Setting timing on a 308

1st need a little info. Do you have points or electronic ign. If points are you running on both the R1 & R2 points. If so you need to disconnect the micro switch on the right rear carb so you only run on 1 set of points. Now look under the oil filter on the clutch bell housing and you will see an alumin. plate with 2 nuts and remove the nuts and be carefull that you don't drop them . Now take the cover off and you can see the fly wheel. attach the timing light to plug wire # 1 on the cyl. bank closest to the rear of the car. Start the motor and warm it up and let it idle at 1000rpm. point the light at the pointer where you removed the plate. I set my 77 at 7Deg. before top dead center. If you need to adjust it you need to loosen up the 3 nuts that hold the distributor to the motor/cam and then turn it until you hit the mark. Tighten the dist and rev the motor to 6ooorpm and read the advance. Should be around 35 deg.now do the same for the rear distributor . you're done.

 

Steve's advice to check the timing at high rpm is important. If the timing is off a little at idle, it will simply introduce drivability problems. If it is off at high rpm, you could damage something.

If your distributors haven't been 'curved' recently, they may be off from ideal, and might not advance simultaneously. Because of this, I'd say that the high rpm check is the MOST important, and you might have to live with some discrepancies at idle between the two distributors.

If the high rpm is set correctly, and things aren't kosher at low rpm/idle, you will need to pay a visit to someone who has an old fashioned distributor machine who can tinker with the advance mechanism. It may simply need to be cleaned and lubed.

 

Steve you said you set your timing to 7 deg advance at 1000 rpm and I know other people have written that they do the same.

The manuals all show no advance at 1000 rpm. My manual also says check that the timing is 34 deg advance at 5000 rpm, but the graph only shows 34 deg at 6000 rpm, so what gives?

Do you just set as much advance as you can without it starting to pink under load? Did Ferrari get it wrong???

thanks in 'advance '

 

Richard -- that graph is for the distributor mechanism only. To get the total advance you need to add the static (idle) advance to 2 times the distributor advance (at 1/2 the crankshaft RPM) -- i.e., at 5000 (crankshaft) RPM the total advance is:

7 deg BTDC (R1 at idle) + 2(14 deg at 2500 distributor RPM) = 35 deg BTDC total at 5000 crankshaft RPM

 

Barnone 308 -- You're sort of mixing apples and oranges. One set of points on a single distributor set-up (i.e., an 8-lobed distributor cam) would be marginal at high RPM. However "single points" in the F dual distributor setup is not a problem because the distributors only have 4-lobed cams (i.e., the F dual distributor set using a single point each is quasi-equivalent to an 8-lobed distributor cam running true "dual points").

 

Actually, you're only running on one set of points (in each distr.) at 6000rpm anyway. There is a switch on the throttle linkage that disconnects the extra points at part throttle. So it's a single point system at anything except idle.

And, if you go with a simple electronic ignition - one like Crane that simply replaces the points with an optical sensor - the car functions like the second set isn't there. You end up setting the timing 10deg higher at idle.

 

Ham after I got my 77 I had a problem with a set of my points going bad. that was before I was on any Ferrari chat sites and found out that this was a weak area. But I fished around and found a guy in Calif. who would convert 1 of my dist. with 2 Pertronix's breakerless set ups with 12V coils. He has been working on Fcars for a long time. He walked me through the set up process and told me that the carb 308's run their best at 7DBTDC. I think the book says to set it at 2DBTDC. So I have been running this for 2 years now and haven't touched this . It runs great although a little rich but when you crank it to 7500 it goes. I think my advance at 5000rpm was 33Deg which is within spec.

 

Barone 308, I hope I'm not high-jacking your thread, but while we got these experts looking in, may as well make the most of it....

I've got another question guys - my 77 308 has got a Crane optical set up which might have some sort of shapeing-tayloring of the signal that goes to the coils, I don't know. Should I be running the sparkplugs gap at the standard 20 thou, or will I get better combustion with a bigger gap?

thanks again
Richard

 

I thought the "standard" spark plug gap for the later 2-valves was .024"-.027" (although I didn't check the '77 OM specifically).

I also had the Crane system and ran .030" gap with no problem -- and I believe others have reported going up to ~.035"

 

I'm using a sort of "skinny .030" with my Crane units. That's where the .030 wire on the spark plug gauge won't quite go, but the next smaller is loose.

Seems OK..........

 

As long as this thread is moving around a bit, I wonder if anyone has installed either an optical or magnetic point replacement while runnuing a MSD box.
My PO installed both high speed sets of points in one distributor then added two MSD boxes. I am guessing that he wanted to set timing with one distributor.
I am in the dark here
any suggestions???

thanks
chris

 

Friends,

I am still trying to get my Euro 308 GT4 to stop stumbling at idle. I am going to check my timing and it has been so long I forgot how to do it. My car is only running 1 set of point s and has rebuilt engine and carbs. Distributors have the early dog drive. I only want to check the initial idle timing first.

Steve says all done after checking #1 wire. I forgot which wire you check for the rear bank?

I apologize I forgot everything I learned since my other GT4 has run so well for so long!

Rob

 

Start by putting the distributor on a distributor machine and check for proper advance.

 

I think you are using the word "rear" in an ambiguous way.

For the 1-4 bank = use cyl #1
For the 5-8 bank = use cyl #5

 

Of course! Thanks
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On a flat crank Ferrari, any 3@8 engine, you can actually check ignition timing from either end cylinder, 1 or 4, & 5 or 8.
Both end cylinders are up at the same time and will fire on the PM marks for the respective bank.
So Robert, just connect to an end cylinder and go.
Or you can send me your distributors and I will add a double electronic ignition to one and you can run both banks off of the one distributor for timing and advance and the other will just be moving spark from the coil to the plugs but the coil timing will all be controlled by one distributor. No more matching two advance curves or having to set timing on two banks. Makes tuning much easier. I just did a carb 308 and it really simplifies tuning.

 

Wade and all,

Thanks all Wade, You are the best. I am trying to make this work I know it only has the 1 set of points which isn't totally correct but my other car rocks so will give it a bit more attention. I am pretty sure its a fuel problem but just anted to rule out the timing!

Rob

 

Probably is fuel. I just drove the 77 308 that I did extensive major service, carbs, and distributors on and I must say, it is one fine running carb 308. It really pulls hard and well in to some scary RPM. The distributors were pesky, had them on the machine several times after running the engine just to get them to do what I wanted. Also had to add some fuel to it, I think the ethanol gas of today is just too lean for these old carbs.

 

When I had my GT4, I only had one set of points and it made the tune much easier. I also added two Crane Cam boxes so it was running super smooth. Don't worry about the second set of points Robert.

 

Friends,

I just disassembled one carb the right rear one. These carbs were rebuilt so fancy, every stud, bolt, washer, etc is re-plated, etc. all the parts are correct for my model, 45 acc. pump jets, 4.5 tube, 32 diffuser, etc. Float heights perfect. It has been a long time since I took one of these apart. The pump jets have very small holes, when blowing air through them hardly nothing comes out. I think I am running down a rabbit hole here and think the idles may be just to lean, but I could be wrong!

I took this carb part as it is a cylinder that flooded recently but it looks fine. I think I am going to put everything back together except the air cleaner, and check if the pumps are squirting. Unless anyone has a better suggestion?

I have one other comment, my 75 car runs rich, stinks a bit, but runs fantastic. This car doesn't stink at all, and im thinking any car from 1974 with 4 carbs not stinking is running to lean. I know thats not very scientific.........
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Wade, when you say add some gas did, you change jets, etc?