Picture Please

I need a picture of an engine at TDC (Compression Stroke) that also shows the cam lobe orientation.

I am LOST.

SOMETHING just doesn't seem correct.

Thanx in Advance.

 

I don't have pics of all 4 cams + the crank at TDC... but what sort of problem are you having?

 

there's a notch in the 1st cam cap that matches a mark on each cam when at TDC

 

The cam cap and cam strike marks are great starting points as BillyD points out.

 

Don't panic there is no reason to feel lost, this is very simple. There is a mark on the flywheel labeled

PM 1 °4 |

Align the pointer with the vertical hash mark after the "4" and you will have #1 at TDC. Each cam has a single hash mark that will align with the corresponding mark on the first journal cap as shown above. That's all there is to it.

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On a US 328 that is almost impossible to see.

Lester

 

Afternoon Mark,
My 328 is US specs. #1 like in the picture, and all 4 cams with the marks aligned, that is caps with cams. I suppose you have the covers off.

John.

 

"almost" being the operative word here, You have to do what you have to do to see it. It's not any harder than seeing the hash marks on the forward bank cams. My harmonic balancer has a mark on it that is straight up at 1-4 TDC but there's no pointer, it's just an "in the ballpark" kind of indicator. The cams also have external marks that align with pointers on the cambelt cover backing plates but they aren't easy to see either.

 

Guys,

Thanx for all the responses.

My car is an '81 GTSi, NA version.

I am indexing my cams. Trying to get each under +/- 0.5 degree.

All my assembly marks (caps & cams) 'line-up' more or less as all cams were initially +/- 6° or less out, on the crank. That's fixed to +/- 1.5° each or less. Ill mod the pins to get rid of the remaining degree errors.

Piston 1 is at TDC.

I have been working this off and on for two years thru a few health issues.


My Observation and Question:

The lobs on Intake Cam Cyl #1 are sticking up in the air. They are Nowhere near touching the valve shim.

Am I looking at TDC of the EXHAUST STROKE?

Am I on drugs or ...?

Once in awhile I do confuse myself.

 

A couple of things: there is only one mark on each cam so unless you got them mixed up it's hard to make a mistake. The #1 intake lobe should not be anywhere near the shim at TDC of the compression stroke, it should be pointing out as you describe. Remember the cams turn half the speed of the crank and on these engines they turn the opposite direction.

 

And that could be it.

Just over-thinking things again.


Thanx.

 

Mark, I recall seeing a lot of discussion about advancing the USA exhaust cams by about 4 degrees to reduce the overlap to the same as the Euro cams-- which do you have? I timed my new CAT cams using the max lift points but I think the factory process was using opening point at a specific clearance (.050" I think.) I think there was also more ignition advance in the euro cars which helped.

 

Afternoon Paul,
On my engine the pointers on cam covers are "easy" to spot on the rear bank...almost impossible on the front bank. I take the cam covers off, because it coincides with checking the valve clearance.
Just a hint!

John.

 

Hello Mark,
I can send you a picture of my engine on Saturday, It's out of the car and cam covers are off, just to guide you where the cams have to be pointing. The only way to get it right is by having 1-4 mark on flywheel aligned with pointer on housing (just like the picture above) and cam caps marks coinciding with camshaft marks.
That's what the manual says and that's the way I do it.
I also tighten the belts like the manual says, that is, rear bank, with #1 on TDC on compression stroke and tension on the belt (applying pressure on the crankshaft with a socket and a breaker bar in the direction of rotation... clockwise from damper pulley). Front bank is the same, but now you must have #5 on compression stroke.

Keep in mind that this engine is looked at always from the flywheel side (not from the damper pulley side), with this said, starting from the flywheel, the rear bank goes 4,3,2,1 and the right bank goes 5,6,7,8.
Rear bank in the one closest to the back of the car and front bank is closest to the front of the car.

Don't want to sound smart, I learned this by reading the manual...ain't no genius

John.

 

There is no need to modify the pins. The stock system has an adjustment resolution of 1 deg increments (so the maximum nominal residual error is 0.5 deg), BUT you need to use the pin holes in the cam sprocket AND move the cam sprocket teeth relative to the (fixed) cam belt teeth (it's this second part that gets missed). Won't argue that it is an easy thing to do (and the reason why on later models they just added a bunch more pin holes in the cam sprocket and cam), but the stock 3 hole -on- 5 hole system, as designed, does support making 1 deg adjustments. The attached table shows how using the pins and skipping belt teeth gives an adjustment for every one degree position between +6 deg to -6 deg (for a total range of 12 deg which corresponds to the tooth pitch of the belt on the cam sprocket).

 

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Morning Mark, bad drawing, hope it helps.

John.

 

These engines are not typically accurately timed from the factory-- read that here on F-chat plus mine were out 3-7 degrees though that may have been old belts being stretched. Mark, which pulleys are you using as I know you've bought at least one set from me and those are easy to adjust. Anyone wanting to fine tune any pulleys can drill a 10mm hole and use my eccentric dowel pins/sleeves to make them adjustable 9 cam degrees (18 crank degrees.) Cost is £40 per set of 4. I now include them with the pulleys sets I sell (round tooth and square tooth.)
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Afternoon Derek!
That pulley is really fancy. It's made to fit a better belt than original, Right?
How much for a set of pulleys and belts? Just curious.

John.

 

£600 for a set of six pulleys and adjusters. Belts for the 2V motors are Gates T201RB, Gates 5352XS, Contitech CT821, or similar. For the QV and 328 you need Gates 920-8M-30, 5441XS, Gates Racing T288RB belts (or the generic part numbers: 40288, 95288, TB288, T288, B288, TX288, 11040142.)

 

Yep. It does.

Thanx.

 

John, please do send the pic. Need to clearly see all the cam lobe's positions but especially #1 and #5.

If you'd be so kind, with #1 at TDC on the Compression Stroke, and

Same with #5.

Bitte, Bitte.



Danke.

 

Derek,

Can you point me to this discussion?

My car has the North American (USA?) cams as it was distributed thru Ferrari of Vancouver, Canada.

It has the OEM NA/USA DIGIPLEX, I have a new/rebuilt spate set on the shelf and I also have a set of new/rebuilt Euro Boxes.

I'm replacing the old Exhaust valves in a couple of years and am planning on trying one of your pullie sets then.

Can you also post or PM all the various pullies you currently have. I was planning on buying two different sets as I recall. I 'collect them as I do gauges and other 'off beat' and NLA parts.

 

Steve, Thanx. Muchly.

But that has been my 'God Sheet' for the past several years of Off-&-On again work.

Appreciate you making it available.

 

Afternoon Mark,
Tomorrow I'll be playing with my engine, with #1 on TDC, you align ALL four camshafts marks with their corresponding cap marks. In the picture you will see in what direction the cams are pointing(all four camshafts). this will give you a very good idea on what you should be chasing.
Keep in mind that the picture will be taken from the flywheel side, OK?

BTW what does Bitte mean?

John.