Cam timing...

For all Carb and Injection engines, standard or modified plus non-standard engine transplants. Heads; Blocks; Cooling (including heater issues related to the cooling system); Mounts etc

Moderator:Scirocco Register

Forum rules
Hints, tips and guides for repair and modification - the FAQ section on the main website is worth checking first for information relating to common faults and technical help. Useful posts and guides will be added to the FAQ http://www.sciroccoregister.co.uk/scirocco-faq
Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15
Cam timing...

Post by Brenjacques » Fri Apr 23, 2021 12:03 pm

Hi all

Had a mechanic out to do the valve stem seals on my 1.8 carb yesterday. Afterwards when started it was idling lower than normal so I adjusted the idle up and drove it home. I noticed it had a loss of power and a flat spot when driving back so I'm wondering whether the cam isn't quite timed up right.

I had quick look last night and I can't see the embossed dot on the inner side of the cam pulley. The only one I have on mine is a square notch stamped in the pulley below one of the tooth grooves. There is however a white dot stamped on the outer side of the pulley, but I don't think this is the one to line up with the head.

It seems like it must only be slightly out but can anyone help with what to look for, is the square notch/stamping replacing the stamped dot as normally seen on these pulleys? I've not looked yet but it is also possible to tell from the oil filler cap? I've had cars before where this has been possible but I've never done the cam timing on this one before so I need to check.

Cheers



User avatar
unknownmale
Posts:991
Joined:Tue Jul 23, 2013 2:34 pm
fill in the right answer:15
Location:London

Re: Cam timing...

Post by unknownmale » Fri Apr 23, 2021 12:16 pm

The white dot is likely just done by the last person who did the belt...Who knows what it lines up to. Go off the notch at the back of the cam pulley.

What carb do you have?

If it's down on power your most likely issue is the distributor is too retarded, or perhaps the vacuum line is disconnected for the vacuum advance, other potential causes could be your fuel mixture, or even what fuel you're using.

Now your valve stem seals aren't leaking you should play around with the mixture and timing anyhow


- David

Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15

Re: Cam timing...

Post by Brenjacques » Fri Apr 23, 2021 12:37 pm

I have the weber 32/34 fitted, it ran fine before the work was done, drove it there in the morning and it was as it should be - drove it home after and it had this problem. The ignition timing wasn't touched during the work so I think it should be fine in that area.

I was wondering whether fuel mixture could have altered but speaking to an old school tuner I know he said it's unlikely to have such a big affect, if any and he thinks it is more likely the cam being slightly out.

Re the white stamped dot on the outer side of the pulley, it definitely looks factory, very clean and tidy but I don't see any reference to this one, nor can I find any reference to a square stamped notch on the inner side that mine has.



Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15

Re: Cam timing...

Post by Brenjacques » Fri Apr 23, 2021 2:03 pm

Just had a quick look on my lunch, I'll check all of the timing tonight or tomorrow. Cam looks to be a tooth or two out and certainly not enough to cause such a big difference in running. Just occurred to me that it's possible the intermediate shaft has slipped a bit when the work was being carried out altering the ignition timing so I'll check the whole lot and set it all back up. I'm now pretty confident that the stamped square is to be set in line with the head.



mark1gls
Posts:3674
Joined:Thu Apr 02, 2009 9:28 pm
fill in the right answer:10
Location:Somerset

Re: Cam timing...

Post by mark1gls » Fri Apr 23, 2021 7:18 pm

You could be 180 degrees out when looking for the dot?

If you had to adjust the idle and it’s lacking power then the belt is a tooth out on the intermediate shaft as that moves really easily when fitting the cam belt.

Few options.....
get the chap back to put the cam belt on right.

Leave the cambelt and set the timing so it runs rights but next time you do the cam belt you may need to adjust the timing again if the belt goes on in the right place.

Not sure what year your car is as timing marks did change for later cars.

Info and pictures of my Mk1 Golf timing marks.
https://vwgolfmk1.org.uk/forum/index.ph ... sed-timing


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15

Re: Cam timing...

Post by Brenjacques » Sat Apr 24, 2021 9:48 am

Thanks for the help, I checked the ignition timing last night and it was quite a bit off. Adjusted it to the 6° diamond stamp on the flywheel and its more or less back to how it was. The cam is definitely a tooth of two out but I can do that over the weekend and re-check ignition timing.

Just a side thought, should the top cam cover have a bolt to secure the main body down towards the engine? Mine only has the two top nuts that hold it down to the valve cover and it feels as though there should be another to keep it away from the V belt as it's very close.



GT_II
Posts:318
Joined:Fri Feb 24, 2017 12:18 am
fill in the right answer:15
Location:Warwickshire

Re: Cam timing...

Post by GT_II » Sat Apr 24, 2021 11:11 am

Is it the metal or plastic belt cover? The plastic one has tabs to mesh with the lower cover -needs a bit of care to line up correctly. The metal one looks to have a large headed screw which goes through holes in both upper and lower covers, but others will confirm.


1992 VW Scirocco GT II 1.8 90PS Brilliant Black 30k
2011 VW Caddy Van C20 Startline 1.6 TDI 102PS 60k
2015 Skoda Yeti SE Outdoor 1.2 TSI DSG 105PS 30k
2013 Fiat 500 Pop 1.2 69PS 40k
2009 VW Fox 1.2 54PS 60k
2009 Smart Fortwo Passion 1.0 mhd 71PS 25k

mark1gls
Posts:3674
Joined:Thu Apr 02, 2009 9:28 pm
fill in the right answer:10
Location:Somerset

Re: Cam timing...

Post by mark1gls » Sat Apr 24, 2021 1:14 pm

The metal cam belt cover has a Allen key bolt like this holding the cover.

https://www.classic-vw.co.uk/upper-camb ... 8588-p.asp

The V belt (alternator belt) does run close to the cover and that’s normal as long as it does not touch it. There may still be a little plastic cover fitted to the metal cover in case the belt does touch it. You can see the plastic cover in the illustration just below the red mark.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

mark1gls
Posts:3674
Joined:Thu Apr 02, 2009 9:28 pm
fill in the right answer:10
Location:Somerset

Re: Cam timing...

Post by mark1gls » Sat Apr 24, 2021 1:18 pm

I’ve found changing my cam belt it either goes on 1st time and everything lines up or you spend ages moving the intermediate shaft and cam to get the belt lines up as when you tension the belt things move a little.
Once you think it’s all lines up turn the engine over by hand a coupe, of times and check it’s all lined up.

I guess yours will just be 1 tooth out as I don’t thing it would run a couple of teeth out.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15

Re: Cam timing...

Post by Brenjacques » Sun Apr 25, 2021 7:15 pm

Thanks all, mine is the metal cam cover so definitely missing the nut. Some searching has lead me to the right part number, apparently they have a rubber grommet too. Checking the mark on the cam pulley it's sitting just above the valve cover so I'll move it down a tooth which should bring it in line with the head.



mark1gls
Posts:3674
Joined:Thu Apr 02, 2009 9:28 pm
fill in the right answer:10
Location:Somerset

Re: Cam timing...

Post by mark1gls » Sun Apr 25, 2021 9:03 pm

Yes there’s a little grommet to stop the metal on metal rattle.

You can get a new one here or measure the size of the hole and try a local motor factors.
You could buy them from VW a couple of years ago as that’s where I brought mine from.

https://www.classic-vw.co.uk/upper-camb ... 8677-p.asp

If you do move the cam belt and have adjusted the timing on the dissy you will need to reset the timing.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

mark1gls
Posts:3674
Joined:Thu Apr 02, 2009 9:28 pm
fill in the right answer:10
Location:Somerset

Re: Cam timing...

Post by mark1gls » Sun Apr 25, 2021 9:06 pm

Looking up other places to get the grommet and found one of my old posts so may be out of stock at VW and classic vw seems the cheapest place to get one.

https://vwgolfmk1.org.uk/forum/index.ph ... lt-grommet


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15

Re: Cam timing...

Post by Brenjacques » Sat May 01, 2021 3:04 pm

Spent some time on the car this weekend after sorting a rubber grommet and nut for the cam cover. Adjusted the cam over a little bit and now it's spot on. When resetting the ignition timing I've left it slightly advanced as it seemed to be much smoother there but it's running nicely and has all of its power back. Just a couple of jobs to do now for the summer, gearbox flange seal (once I sort out a compressor tool) and some new pads on the front and she'll be good to do more long distance without a worry.



mark1gls
Posts:3674
Joined:Thu Apr 02, 2009 9:28 pm
fill in the right answer:10
Location:Somerset

Re: Cam timing...

Post by mark1gls » Sat May 01, 2021 9:32 pm

If you are using super unleaded the engine love a bit more advanced timing than the “by the book” timing marks if using a timing light, listen out for any “pinking” under acceleration just in case it’s to advanced.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

Brenjacques
Posts:109
Joined:Sat Jan 19, 2019 3:07 pm
fill in the right answer:15

Re: Cam timing...

Post by Brenjacques » Wed May 05, 2021 10:27 am

Yep it's running great now, it's not too advanced, the diamond on the flywheel just sitting next to the pointer on the bell housing rather than in line with it.

Next job is to get to the bottom of this rough starting issue it's had for a while. It's also quite hesitant to start when it's been ran for a while then turned off for 20 minutes or so. Noticed some oil in the distributor on the round plastic cover that sits below the rotor so maybe the problem is in this area.