P/N: 12371043
Car: '89 IROC 350

The sprockets are almost touching. Is this normal?

 

I've only used/installed a Cloyes SBC single roller set myself and to be honest I never noticed. I admit that does seem strange.

But if you look at the pics from a review on Summit, it does appear to be normal https://www.summitracing.com/parts/nal-12371043/reviews

 

FYI soak the chain over night, once moving/rotating oil can't get deep into the pins/links. I'm a fan of the single rollers

 

Yes, that spacing is pretty normal. I also like the single rollers - Some may have noticed that in my prior comments. They are tough to ignore for their strength and durability, and fewer joints and sleeves result in less slack and lash. Consider that if every roller bushing needs 1½ thousandths of oil clearance, and there are 23 links in a single roller HD set, that's almost 10 thousandths less slack in than with a 29-link "trouble roller" chain, and that's before ANY load is put on it.

Of course, slack in a cam drive probably doesn't affect valve timing, does it?

 

Good points! Never counted or considered the amount of rollers but makes sense. I like them cause GM used them in the LS and while that's not the-end-all(unknown exact reasons) it's still a good reason to consider somethings use. Also a single row just seems simpler, and double row well kinda sales pitchy. Plus I found an old discussion of dyno testing the two and they made a bit more repeatable power with the single, I think they determined it had to do with valvetrain harmonics and the double row made them worse. Anyways those that were discussing it, was good enough reason for me to switch. I got a few single roller sets for my next builds. Got one in a car that has hundreds of 6000 RPM 1-2 &2-3 shift passes and when I checking the chain swapping bearings it seemed fine but I only had the oil pan off.

 

Also I like the idea of a larger single roller. FYI awhile back when I had the stuff out I compared the weighs, single chain is a bit heavier than a true double roller but not much.

 

I turned the motor by hand and it's unbelievable how close the sprockets are.

Thank you gents.

 

If the crankshaft or camshaft ever move enough for the sprockets to touch, you have more serious problems.

 

I would think that they would become "self-clearancing" if that happened. They would also provide both automatic audible and visual warnings, with a howling alert tone and sparkling indicators in the engine oil. Kinda cool, huh?

 

If you ponder that a little, it might be clear that the sprockets were manufactured to utilize the largest roller chain pitch possible in the space available and at the necessary ratio. That's probably a good thing, and why they are stronger.

 

Just watching the new Richard Holdner vid and saw another good single roller example



vid of course

 

Not a great picture to show without reference. I hope the video explains that when the timing marks are like that in the 6 and 12 locations that the distributor will be firing on #6 cylinder. It's easier to line up the gears like that instead of 12 and 12 o'clock but 12/12 puts #1 piston at TDC on the compression stroke.

 

Just a reminder for some, I guess....

 

The single vs double roller chain is one reason I am building my own 4x reluctor to go into my L31 distributor for my 58x swap. EFI Connection has screwed me by discontinuing their 4x cam sync they offered when I first started buying parts to 58x swap my SBC. Now they want $800 to get a 4x cam sync using a weak and garbage double roller chain setup. Their customer service rep also spoke down on me which was dissapointing to me since I have bought two different 24x setups and word of mouth to a buddy of mine sold another setup for him. The 4x cam sync was a very affordible option even paired with a Holley aluminum L31 timing cover vs their weak $800 custom option they want to push now.