Cam Pulleys

[Higgy 0]

My 2p worth is the following:

 

I have two engine

 

1. 1991 - 3-row ECU non-CAT from Mi16x4

2. 1989 - 2-row ECU non-CAT from Mi16x4

 

Both these engines (if memory is correct) have 2 & 4 pulleys. I guess in the configuration of 4-exhaust & 2-inlet.

 

As far as I believe Mi16x4 had a different exhaust cam to overcome the losses of the hydraulic system (rear suspension).

 

The Citroen BX has a hydraulic system also, so would they not also have the different Mi16x4 cam? Maybe they kept standard cam and just used no.4 exhaust pulley?

 

I have used both engines in my 205 now, and both have 'lumpy' idle and go mad at the top end

 

The 'lugs' on the alloy sump are for the A/C unit. A cast aluminium sump is used to support the weight of the A/C compressor, where as a thin steel sump would not be suitable.

(my 405 GLX has al sump with A/C compressor fitted in this position).

 

What does everyone think?

 

Higgy.

[Higgy 0]

I just found a pic of the current engine I am running. Wait for it................

 

Pulley no. 2 on EXHAUST and no. 4 on INLET

 

 

I will check to see what the pulley arrangement is on my other Mi16x4 engine tonight.

 

Higgy.

[Ahl 4]

Nope, mine is from a '89 BX with alloy sump and #2+#2. So far for logic.

Same as mine.

[Higgy 0]

Info from BX 16v site:

 

XU9J4 (D6C) Engine

 

...The cam pulleys are numbered and there seem to be several factory combinations - The most common variations seem to be the early engines using a #2 exhaust cam pulley and a #4 inlet cam pulley this later changed to a #2 cam pulley on both the inlet and exhaust cam. The combination of #2 and #4 seems to give the more harsh power delivery often noticed with the mi16 engine.

 

.XU9J4/Z (DFW) With Catalytic Converter

 

...These differences are acheived using lower height pistons and the common cam pulley arrangement is a #3 inlet cam pulley with a #2 exhaust cam pulley. It appears that the #3 pulley was used to improve power delivery and help make up for the loss of power due to the cat and lower compression ratio.

 

Higgy.

Edited February 13, 2007 by Higgy

[SweetBadger 91]

Both MI engines I've owned had #4 exhaust, #2 inlet when I got them but the heads had been off at some point in their lives so I can't be sure if thats how they were from the factory.

 

When I had standard cams I preferred #2 on the inlet, the engine didn't want to rev with #4 on the inlet but that was with 0.8mm skimmed off the head so a considerable rise in compression ratio don't know if that had anything to do with it.

 

I've since fitted a Catcams inlet only camshaft and preferred it with a #3 pulley on the inlet - absolutely flew still pulling hard at the limiter untill i bent some valves due to a gravel trap and no cambelt covers! I've replaced that head with one that's got straight valves, only had 0.15mm skimmed off it and it feels preety flat at the top end now so I'm going to try a #4 again when i get the chance.

[taylorspug 7]

Both MI engines I've owned had #4 exhaust, #2 inlet when I got them but the heads had been off at some point in their lives so I can't be sure if thats how they were from the factory.

 

When I had standard cams I preferred #2 on the inlet, the engine didn't want to rev with #4 on the inlet but that was with 0.8mm skimmed off the head so a considerable rise in compression ratio don't know if that had anything to do with it.

 

Exactly the same as i found, only as ive said i had regrinds.

[Higgy 0]

SweetBadger & taylorspug, I have just checked my other Mi16x4 engine and that also has #4 on Inlet & #2 on exhaust.

 

So both of my engine are like that. And the info I sourced from the Citroen 16V site also agrees with this.

 

So, I would say factory spec where a #4 is used, is to have it on the INLET cam.

 

Martin@PRD's tests show that #4 on the lNLET give better 'on road' performance, therefore matching up with what Citroen/Peugeot would want to achieve. Its not like they never dyno'ed their engine to find out whats best

 

Most likely situation on your engines is the cam pulleys were taken off at some point and not put back on correctly, or people were trying to get an extra 4BHP at max rpm so swapped them around

 

Higgy.

[taylorspug 7]

In that case, take a glance at this topic then, where the majority of people with standard motors have 2 inlet and 4 exhaust, and the topic starter is having the same issues with that setup as i was...

 

Cam pulleys

 

None of this changes the fact that my car couldnt pull the skin off a mouldy turd with a no.4 inlet pulley. No top end power, refused to rev, thats not what an MI is all about. And what the hell is the point in having torque or whatever at 3-4k as when im having a tear up my motor spends most of its life firmly in the top 2k of the rev range anyway.

 

Fair enough if Martin has tried it and prefers it that way, everyone is different, especially in the way they drive so im not knocking what he has personally found in any way. But dont comment and effectively tell me im wrong if you havent even given it a go, which it doesnt seem like you have.

 

Try it yourself, you may be suprised.

[Higgy 0]

But dont comment and effectively tell me im wrong if you havent even given it a go, which it doesnt seem like you have.

 

Whoa there, chill. Sorry if I offended

 

Its just I like to know definates and facts (its how I work as an engineer). Its helps destroy old wife's tales.

 

I'm more interested in what was from the factory with a standard Mi engine. I cant believe the factory knocking out Mi engines did not have a proper quality control system and some had #4 on the inlet and some were on the exhaust.

 

Things are done for a reason.

 

Both my engines have it on the inlet and the article I posted earlier agreed. You and Sweetbadger (+ many others) have different experiences. Like I said before things are done for a reason, the factory should have not assembled engines 'willy-nilly'.

 

So what do we think/know? Engines are random or in previous engine work they have been re-assembled incorrectly?

 

I would like it if we 'myth busted' all our 205 old wife's tales and listed the facts. Although what we would then talk/argue about

 

Higgy, just pawn in game of 205 life.

[taylorspug 7]

That thread i posted has evidence that suggests engines were coming from the factory with 2-inlet 4-exhaust (as in pretty much everyone involved in it believes this to be the factory setup). Some of that information in there was gathered from the BX forum aswell!

 

...The cam pulleys are numbered and there seem to be several factory combinations - The most common variations seem to be the early engines using a #2 exhaust cam pulley and a #4 inlet cam pulley this later changed to a #2 cam pulley on both the inlet and exhaust cam. The combination of #2 and #4 seems to give the more harsh power delivery often noticed with the mi16 engine.

 

Now i reckon they have got it mixed up here. They are saying that the 4 inlet and 2 exhaust setup "seems to give the more harsh power delivery often noticed with the mi16 engine". Well surely with the experiences posted (ie Martins, mine, Sweetbadgers), that setup should give alot more 'linear' power delivery over more of the rev range. The harsh power delivery setup is 2 inlet 4 exhaust, as i have found. You lose out alot lower down the rev range, but once 5-5.5k arrives all hell breaks loose. They have the 4 and the 2 in the wrong place in that article...

 

Bloody French...

[Higgy 0]

Some more hard info from the manufacturers:

 

Citroen manual on the 16 valve engine document XB 16 112-*a

 

"Fit the camshaft gear wheels (identical on inlet and exhaust)"

 

Peugeot manual XU9 J4 overhaul (dated Nov 1988)

 

"Depending on the emission standard, the gears are identified by the figure 2 or 3 engraved at..."

 

So from this I could easily see that mechanics working from older manuals would not even know there were #4 pulleys.

 

When did the Mi16x4 come out? Maybe Peugeot re-visited the Mi16 engine for this vehicle and came up with the #4 pulley. It then rolled this pulley out on all subsequent Mi16x4 & BX cars (as both have the hydraulic system to power).

 

Higgy.

 

Parts Cat on cams

[petert 550]

My Mi16x4 ('90, Motronic 4.1) has two #2 pulleys. From the CD it's obvious that early cars had two #2's and later cars had #4 and #2.

 

I have a Peugeot service document showing the physical differences between a #2 and #3. No mention is made of a #4.

 

I wouldn't get hung up on it. Put the one on the inlet best suits your driving style. What's on the exhaust is largely irrelevent as the flow of the exhaust ports is more than adequate for the standard state of tune. Too much in fact.

 

I find it interesting that many people put verniers on and report an improvement in performance. Surely because they've advanced the inlet cam, the same result as fitting a #4?

Edited February 13, 2007 by petert

[KRISKARRERA 2 1 Cars]

I had a late 1.9 Mi16 - June 1992 vintage (355 ecu) - and that was very breathless below that usual 4-5000rpm area. My current engine is from early 1990 (139 ecu) and is alot better at low revs than my old engine. Of course this could be due to differences in engine wear. Anyway Miles is doing my cambelt soon so maybe I'll be able to check what number pulleys I've got.

I think I read on the BX forum that the phase 1 BX16v was more aggressive low down than the phase 2.

[Martin@PRD 0]

Ahhh some interesting recent posts….

 

Are we forgetting about fuelling and ignition maps here?

 

For example standard mi16 from factory not tuned or messed with, lets say it’s later 3 row Ecu with 4 inlet 2 exhaust cam timing, as this is the same as the car in question I was referring with before recommending which pulley suited this car.

 

Again but more in detail

 

Fully Rebuilt MI16 (1000 miles or so), running unleaded 95, Non cat with 3-row Motronic Ecu with knock sensor.

 

10 thou shim to cylinder head, new lifters and standard cams

 

No2 Inlet, No4 Exhaust cam pulleys, (Originally found on the engine when it was removed from 405 (Sorry guys) Pre-rebuild was No4 Inlet No2 Exhaust pulleys)

 

Shortened inlet and re-angled exhaust manifold

 

Standard Gti exhaust system and back box (brand new)

 

Power produced 158bhp at 6750 rpm 123 Lb/ft at 6100rpm (going from memory)

 

With 4-5 more Bhp but at least 8 lb/ft lower than the average M116 on Mikanices rolling road, but from memory I do recall the Bhp line to be extremely straight as in terms of power delivery, no more power or “hunt” at 4 Rpm, power came to a stop with rev limiter cutting in which it didn’t seem to tail off before hand, so it would be interesting how much the engine would develop before the power max out with the removal of the rev limiter, which I was lead to be know was not possible with Motronic?

 

I was not trying to say the first set up was lacking power, but midrange, idle and max torque (sorry if it cam across that way) but the car does feel a considerably quicker from 2k to rev limiter and through out gears after the pulley change, hopefully more power can be achieved after an hour session of tinkering with Afm on the rolling road, but I try and ask for a power graph before this as well.

 

Can anyone clarify the 4x4 features?

 

1. Doesn’t the 4x4 Ecu have a higher rev limiter of 7250?

2. Are the cam pulley or more importantly the fuel and ignition map differ?

3. Does it have different camshafts (is it more lift or duration?)

 

If all of the above is yes, then there is a reason for differant cam pulleys from factory

 

Going back to what I was outlining before about fuel, ignition maps and with the rebuilt engine again (which I hope can further explain with a new power graph :$) lets say it has more power throughout the rev range found with the original Cam timing found on 405 was true, with this I’m fairly confidant the fuelling, ignition or possibly 4x4 cams plays a big role here with regards the lack of midrange with 2 inlet 4 exhaust set-up

 

Looking at the link to “cam pulleys” in talyorspug’s last reply, it seams the 2 inlet and 4 exhaust set-up has better results but this is using Carbs which does in turn remove the crapflap which helps achieve slightly better induction e.g. Top end power, has different ignition using the 8-Valve distributor set-up (Can be advanced to develop top end power, but with sacrifice of the low end and mid range power,) and with no rev limiter or no vacuum advance function. This is a completely different set-up as I was explaining before this would love the extra overlap for top end rev range using 2 inlet 4 exhaust, but I strongly feel is wrong on a standard MI16

 

So breaking this down, same cam timing/pulleys on different engines don’t have the same results therefore require careful tinkering will be required, although as far as the rebuilt engine and its features/spec then I more than positive that the best timing has been found.

 

Oh just spoke to the owner on the phone; he’s going to email me a photograph of the rolling road results and hopefully a date for another hour on the rollers to compare results,

Edited February 14, 2007 by Martin@PRD

[taylorspug 7]

That would be interesting to see a graph. Ive no doubt the 4 inlet makes the car quicker from 2k to limiter, id totally agree there, i just prefer it the other way as im never really at 2k! Also the car you are talking about has a shortened inlet on it, which would also not be helping bottom end grunt. I can certainly see why 4 inlet was a better option for that engine.

 

Yes the 4x4 does have a higher limiter, and the cams run more duration.

[KRISKARRERA 2 1 Cars]

How do we know for sure the 4x4 ecu had a higher rev limiter? The ECUs have the same numbers on them don't they?

[Baz 421]

How do we know for sure the 4x4 ecu had a higher rev limiter? The ECUs have the same numbers on them don't they?

 

Good question! The 4x4 one i have here is a '139, (2row) can anyone confirm that of a 4x4, and if they're 4x4 specific? I would check my other 4bie but it's not here!!

 

My new engine will be running 4x4 cams and ECU, with a #2 Exhaust and #4 inlet, as i was under the impression this gives a broader spread of torque with little loss of top-end, as i think this will be beneficial given the primary use of the car -Sprints. Will the fact that i'm using 4x4 Cams have any bearing upon which pulleys i should run then??

 

Come to think of it, should the 'box (1.9 with Mi final) also have any bearing on which pulleys i should choose??

 

Really confused now...

[petert 550]

How do we know for sure the 4x4 ecu had a higher rev limiter?

 

Because the tacho spins around more?

 

My Mi16x4 ('90 2 row) has two #2 pulleys and is all top end. It doesn't look like moving until it reaches 4500, then is strong as an ox from 6600 past 7000, where Mi's tend to fall off. I've been considering fitting a #3 pulley to move the usable rev range down a bit. It would be a lot nicer to drive in the heavier car.

 

I'd fit two #2 pulleys with the Mi16x4 cams if using the 1.9+Mi gearbox/diff. It will be great in the lighter car and you'll be able to keep it singing all day at 6500-7400.

[Higgy 0]

Doh!! No Myth busting on this topic

 

Looks very much like we will never know the truth of the pulley numbers.

 

Unless.... someone gets hold of the later Mi16 rebuild manuals.

 

So much for Peugeot's 'quality assurance', well that might be why they are at the bottom of the latest reliability survey The engines do seem very random from people are finding.

 

Regarding Mi16x4 ECU's, I will check the number of my 2-row one tonight and I'll try and read the 3-row one also, but its tucked up under the dash. I think the 3-row ends '355'.

 

My rev- counter is out so I can't check rev limit, it hits it about 6750rpm on the clock. Sorr has a nice fancy multimeter that measures rpm, so maybe we can sort something out to measure it.

 

Higgy.

 

(where are all the Peugeot engineers when you need them, don't any of them drive 205's and use the internet!)

[petert 550]

Here's a pic of a 2 row Mi16x4 ECU:

 

Here's a pic of the chip inside it:

 

Here's a pic of the pulley data. As you can see, there was no #4 at time of publication 09/88.

 

On my website, http://www.taylor-eng.com/xu9j4/16v_overview.html, I have provided the data comparing #2 and #3 pulleys. I'll add the #4 so there is no confusion about what happens mechanically.

 

I've tried various ECU's in my Mi16x4 - 139 stock, 139 Powerchip, 3 row 161 stock and 161 from a Citroen factory race car (currently fitted). The stock 161 goes to 7100, the two 139's go to 7400 and the race 161 goes to 7500.

Edited February 14, 2007 by petert

[gizzmo 3 1 Cars]

im no expert at all but im currently having my mi head refurbed and cat cams fitted so have both a set of bx and mi cams and pullys the engine being a bx d6c the mi no2 both inlet and exh the bx is the same both nos 2s but the bx cams have cast nos on them one is 291 the other 256 any one got any ideas what they are and which one is exhaust/inlet cheers

[taylorspug 7]

The inlet cam shouild have a notch on it to locate the rotor arm, where the exhaust one will just have a threaded hole.

 

Not sure about the casting numbers, would have thought they were just batch numbers?

[gizzmo 3 1 Cars]

thanks for that

[Martin@PRD 0]

Well as from last night which I hardly got any sleep with, I was confused over how 2 inlet and 4 exhaust gave more power at top end I was under the impression that it has more over lap but I was wrong (I hold my hand up)

 

For example no4 has more lift than no2 therefore is advanced, so using no2 on the inlet isnt creating a over lap but reducing it, therefore piston is further past Tdc before valve is open, cancelling the overlap effect and top end cylinder fill efficiency

 

No2 of the other hand needs to be used on the exhaust cam to retard the timing to create the vacuum in the combustion camber which then help boosts to drawing in inlet when valve is open at Tdc and so the piston can use its full travel to increase cylinder fill this all works far better at high rpm where pressures are up explaining the 4k kick the mi16 has, and why the graph was so flat with the 2 inlet 4 exhaust.

 

Peter, have you further increased the over lap using your off set wood ruff keys on 4 inlet and switching it round on 2 exhaust, affectively changing it to 6 inlet 0 Exhaust?

 

Dan, I do recall the 5.5k kick with your setting, but is power band of 5.5 to 6.750 a tad to short as max power is on rev limiter which cant be used so in theory 5.5 to 6.5 is only going to be used, I dont think a track is going to have every corner suited for your gear ratios to be able to use your short rev band rev band? Full out acceleration would be better, but again only with a short box eg 1.6

[taylorspug 7]

Running a 1.6 box on mine. Yes the power band is quite short, although its still useful enough from 4k onwards to not need too many gear changes on the back road blasts imo.

Edited February 14, 2007 by taylorspug