Where’s your comfort level?

Gaskets and bearings? Sure, those will all be new. Heads and cams? There just isn't a stock of NOS parts like this waiting for us all to begin engine rebuilds. Any parts like this will be salvaged/used if you need them.

But that wasn't my point. My point is that there could be marks on these cars that are completely unique to that particular engine build. Other parts will fit, but those marks will now be meaningless and need to be ignored. Perhaps that explains you mis-aligned marks.

 

Make -dead- certain that the mark that you have shown in your photo of the flywheel pointer is 100% indeed correct, showing TDC for your specific model.

I recall that these TDC marks can be at different places, before or after the "PM" mark on the flywheel, depending upon the engine model and market.

"Search" is your friend here, as there are numerous posts, with pictures, in the archives which illustrate these differences.

DM

 

That's tricky... Normally I'd pull the cam and run it thru camdoctor to get a lift@deg for a profile, but that's way outside most shops capability. The other is to measure lift and duration events, requires dial gauges and a experience doing that.
It's not a normal thing persay for a shop to do in the normal course of a rebuild. The owner would have requested it. Sometimes what happens is, hey since it's a full rebuild... Let's up compression by changing Pistons and then maybe regrind the cams with a hotter profile.. but that should have been documented, it would be reflected in the cost breakdown on parts and services. Cam regrinding for a qv is going to be a couple thousand...

The only common reasons I can think of that the marks are off would be:
Adv/rtd for performance reasons
Non stock cam profile
Incorrect timing setup.. Along the way..

More often then not... It's due to incorrect setup. Next is someone playing with adv/rtd and lastly custom cams.

 

So when the flywheel is in the TDC range, only intake 1-4 is on mark?

If so, I'd get the crank to an accurate TDC first. Then check the marks. Sounds like it was simply a case of lazy service that caused the cams to drift. I know many like the 'belt swap' option... I don't. Pull the pulleys, pins, replace the cam bolt 'O' ring.. set the cams to the marks, then get the pulleys and belts on with correct tension etc..
Yes it's time consuming and Bank 5-8 is a right PITA.

 

Correct, it would be the same across both heads. Nobody would ever use differing intake profiles in the same engine.

 

Looks good.
It occurs to me you might not be aware of this, if you rotate the engine "back" after passing TDC, the cams will not rotate... Yup, slack in the belt means the crank rotates but the cams will not. So if in the course of trying to find TDC if you go back and forth to get TDC the cams will not be moving in sync with every back rotation.
Which could explain some of the marks being "out".

If you overshoot TDC, it's round the bend again. Interference engines just make things so much more fun...

 

This is a good point.

 

Fair enough - my comment was not meant to question whether you've correctly aligned the index pointer to the flywheel line. Rather, it was to ensure that the particular line that you have noted is -indeed- the TDC mark.

Again working from memory, I recall that there are more than one such lines on the flywheel which are all sorta close to TDC. I was suggesting that you should be completely certain that 'your' line is actually the true TDC line for your model.

Me, I'd be tempted not to blindly trust the alleged TDC line, and I would verify it via the dial-indicator-down-the-spark-plug-hole deal.

Just my $0.02 armchair advice! - DM

 

First, while a QV is an interference engine, the interference is slight, so a couple of teeth off on timing will not cause bent valves. Second with the engine at TDC, if you lock the cams and removed the belts, then adjust each cam, one at a time as you say, so that the timing marks line up. Do not try to rotate the cams 360 degrees. Rotate them forward or backward that 1/4", as necessary.

Think about where the pistons are with #1 at TDC. 1 = just finished compression stroke, I and E valves closed. For 2 and 3, one will have just finished the power stroke and E will be partly opening, I closed. The other will just be finishing the intake stroke and I will be closing with E closed. #4 will have just finished the exhaust stroke and and I & E will both be slightly open (overlap). For the 5-8 bank all pistons will be at approximately 1/2 stroke. One cyl will be 1/2 through the power stroke and one 1/2 through compression, valves closed. For the other two, one will be 1/2 through intake (I opened) and the other will be 1/2 through exhaust (E opened).

P.S. You may not be able to get the marks lined up perfectly but for sure you can do better than they are in your pictured. After you get the new belts on, rotate the engine by hand in the correct direction and make sure the marks are OK.

 

The camshaft will "snap" rotate, if you move it too far by hand. To prevent this, loosen a cam bearing cap, and put a business card between the cap and the shaft. Then slightly tighten the cap. The card will give some friction to prevent the cam from rotating too easily.

 

Interesting; I haven't seen those thread... (post a link? I'd like to read). I can't imagine how you'd break a cap, unless you tightened far more than is necessary to just hold the shaft steady. One wouldn't tighten the cap ALL the way back to final spec... but again, I've never seen/heard this problem. I'm curious to learn more.

I suppose there are other methods that would involve holding the gear itself in place, using some sort of clamp or strap restraint. I've only done it once on the Ferrari, so never explored an alternative method. Interested to see what others will chime in with.

EDIT: Just searched a read a couple threads on this. The guys advising against the paper trick have done this a lot more than I have, so I'll defer to their advice. BUT, I'm still of the opinion that if it's done correctly (you DON'T tighten the cap down flush), the risk seems non-existent to me.