Setting valve clearance on 308 2v

To check valve lash:

1) Insert appropriate feeler gauges (an assortment of the size range) into the gaps between the cam and the shim. Work your way up in sizes and find out which one goes until the next one that doesn't go. The last one that goes in is the clearance.

2) Whatever clearance that is, add or subtract the amount needed to come into the range specified in the manual.

3) Using special tools, depress valve, remove shim and measure it's thickness. Replace the shim with another one that is the right thickness according to your previous calculation.

4) Check new clearance and confirm if it's to spec.

Example:

Intake valves should be 0.20 to 0.25mm, yet you find one that has 0.30mm clearance. You remove it and it measures out to be 3.25mm thick. You would need a shim that is 3.30mm to 3.35mm thick to be within the spec range. I've always gone to the tight lash setting (ie: thicker shim) as it will wear a bit when running in, bringing it into the gap range.

Fiat twin-cam motors (as used in 124 Spiders/Coupes) and Volvo's (from 240 to 740) use the same shims as 308 2 valve motors.

 

The "0.5mm" is the recommended cam lobe-to-shim clearance when checking/setting the cam timing (as it gives the easily understandable result that the valve opening event occurs when motion of the shim is detected, and the valve closing event occurs when the shim stops moving -- although there are alternative methods that we like to argue about ). The "0.5mm" has nothing to do with "setting valve clearance" (which is what Peter described) -- are you interested in checking/setting the valve clearances or checking/setting the cam timing?

 

This is what I did. Measure existing gap, if it's ok, you're fine. If not, write it down, pull the existing shim, measure it (should also be marked but some people have been known to grind them down so I measure) do the math to come up with correct shim size that gives the correct clearance. If you don't own a huge collection of shims you can document where each shim goes and sizes and pull all that need adjusting then see if you can mix and match some you already have before buying. Someone in your area may have some lying around as well. They have a way of collecting in tool boxes or on shelves.

 

No, you want some lubricant present to protect the all the surfaces -- the lubricant film thickness is very thin so don't worry about it altering the dimension.

 

Tom,

When I set the valve clearances on my former '78 308, I was lucky and found that I only needed a couple of shims. I followed the recommendation here and picked up the shims from one of the known suppliers who sent me just the shims I needed. If you check the stickies at the top of this forum, you will find that their is an alternate source for shim kits. IIRC, you can use Volvo 240 shims and they fit perfectly, and a box of assorted sizes costs a fraction of a "Ferrari" labled shim kit.

Have fun and do report back on your success. Pictures always make for a fun thread too.

Steve

 

I also have a 78. I made the measurements twice in succession then based on what I decided I needed went to the Volvo dealer to buy the shims.

 

I've never come across two valves that have had the same thickness of shims. They've all been different.

I should also emphasize, that I mentioned the Fiat/Volvo source for shims, but the last time I went to several of my local Volvo dealers (in and around Vancouver, BC), none of them had them in stock anymore. It wasn't too bad as it only took two days for them to come in from the central warehouse in Toronto, but there was a time when the local dealers HAD them on the shelf. Just like our 308's, the 740's are oldtimers now, and they're disappearing from the roads, so there's less and less need to keep their parts in stock. Maybe there'll come a time when future Volvo collectors will need to buy their shims from the Ferrari suppliers

 

Im also doing this now. Peter says he goes with the smaller lash but I read that the clearances get smaller over time. I posted my lash values here if anyone want to suggest which ones I should change???

http://www.ferrarichat.com/forum/showthread.php?t=322385&page=2

I know too small is not good..........

 

When i did a major, a couple of years ago, i borrowed a shim set from a friend who was a fiat mechanic that went out on his own. Worked slick. Even booowed the tools.

I did find a couple of valves with almost NO clearance and most of them were tight, not loose, which seems to suggest valve/seat wear, not shim/cam wear. (But, i am way not a mechanic and have only done this one valve adj). YMMV

So, i set my lash at mid to high spec, not tight.

I am looking for a reason to pull the engine to go to high comp forged pistons and bigger intake stainless with smaller stainless exhause,( to get rid of the delicate sodium grenades), unfortunately, the budget is not there.

hth,
chris