Chain Ramps

[bhaubold]

I'm going to be installing new chain tensioners in my 67S. Although I have never done this before, I think I have a good idea how to go about it.

What I'm wondering about is the chain ramps. I can see that the two outside ramps seem to just pull off the studs. But how do I remove the four inner ramps? Is it just a matter of removing the bolts and removing the ramp? Are there any washers or hardware inside the case that will drop when I remove the bolts?

Thanks for any help you may have,

Bob

[Early_S_Man]

You have to support the engine with a jack or jack stand at 'normal' height. Then take off the rear cross-piece and mounting bracket for engine mount ... eight bolts secure the 'inner' four ramps.

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[bhaubold]

Warren,

Thanks for your reply.

Actually, I have the engine out for a transmission rebuild and new clutch. I removed the chain covers to inspect the tensioners and found the last owner had installed machanical tensioners.

I plan on installing the later style tensioner (non pressure fed) with the updated chain wheel supports. I've heard that to install the pressure fed units on the 67 model requires machining of the cover plates. This time around I'm just going to use the updated original style.

When is the best time to install the new chain ramps? With the tensioners in or out?

Thanks,

Bob

[Early_S_Man]

Bob,

Remove the old tensioners, then replace the ramps, and put the new tensioners in.

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[bhaubold]

Warren,

Thanks for your help.


Bob

[T Bird]

Bob
Start on the left (driver's) side. Leave the tensioner in place. I put a small piece of string through the chain at about the middle of the outer chain ramp, pull up slightly, and tie the string to one of the upper chain case studs. This supports the chain while the outer chain ramp is removed. (Probably not mandatory, but it gives me a sense of comfort!)

I remove the outer chain ramp as follows: I loop a piece of sturdy nylon string around the center of the outer chain ramp. While pulling on the string away from the chain case, I wedge the blade of a small screw driver in the slot on the ramp that snaps over the groove in the stud. Be careful here as the ramp will generally release without warning as you pull on the string and simultaneously pry open the slot. It's easy to punch yourself in the face here (ask me how I know). I use this method as opposed to prying the ramp away from the chain case with a screw driver, as the chain case is made of soft material and can be knicked by the screw driver.

Once the old outer ramp is out, and before you replace the outer ramp, work on the lower inner ramp. (Do one ramp at a time.) Remember that the ramp snaps into the groove on the inner bolt. The outer bolt just positions the ramp under the chain. I use 10" needle nose pliers with a 45 degree bend to hold the ramp while I back out the bolts and then withdraw the old lower inner ramp.

I replace the lower inner ramp as follows: I tie a piece of safety string through the outer hole of the ramp. (Long end of ramp points toward intermediate shaft sprocket.) Using the needle nose pliers, I insert the ramp in the chain case and position it in place, while I wrap the safety string around a lower chain case stud. The safety string is just cheap insurance in case you drop a ramp into the crankcase.

I then insert a small screw driver in the inner ramp bolt hole and make sure that it passes through the ramp. I then remove the safety string from the outer hole of the ramp and insert the outer ramp bolt (with new washer) throught the hole and tighten it down all the way (finger tight only). Next, while holding the ramp in place with the needle nose pliers, I remove the small screwdriver from the inner ramp bolt hole and start the inner ramp bolt (with new washer) by hand. Once it begins to pass through the ramp, I remove the pliers.

Now, I place a small screwdriver behind the chain ramp to support it. As you tighten down the inner ramp bolt, it will want to push the ramp forward. The screwdriver (or other suitable device) that you insert behind the ramp helps to ensure that the groove in the ramp bolt will properly engage the snap on the ramp. Remember that while it's easy to let the inner ramp bolt push the ramp away and not engage, it's also easy to be too aggressive with the screwdriver behind the ramp, such that the ramp bolt passes too far through the ramp.

When you have the inner and outer bolts all the way through, try pushing and pulling on the ramp to ensure that the snap has properly engaged the groove on the inner ramp bolt. The ramp should be positioned parallel to the chain and resist any attempt to make it slide on the ramp bolts. Also, the same portion of the ramp bolt tips should be protruding from each hole in the ramp. Now you can torque down the ramp bolts.

Next, do the upper inner ramp the same way. Finally, snap the outer ramp in place and remove the string supporting the chain. Now you can replace the left side tensioner. The safety wire that you use to hold the chain in place when you remove the tensioner will block access to the outer ramp and the lower inner ramp. This is why I do the ramps first.

On the right (passenger) side, you can remove the outer ramp, remove/replace the upper inner ramp, and then replace the outer ramp. To remove/replace the lower inner ramp, you will need to first remove the tensioner, as it blocks access to the ramp.

Besides the 10" 45 degree needle nose pliers, other useful tools are a small inspection mirror and a flashlight to inspect the ramps to ensure proper placement directly under the chains. I use a small (6") tack remover to insert behind the inner ramps when tightening down the inner ramp bolts instead of a screw driver because it has an angled head and thus fits better. I also liberally oil the inner ramp snaps and "exercise" them a wee bit with a screw driver before installing them. This helps the inner ramp bolts to properly engage the snaps without too much resistance.

Hopes this makes sense. Sorry for such a long reply!
Good luck.
John

[bhaubold]

John,

Thank you for the excellent reply. I hope to change out all the parts this next weekend. I've been very busy at work and can't get the time I need to keep up on the car.

The person rebuilding the gearbox just called and it is ready. So, I have lots to do.

Thanks again, you have been a big help,

Bob