'86 420 SEL Chain Install Tool
 

Anyone ever use one of those tools which hold the chain on the right-side sprocket while you are barring it through? Does it work OK? Does anyone have one they want to sell? Thanks.

I used one called zip-ties. Worked really well and cheap too. Of course, it was a REALLY slow process. :)

I understand; right now cheap would help a lot: I priced the OEM tensioner OUCH. Why the heck can't the aftermarket ones be as good?
I am interested: how much force does it take to hold the chain ends on? I hate to disturb the rockers (and I hate to buy a spring compressor, too). Dang, the first time is tough (hope it's the last time, too).

Did you read my DIY article on timing chain replacement?

http://www.peachparts.com/Wikka/M117TimingChain

The m116's chain is a bit shorter, which means the process will take less time on a 4.2 than it did on my 4.5. It's easy to do, the mini vicegrips I used were like $0.99 each at Wal*Mart. Your guide rails will be plastic though, you WILL want to replace them.

I have one, and I used it. It worked very well, and makes the grinding off of the pins much safer, because you don't have to worry about the ends flying off after you do it. Not being a mechanic, I didn't want to take any chances dropping the chain or skipping it, and this looked like good insurance. My assistant (wife) has even less experience working on engines. She fed the chain while I turned the crank (supposedly, this cover makes this a one-man operation, but I didn't want to drag the chain(s) on the fender).

Nonetheless, I did manage to do two idiotic things in the process:

1. I had (clean, lint-free) rags stuffed down the sides near the chain in the event I dropped something in. One of the rags got caught in the chain between it and the cover. I couldn't turn the gear backwards so I had to cut it out with a razor blade before proceeding.

2. The cover bolts on top of the front cam tower. When I removed the cover, I didn't torque the bolts to spec, and I turned the engine over by hand with the lifters reinstalled (NOT GOOD). Fortunately, I didn't do this at any speed, and after removing the lifters, torquing the front cam tower, and checking that the cam turned without any binding or tough spots (meaning, I bent the cam), I reinstalled everything and then TORQUED THE FRONT CAM TOWER BOLTS for the last time, ever, hopefully!

On removing the cam followers, once you have the tool, it's very easy. There was some debate on another board on whether or not this can be done safely if left in AND the tensioner left in also. Obviously, it can be done, because people have done it. So, why do MB and Haynes, Chilton recommend removing them? I think it's for two reasons:

1. Unexpected movement of the chain/gear due to spring action

2. If you remove the tensioner (which is recommended in the books), the RH side of the chain has a lot of slop in it, certainly more than a tooth's worth, and certainly more than enough to cause interference. Having the tensioner in makes the job a little more difficult; If your tensioner is older, it probably leaks a little, the spring is old, is it really going to hold enough tension? I did not feel like gambling $2000 to find out (note that the LH side is always under tension during the process and unless something really gross happens, you can't skip a tooth on that side).


My 0.02: Unless you are a seasoned mechanic (I'm not) or just plain born lucky (I'm not), I'd go by the book. But I think the vise-grips are a neat idea.

OK thanks Tomguy (great info on the site!) and Strife. A question for Tomguy: in your process is the tensioner left undisturbed and the rocker arms left in place until the new chain is in (I am buying a new OEM tensioner (gulp))?
I know (at least, I think I know) that everything will be OK as long as both ends of the chain remain on the right-hand sprocket, thereby not allowing it to jump out of time.
I am replacing the three plastic guides: mine are a nice caramel color, and I don't even see any surface grooving, but they were 20 years old in November, and have 149,000 faithful miles behind them, so they are retiring. I am also replacing the tensioner rail: do you have any recommendations as to OEM v aftermarket, etc? Again, if there is more than one style available, I will not know which to buy.
Thanks again to everyone; I could not make it without your help and advice!

For your engine, there is pretty much just ONE verion available for the 3 guide rails - solid plastic.
You MIGHT get lucky and find an aluminum-backed one from a 3.5 on eBay. I MIGHT have one or two in my garage. Problem with these is I don't know if you can get the hard plastic (rubber?) to resurface them - but they wont ever crack.

There is a reason I used 3 vice grips. At all times, there must be at least 1 of them holding each end of the chain to the sprocket. If you make sure of this, and you go slowly and steadily, you will have no problems putting your chain on. Even if you do skip a tooth on the cam, it's easy enough to fix when you get to the end.

I have the three new plastic guides; I was asking about the tensioning rail. Since my three guides lasted 20 years, I am not worried about the fact they are plastic. Apparently as long as you don't have much tensioner trouble and change the oil, you have a good chance of being OK with these guides.
Anyway, I either have the parts or have them on order; let the games begin!

Yeah, I didnt touch my rails or tensioner when I did my chain. I had already changed my tensioner before. It may be easier to change with the older, stretched chain than on a new one. You'll have more clearance. I forget if I needed to remove the cam gear from the cam and then the chain from the gear to do this... I might have had to but I cant recall.