Author Topic: Camshaft timing out  (Read 1409 times)

Offline Hercplt

Camshaft timing out
« on: December 14, 2020, 03:15:40 PM »
Rather than resurrect my original thread, that started about Twin Carb needles and devolved into general engine problems... Seems more appropriate to start a new thread to continue the saga.

So, I spoke to the original engine builder (from 20 years ago) and as soon as I described my problems (low compression, lack of power, mis fire etc....) he immediately said "Sounds like your Cam timing is out by a tooth"!  Shocking.

I mean I have gone through everything but the cam timing.  Now that I have a dial indicator and base, a big ass wrench to get the crank bolt off.. I now have the timing chain exposed... good times.

So, I have educated myself on cam timing and how to dial it in... printed a degree wheel and low and behold... this is what I found.

VP7 cam spec sheet says that ATDC #1 inlet (max lift) should be about 103 to 104... mine reads 129!!
Lobe centre should be 106... mine times in at a whopping 127!!  And yes, I measured this several times...  :-[

At TDC the dots on the gears are nowhere close... 

So, I guess the next step is to set it up again... and see how I can reset the timing.  The Saga Continues...

BTW... how much movement (side to side) can I expect in the timing chain (no tensioner version)??  Seems like there might be too much slack...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline 94touring

Re: Camshaft timing out
« Reply #1 on: December 14, 2020, 03:19:52 PM »
Great find!  Good luck getting it sorted.

Offline BruceK

Re: Camshaft timing out
« Reply #2 on: December 14, 2020, 03:31:27 PM »
I like how the engine build expert knew right away what the problem likely was.   Learned that lesson by experience no doubt.
1988 Austin Mini
2002 MINI Cooper S
2007 Triumph Bonneville (just sold!)
1992 Toyota LiteAce (JDM)
1992 Honda Beat (coming soon!)

Offline MiniDave

Re: Camshaft timing out
« Reply #3 on: December 14, 2020, 07:27:31 PM »
Is this a pre A motor? A+ have a chain tensioner, early cars don't. Make sure you haven't sheared a key.

There will be some slack, but if there's enough to skip a tooth something is really worn out. Check for excessive wear on the cam and crank gears.

I always start setting the cam timing by aligning the marks on the gears, then use the dial indicator to set it where the cam mfr wants it to be. I use offset keys to set it when not using a vernier adjustable cam gear.

Another way is to get the cam in general starting position is to set the lobes on cyl  4 in rock, where moving the crank back and forth slightly will open and close both valves.

Remember, the #1 intake pushrod is the second one, the first is the exhaust .

Also, once you have the crank set at TDC using the dial indicator, recheck it with the dial indicator - don't just go off your pointer - after you've measured the valve gear settings before checking the cam position again.
« Last Edit: December 14, 2020, 07:34:42 PM by MiniDave »
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #4 on: December 15, 2020, 06:35:47 PM »
Definitely not an A+ (its 1979/80).

I think the chain might still be good, but I will replace anyway and see if there is a big difference.  As for the teeth on the gears, they are in mint shape, so I don't think they skipped at all... I think it was just a bad install when they put it together most recently.

On the plus side... I'm hoping to save some $ by doing this myself, and getting more comfortable.  I have another 998 that I may tackle as a rebuild project...

More to follow! 
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #5 on: December 15, 2020, 07:33:18 PM »
So it's been changed since the original build? Who did that?

You can't go wrong lining up the marks first and then seeing what it measures out to......

See if you can get an Iwis chain, they're supposed to be the best.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline gr8kornholio

Re: Camshaft timing out
« Reply #6 on: December 15, 2020, 08:07:24 PM »
So crazy this thread shows up.  Had a long conversation with Dave about this.  Question is was the motor out of the car and was the head on?
I am the GR8KORNHOLIO! Are you threatening me?

Saussie Aussie 1965 Australian MK1 Mini.
"Beavis" - 07 MY/MY MCS, B/MY Konig Daylites, JCW sideskirts, TSW springs, TSW lower rear control arms -- Exploring the country with new friends since 11/09.

Offline MiniDave

Re: Camshaft timing out
« Reply #7 on: December 15, 2020, 08:42:44 PM »
You can do it with the head on, just set your dial indicator on the top of the screw on the rocker arm.....
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #8 on: December 16, 2020, 02:30:00 PM »
So it's been changed since the original build? Who did that?

You can't go wrong lining up the marks first and then seeing what it measures out to......

See if you can get an Iwis chain, they're supposed to be the best.

I guess I should have been more clear.  The timing chain and gears were not changed when the engine was "put back together" most recently.  At the time we figured that it had low miles overall but sitting so long it needed new seals etc... I think they just re-installed the timing gears and chain incorrectly.  The motor was completely out and the body was restored.  I think the chain is ok... but cheap enough to simply replace it now on spec.

Right now the motor is in the car with the head etc off while I mess with the timing.   
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #9 on: December 16, 2020, 04:40:56 PM »
OK, so it's just a matter of putting it back together correctly and you'll be good to go.   77.gif
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #10 on: December 16, 2020, 04:47:18 PM »
OK, so it's just a matter of putting it back together correctly and you'll be good to go.   77.gif

Thats the dream...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline tsumini

Re: Camshaft timing out
« Reply #11 on: December 16, 2020, 10:31:33 PM »
Just curious, I'm not fluent im cam timimg or installation but i beleive it's a factor in setting valvees. My qyuestionn of the experts here is why wasn't the cam clocking apparent when  the valves were set?

Offline MiniDave

Re: Camshaft timing out
« Reply #12 on: December 16, 2020, 10:57:33 PM »
If you use the "rule of 9" method to set the valves, then no it wouldn't be apparent.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline tsumini

Re: Camshaft timing out
« Reply #13 on: December 16, 2020, 11:32:20 PM »
Yeah rule of 9 wouldn't expose it but TDC should.

Offline Hercplt

Re: Camshaft timing out
« Reply #14 on: December 28, 2020, 05:51:50 PM »
So, I have messed with the timing set up a bunch and now have it reset to time in at about 109 instead of the 106 that the VP7 needs... I need a 3 degree woodruff key...

Looking at the crank end from the front of the engine... which direction (left or right) would the key sit?
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #15 on: December 28, 2020, 06:18:05 PM »
You want to retard the timing, so the offset goes to the right as you're facing the front end of the engine. So, when the points align the cam won't have moved quite as far, retarding it.
« Last Edit: December 28, 2020, 06:20:07 PM by MiniDave »
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #16 on: January 22, 2021, 09:01:43 PM »
Ok... WTF.

I ordered a 3 degree offset woodruff key to time in my cam.  I presumed... it goes on the crankshaft??  but the key that came out of the crank is huge compared.  See pic.

Does this go on the cam as the offset to bring the timing back in?

If not... what the hell did I get?!

 8.gif 9.gif

EDIT:  Sorry... the pic is very large... not sure why...
« Last Edit: January 22, 2021, 09:35:27 PM by 94touring »
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #17 on: January 22, 2021, 09:29:07 PM »
The offset key goes on the camshaft....
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #18 on: January 22, 2021, 09:38:18 PM »
 :-[
huh... kinda feel dumb now....

Ok, so like you said before, its around 110 now, so add the key with the off set toward the right (looking from the front) and simply adjust the cam so the gear slides on remaining dot to dot (ish).... stop me if i'm wrong here...

Cheers...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #19 on: January 23, 2021, 09:13:14 AM »
yes. then recheck it.....start over from the beginning
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #20 on: January 23, 2021, 01:01:05 PM »
Got it!  Thanks...

Any tricks to getting the old key out of the cam??  Or is it a matter of brute force and ignorance?
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #21 on: January 23, 2021, 02:09:27 PM »
I use a pair of side cutters (dikes) grab it on one end and lever it up
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #22 on: January 24, 2021, 12:54:07 PM »
alright... not sure why, but now that I have everything set up... the best I can do with the 3 degree woodruff key is to get the timing in at 109...  I thought that I was at 109 already, but now that I have tried again with the new timing chain, the best I can do is 109... and I checked and rechecked.  clearly I needed a 6 degree key.

The VP7 cam says it wants 106.  My timing is still retarded by three degrees.

Question is, if I leave it here... what are the issues?  Calver article says that slightly retarded ends up losing down low, but gain peak, but then suggests that Minis like to be advanced slightly (maybe on the other side of 106?)

Welcome thoughts on the above...

Also wondering if I simply tried the old chain again... Its in great shape... can't imagine that would be an issue...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Offline MiniDave

Re: Camshaft timing out
« Reply #23 on: January 24, 2021, 01:29:28 PM »
If you're at 109, you're advanced, not retarded.....106 is retarded from 109 or 110 if I understood what you wrote. (it's possible I didn't my brain is a bit foggy these days) was 110 with the standard straight woodruff key in the cam drive?

Just for the experience of it, turn the woodruff key around and recheck it....it should in theory go to 112 or 113, that will confirm you had it in correctly. Don't skip a step, set it at TDC with the dial indicator on the piston, then set your degree wheel to TDC, then measure the valve lift.

You're measuring the intake valve at it's most wide open point at so many degrees after After TDC.....you don't want it open too soon or too late.
« Last Edit: January 24, 2021, 01:32:36 PM by MiniDave »
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Offline Hercplt

Re: Camshaft timing out
« Reply #24 on: January 24, 2021, 02:28:23 PM »
Thanks Dave.

However, what you say seems to contradict the following from Calvers website;

ADVANCED cam timing means that the valve events are occurring BEFORE the recommended point. Your measurement will therefore compute a reading LESS than 106. Generally this increases bottom and mid range outputs, but losses a little peak output. To correct this the cam will need turning counter-clockwise (anti-clockwise).
 
RETARDED cam timing means valve events are occurring AFTER the recommended point. Hence measurements and computations will give a value MORE than 106. Generally this increases peak outputs, but will lose bottom and some mid range output. To correct this the cam will need turning clockwise
.

If 109 is advanced, I think that might actually be ok... other places I've read, including calver, suggests being slightly advanced at the cam helps...

Thoughts?

1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!