4.9L - Time saving tips for timing chain adjustments?

In order to tension the cam chains it is necessary to be sure the crankshaft is off top dead center so that none of the valves are being depressed by the cams. You need to remove the valve covers to check this. This also allows you to take the slack out with a screwdriver pressing on the chain before you move the chain tensioner. Once all the slack is moved to the tensioner sprocket the indexing pin can be moved and inserted by hand. This is also a good time to check the cam timing. When the chains stretch and the slack adjusted the cam timing will also change. I have found the marks on the cams are very accurate in the Maserati engins I have checked. To be absolutely certain you need to use dial indicators to confirm the correct valve openings at TDC.
Usually timing chain rattle only happens at low speeds and when the enging is cold. If you are hearing a rattle at 3000rpm it is likely to be something else

 

I'll only add that you make certain none of the cams on the bank you're adjusting are on the very edge of the lobe so that with the lightest movement due to a change in chain tension the cam can snap in rotation and whip a wave along the loose side of the chain. This can cause the chain to jump a tooth on the main drive. Very ugly stuff to rectify.

Make a good tool that's secure enough on the adjusting eccentric.

Some guys actually adjust these while engine is running, so I've heard anyway. Gulp!

 

Refering to the workshop manual, the tention is to be adjusted while the engine is running... But I would think the first reply here is a good one!

 

You are probably referring to the QP3 workshop manual.

There is an translation error in the workshop manual. The English text reads the engine should be running but the Italian text reads "AVVERTENZA - L'operazione non deve essere eseguita con motore in moto" which translates to WARNING - the engine should NOT be running.

It is a really bad idea to adjust the chain tension with the engine running !

Ivan

 

My Bora factory-printed manual says the tensioning should not be carried out with the engine running, but I swear I saw some version where the Italian said "should not" (or rather, non deve essere) while the English in the second column said "should". I'll check when I get home - it might have been in the photo-copied manual I have. I wonder if a mistranslation has led to the confusion.

 

While the engine is running........DONT DO THIS............Good Greif
Adjusting it while running will have it adjusting your wallet at lot more that you bargined for.

The cam chains on a Classic Maserati V8 engine run a torque of 1 FT/LB where as Ferrari run rediculios tensions.

It is very common for the older Maserati engine chains to loose some tension.
It is also very very important to do the tension correclty, The excentric unit has a large range of adjustment and generally only neds the retainer pin moving one hole.

the small pin in the adjuster has a 4mm internal thread right through and is sort off self extrating.

Read the hand book/manual and take you time.

Another word of advice is that to remove the cams, there is a split in the chain, that will eventualy come to the top at the same time as top dead center. up to about 7 revolutions from memmory.
Don't remove the nut on the from the front of the cam and then rely on the stamped marks on the cam and forward cam cap as they are only a general alignment assesmbly only.
So many early V8 maserati's have had the cam timming put way out by removing the nut on the cam and not the link in the chain.
If you do remove the nut, you will need to start all over again with the cam timing and you might as well do the shims while your at it.
The only accurate TDC mark in on the flywheel is viewed through the belhousing underneath the car and need to have a pointer made. You will need dial indicators on the cam buckets, If its you first time it is a very frustrating job. The result is well worth the perseverance.

Graeme

 

My main experience has been with Alfa (45 years) and the chain tension method is some what similar. As many times as I have rebuilt engines, tensioned chains, adjusted valves, etc I always turn the engine by hand a few revolutions to check cam timing.....NEVER do I just hit the starter.
Kindest regards, Ian (107-1202)

 

LOL, I forgot about that one. There a few real gems in the Maserati service manuals. The four valve engine service manual has some equally disastrous advice in a couple of places.

Got to keep your wits about you gents!

None the less I have heard certain persons brag about adjusting them in this manner.

 

Which reminds me - Ivan's right, it was the QP3 engine manual where I saw the error, but the reason I was looking there while working on a Bora is that the Bora manual illustrations for setting distributor timing (31 and 33) are for the wrong engine! I was a little surprised when I removed the front cover and the timing gear came with it.

This is the first Maserati engine I've seen in the metal. I now know not to believe everything I read.

 

The QP3 has some good pictures however there are lots of significant changes to the engine internals that will catch the unwary out.
Compared to the earlier V8's the bearing sizes and the valve seat angles are different to start with.

On the cam chain tension, Alfa and Ferrari use an spring loaded adjuster with a lock, the Maserati used a verniered eccentric cam, locked by a pin. As there is no spring

parts 21 in this diagram curtesy of Eurospares website

http://www.eurospares.co.uk/partTable.asp?M=3&Mo=712&A=1&B=42514&S=

Graeme