Mi16 Conversion Finished..

[welshpug 1,621]

So basically the problem isn't oil surge as such, just the volume of oil that the Mi16 consumes with ease due to piston located rods, but is highlighted by oil surge far sooner than in the 8v and gti6.

 

are the 1.9 and 2.0 Mi16 engine the same in this respect? (piston located rods)

 

So...I have Mi16 pistons / rods, Mi16 crank, Gti6 pistons /rods, 8v crank, 8v piston /rods, Mi16 block / liners, GTi6 head ............what do I do ??????????????

 

going from what Nick and Martin have produced, I would be inclined to use;

 

8v crank + rods,

 

mi16 piston machined to suit 8v rods

 

mi16 block +liners

 

gti6 head (smaller chamber volume, higher compression ratio if used with the Mi16 bottom end)

Edited July 9, 2008 by welshpug

[SPGTi 2]

Just a quick thought, are the crank journals different widths between the 8v and Mi16 ? Or is it just a difference between conrods only ? . I will measure all these once I have disassembled the 8v bottom end. I presume you used an 8v crank because that is what you had Going on what you have found, would you concur with this :

8v crank + mi rods = surge

8v crank + 8v rods = no surge

mi crank + mi rods = surge

mi crank + 8v rods = no surge ??????

 

as the surge factor appears to be the rods ?

 

Steve

[James_m 0]

Why would this setup make any more power than stock rods/crankshaft? is the CR increased from the 8v rods?

[nick 3]

Spgti, the way we see it is that the narrower big end on the Mi rod is letting the pressure out quicker, so yes, what you have put is correct.

 

James, it won't make any more power, but the PeterT inlet will (did you not read the full post??)

 

Nick

[Alan_M 66 1 Cars]

Spgti, the way we see it is that the narrower big end on the Mi rod is letting the pressure out quicker, so yes, what you have put is correct.

 

James, it won't make any more power, but the PeterT inlet will (did you not read the full post??)

 

Nick

 

If the Mi rod big-end is narrower, is there an issue with using the 8v rods ( I assume these are wider then) with the Mi crank?

[James_m 0]

Spgti, the way we see it is that the narrower big end on the Mi rod is letting the pressure out quicker, so yes, what you have put is correct.

 

James, it won't make any more power, but the PeterT inlet will (did you not read the full post??)

 

Nick

 

I did, but was unsure if the 8v rods but run different rod heights anyway.

I also run a a stage 1 btw, goes well from 5k+!

[nick 3]

Alan, not tried an 8v rod on an Mi crank, but I reckon it would fit no problem (don't quote me on that!)

 

James, oh yes.... goes very well after 5k!! and not too bad before it!!

 

Hoping to get it on the Scooby clinic dyno very soon, this is known to be a very accurate dyno.

 

Nick

[SPGTi 2]

Just going back to the 8v rods with 16v pistons.

Does that make the rods crank and piston located ? Or does the machining change the rods to only crank located ?

If they are crank and piston located, what problems would this give ?

Would there be any other reasons for Peugeot to change the location method for the Mi16 from what they did in the 8v ?

 

It is just that I have lots of bits, and I am trying to decide which will give me the most reliable engine.

 

Steve

[nick 3]

Steve, The pistons are machined to give the same little end/piston clearance as the 8v, so they are just crank located. I imagine that if the piston was located on both the crank and the piston there would be no sideways movement and it would just smear the piston up the side of the bore..!!

 

Nick

[SPGTi 2]

Steve, The pistons are machined to give the same little end/piston clearance as the 8v, so they are just crank located. I imagine that if the piston was located on both the crank and the piston there would be no sideways movement and it would just smear the piston up the side of the bore..!!

 

Nick

 

Thanks. I didn't think it would be too pretty if they were located at both ends.

I am just getting a load of bits to take to the engineering shop so will ask what he thinks (well how much it will cost !!) about changing the pistons to use the 8v rods.

I think I will be running

Mi16 crank

Mi16 liners

8v rods

Mi16 pistons

Gti 6 oil pump with baffles / chain and gear wheel

Gti6 sump

Windage tray (?)

 

I just want a strong, light and reliable bottom end.

 

Steve

[philfingers 5]

8v crank is 3-4kgs lighter too I believe. Got to help it spin up faster! Will that work with a Mi16 block, flywheel and std management?

[SPGTi 2]

8v crank is 3-4kgs lighter too I believe. Got to help it spin up faster! Will that work with a Mi16 block, flywheel and std management?

Nick is running the 8v crank. It is lighter and there shouldn't be a problem with the std management.

 

I want to use the Mi16 crank as I have very good one, at the moment the 8v crank I have is in a bottom end that I need to strip down. If the 8v crank looks good maybe that will be another option to look at.

 

Anyway my simple engine build is starting to get less simple and more expensive.

 

Steve

[philfingers 5]

std GTi6? That extra 20kgs is great ballast for those muddy whites!

[nick 3]

I didn't use the 8v crank for any other reason other than it is what I had in it when I bought it!!!

 

You would think that the 8v crank would make it less torquey coupled with the no-split down pipe, but mine will pull from 1000 revs in 5th no problem.

 

Nick

[luggy 13]

Martin mentioned it sounds like no other Mi he's heard either, I'd hoped to see it last week when I was in Belper around the last Ring trip to hear & see it in action.

 

 

Graham.

 

Hi Nick, love to hear what the hybrid MI sounds like!.

[Cameron 16]

Baffling an Mi sump does next to nothing to help it's surge issues and when people refer to problems with the head design they are just repeat stuff they've read on hear. I've never seen a post that says I've put external drains on a Mi head and cured the oil surge problem.

We've approched the surge issue from a different angle and I'm pretty sure we've got to the bottom of a problem that people have been barking up the wrong tree on for years, although it's come a bit late as most Mi engines.

Cheers Martin.

 

 

Well to be honest, its been mentioned so many times that its pretty common knowledge.

 

 

Did you measure the clearance between the side of the rod and the crank, or do you know what it is?

 

I've gone a different route to you by using Mi block and GTi6 head, sump, pump, sprocket & chain (ditched the spacer) and seem to be getting pretty good results. I had some problems at first due to breather issues and the leaking sump gasket losing oil quicker than I could put it in but now that's sorted I can throw it around as hard as Im willing to do on the road and the pressure seems to be solid. Will see what happens in Germany.

Edited July 27, 2008 by Cameron

[SPGTi 2]

Now I have a garage full of engine bits I quickly measured the crank journal width, the width of the bigend on both 1.9 8v and 1.9 16v rods.

crank journal (Mi 1.9 16v) - 24.45mm

big end 1.9 8v rod - 24.40mm

big end 1.9 16v rod - 22.50mm

 

I am not claiming these figures to be deadly accurate as I only had a vernier caliper but it does illustrate the difference between the rods. The big end bearings are the same for both rods though (will search through bin to find one to measure). So is it only the extra width of the 8v rod that is sufficient to stop the pressure loss when compared with the 16v rod even though they are clamping the same size bearing on the crank journal ?

 

All interesting stuff, it is just the guy who will be machining bits and pieces for me is "old and wise" and has built lots of race / rally engines so just want to be clear when he asks me why I want it done like that .

 

cheers

 

Steve

[welshpug 1,621]

just measured a 2.0 Mi rod, 24.20mm (just a pair of verniers)

[SPGTi 2]

just measured a 2.0 Mi rod, 24.20mm (just a pair of verniers)

Are the rods are crank located then ? Any idea on the crank journal width ? I also have a GTi-6 crank and rods in the garage. I will measure these when I get chance.

Are there ever any reported surge issues with the 2.0 Mi ?? (sorry for the questions but have never been interested in 16v engines before).

 

cheers

 

Steve

[crf450 0 1 Cars]

Well to be honest, its been mentioned so many times that its pretty common knowledge.

 

 

Did you measure the clearance between the side of the rod and the crank, or do you know what it is?

 

I've gone a different route to you by using Mi block and GTi6 head, sump, pump, sprocket & chain (ditched the spacer) and seem to be getting pretty good results. I had some problems at first due to breather issues and the leaking sump gasket losing oil quicker than I could put it in but now that's sorted I can throw it around as hard as Im willing to do on the road and the pressure seems to be solid. Will see what happens in Germany.

 

What crank/rods did you use?

[Cameron 16]

1.9 Mi ones.

[SPGTi 2]

Which gudgeon pin was used for the pistons ? 8v or 16v ? Any mods needed here, or is it just a question of machining the pistons so that they are no longer locating the rod, using the Mi16 pin in a press fit ?

 

cheers

 

Steve

[Alan_M 66 1 Cars]

So if you wanted to build a 2.1 GTi6 lump, there would be no need to change anything if the pistons are crank located? I got some in the garage. Might drag them out for a quick measure up.

 

You've basically got the 1.9 Mi crank, GTi6 rods and pistons (which I assume would be the same as the 2.0ltr Mi ones?).

 

It surprises me why Peugeot built the 1.9 Mi16 this way TBH.

[welshpug 1,621]

GTi6 rods and pistons are different to 2.0 Mi16 ones, longer rods + shorter piston, with a lower compression height due to a smaller combustion chamber in the head.

[bensonmi 4 2 Cars]

excelent, very usefull pics cheers