Verifying Procedure: Valve Shimming for 328

I just did a valve adjustment on my 328. I took the camshafts out, but supposedly you can change the shims without removing the camshafts. The Ferrari manual shows a pair of tools used and I've also read (on FerrariChat I believe) that you can get them out with a quick shot of compressed air. The rest of your procedure sounds fine. Definitely mic the shims, both old a new. Then recheck the clearances with the feeler gauge once everything is reinstalled. Two tips: find a metric feeler gauge with fine precision, and find a good metric micrometer. The gauges set up for English units don't have the metric precision you'd like. And I used an English unit Vernier caliper which really wasn't precise enough.

My biggest advise is to avoid taking those camshafts out. That was some tense moments. And my buddy dropped a nut from one of the caps into the oil duct that runs down into the crank. Luckily we fished it out of the oil pan.

 

+1... I'm sure the original Ferrari tools are expensive, but T Rutlands has repros available for $100 or so per set. I got these, before I decided it was easier to just remove cams anyway At least once engine is timed and I take final lash measurements, I can change shims again if necessary without removing cams again

 

These two tools are what you need. One can be made easily, the other can be bought (I made both though). The ruler is for scale.

The screw driver thing is used to depress the shim bucket down, while the hook thing is crammed in between the bucket and the cam shaft to create a big space. now, with a automotive dental pick, you pry up on the shim and it comes out.
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A little advice, If you remove the cams, remember that the camshaft upper bearings has a guide that sometimes follows the upper bearing when you remove it, this little guide is critical, if you turn it upside down this cause a failure on the whole camshaft bearing, dont ask me how i know, the guide is bigger at the bottom.

Check the guides before the camshaft is in.

/Patrik

 

step by step with pics - - enjoy

http://www.ferrarichat.com/forum/showthread.php?t=199409&highlight=cam+shim

rgds, Vince

 

It was easier to get shims out with the cams removed. But you certainly then need to adjust valve timing on the engine when reinstalling the cams. I wanted to check and adjust (if necessary) the valve timing on the engine anyway, so it was a no-brainer for me. I'm still glad I have the tools to do it with cams in place.

 

I was advised by a reputable independant fcar mechanic to take 3 seperate measurements (spinning the engine each time) on the gap of each valve in order to avoid any anomolies that may occur from a single measurement.

Before I did my adjustment my mechanic, who has 308 experience, said the valve noise was to quiet. Once I measured the gaps, sure enough several were too tight. Once back together,and adjusted properly (done by me) the same mechanic immediately said that sounds better. There wasn't a huge increase in noise but there was some and to his trained/experienced ear it was now normal. So to answer your question, if you have valves that have too little gap, expect more valve train noise, but really nothing obtrusive. If you have gaps that are too wide you may get a quieter engine once properly adjusted.

I don't know about the 4v but the volvo 240 series shims worked fine in my 2v.

Someone here mentioned a rogue nut down an oil journal....I had a rogue cam cap washer that took me 45 mins to find....advice...place a clean rag(s) to cover all oil journals and sparkplug holes, take your time and be careful. I don't know about the 4v but in removing the cam caps there was a "sweet spot" on the cam rotation where there was the least upward spring pressure on the cam caps which allowed for pretty easy removal with unbalance pressure on the cam. This requires a knowlede of where your pistons are in each bank so as to avoid contact with the valves.

Once again on the 2v the cam caps are dedicated to their saddles and the specific position on thier saddles, so mark them for location and orientation before removal. I found out that on the 2v the factory has done this for you by stamping numbers on the end of the cam caps which correspond with a number on the head. Don't know if the 328 or qvs have this or not. Anyway, wish you well and don't be shy about asking even seemingly stupid questions.

Good luck.

 

Anyone get the shim kit?
Can't help but wonder if you found you predominately needed one size shim or one size up or down.
Better off buying a few packs of four or the kit, in your opinion?

 

Because the 308 is a flat crank engine, each bank is a typical 4 cylinder inline engine. When the engine is on #1 TDC (#4 is also) all FRONT bank pistons are midway in thier bores and safely away from any possible valve contact. Once any of the cams are out of any bank, all valves on THAT bank are fully closed and therefore completely safe. So idealy you only need concern yourself with the REAR bank as long as your on #1 cylinder TDC, the fronts are all out of the way. Also, because it has two seperate timing belts, the FRONT bank can remain camless (and therefore absolutely safe) while the rear bank cams and initial valve timing are set up. As to a sweet spot, its about 1/8 turn of the cam in either direction from a point where any lobe has a valve completely open.

For example, to disassemble (cam covers removed) I put motor to TDC #1 and remove both timing belts. I then remove the front cams. I start by carefully rotating the cam to a balanced position, your "sweet spot" and I then remove that cam. By placing the cam between lobes, it is not opening any one valve fully, but two partially and simultaneously. This better allows loosening the caps without putting undue strain at any particular point. On the rear bank, I next rotate the motor away from TDC a little ways, and repeat.

I reassemble in basically the reverse order, noting the following. With the engine turned slightly away from TDC #1, I install the REAR bank cams with them rotated off thier marks slightly, balanced over thier lobes same as removed. Once the cam caps are all down, I rotate both cams to thier index marks, and then rotate the engine back up to TDC and install the belt. With the cams out you can remove the belt sprocket bolts and pins and clean everything up. I put the cams back in with the sprocket bolt finger tight and no o-ring. That will all be put right after the cams are re-indexed with the degree wheel. Once the rear bank belt is on, I turn my attention to the front bank. Remember, with the engine on TDC #1, the front bank is safe from any contact.

Another issue is particular valve clearance. I generally pick between min and max, so (for example) on a setting which says .008" to .010", I pick .009". You dont want it tight (less than .008"), because as the engine gets hot the clearance can close up and can lead to a burned valve. You also dont want to go too loose, (beyond .010") because this can lead to excessive wear, and in the case of a 308, flipping out a shim. Also, in rocker arm engine's, loose clearance can allow a pushrod to jump out. Other factors to consider is that tight valve's run hotter as they have less seat time and are harder on the springs, but cause longer cam timing duration and give a bit more power. Loose clearance allows cooler valves, is easier on the springs, but offers shorter duration and less power with more noise and wear.

So in this case, I pick .009" (the obvious happy medium) and I use .010" feeler as a no go. If you check clearances before cam removal, you can reset different shims as needed before cam re-installation.

 

Thanks Paul,

That was one of the most lucid bits of advice i have seen on the adjustment process. I recently did a cam out, (so i could do the seals) valve adjustment and did a couple of measurements on each lobe because i was coming up with tight and loose .008s and tight .0015s - scary.

The sweet spot bit would have helped the anxiety of loosening the caps.

I was a bit anal about counting the washers and nuts and being methodical about the removal process, but screwed up the replacement process, not paying attention to the orrientation of the caps - I got them in the right order but the orientation was wrong and the cam wouldn't turn.

On rechecking the clearances after the cam and seal replacement, i wasn't happy with a couple of shim clearances, so i went back to the old Fiat shims, (that i borrowed from a couple of mechanics that used to work for me at a dealership) and shuffled a few to get good numbers. The process isn't super precise. It is nice to have some shims to "get it right".

Thanks, Paul,
chris

 

This last car had clearances all over the map. I had some exhausts as loose as .024", a couple as tight as .006", one intake as tight as .004" and a bunch past .015". But the cool part was that I was able to swap the the shims around enough that I only needed two.

I have taught myself to be more concerned with equality that the physical number. Same with valve timing, making all four cams sync with each other makes the motor smoother. Making the clearances all match does the same. And then when you sync the carbs and dual ignition, it all comes together like a finely tuned instrument. Which reminds me.

Ive never seen it discussed anywhere on this forum, nor anywhere with Ferrari, but Modena is only about 10 miles or so down the road from Cremona, the home of Antonio Stradivari
. Cremona is also along the Mille Millia route. Interesting how both men's products are known so much for for both sound and beauty.