Getting A Gti6 Lump Ready For Track Work

[Mac210882 0]

Hi All,

 

I am having a GTI6 engine installed in my track car soon by Dan (talyorspug) after my Mi16 died a death on track. I'd like to think ahead and 'track-proof' the engine as much as I can to avoid any major issues in the first few outings.

 

As I understand it, the '6 engine doesn't suffer from oil surge as much as the Mi did - does it suffer from it at all or did Peugeot completely cure it in the '6 engine? If not, is it worth fitting baffled sumps, extended pickups etc or does it cope OK as standard?

 

The car will be running a 13 row Mocal oil cooler to try and keep temperatures down on track, but is there anything else I should be considering?

 

Cheers

 

Iain

[Baz 421]

You can never cure surge! It's physics, something that happens with any movable object, in this case oil when forces are exerted in any direction. Sorry i'm speaking on a large scale and being slightly blunt!

 

The problem with Mi's is starvation in the bottom end caused by a lack of return from the head, so giving that you're using a complete 6 you won't get that problem, but you'll still have your oil sloshing around in the sump, so IMO always best to have some kind of baffling in there at least.

[Miles 331 1 Cars]

I;d fit the french/UK spec baffle system, not cheap but cue's surge which I think is easy to get with a std 6 lump even on P6000's

[Cameron 16]

What Baz said.

 

How badly did you kill the old Mi engine? If it would still be useable after relatively little work - i.e. a re-grind, then I'd recommend making a hybrid out of the 6 head and Mi block. Means you get the reduced starvation of the 6 engine coupled with the massive reduction in weight from ditching the iron block.

If you have a complete 6 engine it also means you can nab all the good bits such as lighter cam pulley and sump / baffles.

 

Only problem is it is more expensive as you need management, but worth it! My engine (on Emerald but otherwise standard) and with dodgy cam timing made 176bhp. Not too bad considering it's 100cc down on a 6. Dave Walker reckoned it'd be good for 180-190 when it's set up properly.

 

Edit:

Oh, and just to comment on the oil starvation. Not a hint of it since I sorted the breathers out (oil starvation caused by it being all over the engine bay ) and it's running on A032's.

Edited September 24, 2008 by Cameron

[fletch 0]

I've never heard of a 6 engine having bottom end problems due to oil starvation on track. The standard baffled sump probably helps a lot.

[Cameron 16]

From what I've heard it's more to do with the head having a smaller capacity for oil and better drainage. Helps keep the oil in the sump where you need it.

[crf450 0 1 Cars]

In my opinion the surge issues on a Mi engine has nothing to do with head design and I think unlike most people that post on the subject I've had loads of experience dealing with the problem.

I did an extended oil pick-up/low sump conversion before they were being sold on here, I've baffled the sump in every way shape and form but I didn't solve the surge issue until I fitted a 8valve crank and rods. I haven't got time to explain why the Mi engine has it's surge issues but I'm 99% sure I've sorted it and if your search the user "Nick" he"ll explain what we did.

As for the GTi6 engine, I though my six engine was indestructible until my last track day when a shell picked up. Under normal circumstances it would have spun but having had so many Mi's I now recognise the signs and as soon as I felt the engine tighten and fight the revs I dumped the clutch and didn't run it a again, I think I've got away without bending the crank and ovaling the rod but it'll need a grind and a set of shells.

My six engine had been sound for ages but I changed oil brands and I think this was why I encountered problems. When the motor goes back in I'm going to fit a big oil cooler with a stat and I'm confident I wont have any more problems. So if you've fitted a cooler I think you'll be ok. Hope this helps.

Cheers Martin

[Cameron 16]

It's pretty common knowledge that head design is a major contributing factor, so I wouldn't go dismissing it like that. It's an interesting idea about fitting the rods and crank from an 8V but if you ask me I can't see it having that big of an impact. Sure the non crank-located rods of the Mi might lose oil a little faster but where does it go? Straight to the sump. So it's unlikely that it's the cause of starvation. It might help by keeping the oil film in there for a precious second or so, and help minimise damage, but I very much doubt that it's the be all and end all cure.

I'd imagine that if you had your car on decent tyres - semi's or slicks - and gave it some death you'd find you still have problems.

[crf450 0 1 Cars]

It's pretty common knowledge that head design is a major contributing factor, so I wouldn't go dismissing it like that. It's an interesting idea about fitting the rods and crank from an 8V but if you ask me I can't see it having that big of an impact. Sure the non crank-located rods of the Mi might lose oil a little faster but where does it go? Straight to the sump. So it's unlikely that it's the cause of starvation. It might help by keeping the oil film in there for a precious second or so, and help minimise damage, but I very much doubt that it's the be all and end all cure.

I'd imagine that if you had your car on decent tyres - semi's or slicks - and gave it some death you'd find you still have problems.

Mi heads holding oil is common knowledge because people repeat what they read on forums, Its like seven or eight years ago if you posted that your putting a Gti6 engine in a 205 you'd get flamed for it because people who had done it read on forums that if you put a cast iron block engine in a 205 you'd upset the fine handling of a 205, now everyone know that thats s*ite. If you can tell me that you've put external drains on a Mi head and cured surge I'll listen, if you haven't shut the f*** up.

[Cameron 16]

This is exactly why Im not a regular on this forum, the "my opinion is fact, yours is wrong" attitude of some members is a real pain in the arse. There's nothing wrong with a bit of a debate, but to tell me to shut the **** up because you disagree is f-ing childish.

 

It doesn't take a finely honed understanding of vehicle dynamics to now that changing the weight distribution of a car will affect the handling, and since the 205's is heavily front biased then I would think it's safe to assume that it is slightly compromised by fitting the heavier engine. I haven't weighed the blocks, but I have tried lifting both and it's probably a safe estimate that the iron block is at least 20kg heavier.

 

And yes, I am repeating what I've heard and so my claim that the head holds oil may well be wrong, but I imagine it has been widely accepted by so many people because somebody came up with the hard evidence in the first place. Which moves me nicely on to my next point: have you obtained any proper evidence that what you've done has made a difference? Now before you pipe up and say "yes, I don't get surge anymore" bear in mind that that isn't proper evidence. That's an opinion, and from what I remember reading the topic on this you have only tested it on the road.

By proper evidence I mean some test of the way the bearing uses oil when the rod is crank or rod located. I'm not exactly sure of the clearances with the crank located rod but I imagine they aren't as tight as the actual bearing clearance and so don't hold as much pressure back as you claim. I understand that it's difficult to do these tests, but until you have then like I said it isn't the be all and end all cure.

So on to the GTi6 head, it does have a smaller capacity for oil and it does have an extra drain in the head so I can back up my claim (at least a little) that it helps to combat oil starvation.

And no, I haven't fitted an external drain to an Mi but I know that some people have and it would be interesting to hear their results. What I have done is fitted the GTi6 head to the Mi block and so far I haven't had any problems. Just for reference the car is running soft / super soft compound semi's front & rear respectively.

Edited September 27, 2008 by Cameron

[SPGTi 2]

I am building a similar spec engine to Cameron (GTi6 head on 1.9 Mi16 block) at the moment and on reading Nick's thread about his engine, I also looked at using 8v rods in the Mi16 bottom end. The machine shop that I use is run by an old guy who has been building race engines since the 60's and I discussed with him at length this issue but in the end decided to stick with the 16v rods. Whether this is right or wrong I don't know but from crf450's comment that his 306 GTi-6 engine suffered from surge/ starvation and having seen 8v engines that have also spun a bearing I think using the better 16v rods was the right decision for my build as the initial argument was that the 8v and GTi6 engines never suffer from this problem and they are crank located.

From memory though Nick's engine is also running a baffled sump (XU10 ???) and a XU10 oil pump so the comparison with his old engine is difficult, also the comparison needs to be be 2 freshly built up engines, with the only difference the rods as I am convinced that a fresh well built Mi16 will not surge that easily anyway. Doesn't a 306 run in the LMA series with a MI16 engine ? That is thrashed on slicks with no surge.

Other changes that I am making which I think will help surge/ starvation are to run the tin 8v sump with a baffle system. This is because with the use my car gets I would rather have a tin sump which bends than an ali one that will crack, also I don't like the shape of the MI16 ali sump.

Anyway whatever the cause of the surge / starvation issues in the 1.9 MI16 engine I think the engine in Nick's car seems awesome and it is great to see different engineering solutions being tried and posted on a public forum. I am also a fan of Cameron's engine esp. after reading his build thread and realising he basically built it in his bedroom. IMHO these are 2 well executed builds to combat the same problem, so could you both please keep posting !!!

 

cheers

 

Steve

[welshpug 1,661]

there will ALWAYS be oil surge (unless you dry sump...)

 

oil starvation is the problem NOT surge! (though of course it is a contributing factor)

 

 

as you mentioned it would be very interesting to see the 2 approaches and the results from them.

Edited September 27, 2008 by welshpug

[Alastairh 47]

To the answer to the original question. If was me that was telling Dan what i wanted doing pre conversion.

 

Full service, change the shells and inspect the crank and fit your cooler.

 

Tbh, i would of thought Dan would do that anyway. You should have plenty of use out of that, and reduce any weak spots with the original engine, with out going off and spending thousands.

 

Al

[taylorspug 7]

Thats pretty much the plan, and is always what i reccommend for conversions at the very least.

 

We arent looking to build hybrid engines etc, just get Iain a nice reliable track car, which 99% of '6 engined cars are...

[Matt Holley 11]

My six engine had been sound for ages but I changed oil brands and I think this was why I encountered problems. When the motor goes back in I'm going to fit a big oil cooler with a stat and I'm confident I wont have any more problems. So if you've fitted a cooler I think you'll be ok. Hope this helps.

Cheers Martin

 

What oil were you using when it went wrong and what oil would you recomened for a track engine?

[crf450 0 1 Cars]

What oil were you using when it went wrong and what oil would you recomened for a track engine?

 

The oil that gave me the problems was Silcolene pro4+ I think its a bike oil realy I only used it because i've got a lot of it spare.Before that I'd ran it on Millers without any problems.

[Spiky 37]

i run silkolene pro s and used to run silkolene pro r in my cossie

 

 

never had an issue

 

i run a 16 row 285 with stat on my 205

 

 

no issues to report

[Mac210882 0]

Thanks everyone, I've spoken to Dan about this and the plan is to take the sump off and inspect the shells. If they look to have any sign of wear then replace them. Fit the oil cooler, new cambelt and tensioners, and new water pump and see how it goes from there.

 

Like Dan says, I just want a nice reliable track car. I'm not chasing horsepower and I don't want to spend thousands chasing lap times, I just want a car that I can have fun with on track.

 

Cheers

 

Iain