Help with a Cam timing issue?

[Se7en172]

Hello, today me and my Uncle changed the cam belt and Aux belt! the changing of the belts was no problem at all all done finished. But we have definetley bollocksed up the cam timing. I have Schrick cams, and since the change the car does not come on cam like it did, and there seems to be more torque low down. But power delivery is the same throughout the rev range. Can someone help me on how the cams need to be set in order for the timing to be right again?

 

[Se7en172]

We used the cam locking tool but it is definetley the timing

 

[doh123]

So... same power as before but more low down torque. Seems like you guys did a good job. lol

 

[Se7en172]

No look carefully, The top under power is no longer there, but there seems to be more torque lower down!

 

[Se7en172]

When I say power delivery is the same, I mean the car does not come on cam, it just pulls at the same rate right through!

 

[ditz]

thats better then surely? different cams will have different charecteristics

 

[Se7en172]

No it's not better as it pulls like a normal 172 low down, and continues to do so up high!

 

[SkidMarx]

Did u re-check the timing after tensioning the belt and turning the belt while the pulleys were free floating??

 

[doh123]

Non standard profiles may need a different set up technque.

 

[SkidMarx]

No dont think so, they should use the same timing slots as standard surely?? Its just the profile thats different.

 

[sideways danny]

might be slightly off at a tangent but did you plug the de-phaser in ? Would have been unplugged to get access to the belt and pulleys by moving the loom

 

[lemonnobby]

did you pin the bottom?

 

[Se7en172]

did you pin the bottom?

Mike at Ren-tech said they are set up the same as the Renault ones!
Pin the bottom, please elaborate.

 

[SkidMarx]

Put pin in to lock crank. remove old belt. top cam tool in, with big D's to the top. New belt on. Tension belt with crank pulley off and top pulleys loose. Turn belt over one revolution. Tighten cam pulleys. tighten bottom pulley.

 

[Jamesstone]

The pin that locks the bottom end up

 

[lemonnobby]

yea pin that locks the crank up. plus you can get the cams 180 degress out. should be big top little bottoms

 

[Se7en172]

I'll ask this question whilst we are on the topic, why do some people say to look out for tippex marks when you have had the cambelt done?
I have always wondered this!

 

[Mark One]

did you pin the bottom, that is vital. Have you not got veneer pulleys?
Do you mind if I ask, where you got your locking tools and how much you paid for them if you did?
Your lucky you were working on a cup, i have AC to contend with

 

[SkidMarx]

Tippex is ok on some cam belts, but modern engines need to be pinned up and locked to make sure timing is bang on.

 

[lemonnobby]

tipex is ok on 8v engines mainly to highlight the marks already used by the manufacturer

 

[Se7en172]

Yes I did "pin" the bottom!

 

[lemonnobby]

did you have the cams right with big D's top little D's bottom

 

[Se7en172]

I think I know the problem. The Uncle Thought the top cam was loose and moved it (prior to tightening) So obviosly when he moved it he cocked it up! He said he only moved it about a tooth but Iguess thats alot in terms of cam timing!

 

[Se7en172]

Are they timed the same way as the Renault standard cams?

 

[lemonnobby]

how did he move it if it was locked?

 

[ditz]

yeah, you obviously arent following the timing procedure if thats the case

 

[avstar1]

I'm not an expert but it may have been timed with advance with one tooth ahead... Thats what we found with my car when i had cat cams...

 

[sideways danny]

I'm not an expert but it may have been timed with advance with one tooth ahead... Thats what we found with my car when i had cat cams...

f4r timing isn't done by teeth at all though

 

[SkidMarx]

^^ True that.

All the pulleys are free floating, so u cant change the timing by teeth really. The timings either right or wrong.

 

[avstar1]

Sorry... my bad.

 

[Se7en172]

By moving I mean he altered a tooth, God knows why? and I think that is the issue! Would this have messed the car up?

 

[ditz]

you dont understand the timing procedure mate, teeth have no relavence to anything the belt just goes on then timing is set on the free floating pulleys.

i'd imagine the fact that it wasnt timed up correctly (it cant have been given the talk of 1 tooth out etc) would have messed it up yes

 

[mini-valver]

The pulleys are friction fixed right. You dont need to undo the pulley bolts to do the belt so you lock them and just swap belts. If you wanted, you could turn the cams by the pulley, if you didnt undo the pulley bolts....

I've not changed a belt on these engines but that would be the logical way of it being out....

 

[ditz]

yes,,, but the cams are locked via the rear of them. so if the setting bar fits in the cams, it cant be a tooth out simple as that.

also, if you were to follow renaults timing procedure, it requires you to slacken both cam pulleys, fit the belt, tension it.. and rotate the belt on its pulleys whilst the cams and crank are locked to distribute the tension.

sometimes if you cant get the slack out of between the two cam pulleys you do have to slacken them off anyway

 

[mini-valver]

Ah right, I know what you mean! I thought they were locked at the front by the holes in the pulleys! Amateur!

Everydays a school day!

 

[sideways danny]

Your K4M is the same rear as dammit. Slighty different locking tool on the pulley end. but still uses a bar that slots into the back end of the cams and a pin through the block into the crank, to get them in the right place. Then you tension the cambelt with the pulleys fully loose so they can move as you tension the belt. It's a more accurate way of doing timing than with keywayed pulleys as it takes out the variance that deck height and head thickness can cause to the timing. Pain in the arse though lol

 

[mini-valver]

I know yeah, for some reason, I presumed te holes in the pulleys were for the locking tools!

 

[sideways danny]

ah gotcha. No there's another tool that locks the pulleys once the belt is tensioned by engaging in the teeth so you can tighten the nut and bolt rather than pinning through holes.

 

[Se7en172]

you dont understand the timing procedure mate, teeth have no relavence to anything the belt just goes on then timing is set on the free floating pulleys.

i'd imagine the fact that it wasnt timed up correctly (it cant have been given the talk of 1 tooth out etc) would have messed it up yes

Look ditz, I used the appropriate tools needed to lock the cams, pinned them down, loosened the belts ect. I have been in there since three times. I bet you when I take it to GDI you might even find that the cams are actually timed fine. I am no Mechanic that I admit (Self taught and all previous work I have carried out was successful), but seeing I had the assistance of a mechanic I think what was done is 'Almost' right after all the car is running with no issues ect the car does not seem to come on cam like it did. It's even been plugged in and no fault popped up! So whatever is wrong it is no going to blow my car up. The teeth on the cams are adjustable and when we first fitted the cam belt and aux belt and put the car back together it was reading a misfire 1,2 and 3 when we plugged it in, so we got back to the cams, he adjust the back cam as he said it was slightly offset (maye this was how it was supposed to be, I don't know, at this time I was not present) But he explained to me that he moved the tooth forward one as thats what it said it should be in the Big Renault book he has. Put it back together plugged it in, it read no problems, the misfire 1,2 and 3 had gone. Drove the car, not coming on cam properly? Thats what happend, and that is the way the cookie crumbled, don't bang onto me about not knowing the timing procedure properly as this has pissed me off enough as it is. Over these last 4-5 days I have learnt enough about cams and timing to last me a life time, and quite frankly it is starting to f**k me off.

 

[Se7en172]

Prior to even attempting this I put alot of research into the procedure as well, I would have never attepted this unless Iwas confident it was acheivable.