(Engine knock) Okay.....timing checked.

[jinjur]

Right, so based on the knock detection issues that I have been having in this thread (which was closed by someone)

I have been directed to look at:

• The engine timing following a main dealer belt renewal
• Engine mounts possibly causing fale knock signal. Henk thinks the p'flex dogbone may contribute
• Knock sensor being faulty

So, first port of call, I was going to ask Cro to do this but a couple of Stella's in me tonight and I had the dutch courage, so I pulled it to pieces (Sorry mate)

With a 7mm drill bit locking the crank this was the view on the cams:

View attachment 52275

So I think they are in fact pretty much on the money.

So I am still left with a power run looking like the following:

View attachment 52276

Following the purple curve (Knock Signal), you see a huge spike at ~5500rpm and then the blue curve (Knock Correction) hits the ceiling.

Not such a big deal on the standard map although you can feel it holding back.

But when its remapped, its flat as anything top end and really struggles to the red line

Next stop will be to disconnect the Knock Sensor tomorrow for a back to back run to see how it feels. If that is just a £30 part and it feels better doing this ill just replace it.

The last suggestion of the mounts worrys me, im not exactly sure how to remedy that. The benefits of having the p'flex fitted are well documented and all the upper g'box one was replaced with OEM. The upper engine and lower gearbox are probably a bit tired but thats all.

Any and all further advice and thoughts appreciated.

Wouldnt mind seeing another 172 live data capture, 3rd gear 2k-limiter to see how the knock signals etc look there too.

Thanks
Andy

 

[Fred@BTM]

that cam timing is out slightly, you can see it on the inlet cam, its 8mm to lock the crank too by the way

you checked plugs, leads, injectors?

 

[jinjur]

Ahh, I didnt know what size exactly......was doing this all on my own and it was difficult to get the bit in at the right point and turn the wheel to get tdc etc.

Surely such a micro amount wouldnt cause pinking Fred......there is also potential that my Stella hand may not have been the straightest. It did look on the money I think.

Plugs are just new, made no difference. Correct NGK items used.

Leads seem fine. All I could do was a pitch black running check to look for any arcing....didnt see any. Did note that revving the car up to around 5500 and above that it almost feels like its out of balance. Could this point to leads/coil pack too? Is it likeley that it starts to show breaking down first at higher revs?

Have not looked at injectors Fred at all.......didint think they were an issue on these. Car has 50K on the dials and runs fine the rest of the time albeit for a minor thrum or pop from the exhaust at idle, which I thought was standard fare on these

Andy

 

[Fred@BTM]

did you check TDC at the gearbox end by looking at the flywheel through the inspection hole? i've seen dealers (amongst others) stick the pin in the wrong hole

 

[jinjur]

No........

But if the wrong hole completely was used Fred, would the thing not idle like a dose?

A

 

[Fred@BTM]

will be flat as f**k to drive

 

[jinjur]

Ach FFS......you have me doubting myself now Fred

 

[Fred@BTM]

don't worry TBH i doubt it would make it knock that much

where you based? i can post you my "spare" timing tools and you can check it properly then

 

[jinjur]

Dude.....Belfast.......

Very nice gesture though. I might "fashion" my own

Ultimately, if i lock it with teh drill bit, CHECK THE FCKIN GLORY HOLE and then check the cam alignment........that has to be that. Bear in mind.......it took these guys (Main Dealer) 2 days to do this.......after that, I had the "its not right" thing going on in my head. I sent it back and they checked it and ASSURED me it was fine. I then had it RR'd and it seemed ok.

Cant remember quite why I didnt think it was right............there was something, just....well I think it drove a bit different. You know.

Right now, it is a bit flat.........then it hits 5K and goes boogaloo. Wouldnt mind a wee head to head against a std one to see.


Tbh....I may go for the knock sensor anyway for £30

Andy

 

[Setone]

View attachment 52275
Andy

Are the two rubber caps you have removed to show the end of the cam shafts, re-useable?

 

[Fred@BTM]

sounds sensible, posting to Belfast can't be that expensive?

 

[Fred@BTM]

Are the two rubber caps you have removed to show the end of the cam shafts, re-useable?

no

 

[jinjur]

sounds sensible, posting to Belfast can't be that expensive?

Probably not mate but im off on holiday next Tuesday so with our "special" mail service in NI, theres a fair chance I wouldnt get them returned to you before I go, you know.

A

 

[Fred@BTM]

they're just a back up set anyway, doubt i'll need them

 

[jinjur]

Maybe overkill chap as I am only going to be checking......if i do get an inkling even from my basic check, it will be straight back at that dealer.....

Unless you think that my ghetto skills would be accurate enough?

Appreciate that the tools are THE accurate way but as there is no chance on earth that I will be changing the timing I might leave it bud, again....sound offer...cheers.

Might take you up on it in the future though, if i get ADVENTUROUS....lol.

In the meantime, 8mm..........locked.....and what am i looking for in the window. Green mark to the left?

If the cams are out by an ants pube would it make a big difference? Enough to cause pinking?

A

 

[Fred@BTM]

see the line with the 0?? in front of that on the flywheel is a machined line you can just about make out, they line up = TDC

 

[Darr3n88]

JinJur, I'm based in Belfast and have the timing tools here if your needing to check it over or whatever would save Fred having to post them over. Where on Belfast are you?

 

[jinjur]

Hey chap......I work in Upper Crescent area of Belfast.....up near the globe.

Sorry it took so long to get back on this.

Had the not so minor issue of replacing a turbo on our E91 BM. bad times.

J

 

[Darr3n88]

Thats cool. Im sure that was an enjoyable task. How come you never fitted the belts yourself then? If your wantin to check the timing and not reset it, you can borrow them no bother. Only thing is i dont have the pulley locking tool.