Guys, 78 308 GTS with carbs. I was working on my idle today and noticed this behavior and wanted to get your opinions on what you think might be going on. 1) I can adjust the fast idle cam up to about 3000 RPM (the manual says this clearly) when it is cold. When the cam warms up and rotates, the flat spot is exposed to the little arm (as shown in the picture) and the idle drops down to what you have the throttle linkage set to. In my case this was a bit of a pain because every time I set the throttle to, say 1000 RPM, it would creep up to 1500 or 2000. The return spring was not pulling it back hard enough. I lubed the four springs on the carb but it is still not a strong enough, repeatable return. Any ideas to get the throttle to return to the same place each time? 2) Here's the wierd one. First, notice the three dark barrels. Every now and then, while idling, these squirt a little gas stream/droplet straight up about 3 inches. Sometimes it drops back into the barrel and sometimes on the outside ring. This seems dangerous to me and probably not normal behavior. The engine is running and popping at the carbs with occasional backfires (soft) at the exhaust. Then, the one carb in the right front (towards the front of the car) squirted a strong, heavy mist from the small opening between the barrels shown in the picture. Is this supposed to happen. What's going on with these squirting carbs? 3) I am trying to check the timing and I can't see any marks on the flywheel. I can see the gear teeth and the static pointer real well but there seems to be nothing on the wheel itself. I pulled cylinder #1 plug (right rear) and put a long, skinny flat blade screwdriver, GENTLY into the cylinder and put the car into 5th and pushed it to watch the screwdriver top out under its own weight (trust me, I am not hurting the piston head). The problem is, I don't know which stoke is compression. I figure if I can find TDC, I can mark the flywheel.The R2 points are disabled for now. How do I mark TDC and the required 34 degrees advance mark for R1 timing - on the flywheel? ...and how do I know which is the compression stroke? 4) Since the position of the rotor within the distributor is fixed relative to the small shaft it is mounted on, does this mean that it is an indicator of cam position? When you pull a distributor, is this shaft keyed to the camshaft or is it adjustable? I am still trying to find out if my timing belt change last fall left the cams in the right position. I simply copied what it was before and I am trying to figure a clever way to know this without removing the cam covers. Any ideas? Thanks, Rjay Image Unavailable, Please Login
Wow, so many questions! the spitting back through the carbs is commonly associated with running lean. Try playing with the mixture screws on the throats that are exhibiting the problem. I know when I rebuilt my carbs it went away.... The high idle cam... is sitting in my garage right now! I hope to put it back on soon as I wanted it out of the way when I was struggling with carb problems. The flywheel does have (unless it's been turned down and the marks are gone) marks, but they can be hard to see if the outer ring of the flywheel is rusty. Get #1 TDC and shine a bright light. Then try the other TDC for #1.
Don, Thanks for the reply. Yea, I guess I piled too many questions into an initial thread. I looked at the flywheel with a bright light and I think i see some marks. Are these marks just under the pointer on a thin surface ring? The GT4 manual implies that there are marks and my ring is mildly orange rusty. I cleaned with alcohol and it seems to help but I would like to be sure. I have since found the threads on "spitting carbs". I didn't know what to call it so I couldn't find it. I used the term "squirting" - oh well, live and learn. It looks like this is caused by a lean mixture, as you said. It is also caused by misaligned timing. It looks like that can be caused by both improper advance and/or wrong cam timing i.e. off a tooth. I would still like to know if anyone knows how to figure out if the cams are in the right position without removing the cam covers on a 2V engine. Thanks again Don, Rjay
Its impossible, at least on the front bank, but you may be able to see through the oil filler to see a mark on the rear bank. I was dumb and put sealant on my cam seals when I put it together, don't do that. They kept pushing out. I got good at removing the front cover, last time it was off in less than half an hour.
Guys, Verell wrote me a nice note referencing his cam lock and some marks on earlier 2V cams. These marks do not appear on my cams but at least I knew exactly where to look. As far as the spitting carbs, I also found a broken wire in the forward dizzy that, luckily, was getting progressively worse. I noticed that when this connection was broken off & on, the carbs would spit a lot and the exhaust would backfire. I will troubleshoot this later. At this point, I can see that the only way to check alignment is to remove the covers (arghh). I don't mind the work but the gaskets sell for $95. I am, shall we say, frugal. I will not rest until I know if the cams are in the right spots. Is there anything I should be aware of when removing the two valve covers? I only want to take em' off and check the marks (move a tooth or two if need be). When this wire was intermittent, the tach was also not registering but the engine sounded fine. The tach should have been my clue early on but the darn thing jumps anyway. The timing light showed no activity on all four plugs but the car actually ran and went in and out of the garage fine - it just had no power. She was running only on the rear 4!! Rjay
Bob, If you end up pulling the cam cover, might as well replace the timing belts because they are cheap and the most likely thing to harm your engine should one break. If you end up having to change the cam timing because you are off a tooth, you will have to remove the belts anyway, and once they have been removed, you are not supposed to replace and retention them. When my car was spitting, I discovered it was that the idle jets were too lean for the exhaust system. A PO removed the original muffler and replaced it with Ansa. The car responded well to one size larger idle jets. Birdman
Jonathan, Thanks for the info. Verell also mirrored what you said about changing the belts. I guess the FSM manuals are explicit on retensioning i.e. don't ever. I suppose for the $40 or so, it is well worth it. On the idle jets, do you know what I would do at high altitude? We are at 5200 ft. I bought the car from an owner in Connecticut and it hasn't been adjusted yet for high altitude. You would think it would be too rich up here. Would the larger jets work? BTW, I am still keeping my eye on your fuseboxes for the future. Rjay
Bob: I hate to go against conventional wisdom (not really, but I thought I'd say it anyway) but I think that you have the distributor on the front bank set 180 degrees off. The engine will run, but the spark will fire the front bank on the intake stroke, with the intake valves open, and the flame will go up the manifold to the carbs. I humbly admit that I speak from experience. To get yourself oriented, take the cover off the rear distributor and look for the notch in the rim of the distributor body. Hand crank the engine over until the rotor points to the notch. Now look at the flywheel. You should see PM 1-4 or the +7 mark. Since the rear bank is running OK the distributor-crank timing is probably correct. If you can't see the marks, at least put a drop of white paint on the flywheel at this point. Now slowly crank the engine and look for any marks on the flywheel about 45 degrees after the mark you made. The marks are A5 34, AF 16, +7 and PM 5-8 in that order. The PM 5-8 is the TDC for the front bank. Now look at the distributor for the front bank. The rotor should be pointing to the notch in the case. I'll bet its 180 degrees out. Put another drop of white paint on the flywheel at this point. Get both distributors -rotors to line up with their notches when the TDC dot is under the pointer. I wouldn't mess with the rear bank distributor - it seems to be workiing OK so leave it alone. You want your static timing to be 7 degrees BTDC, which is about 3/4 of an inch to the right (when looking from the driver's side) of the TDC (PM) mark. If you look really carefully you might find an artifact of the stamp on the flywheel. I'm leaving for Denver tonight to attend my son's graduation from the Graduate School of Architecture on Saturday. If you are in Denver or anywhere along my route (US 80 from nothern Nevada) I'll be happy to stop by and give you a hand. Drop me a PM with your phone # and I'll give you a call.
Points removed and cleaned in both dist. The forward one was pitted and had a "spike" that had grown on one side of the contact. Both points cleaned, relubed and put back. The R2 points were removed for now. The rotor position was checked against the GT4 manual and was fine. Everything put back and the engine started quickly and ran a lot more smooth. Question 1- When the R2 points are removed, it leaves a hole exposing the mechanical advance. Does this need to be covered? There was a bit of oil on the back of the point (clean brown oil), will it slosh all over the points? Has anybody had this experience? Question 2 - If the rear rotor is pointing at #1 and the front rotor is between #1 #2, is'nt this TDC compression for #1? (assuming the t-belts are in the right spot) Thanks again in advance, Rjay
The 308 is an odd motor, in that the front cylinders are actually 5-8, yet the cam cover numbers them 1-4. Actually the firing order is 1,3,4,2. So with rear bank on #1 TDC, rear distributor rotor should point at #1, and as the front bank wont (shouldnt) fire for another 90 degrees crankshaft rotation, it would be correct to see the front distributor rotor between #1, and #2 (#5 and #6) as #1 will be next in sequence. Now you should try to find your 34 degree full advance marks on the flywheel and with a warm engine, check timing as you rev the engine smoothly and slowly up to 5000 rpm. Watch the timing light on the flywheel as the speed comes up and make sure it advances smoothly, and that it reaches full advance @ 5000 rpm and not at a lower or higher rpm. It is more important to set your timing at 5000 than at idle, so you dont hurt the engine. If the advance is working pretty good the idle timing should be fairly close to spec, but if it otherwise stops at 34 @5000rpm, is smooth going up, and drops back within a few degrees of spec at idle, you should be fine. Oil in the distributor is probably due to either a bad seal on the engine cover plate, or a bad plug seal in the cam end. It shouldnt be full of oil inside the distributor. In removing the extra point set, nothing should be left loose, like adjustment screws etc..
Thanks Paul, What's even wierder is that the forward bank cam cover is embossed with 1-3-4-2 and the rear most is numbered 1-2-3-4. I wonder if someone has made a swap on the forward cam cover during the life of the car. There was only a little bit of oil and since it was clean, it was probably the lube for the advance mechanisms. Probably not to worry - thanks. I really appreciate the timing info and the verification of rotor position. I know the GT4 manual has all this info but I am still disoriented a bit. Having your direct comments really helps me. Question - What do I adjust to move the timing? Do I rotate the dist. on those three bolts? Do I have to break a seal to do it? Regards, Bob
No seals to break, just as you surmised, loosen the bolts just enough to rotate the distributor. Make sure the points are set before you time the engine.
