308 Cam Timing and Adj.

I have been reading the old posts and read that a lot of people recomend checking the cam timing. I also read that others feel that the Timing marks on the cams are not to be trusted. The recomendation seems to be get a degree wheel out and a dial indicator. Here are my questions:

1. What type, size, how do you mount to the crank pully ect.
2. What is the best way to mount the Dial indicator.
3. What are the specs on a 79 308 and an early 308. The owners manual has these numbers but I am confused as it is written as if you are only checking one bank.
4. Adjustment - Use the belt teeth or the pins. - or both

Can somone please give me a step by step walk through on how todo this. If you can walk me through the process. When I do it I will post pictures of the procedure.

Joe

 

1. Verell and I made a paper degree wheel approximately the diameter of the damper and glued it on. Make sure you remove the wheel and ALL the glue after timing is complete. We bolted a metal pointer to the alt. mount bolts. See photo.

2. We just gently bolted it to a cam cover stud. It was difficult finding a place to use the magnet base. See photo.

3. Obviously, you could dial out the cams to confirm the timing marks, and for that you would need the specs on the cam lobe durations etc. I did not do this and assumed the marks on the cams were correct in relation to the lobes.
We only dialed and degreed to confirm the timing marks on the cams in relation to the marks on the cam caps in relation to TDC #1. Also confirmed the markings on the flywheel.

The experts would know how to answer this question better than I can.

4. Both, in my case.

Good luck, and please post photos for future use- thanks.
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Wow, I really think that was a smart idea. I wonder if it would be possible to make that degree wheel from stainless and attach it permanently to the harmonic with screws. That would be a nice thing to have.

 

I would not try that, as you would upset the balance of the damper. Unless, you added the wheel/screws and then balanced the damper. You can see the factory holes in the damper that are for balancing. Mine had three holes about 1/2" deep. See photo:

Maybe someone has tried this?
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I notice that the Dial indicator is in the spark plug hole. Where you really trying to measure true TDC. BTW I like the idea of a paper dial indicator - My plan is to go to a local hot rod shop buy a metal or plastic one, cut out the center and use magnets to hold it in place.

Seems like more people would have done this on a Ferrari motor than have responded.

 

yes- we were just confirming TDC so the timing marks on the cams and cam caps could be confirmed. Flywheel marks also confirmed. In this case, we also had the timing drive gears confirmed because we were taking them off for bearing/seal replacement- but that's a whole different story...

It might be difficult to buy a wheel that fits perfectly, that's why we just made a disposable one and scaled it to fit the damper. Also, if you use magnets, make sure you still mark the wheel and damper to confirm that it has not moved during the timing process.

 

Jwise, I don't understand the picture. It looks like your about to remove the timing gear cover?

I had made a adapter for attaching a degree wheel, but its to big of a wheel, and wont clear with the engine in the car and the water pump on, etc. I really think the paper thing you guys used is pure genius, just glue it on, and throw it away.

 

Yes we were, but the only reason I attached the photo was to show the balance holes in the damper and that was the best shot I had. Sorry for the confusion.

Here is the reason for the timing case removal- enjoy..

http://www.ferrarichat.com/forum/showthread.php?t=28437&highlight=308+timing+gear


edit: oops- Krowbar, I see you posted in the above attached timing gear thread- so you already have seen it. It's a good one anyway

 

Ha! I thought that pic looked familiar. That was an awful job for you, but you really could not have found a better friend than Verell to help you. Its also refreshing, in a sick sort of way, to see others like myself with our dirt and grease on these old cars. Yours was clean compared to mine, but both will change I am sure.

 

You know, these figures being tossed around, I really dont understand why it would cost 3 to 6 times as much as a Jap car to bore out that throttle body. My son can find them all day long for his Mazda for under a 100 bucks. And they are ALL one offs, made from the body you send them. One site explained how to DIY. Its not rocket science. The hardest part is getting the throttle plate symetrical and to fit tight in the bore so the car idles right.

Anyone have any insight on cam timing?

 

Oops. I posted that in the wrong thread. One of THOSE days!

 

Yes, It's the old tried & true way of finding TDC.
BTW, There's about a 6" extension on the dial indicator. I'd borrowed from Spider348 for this project.

We were installing the belts, but the engine was on a stand. Had the flywheel off, & couldn't install the flywheel till we removed the engine from the stand. So had to use an alternate method of locating TDC.

While I was at it, we also used the 'piston stops' that came with my Summit Racing timing wheel (12" too big for a 308) to locate TDC. They gave the same results as the dial indicator, but you have to really be careful when marking the timing down, then finding the mid-point.

What I'd like to do is get a shop to print a timing ring on magnetic stock, with a slit thru the ring so you could slip it on & off with the belts on.

The paper worked fine, but got pretty grungy by the time this project was over, but then John & I were a tad grungy as well. Only thing that wasn't grungy was the engine!

To check cam timing, you can mount the dial indicator rod to one of the cam cover studs, then pick up the top of one of the cam shims. You can then use the dial indicator to tell when the cam starts moving (ie opens) the valve, & stops moving(ie: closes) the valve.

With the other bank on TDC, the bank you're working on will be on half-stroke, so you can safely rotate the cam 360 degrees while you're calibrating the cam.

Many hot-rod books tell how to dial in cams, along with pix. It's lengthy & hard to describe.

If all you want to do is verify that your cam's marks are where they should be, all you need to do is:
-mount a timing wheel to the crank,
-make sure the wheel's zeroed when the crank is on PM1-4,
-pick a cam & note the degree wheel readings when the valve opens & closes.

Compare those readings to the specs.

Unless you have perfect thickness shims(yeah, right), the readings won't be identical to the specs, but they should be off by the same amount. Ie: If the shim is slightly thin (ie: larger than spec shim-cam thickness) , the valve will open n degrees late compared to the spec, it should also close exactly n degrees earlier than spec.

Similarly, a thick shim will make the valve open slightly early & close late by the same amount.

The 308s had a lot of different cams & cam timings over the years. Especially the carb'd cars. Make sure you have cam timing specs that match your engine.