Doing the timing belts / exit AC

That is exactly what I did. Removed the A/C compressor, brackets, and put them in a box. Then, I put rubber stoppers in the A/C lines and taped them up. Seven months of the year I live in a sweat box so I may entertain trying to bring the A/C back to life . (Though given the $$$ I have dumped into my otherwise trouble-free Rx-7 to have A/C I have to wonder about embarking on the same path with the 308.)

Seamus

 

Yes, don't forget about the water pump if it needs/should be replaced and replace all auxiliary belts too. I have also removed the tensioners, replaced the springs (they were 19 years old!), cleaned and repacked with grease.

 

The tensioner springs will probably be good for MANY decades. They don't even do any work except for two hand turned revolutions of the engine every 3 or 5 years (when changing belts). Yes, they spend the rest of the time compressed to some extent but I seriously doubt they will lose any critical amount of strength for a long, long time. Your valve springs are 19 years old and they go through hell when the engine is running. Your oil pressure spring is 19 years old and probably still works just fine, your throttle return springs still work, your suspension springs are likely original are probably just fine. All these springs are subject to movement and thus a tiny bit of wear and I assume you did not replace them.

The tensioner springs are probably the last springs I would worry about on the car. Most important thing is to do the tensioning adjustment correctly so the springs can do their "thing" until the tensioner bearing is locked down tight. Cleaning the tensioner assemblies and re-greasing before doing the tensioning is certainly a good idea.

 

Yes, you are probably right. But the fact that I had new ones in hand and they were about half-inch longer than the old ones made me replace them !

 

Tightening torques (lb/ft):
Valve covers 6.5
A/C Compressor to support 15
Timing belt stretcher 40
Pulleys to camshaft 79

 

PM sent. Give me your email and I will send my notes from this project last winter. I have the same car. Am hesitant to post here for fear of critique from the gallery . I have driven the car almost 2,000 miles since then so I guess I didn't muck it up too much . Or, you could follow my approach which was to research here on this site for 10 hours or so before commencing!

 

Hopefully, you are using a tool to lock the cams before you proceed with step 2. If not, the tension of the valve springs will cause your cams to move and you will almost certainly jump a tooth on the belt.

Also, be very careful with step 6. If you rotate the engine with the tensioner loose, the spring alone will not hold the belts sufficiently tight and again, you may jump a tooth or more on the belts (ask me how I learned that one!). The best way to do it IMHO is to press against the tensioner to make sure that it is properly extended, then hand tighten it in place before turning the engine over a couple of times by hand. Return the engine to TDC on #1, check your timing marks on the cams, loosen the tensioner and push by hand again to be sure that it is fully extended under spring pressure, and then tighten it up and torque it. If you had to make any adjustment in the cam timing, repeat the whole thing again before doing the final tightening of the tensioner. Remember, the spring is only there to set the proper tension, it is NOT intended to hold the belt when the engine is turned.

BTW, it is important to check the cam timing against the factory marks on the cams and caps. Many folks say that you can align with the factory marks and be very close to accurate. But if you do that, the marks must be dead-on. The width of the mark is about 3 deg. of timing, so it's easy to be off if the marks are not spot-on. Of course, if you are not degreeing the cams, you can't be sure that they are accurate to begin with. And as long as you have the cam covers off anyway, check your valve clearances. It is worth the effort.

 

F106AE is the engine family designation for all '78 and '79 US 308. They do start over on the SN for each new engine family so your engine SN really isn't that low -- my Nov 1978 built ex-308 had F106AE engine SN 00455 so yours was a little before that.

 

So what's your SN? I have a '78 GTS, US model. While you are waiting for the new belts, consider checking the valve clearances (if you can put that bearing back on or mount the new one, put the old belts back on temporarily. When I did mine, I found that all the intakes were fine, but several of the exhausts were off. I was able to swap some of the shims around and ended up only needing to buy a couple of shims to get everything right within spec. tolerances. Just a thought. Consider changing the cam end seals also, as they are prone to leaking.

 

No, they assign a new engine family designation to each new engine configuration -- not based on year (i.e., I think all '73-'77 US 308 are F106A and all '78-'79 US 308 are F106AE).

 

I turned over my engine many (10~12) revolutions with the spring tension only (tensioners loose) and never had a problem. I think it's important to turn it over in a smooth manner (no jerkiness) using a tool with a long handle AND the spark plugs removed to get rid of all that compression resistance. It should not be an issue then. This was on a 4 valve engine. Maybe it's different with a 2 valve. In any event I would not want to try it with the spark plugs in on either version of the engine.

 

Well- #5 is a doozie! What exactly do you mean by "fiddle" with the cams?

Also- To set the belt tension, I was told to rotate the engine with the tensioners loose and watch the movement of the tensioner itself. It will loosen/tighten the belt as you rotate. I would lock the tensioner when it was applying the greatest tension to the belt. This way- it is impossible to over-tension the belt.

 

Do you have this timing belt change procedure:

http://www.camerafilters.com/ec/ofsm.htm

While the tensioner springs should last forever, the grease on the springs gets pretty dried out. Thus the tensioners should be disassembled & cleaned each belt change. Also, apply fresh grease sparingly to the springs so that it doesn't clog the drain holes at the bottom of the spring hole. The front bank tensioner tends to not collect moisture, but If the drain hole in the rear tensioner is clogged, water from washing the car, etc. will just stand in there & rust the spring.
Early tensioners didn't have that 2mm/3/32" drain hole, If yours doesn't, drill one.

Here's a couple of pix:

1st one shows how the cam marks line up. I used white paint on each side of the marks to highlight them. The lines were crisper to the eye than they appear here. I was using a paint stick. An artist's brush would be better. Alternatively, You might try just rubbing a yellow china marker over the cam to fill in the groove, then wipe it off of the raised area. A black fine tip marker will highlight the cam cap groove.

TIP: Use a digital camera's macro setting and take pictures of the marks straight down the cam's centerline. Then you can blow the picture up to check alignment. If that were done with the cam in picture #1, it would show that the mark is actually slightly off!

The 2nd picture shows how you can use binder clips to hold the cam belts in place.

The 3rd picture shows the Unobtainium Supply 2V cam clamps (shameless Ad) with alignment marks that can be used for cam timing confidence checks if your cam gear mounting flange has the flat with a timing mark. In stock if you want a pair.

Odds are that you'll discover you've been running with at least 1 cam whose timing is slightly off.
If you find that a cam's marks indicate the cam is off, but not by a full tooth, you'll have to change the cam gear's position on the cam. You remove the cam gear mounting bolt & the pin that's aligning the cams to the cam gear. You then locate a cam - cam gear hole pair that puts the mark dead on when the cam belt is in place, reinstall the pin, put a new o-ring on the cam bolt & torque it down. Real PITA as you'll probably have to try 2-3 hole combinations before you find the right one.
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I removed the cams entirely. Advantages:
- Easy to replace cam seals.
- No danger of damaging sprocket which otherwise would have to be removed to replace the seals.
- No special tool needed to remove valve shims.
- Valve shim replacement a breeze.

Remember to measure the valve clearances before removing the cams so you know which shims need replacing .

If you are replacing the belts and tensioners you probably also need to replace the cam seals and adjust the valves. The disadvantage to my approach is having to carefully remove and replace the cam caps. Plus, if you are not using a tool to hold the cams in place it is a little tricky to get things buttoned down and on the marks but it can be done.

Seamus