So I've had the timing chain and timing all set on my 360 for a little while now, the heads are all torqued on and I'm putting the rocker arms together. But I keep seeing the timing chain and I've come to the conclusion that there is too much slack, I didn't measure it but both sides can easily be moved back and forth about a 3/4 inch, and it's brand new! There has been a lot of block work, so I'm thinking I need a slightly shorter timing chain because the crank needed some work. Can I get a shorter timing chain easily or are they hard to find? And can I change it without messing up the timing? Or is a little slack okay? It's only slightly less slack than the old timing chain that came off had.
Slack in new timing chain
- Thread starter DartVadar
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txstang84
Well-Known Member
Goo! 3/4"? What kind of block work was done? Moving the crank centerline up? That's some ugly slack=especially for a new chain. Even if the crank was turned, the timing set should be nice and snug. When I pulled my old one off, it was probably as bad as 3/4" and when I replaced it with a new unit from Summit, the slack was all but gone...then I drove it 10k miles, and it was bad again 
The answer is yes you can get a shorter chain and gear set; Cloyes and others make them. The thing is you will need to tell them how short. Best way is to get a set of 8 inch calipers and measure from the crank shaft to the cam outside to outside, measure the crank and cam diameter, divide them in half, subtract half the crank, and half the cam and you should have distance between center lines of the crank and cam. For reference, blueprint spec is 6.12 inches.
Goo! 3/4"? What kind of block work was done? Moving the crank centerline up? That's some ugly slack=especially for a new chain. Even if the crank was turned, the timing set should be nice and snug. When I pulled my old one off, it was probably as bad as 3/4" and when I replaced it with a new unit from Summit, the slack was all but gone...then I drove it 10k miles, and it was bad again
Maybe not that much, 1/2 inch may be more accurate, but it's just not snug like a new chain should be. It was align bored (I think that's what it is), my uncle was saying that could be why it's so loose. It's a comp timing set too, so I would think it would fit better. It just feels like it's already drove a few thousand miles with the slack it has.
This will take up the slack but a new chain and gears with no line boring of the block should have that much slop. Never mind. It looks like my Cloyes set up had that much slop. lol tmm
I actually was just looking at threads about tensioners, and I like the idea of it because even if I get one that is tighter, over time it will stretch, and the tensioner should keep it tighter for a longer period of time. And they really aren't that expensive to put on, don't see why I wouldn't. Have any of you guys had success with tensioners?
fishy68
Tyr Fryr's Inc.
I run tensioners with good results. Their not for everything such as a solid roller cammed engine that have a bunch of valve spring pressure, but their fine for normal street and strip action. One thing to keep in mind is when you have slack in the chain most likely the cam timing will be retarded. If I were building it I'd get a chain that fits right (I think Milodon makes chains .005" and .010" shorter) and degree the cam in and if the valve spring pressure isn't real high I'd use a tensioner. Just my .02
Even if the block was line bored and or honed, if done correctly, it will hardly move the crank at ALL. A good machinist will remove more off the main caps than the block. When we did them, we always barely skinned the main saddles in the block...and I mean BARELY. You simple remove material from the main caps, reinstall them and line hone it more toward the caps. At least that's how it's supposed to be done.
That makes sense it should be done that way, and I'm sure it was done right, the shop that did the work has a really good reputation. My uncle and grandpa have gone there multiple times for block work. Could the chain just be slightly larger than it should be? Or I could be worrying for nothing, because isn't there supposed to be some slack? I will try and post a picture or something of the slack. Would it be best to replace the chain with a tighter one? It's only for a street engine after all, won't see high revs often either.
Those are questions that I cannot answer without seeing it in person. I will say this. I like the timing chain tensioners so much that I modified one to fit on my 331 Hemi. They work well, however, I have seen where people had trouble with timing set types other than Cloyes. Something about other make chains don't line up just right and tend to "saw" away at the tensioner shoes. Cloyes makes those for Mopar Performance, so the Cloyes chain sets seem to be a good match. Make sure you get the Cloyes tensioner, instead of the MP unit. While they are the same piece, you will pay a higher markup for the one in the MP box.
That makes sense, can't really just go off a description. And I'll look into the cloyes tensioners.
But another question I have is about how the timing chain gets oiled. On the thrust plate there are only three bolts but 4 bolt holes, and the slinger thingy that goes on the bottom left bolt that I assume deflects oil onto the chain. I think I may have the bolts in the wrong holes at the top. I know earlier la engines had 4 bolts and one had a hole through it but mine has three. What hole is left open to oil the chain properly? I'll post a pic of the bolt orientation that I don't think is quite right.
TrailBeast
AKA Mopars4us on Youtube
The bolt on the upper left in the picture have a hole in it?
If not, that is the bolt you leave out for chain oiling.
I have also seen where people said that if you have that drip plate you don't need oiling from the cam oil, so might check into that a little more.
If not, that is the bolt you leave out for chain oiling.
I have also seen where people said that if you have that drip plate you don't need oiling from the cam oil, so might check into that a little more.
autoxcuda
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The small block mopar with a 6.12" crank to cam centerline distance is one of the longest of all V-8's. That creates an inherent situation with chains getting loose.
I put on a fairly tight new Rollmaster chain. Seemed above average compared to other SB timing chains I used. Then I degreed the cam. Then I put on the MP timing chain tensioner and degreed the cam AGAIN...
The cam timing changed 1 whole degree with the tensioner!
There isn't a hole in that bolt, or any of the other bolts for that matter, I'll be sure to change that out then and move it to the lower hole leaving the top left open.
I'm just going to do what they did in the factory, this build isn't anything special, it's really stock specs for most parts.
Well I've been thinking about this like crazy and feel like keeping my current timing chain and just adding a tensioner is kinda just like a band aide. Can I just get a new chain that is shorter? And not have to buy new sprockets. Because everything is brand new and I can't take it back toget another one. So I will measure and see if I would need a 0.005 or a 0.010 shorter chain (I think I only need a 0.005 shorter). I feel this is the proper way to fix the problem, and then I'll add a tensioner to the better fitting chain.
I agree with your thinking. Get a good fitting chain first, and then the tensioner. =D>
Where would I even find a shorter chain anyways? I called around and everybody just has the standard length ones. I assume I would have to get it online, and would I have to get a comp chain because I have comp sprockets? Or does it really matter the brand of chain on the sprockets?
Well the work done was just to get the block ready to build, just cleaning stuff up, it only had 70k miles on it so they really didn't take much material off, that's one reason why I don't understand why the chain is that loose. I mean it's not super loose, it only moves when I press on the chain, and not when I turn the crank, it just moves enough to make a slight 'click' noise. I'll show my uncle and see what he thinks, it may be okay for my application.
The slack you are experiencing in the timing chain may be normal. There's no way for any of us to tell over the internet. None of them fit really tight. That could cause cam and crank bearing wear. IMO, I think you should simply get the good Cloyes true roller and the Cloyes tensioner. Put it all together and degree the cam with the tensioner in place. Regardless of how the chain fits, it is going to change cam timing once you install the tensioner, so you may as well get the chain that works best with the tensioner assemble it all and degree it that way. The cam timing is the underlying issue here and that would be the best way to make sure the cam timing is correct. Any timing chain stretch from the engine running from that point, is out of your control anyway, regardless of which chain you choose.
moper
Well-Known Member
Honestly - the Comp chains are terrible. I like to use the Summit brand billet and I use the MP tensioner with them.
goldmember
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Send the Sa gear BS back and order a Cloyes set. common problem with the crap on the market today. tensioners are ok with the right combo,but other combos eat them up putting lots of plastic thru the pump.
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