1.9 Cam On 1.6

[lagonda 41]

So, after a lot of cleaning, dismantling etc, I finally get my head to the machine shop for skimming ... & they spot the head is cracked between the spark plugs & exh valve seats in chambers 2 & 3. Fortunately they had a reasonable spare head from a 1.9.

I know the heads are identical but the cams aren't. The 1.9 cam is fine but my original is starting to wear badly on one lobe (rebuilder says 1.6 cams do wear quickly) so putting that in isn't an option. Rebuilder says there's little difference between the 2 cams anyway.

So ... is that the case? Am I likely to encounter any problems running a 1.9 cam on a (standard) 1.6? I aim to use Puma Racing's settings for valve clearances. Will I need to time the cam differently on the belt or make any other adjustments?

 

Laurence

[Guest ashnicholls]

No, They will work the same.

 

Same timing.

 

Just as you say, the 1.9 cam does not wear as quickly as the 1.6 cam.

 

So will run alot better, and produce more power than an old worn 1.6 cam.

[Alastairh 47]

It'll work, James Turnell was running one for a while with his fancy head, although he did notice a slight difference in power.

 

Alastair

[j_turnell 134 3 Cars]

Depending on what your 1.6 cam is like but on my fettled head the power band felt very flat with a 1.9 cam and not willing to rev. Whereas once i put a good 1.6 cam back in i noticed an incrase in power and more free revving. So personally i wouldnt bother, try and find a good 1.6 cam.

[lagonda 41]

Depending on what your 1.6 cam is like but on my fettled head the power band felt very flat with a 1.9 cam and not willing to rev. Whereas once i put a good 1.6 cam back in i noticed an incrase in power and more free revving. So personally i wouldnt bother, try and find a good 1.6 cam.

 

Hi, thanks, seem to be getting conflicting info here!

 

Is it possible your tuned head would magnify a difference that would only be marginal on a car in standard tune?

[PumaRacing 1]

Depending on what your 1.6 cam is like but on my fettled head the power band felt very flat with a 1.9 cam and not willing to rev. Whereas once i put a good 1.6 cam back in i noticed an incrase in power and more free revving. So personally i wouldnt bother, try and find a good 1.6 cam.

 

How can a power band be both 'flat' and 'not willing to rev'? These are conflicting symptoms. Clearly all it points to is that the 1.9 cam wasn't set up properly as enough people have swapped them for it to be known that they aren't that different and both work fine in either engine.

[PumaRacing 1]

Am I likely to encounter any problems running a 1.9 cam on a (standard) 1.6?

 

No

Edited September 29, 2006 by PumaRacing

[lagonda 41]

No

Thanks for that! Looking forward to getting it back on the road.

[24seven 104]

from what I've gathered on this site the 1.6 and 1.9 cams are slightly different, with a standard 1.6 feeling less energetic running a 1.9 cam.

 

With the head being cracked, mine is in exactly the same state and if anyone knows of a good condition head (1.6 or 1.9, I've got a camshaft for it. if it needs a skim but isn't too far gone then it's ok too) going then I'm quite interested.

[pug_ham 242 3 Cars]

I recently swapped a a.6 engine on a friends car that had done nigh on 150k with dubious servicing until she got it 11k ago & even with the new engine in that has a rebuilt head fitted a few thousand miles ago with a 1.9 cam there is a noticable difference in response to tthe throttle & it doesn't seem as willing to rev & not as eager.

I remember the previous owner of the replacement engine saying that the cam & crank timing pins don't line up very well (nearly half a tooth out iirc) so I'm hoping to get the car for a day or two soon & check this out to see if its a cam timing issue, as this would explain the difference as I don't believe a skim of a few thou would make this much of one.

The strangest thing is that the SAD worked perfectly before the swap & doesn't now. All thats changed is the two coolant sensors in the back of the thermostat housing for coolant temp guage & warning lamp.

Graham.

[lagonda 41]

OOO - err ... let me know if you find setting the cam sprocket one tooth back/forward improves things!

[jim21070 2]

Slightly OT but does anyone have figures for the Duration and Lobe Separation Angle for a standard 1.6 and 1.9 8V cam?

 

The same figures for the standard Mi16 cams would be very intersting too.

 

I'm interested as I'm currently reading about cam tuning theroy for a bit of bedtime reading and would like to compare it with what I'm learning about cams...

[jim21070 2]

OOO - err ... let me know if you find setting the cam sprocket one tooth back/forward improves things!

 

One tooth back or forward amounts to a good few degrees of retard/advance and if the theroy I have been reading up on is true then that kind of deviation from design cam timing will make a tremendous difference. IIRC, one tooth out is gettig on for 12 degrees and that is a lot in cam timing terms. Hence the use of a vernier pulley to set it spot on when using hot cams on a performance motor.

[lagonda 41]

Yes, but if I'm getting the right impression, I'm going to find the timing marks won't line up, in which case I'll have to choose one tooth or another. If it's very close the nearest tooth will presumably be best option. If it's halfway, then I've got to suffer being 6 degrees out. Be interesting to hear how others have resolved this.

As already stated, I'm planning on using Puma Racing's (narrower) valve clearances, which will of course also alter the valve timing to a degree. Ooo a pun.

[24seven 104]

found the same cam & crank issue when stripping my 1.6 engine. the tensioner was far too slack effectively advancing the camshaft 1 tooth (or however many degrees that equates to).

[pug_ham 242 3 Cars]

Yes, but if I'm getting the right impression, I'm going to find the timing marks won't line up

The timing marks will line up but the belt won't fit as smoothly as normal imo.

 

You'll still fit the belt with it as tight as possible on the front run between the cam & crank pulley so any slack is taken on the by the tensioner when released with minimal movement between the two pulleys.

 

I'll know more when I've checked it for if its that far out but I'll try to find out how much was skimmed from the head as well. Even a big skim shouldn't change the distance between the front pulleys by that much imo, certainly not a tooth anyway.

 

Graham.

[jim21070 2]

I'm surprised that a small skim should make such a difference but anything that changes the spacing between the crank and cam sprockets is going to upset timing because there is no second tensioner on the "pull" side of the belt to compensate. If the error is not too big then put the belt on the tooth that gives a slight anti-clockwise error (cam retarded) so that as the engine warms and expands the timing error tends to reduce.

 

The only other way to correct the error (except to use a vernier pulley) is to use an offset woodruff key on the cam sprocket. It is not impossible to make an offest key as it does not need to be made of hard material. It is for accurate location and not the transmission of torque. Torque is transmitted via the friction between the sprocket and it's bolt.

[GLPoomobile 958]

This is of interest to me but I wish someone had a definative answer.

 

I swapped to a 1.9 cam recently and found the timing belt to be a complete bastard to get on (someone mentioned issues above). Firtst belt I've done so assumed it was normal. I have a running issue that I can't describe, but think it may be the inlet manifold blocking the injectors slightly so forget about that for now.

 

I noticed that the car seemed as fast, if not faster than before, but consideing the 1.6 cam has some wear and it was burning a s*it load of oil before, not surprising.

 

Problem is I need to get my valve clearances sorted and I'm thinking of paying to get it done as I just can;t be bothered anymore. So do I keep the unworn 1.9 cam and get the clearances done, or do I get a new 1.6 cam and then get them done?

 

The other factor is that part of me thinks I'll never know the difference as I'm not that well 'tuned in' to my cars performance, but hate the thought of throwing money at the car and not having the best out of it.