Engine Harmonics and Timing Chain Stretch
#1
Engine Harmonics and Timing Chain Stretch
Hi
I have a '70 455, mild build, 230⁰ at 50, roller rockers, 9.3 to 9.5 to 1 compression, 4speed, 4.10 gears, torker single plane intake,,, that i rebuild a long time ago but it has really low hours on it.
I am not sure of the timing chain brand i installed decades ago. Looks exactly like 1st pic.
It is a double chain, but not roller chain, with adjustable keyway for changing the cam timing.
IMHO there is way to much slack in the chain.
I found this confusing. I saw a simple video that said the timing chains with adjustable cam timing can have premature wear.
I have a few questions (i searched but didnt mind info)...
1- is it true that adjustable gears setup wear due to engine harmonics?
2- I want to install a true, real roller chain. I'm looking at Cloyes. But my knowledge is 30 years old so companies that used to be great might not be anymore. See attachment for what I'm thinking of getting. Do you have a recommendation for double roller chain set up?
3-The setup installed was at factory, 0⁰ advance.
Should i use a non adjustable setup since i didnt previously advance or retard the cam timing?
4- are direct drive gears are a viable option? How noisey are they? Good things? Bad things? Tranfer more crank harmonics ?
My main concern is that there was just too much slop in the setup.
On my dirtbikes you can measure the chain stretch and see the gear wear but it's difficult and/or irrelevant where the play is from.
Thanks
I really appreciate the detailed replies.
OldOldsLover (paul)
I have a '70 455, mild build, 230⁰ at 50, roller rockers, 9.3 to 9.5 to 1 compression, 4speed, 4.10 gears, torker single plane intake,,, that i rebuild a long time ago but it has really low hours on it.
I am not sure of the timing chain brand i installed decades ago. Looks exactly like 1st pic.
It is a double chain, but not roller chain, with adjustable keyway for changing the cam timing.
IMHO there is way to much slack in the chain.
I found this confusing. I saw a simple video that said the timing chains with adjustable cam timing can have premature wear.
I have a few questions (i searched but didnt mind info)...
1- is it true that adjustable gears setup wear due to engine harmonics?
2- I want to install a true, real roller chain. I'm looking at Cloyes. But my knowledge is 30 years old so companies that used to be great might not be anymore. See attachment for what I'm thinking of getting. Do you have a recommendation for double roller chain set up?
3-The setup installed was at factory, 0⁰ advance.
Should i use a non adjustable setup since i didnt previously advance or retard the cam timing?
4- are direct drive gears are a viable option? How noisey are they? Good things? Bad things? Tranfer more crank harmonics ?
My main concern is that there was just too much slop in the setup.
On my dirtbikes you can measure the chain stretch and see the gear wear but it's difficult and/or irrelevant where the play is from.
Thanks
I really appreciate the detailed replies.
OldOldsLover (paul)
Last edited by OldOldsLover; March 26th, 2022 at 04:37 PM.
#3
There are many kinds of adjustable timing gears. Some, like the ones in the photos, use multiple keyways. Some use offset bushings for the dowel pin in the cam gear. Some use retaining bolts on the cam gear that only lock it into position with friction. That last one is the only one that could POSSIBLY slip. Wear is a non-issue - I have no idea where you heard this. Adjustable gears are to allow you to set up the cam properly. That means degreeing the cam at installation. Every cam, engine, and timing set will have machining tolerances. The adjustable gear set allows you to correct for this. If you don't plan to do this, then 1) you may be giving up performance, and 2) you don't need to spend money on an adjustable set.
#5
#6
There are many kinds of adjustable timing gears. Some, like the ones in the photos, use multiple keyways. Some use offset bushings for the dowel pin in the cam gear. Some use retaining bolts on the cam gear that only lock it into position with friction. That last one is the only one that could POSSIBLY slip. Wear is a non-issue - I have no idea where you heard this. Adjustable gears are to allow you to set up the cam properly. That means degreeing the cam at installation. Every cam, engine, and timing set will have machining tolerances. The adjustable gear set allows you to correct for this. If you don't plan to do this, then 1) you may be giving up performance, and 2) you don't need to spend money on an adjustable set.
What's got me bothered is there was way to much play in a setup with such little time on it.
the double chain was not a true roller chain an maybe that's why.
the next set will be a true roller chain..
The cam isn't even that radial..it's comp cam magnum 280H which is 230 at 50.
lift at cam is .306 then w 1.6 rocker it's. 49
thanks
Last edited by OldOldsLover; March 27th, 2022 at 12:31 PM.
#7
#8
The now discontinued Cloyes Street roller timing set had slack new. After a few thousand miles, it was very slack, looked like the top picture with a 3 way adjustable crank gear. That Cloyes Premium set in the bottom pic is much better for fit and about the best on the market. Any set you get, degree it, some sets are multiple degrees off spec. I couldn't find an Olds timing set through Howards Cam. Good luck.
Last edited by olds 307 and 403; March 27th, 2022 at 02:19 PM.
#9
So what exactly is "too much" ?????? I have found that a lot of chains stretch a fair amount almost immediately but then they stay the same forever after that. Personally I try to use Cloyes whenever possible. Over the years they have been the most consistent and high quality.
Was the block align honed ?
Was the block align honed ?
#10
I installed Cloyes 93513 set in mine. Runs like a champ. I've not heard anything negative about Cloyes. I'm a garage mechanic and have used Cloyes sets three times. Never an issue for me.
#11
Cloyes is still top dog in timing sets, at least for what's available for Olds. BTR makes his own sets. RR might also.
As Joe said, if you're not degreeing the cam then it doesn't particularly matter. The 0 degree mark could be off by 4 degrees or more. The no-name sets (e.g. Summit) have been known to be several degrees off from their markings. Cloyes tends to do better, but you still have variables that means it really should be checked. But, ignorance is bliss, and in the end it probably doesn't *really* matter.
In my personal experience, the timing sets tend to install further retarded than the marked indications.
I'm pretty sure there's no gear drive made anymore. Some were made in ... the 80s, maybe? BTR or RR might have some or be willing to make some. But, you're getting into esoteric land there. Gear drives just haven't been used very much for quite a while. They are noisy, but some like the noise.
IMO the Cloyes billet sets are well worth the money. That's also the only way now to get undersize sets. If a stock size set - of good quality - still has slack then you might need to switch to an undersize.
As Joe said, if you're not degreeing the cam then it doesn't particularly matter. The 0 degree mark could be off by 4 degrees or more. The no-name sets (e.g. Summit) have been known to be several degrees off from their markings. Cloyes tends to do better, but you still have variables that means it really should be checked. But, ignorance is bliss, and in the end it probably doesn't *really* matter.
In my personal experience, the timing sets tend to install further retarded than the marked indications.
I'm pretty sure there's no gear drive made anymore. Some were made in ... the 80s, maybe? BTR or RR might have some or be willing to make some. But, you're getting into esoteric land there. Gear drives just haven't been used very much for quite a while. They are noisy, but some like the noise.
IMO the Cloyes billet sets are well worth the money. That's also the only way now to get undersize sets. If a stock size set - of good quality - still has slack then you might need to switch to an undersize.
#12
Some vague info here.
NOBODY makes their own timing sets, not BTR, not Rocket, nobody like that. They’re all done for them..
A std 9-3513-x9 Cloyes is a good set, but it’s not a truly “matched” set. However the 9-3613x9 is. You’ll see a difference in the fit apples to apples.
And a lot of times you’ll see “Made in the USA” on the sprockets. But that doesn’t mean the chain was made here too. Often times they’re made somewhere else, ie China and India are the most popular origins these days.
Hope this helps.
NOBODY makes their own timing sets, not BTR, not Rocket, nobody like that. They’re all done for them..
A std 9-3513-x9 Cloyes is a good set, but it’s not a truly “matched” set. However the 9-3613x9 is. You’ll see a difference in the fit apples to apples.
And a lot of times you’ll see “Made in the USA” on the sprockets. But that doesn’t mean the chain was made here too. Often times they’re made somewhere else, ie China and India are the most popular origins these days.
Hope this helps.
Last edited by cutlassefi; April 2nd, 2022 at 09:17 AM.
#13
I'm going to use 9-3613x9
Cheers!
Last edited by OldOldsLover; March 30th, 2022 at 09:10 PM.
#14
#17
#18
Cloyes, among others, has what the blueprint dimension is between the cam and crank centerlines. Their gears are machined in batches. The std 3513 set gets gears from these batches at random. The MATCHED sets get gears hand selected that will more closely give the correct center to center dimension, hence typically a “tighter” chain right out of the box.
#19
Some vague info here.
NOBODY makes their own timing sets, not BTR, not Rocket, nobody like that. They’re all done for them..
A std 9-3513-x9 Cloyes is a good set, but it’s not a truly “matched” set. However the 9-3613x9 is. You’ll see a difference in the fit apples to apples.
And a lot of times you’ll see “Made in the USA” on the sprockets. But that doesn’t mean the chain was made here too. Offers times they’re made somewhere else, ie China and India are the most popular origins these days.
Hope this helps.
NOBODY makes their own timing sets, not BTR, not Rocket, nobody like that. They’re all done for them..
A std 9-3513-x9 Cloyes is a good set, but it’s not a truly “matched” set. However the 9-3613x9 is. You’ll see a difference in the fit apples to apples.
And a lot of times you’ll see “Made in the USA” on the sprockets. But that doesn’t mean the chain was made here too. Offers times they’re made somewhere else, ie China and India are the most popular origins these days.
Hope this helps.
I have been known to even question Cutlassefi on occasion.
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