[gtofreek]

Originally Posted by rexs73gto

I have a question? If the block has been line bored does it need to have the longer timing chain every time?? Also how do you know how much longer do you need??? Is it nessasery to use a longer chain each time when the block has been line bored?

No. We align hone almost every engine we build, and never need a shorter chain. I have found that in the cases were a chain is loose, it is the brand of timing set that usually causes it. Another set fits tight. I installed billet caps on a 400 Pontiac, had them align bored to within .015" of finished size, then align honed the rest out to size. When I measured the cam to crank centerline, it was only .0025" less than stock. A standard Rollmaster set fit tight. I have found that SA gear sets usually always seem to fit loose, and require the .005" under set. When measuring the root diameter of the two gears, then adding them together, I have found that the .005" under S.A. Gear sets add up to the same as the standard Rollmaster set.

I like the billet gear sets personally, especially with a roller cam.

[rexs73gto]

The reason I asked is I have the cloyes true roller & it is a little loose & wondered if I should take it back? It's not real loose but on the coast side I can move it about 1.4 inch in & out.

[grivera]

Originally Posted by rexs73gto

I have a question? If the block has been line bored does it need to have the longer timing chain every time?? Also how do you know how much longer do you need??? Is it nessasery to use a longer chain each time when the block has been line bored?

The line boring would bring the cam and crank tunnels closer together so if it were needed, it would be a "shorter" chain. In reality, those sets have larger gears not shorter chains- I'm not sure if it's the cam or crank gear that's made larger in diameter.

[gtofreek]

Originally Posted by rexs73gto

The reason I asked is I have the cloyes true roller & it is a little loose & wondered if I should take it back? It's not real loose but on the coast side I can move it about 1.4 inch in & out.

That is a lot! If you have some calipers, take them with you to the parts store, and measure the root diameter of the gears of the set you have now, add them together, then compare that to another set they might have. See if there is a set with a total .004"-.006" larger than what you have now. As Grivera said, it's the gears that are larger, not the chain shorter. They usually make each gear slightly larger. But I have found different measurements on the gears themselves. That's why you have to add them together, not just compare gear to gear.

[gtofreek]

When align honing, the vast majority of material is removed from the main caps, not the block, since it is the caps that are cut to produce a smaller bore diameter, and now out of round. The hone, hones the majority of metal from the most out of round areas, which is the cap. Because of this, the cam to crank centerline doesn't change much. On a normal align hone job, it's maybe .001".

[mgarblik]

I think that change of .001 approx. for each properly done line hone is right on. Just line honed one of our blocks for the 6th time and a -.005 chain set fits perfect.

[OCMDGTO]

With all the chain stretch issues, why not eliminate them and use a timing gear set up? My double roller chains have worked fine for me for years, BTW. I've always wondered about the gear only set up.

[grivera]

Originally Posted by Singleton

Yes, that's the old Mopar offset keys that used to be available, wish they would bring them back.
The only thing that summit has is the Mr Gasket 987G 2 degree cam key, which would be 4 degrees at the crank. So if you needed to advance or retard 1 or 2 degrees, it would be useless

I just found a couple of the Mopar offset keys I had stashed away- a red one and a natural color one. What degree offset do the colors signify? These are in original packaging and no sheet with specs...

[grivera]

Originally Posted by mgarblik

The Mercedes keys are about $15.00 each. 2 degree key #16075-01075664
3 degree key #6202-01075663 5 degree key # 6125-01075661. Available on-line.

Here is a link for the 2, 3, 4, and 5 degree if anyone is looking:

http://www.partsgeek.com/catalog/198...?brand=genuine

Amazon has these as well and they're eligible for free shipping with Amazon Prime

[grivera]

Originally Posted by grivera

I just found a couple of the Mopar offset keys I had stashed away- a red one and a natural color one. What degree offset do the colors signify? These are in original packaging and no sheet with specs...

I was wrong on the red, it's purple. Anyone know how many degrees offset purple is?

[HWYSTR455]

Ha! Must be a popular topic this year!

On both, double roller and link plate chains, the ones with the larger pins in them are the ones that last longer. Link type chains definitely stretch less. And I too have had personal experience with the Cloyes true rollers, they tend to be accurate and last fairly well. It's generally my go-to.

My question is: HOW MUCH does a double roller stretch?

I would like to hear first hand info that has been verified by degreeing, not a guess. I generally don't' degree a cam when I disassemble, so it's not clear to me actual numbers. But I've heard 1-3 degrees as memory serves me.

.

[BruceWilkie]

Originally Posted by mgarblik

The Mercedes keys are about $15.00 each. 2 degree key #16075-01075664
3 degree key #6202-01075663 5 degree key # 6125-01075661. Available on-line.

Thanks Mike

The alternative to offset keys is to drill sprocket and cam for a Ford pin(289/302/351/429/460 same) and use easier to find(usually cheaper as well) degree kits (for Fords) that use offset bushings.
The Ford cam nose/timing gear/retainer plate and pump ecentric look eerily familiar to our Pontiac except they use a pin(@5/16") instead of keyway.

Not something you attempt with a hand drill!
The "plus" to the Ford method is strength...offset keys get weaker as offset increases.

BTW Scat tech literature on crank breakage causes, used to recommend against 9 key way lower sprockets... Last I looked though it wasnt there anymore. Hmmm???

[mgarblik]

I was also concerned about the 9 keyway sprocket for use in the Nitro engine with all the harmonics, blower load and extreme valve train load. We cut an additional keyway in the crank snout so we are driving on two keys for extra insurance. The Cloyes 9 keyway sprocket is symetrical , so you can still get almost full adjustment and drive off two keys. So our crank shaft actually has 4 keyways. 2 square ones for the blower hub and the 2 woodruff keys for the timing set.

[Cliff R]

"My question is: HOW MUCH does a double roller stretch?"

I ran the Rollmaster in my last 455 and it survived fairly well for quite a few years. That engine was placed in service in the late 1990's and ended up being the test/proving grounds for the KRE heads:

http://www.hotrod.com/how-to/engine/...-dyno-results/

I also used that engine for my cam degree testing, moving it from 109 to 107, then 111, and on to 113ICL and recording all the results, etc. The Rollmaster is an EXCELLENT part when it comes to that sort of stuff, deadly accurate for cam movements, etc.

Each time I pulled the timing cover the chain was relatively tight, it seemed to stretch the most the first few hours that it was placed in service, then stayed about the same for several years. I was racing the car twice a week back then, and still driving it on the street nearly every day. I retired in 2003 and moved here to Ohio and opened up our shop. The car was still being raced but really starting to slow down, so I figured the engine was just getting "tired". I wanted to do a bearing inspection/replacement, and cam swap at the same time, to up the power level a bit.

To my surprise, when I pulled the engine down for the work, the timing chain was stretched out so far you could just about walk the chain off the gears!!!! The bearings were fine, cam/lifters in perfect shape, and hind sight being 20/20 I should have just put a new chain on it and put it right back in service.

Instead I opted to install a custom ground flat solid cam, which ended up being a "turd", then went to a custom ground HR cam, which $1000 later BARELY outran the old Crower 60919 cam. Got 3hp/4ft lbs torque for my efforts, and a HUGE rear seal leak that we ended up having to pull the engine back out for twice before getting it fixed. I retired that engine about 6 years ago, far as I know the replacement Rollmaster chain was still fine, the car hadn't slowed up any at the track and still idled fine, etc.

Anyhow, the new 455 uses the Melling link plate timing set. It's been in place now quite a few years, and I've inspected in 3 times. Just had the timing cover off last month, the chain stretched out a little at the very beginning, and hasn't really changed since. There's about 3/8"-1/2" slop in it, gears are in mint condition, and I'm going to leave it in place and keep inspecting in on occasion to see how it holds up in long term service.

Going back thru all my years of doing this stuff, both times I've tried "double roller" timing sets in engines they failed. I did one very early on in an SBC build in the mid-1970's. After that deal went to factory link plate sets, and didn't try another double roller till the Rollmaster deal above. Done with them here in my own engines.....FWIW.....Cliff

[mgarblik]

Cliff, if you are willing to wait, I will have a good answer for you under the most extreme conditions by September. I am building a fresh engine for the Boss Bird this week. It will use the best stuff Cloye's makes, Billet gears and IWIS chain. We will run it all year and I will take careful measurements before we tear down at the end of the season and I will get back. I don't have any reliable numbers to give you now.

[Cliff R]

Here's what I do know about this topic.

The high end billet sprocket stuff with the good chains are very accurate for cam movements and hold up pretty well.

Any "true roller" type set-up less than that is probably fine for 99 percent of these applications.

The stock replacement Melling set will go 100,000 miles with a flat cam, and probably twice that far with a roller cam set-up. The stock sets are strong, reliable, relatively quiet, and the constant tooth contact design reduces harmonics and I see the timing marks on the balancer bouncing around less when I follow them with a timing light when we are making dyno pulls.

So there may be some ever so slight advantage with the link plate sets, as one of the "old timers" I knew years ago suggested.

In the big scheme of things what set you choose really doesn't matter all that much, as long as you are able to effectively degree the camshaft. None of them break easily, or wear slam out quickly. Very few folks use these vehicles for "daily driving", most are casual use, and many will not see 10,000 miles in the next 30 years.

Since most of these vehicles now fall into the "toy" category, the timing set choice becomes less important, as nearly any set you find from any source is going to do pretty well short term/low mileage.

Even with that said, it still pays to go to the upper end of the range rather than the lower end, just to sleep a little better at night if nothing else.

I've ran the gauntlet with timing chains, and my own engines get the stock replacement link plate sets, because I like the design, the strength, and have had 100 percent success with them. I also have the ability and don't mind spending the extra time to degree them.

Most of the custom engines we build get the Rollmaster 9 keyway set. It's a good quality part, and degreeing the cam is simple and accurate.

We can kick this topic all over the map, and run it out for many pages, the basic facts don't change. Pretty much any decent set you buy will do a fine job of keeping the cam turning with the crank, and not wear out in 6 months or break and bend half the valves in your heads. We really don't know about long term service for most of the choices out there, feedback is spotty in that area, and to me it really makes no sense at all to go to a "low end" or even a "mid-range" set for your new engine build. Cowboy up and buy the good stuff, and go worry about something else......FWIW......Cliff

[dmac]

I see no answers about using gear drives- is it the expense, reliability, or ????????

[zeebo]

cliff, what are the part numbers for timing sets you recommend for a 1976 chevy 350 and a 1973 pontiac 400 both mild builds and daily drivers in the summer months. thanks..the IM isnt working....cliff s.

[lust4speed]

Originally Posted by dmac

I see no answers about using gear drives- is it the expense, reliability, or ????????

Always heard the down side of the gears was the harmonics and the resultant spark scatter.

[Cliff R]

For small block Chevy (pre-1987) builds I use the 3-489S, which is the 3/4" wide link plate set for the early engines, not the 5/8" wide set the later engines used. The 5/8" set is part number 3-499S.

For Pontiac engines I get the stock replacement set from NAPA, don't have the part number handy, but it will be the wide link plate set.

As it relates to this topic we assembled a really nice 455 last year with 310cfm KRE heads, and hefty solid roller cam. The owner provided one of those "mid-range" Cloyes true roller sets with the iron gears and 3 keyway design, same as the one in the pic that B-man has been showing on his 421 thread. Chain was nice and tight, cam timing came right in without having to move it around, etc. When we fired the engine and went to time it, we were rewarded with a nice "bounce" at the timing marks which was pretty noticeable at idle speed, the mark was going back and forth about 3/16" on the balancer. The "bounce" continues thru the entire rpm range. We ended up tossing the MSD billet due to some issues it had, and put in one of our HEI distributors, but the "bounce" continues.

I can't remember a single build we've done with one of those timing sets that didn't do the same thing, some a little worse, some not quite so bad, but they all "bounce" some. As mentioned previously, not really a big player in the big scheme of things, that engine pushes a pretty heavy car into the 10's without much effort.........Cliff