How to Choose Timing Gear?

In this Summit Racing Quick Flicks video, Al discusses the basic differences between timing chain, timing gear, and timing belt drive systems.

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Learn how to determine which timing set will work best for your street machine or race car.

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Author: OnAllCylinders Staff

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you can make this complicated but its really not, a good dual roller chain by CLOYES fits under the stock cover and is the correct choice in about 90% or more of the carburetor equipped engines that don,t run really exotic components and probably a reasonable choice in the remaining 10%, if you have any questions you may want to call or cloyes and get suggestions like Ive done several times, but I think youll find the standard cloyes roller timing sets do a decent job.
its also a real good idea to drill the pass side oil plug under the timing cover with a .030-.035 drill so oil constantly sprays on the timing chain during use,and while IM discussing cam timing sets Id say that about 90% of the time a good CLOYES timing chain set should be used on street cars vs a gear drive if that's one option your thinking about.






READ THE LINKED INFO CAREFULLY
http://garage.grumpysperformance.co...ped-nose-cam-in-early-block./#post-

http://garage.grumpysperformance.com/index.php?threads/semi-fool-proof-cam-sellection.82/

http://garage.grumpysperformance.co...-street-roller-cam-selection./#post-

http://garage.grumpysperformance.co...a-better-cam-to-a-zz3-350-sbc.182/#post-

a basic timing chain set like this from cloyes works great in most SBC applications
https://www.summitracing.com/parts/CLO-9-/
FIRST GEN, SBC CLOYES ROLLER TIMING SET
https://www.summitracing.com/parts/clo-9-/overview/

MARK IV BBC CLOYES ROLLER TIMING SET -90
https://www.summitracing.com/parts/clo-c-x/overview/

MARK VI BBC CLOYES ROLLER TIMING SET -95
https://www.summitracing.com/parts/...-specific/engine-family/chevy-big-block-gen-v




above is a picture of how a typical timing chain looks with the DOT-TO-DOT install having the crank gear at 12 o'clock ,(B) and cam gear (A)indexed at 6 o'clock, NOTICE THE WOOD RIFF KEY AT 2 O'CLOCK,IF ITS ANYPLACE ELSE YOU HAVE IT INDEXED INCORRECTLY(C) naturally youll need to rotate the engine one full revolution to get the upper gear index to 12 o'clock and the lower gear back to 12 o'clock before dropping in the distributor

http://www.butlerperformance.com/produc ... Chain.html (pontiac)

keep in mind the KEYWAY matched to the matching index mark will always be located at approximately 2 O'clock on the crank gear
ON CLOYES SETS the SHORTER CHAINS used ON LINE HONED BLOCKS ,GENERALLY HAVE A PART NUMBER ENDING IN EITHER -5 or _10 INDICATING A .005 or . TIGHTER timing set
read THESE links
http://garage.grumpysperformance.com/index.php?threads/timing-chains-stretch./#post-

http://garage.grumpysperformance.co...hanics-of-adv-ret-a-camshaft./#post-

http://garage.grumpysperformance.co...et-it-to-last-cam-install-info.90/#post-

http://garage.grumpysperformance.co...nter-1-for-timing-ignition-cam.966/#post-

http://garage.grumpysperformance.co...e-train-clearances-and-problems.528/#post-668

http://garage.grumpysperformance.co...king-piston-to-valve-clearances.399/#post-488

http://www.competitionproducts.com/Camshaft-Degreeing-and-Cam-Measuring-Tools/products//
THERE ARE TIMING CHAIN TENSION-ER KITS AVAILABLE
http://www.speedwaymotors.com/S-B-Chevy ... ,.html



drilling the pass side oil passage plug with a 1/32" bit so oil constantly sprays on the timing gears helps extend chain and gear life.
Ive occasionally been asked what you can do too reduce the slack in the timing chain if your blocks been line honed,
to straiten the main bearings and that resulted in a slightly closer crank to cam center-line distance,
that results in a slightly increased slack in the stock timing chain sets.
a negligible amount of metal is generally removed from the main bearing saddles in the block, they usually try very hard to minimize that, metal removal so standard parts still fit,during a line hone , but they do sell slightly tighter timing chain sets to correct excess slack if that's required.




the double roller cloyes timing chains tend to last longer before they wear and have excess slack
and they can be used with the stock O.E.M timing chain cover




TRUE DOUBLE ROLLER TIMING CHAIN SETS FROM QUALITY MANUFACTURERS TEND TO BE MORE DURABLE





https://www.summitracing.com/parts/clo-9--5
Timing Chain and Gear Set, Original True Roller, Double Roller, -0.005 in., Iron/Steel Sprockets, Chevy, Small Block, Set
for line honed blocks where the crank is .005 closer to the cam


https://www.summitracing.com/parts/clo-9--10
for line honed blocks where the crank is .010 closer to the cam
Timing Chain and Gear Set, Original True Roller, Double Roller, -0.010 in., Iron/Steel Sprockets, Chevy, Small Block, Set

related info
http://garage.grumpysperformance.co...ped-nose-cam-in-early-block./#post-

http://garage.grumpysperformance.com/index.php?threads/cam-drive-details./#post-

http://garage.grumpysperformance.co...hanics-of-adv-ret-a-camshaft./#post-

http://garage.grumpysperformance.co...-get-it-to-last-cam-install-info.90/#post-114

http://garage.grumpysperformance.com/index.php?threads/cam-spacer-buttons./#post-

http://garage.grumpysperformance.com/index.php?threads/chain-vs-gear-drive-cam.781/


ALL TIMING CHAINS STRETCH OVER TIME, the BETTER/MORE EXPENSIVE ONES TEND TOO LAST FAR LONGER, and PROPER LUBRICATION HELPS THEM LAST LONGER
yes you can spend a good deal more and buy a billet roller timing chain, but the fact remains that the cloyes true roller timing chain sets that cost less do an adequate job with very few failures so they are a great value
this is what most sbc engines use
http://www.summitracing.com/parts/CLO-9 ... refilter=1

http://www.jegs.com/i/Cloyes/220/9-X9//-1

IVE used dozens of these on SBC applications without one failing

http://www.summitracing.com/parts/clo-9-

don,t forget these if its an early non roller application
CLOYES # Fits - TPI Corvettes with Factory Roller Cams.
$104.79 Summit Racing.
http://www.summitracing.com/parts/clo-9-x3
- $239.97

LT1 stock cam sprocket (93-94) =
LT1 stock cam sprocket (95-97) =


http://www.summitracing.com/parts/cca-202

http://www.summitracing.com/parts/man-/overview/

http://www.carid.com/loctite/272-high-t ... fgodAgUADA

http://garage.grumpysperformance.co...ng-cam-and-shifting-the-lca./#post-
READ THRU THESE CAREFULLY


LT1




http://www.cloyes.com/Aftermarket/TechH ... fault.aspx
YOU CAN AVOID POTENTIAL CONFUSION & PROBLEMS IF YOU TAKE THE TIME TOO, DEGREE THE CAMSHAFT IN, instead of relying on "dot-to-dot".
theres a BIG difference in quality between the entry level and good quality parts made/ sold by cloyes

http://www.summitracing.com/parts/CLO-9 ... refilter=1
($92)

http://www.summitracing.com/parts/CLO-C-X/ ($21)

http://www.summitracing.com/parts/CLO-9-A/ ($132)
http://static.summitracing.com/global/i ... 00a%20.pdf


look closely theres three crank key slots and each is marked, with the crank key (R or rectangle) =(retarded 4 degrees) (0) strait up) and (A or triangle) =(advanced 4 degrees) located at approximately the 2 0,clock position the related mark(R or rectangle)= (retarded 4 degrees) (0) strait up) and (A or triangle) advanced 4 degrees) is at the 12 o,clock location that you use to line up with the cam gear while thats indexed at approximately the 6 o,clock location






CHEAP LINK CHAINS TEND TO STRETCH FASTER


dual roller chains tend to last significantly longer

http://garage.grumpysperformance.com/index.php?threads/timing-chains-stretch./#post-


The Cloyes® Patented 3-Keyway crank sprocket allows adjustment of the crankshaft timing by ±4°.


look closely theres three crank key slots and each is marked, with the crank key (R or rectangle) =(retarded 4 degrees) (0) strait up) and (A or triangle) =(advanced 4 degrees) located at approximately the 2 0,clock position the related mark(R or rectangle)= (retarded 4 degrees) (0) strait up) and (A or triangle) advanced 4 degrees) is at the 12 o,clock location that you use to line up with the cam gear while thats indexed at approximately the 6 o,clock location, its fairly common to screw this up if your not paying attention and that can result in bent valves

Remember: The camshaft angle is half of the crankshaft angle, therefore the camshaft will correspondingly advance or retard by ±2°.

By changing the cam timing, enhancements to the camshaft characteristics can be achieved. For example, retarding the cam timing will increase high RPM horsepower, and advancing the cam timing will increase low-end torque.


I generally just use one of these two cam drives on a SBC, (usually the chain drives on most engines)

gear cam drives tend too, at least in theory to be more accurate, Ive used one in almost all of my corvette engines for many years, but it can drive knock sensors crazy on efi systems and its generally not going to provide much of an advantage at the rpm levels most street engines operate at.
http://www.summitracing.com/parts/CLO-9-/

http://www.summitracing.com/parts/SUM-G-Q/

http://www.summitracing.com/parts/CLO-9 ... refilter=1




related threads



yes there is a good reason to avoid those cheap import timing chain sets that auto parts stores frequently sell for under $30.........heres one with less than an hours of run time


CROSSFIRE



LT1/LT4


LT5

L98
just want to say that grump's advice to stick with the CLOYES roller link timing chain sets is spot on!
http://www.summitracing.com/parts/CLO-9 ... refilter=1
a basic timing chain set like this from cloyes works great in most SBC applications
https://www.summitracing.com/parts/CLO-9-/

the Cloyes 9-X3-5. Single roller with billet crank gear for the newer single roller BIG BLOCK CHEVY MARK V- and ESPECIALLY MARK VI with plastic timing cover engines that won,t allow use of the older thicker dual roller chain timing sets.
we pulled down my friends small block Chevy after it only had 54,000 miles on a auto parts store bargain basement $21 timing chain ,IT HAD INDIA STAMPED ON THE TOP GEAR
The timing drive system in your engine is just that, a system, with inter-related components. For "peace of mind", to reduce the chances of having to re-do the job,and to reduce the chance of future problems,with the timing set, and for continued dependability & performance, it is strongly recommended that all components (gears and chain as a matched set) are replaced together, as a unit.

TRUE DOUBLE ROLLER TIMING CHAIN SETS FROM QUALITY MANUFACTURERS TEND TO BE MORE DURABLE


the double roller cloyes timing chains tend to last longer before they wear and have excess slack
and they can be used with the stock O.E.M timing chain cover


This looks like a darn bargain
the double roller cloyes timing chains tend to last longer before they wear and have excess slack
and they can be used with the stock O.E.M timing chain cover



http://garage.grumpysperformance.com/index.php?threads/timing-tabs-and-indicators./#post-

https://www.ebay.ca/itm/SB-Chevy-Ch...?hash=item2a6ce:g:jPgAAOSwRgJXiXxM

TRUE DOUBLE ROLLER TIMING CHAIN SETS FROM QUALITY MANUFACTURERS TEND TO BE MORE DURABLE



and his current gear set that he had installed previously because he wanted to install a new cam,when he previously rebuilt the engine was a $21 auto parts store imported no-name part, link belt design

with its single tooth design gears


not roller link design, with its dual teeth and roller link chain

YOU CAN AVOID POTENTIAL CONFUSION & PROBLEMS IF YOU TAKE THE TIME TOO, DEGREE THE CAMSHAFT IN, instead of relying on "dot-to-dot".
TRUE DOUBLE ROLLER TIMING CHAIN SETS FROM QUALITY MANUFACTURERS TEND TO BE MORE DURABLE

the double roller cloyes timing chains tend to last longer before they wear and have excess slack
and they use the stock O.E.M timing chain cover

http://garage.grumpysperformance.co...le-valve-timing-kit-chev-sb./#post-

http://garage.grumpysperformance.com/index.php?threads/timing-chains./#post-

http://garage.grumpysperformance.com/index.php?threads/how-to-pick-timing-gear-set./#post-

a basic timing chain set like this from cloyes works great in most SBC applications and fits under the stock stamped steel timing cover
https://www.summitracing.com/parts/CLO-9-/




and the timing light indicated there was some play in the timing as it jumped as rpms changed and there was a good deal of slack in the chain links even though he changes oil frequently and there was very little indication of varnish or sludge build-up on the parts indicating that the oil had been changed regularly.
on opening the timing cover there was contact marks at one point on the inside of the timing cover where the slack timing chain was just barely touching the inner timing covers outer surface at times so I have little doubt that he prevented a major failure by replacing the timing chain,gears and cam/lifters etc

related threads
http://garage.grumpysperformance.com/index.php?threads/chain-vs-gear-drive-cam.781/#post-

http://garage.grumpysperformance.com/index.php?threads/timing-chains-stretch./#post-

http://garage.grumpysperformance.com/index.php?threads/how-to-pick-timing-gear-set./#post-

http://garage.grumpysperformance.com/index.php?threads/cam-degreeing./#post-

http://garage.grumpysperformance.com/index.php?threads/timing-chains./#post-

http://garage.grumpysperformance.co...rect-variable-valve-timing-kit-chev-sb./

http://garage.grumpysperformance.co...get-it-to-last-cam-install-info.90/#post-

http://garage.grumpysperformance.com/index.php?threads/cam-spacer-buttons./#post-

http://garage.grumpysperformance.com/index.php?threads/how-to-pick-timing-gear-set./#post-

http://garage.grumpysperformance.com/index.php?threads/timing-chains-stretch./#post-

http://garage.grumpysperformance.co...s-a-flat-tappet-design./page-2#post-