!
It seems a dumb question, but knowing the problem in the transverse layout as I do, and having never seen an in-line layout I'm really not sure how it will react!
Kitchski said:
So is the general consensus that the effects of oil starvation on an engine with these characteristics will probably be less severe in the in-line config rather than transverse?
It seems a dumb question, but knowing the problem in the transverse layout as I do, and having never seen an in-line layout I'm really not sure how it will react!
It should be less severe, but given that oil starvation is well known a baffled sump is probably a decent idea. It'll need to be baffled a bit differently for inline use I should think.It seems a dumb question, but knowing the problem in the transverse layout as I do, and having never seen an in-line layout I'm really not sure how it will react!
Remeber, it's not just the oil sloshing in the sump that can be an issue. For sustained high G loadings, oil tends to "hang up" in the head and lifter galleries etc. If you are changing the orientation of the engine, you need to take a close look at the oil return paths from the upper parts of the engine, ensuring that excessive quantities of oil cannot pool up top, and hence starve the oil pump of its oil feed (with predictable consequences!).
Generally speaking, typical road car engines will be capable of 1G in most direction for a max of approx 10 to 15 sec before they see issues. Carefull attention to the sump (which you will almost certainly want to reduce in height to get the bonnet line down) and maybe even additional external oil return lines from the cylinder head will massively improve that capability
Generally speaking, typical road car engines will be capable of 1G in most direction for a max of approx 10 to 15 sec before they see issues. Carefull attention to the sump (which you will almost certainly want to reduce in height to get the bonnet line down) and maybe even additional external oil return lines from the cylinder head will massively improve that capability
This particular engine uses a spray bar to each cam lobe though a single oil feed in the head, and drains it back via two drainage ports at either end. Having looked at them yesterday, the clever bloke I work with (hello Steve!) reckons there is a fair bit of material that could be opened up, allowing faster drainage. I had to ask myself why they wouldn't do this from the factory, but I guess production costs are probably the reason.
I think knowing how to baffle the sump will be important. I'm also told later versions of the Peugeot engine (such as those fitted to the 306 GTi-6 etc) actually use a baffle on the oil pickup too.
I think knowing how to baffle the sump will be important. I'm also told later versions of the Peugeot engine (such as those fitted to the 306 GTi-6 etc) actually use a baffle on the oil pickup too.
I have seen this engine in a 7 replica and it seemed like a good idea, I think the reason it has not been used is down to the width and height, the engine when normally fitted is canted over quite a long way and therefore takes up a lot of width, if you then roll it more upright it is tall engine, I believe that it also suffers from oil return issues when installed upright.
However all things are possible with enough effort(money), however i am a believer that as the engine is as good as people say, then we would have seen it used more often.
However all things are possible with enough effort(money), however i am a believer that as the engine is as good as people say, then we would have seen it used more often.
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