My 1.6 8v Running A Bit Rough

[GLPoomobile 958]

I've finished fitting everything back after buggering about with my cylinder head. Basically my stem seals were shot so I cleaned up my spare 1.9 head as best I could, and fitted new seals etc. I used the 1.9 cam as the 1.6 looks a bit worn (only a short term solution though).

 

I had to use the old timing belt as I could not get the new one to go on.

 

However, although the car started no problem and will repeatedley start immediately, and will idle without dying, she sounds a bit rough. It sounds like she is only firing on 3 cylinders, but I have confirmed this is not the case by taking off each lead in turn. The engine is vibrating more than usual due to the rough running and you can here the put put put coming through the exhaust, sort of like an off-beat idle.

 

I have no idea how drives yet as need to get her MOT'd tomorrow.

 

The cam timing is spot on as far as I can tell (timing holes still match up after numerous checks) and I have tried altering the ignition timing too.

 

The only things I can think of are:

 

1 - Stale fuel - Have a couple of gallons of Optimax in the tank but it has been sat for 1-2 months

2 - Valve clearances - they are way off! Most of the inlet valves are about 0.03 over the specified tolerances but all the exhaust valves are way under at between 0.15 to 0.20 when should be between 0.35 to 0.45 (IIRC)

3 - Injector fault - when I removed the injectors from the manifold some of the yellow caps popped off. I carefully cleaned up the caps, O rins and ends of the injectors and re-assembled them. I took care not to touch the injector needles though. Could I have done anything wrong?

4 - Timing belt - although the timing seems OK, the belt may be too slack I'm getting a squeeking noise at low revs and I could twist the belt by about 90 degrees, but could not get it any tighter no matter what.

5 - Cam - would using the 1.9 cam cause this? Is the timing different. I thought not!

 

 

Any ideas anybody?

[ALEX 98 1 Cars]

The 1.9 cam is higher lift AFAIK.

If you're still using the 1.6 injectors it will probably be under fuelling

[jackherer 543]

  GLPoomobile said:

1 - Stale fuel - Have a couple of gallons of Optimax in the tank but it has been sat for 1-2 months

 

I've had problems with stale fuel but 1-2 months isn't that long. Is there much fuel in the tank? if not its probably worth putting a bit in to dilute it.

[GLPoomobile 958]

  ALEX said:

The 1.9 cam is higher lift AFAIK.

If you're still using the 1.6 injectors it will probably be under fuelling

 

Well once the MOT is out of the way I'll need to have another crack at fitting the new timing belt and sorting the valve clearances, so I'll probably just chuck the 1.6 cam back in. Unless the problem is resolved when I fill up with fresh petrol.

[ashlee205gti 1]

I fitted a 1.9 cam in mine without any side effects.

[bitchass 205 0]

doesn't the 1.9 have a sump spacer on the bottom so the cam can make a full rotation? It the engine is vibrating then that could be the case?

When i sold my old 1.9 i was told that the bottom end was a 1.6 because you could see that it had no sump spacer?

[ashlee205gti 1]

  bitchass 205 said:

doesn't the 1.9 have a sump spacer on the bottom so the cam can make a full rotation? It the engine is vibrating then that could be the case?

When i sold my old 1.9 i was told that the bottom end was a 1.6 because you could see that it had no sump spacer?

 

I would hazard a guess at that being because the 1.9 crank has a longer throw? It certainly wouldn't affect the operation of the camshaft.

[bitchass 205 0]

  ashlee205gti said:

I would hazard a guess at that being because the 1.9 crank has a longer throw? It certainly wouldn't affect the operation of the camshaft.

 

Yes,

 

After a little thought, and please correct me if i'm wrong, cam runs along the top of the cylinder head (ish) and crank rusn vertically?

 

So yes, it would affect the cam at all.

 

Edit

 

(walking out of the room with head down and tumbleweed blowing across!!)

Edited August 1, 2006 by bitchass 205

[ALEX 98 1 Cars]

A least your honest!

 

 

Though I had a 1.9 engine from a 405 without a sump spacer.

It had a deeper sump though.

[GLPoomobile 958]

I put a tenner of Ultimax in yesterday (not that a tenner goes far now!) and it is still the same.

 

It's not exactly rough, more of an uneven idle. Hard to discribe.

 

Hopefully it will back to normal when I put the 1.6 cam back in and sort the valve clearances.

[ashlee205gti 1]

  bitchass 205 said:

Yes,

 

After a little thought, and please correct me if i'm wrong, cam runs along the top of the cylinder head (ish) and crank rusn vertically?

 

So yes, it would affect the cam at all.

 

Edit

 

(walking out of the room with head down and tumbleweed blowing across!!)

 

 

Crank is horizontal.

 

I doubt its the cam causing the problem, theres not that much difference between the two, i've chopped and changed between 1.6 and 1.9 cams several times without side effects.

 

If it sounds like its missfiring then i would focus on the ignition and fuelling side of things. Maybe swing the ignition timing a few degrees either way to see if that smooths it out?

 

I had a similar problem with my old 1.6, i had a constant misfire and i couldn't for the life of me figure it out. Finally turned out to be a faulty HT lead.

[GLPoomobile 958]

I put a tenner of Ultimax in yesterday (not that a tenner goes far now!) and it is still the same.

 

It's not exactly rough, more of an uneven idle. Hard to discribe.

 

Hopefully it will back to normal when I put the 1.6 cam back in and sort the valve clearances.

[newdean0 0]

You said the inlet valve clearances were too big and the exhausts too small - I don't know much about this head never having taken one apart but you couldn't have got the shims mixed up could you? Running with exhaust clearance which are way too small will burn your valve seats and would cause the engine to run rough if the valve wasn't sealing enough so that compression was being affected.

[GLPoomobile 958]

  newdean0 said:

You said the inlet valve clearances were too big and the exhausts too small - I don't know much about this head never having taken one apart but you couldn't have got the shims mixed up could you? Running with exhaust clearance which are way too small will burn your valve seats and would cause the engine to run rough if the valve wasn't sealing enough so that compression was being affected.

 

I think I may have mixed up the shims, but only in the order of left to right, hence shim 8 my be on valve 1, shim 7 on valve 2 ect.

 

I suspect this must be the problem if other s have not experienced this when swapping to a 1.9 cam.

 

Drving home last night on a steady throttle at lowish revs in 5th, you could actually hear the engine making an oscillating thrum. You know the whoosh, whoosh, whoosh sound you get if you drive past a wall with regular gaps with the window open? It was like that but it was the engine note making the noise.

[ashlee205gti 1]

Sounds odd, if the shims are out by that much then there would be quite a noticable "tak-tak-tak" noise coming from the rocker cover area.

[GLPoomobile 958]

Yep, it is very 'tappety', but then it was before hand and my previous 205s were too! Will be interesting to see what t sounds like with the clearances sorted out and a properly sealed exhaust manifold as I've never had a quiet GTi. The ignition components can bit quite 'ticky' as well though, can't they?

 

Anyway, nothing will be done for a few weeks as I really need a break from working on the Pug, so I'll probably rake this up some time in the future when I have swapped back to the 1.6 cam and sorted the clearances.