timing chain V.s gear drive
d-racer
advantages over a good quality timing chain or if its better to put my
buck's on something else
bye the way the engine vill only be used for bracket racing
any answer appriciated
d-racer
Rob E. Zwissler
weights (or friction?) of a gear drive can rob 10-15 hp over a double
roller. I believe a lot of gear drives require some machining to the
block (don't know to what extent)... I went with a nice Crane chain...
later
Rob
In alt.autos.rod-n-custom d-racer <drag.r...@spamswipnet.se> wrote:
: hi i'm about to rebuild my 454 iand I wonder if the gear drive give any
Bob Hoffman
Can anyone back this statement up?
Rob E. Zwissler <ro...@masu.wwa.com> wrote in message
news:A0ta4.1769$h3.6...@ord-read.news.verio.net...
Le Grande Raoul
advantage of a gear drive was that the cam timing was more stable- no
problems with chain stretch, worn cogs, etc., etc. Also, since the timing
with gears was so stable, small amounts of timing changes could be made
for performance gains.
10-15 HP loss gear to chain sounds like quite a bit but, as with
everything, it could be. Anyone seen a side-by-side dyno test?
Jeff
> I'm no expert on this, but I was told by a Comp Cams tech that the higher
> weights (or friction?) of a gear drive can rob 10-15 hp over a double
> roller. I believe a lot of gear drives require some machining to the
> block (don't know to what extent)... I went with a nice Crane chain...
>
> later
>
> Rob
>
>
> In alt.autos.rod-n-custom d-racer <drag.r...@spamswipnet.se> wrote:
> : hi i'm about to rebuild my 454 iand I wonder if the gear drive give any
> : advantages over a good quality timing chain or if its better to put my
> : buck's on something else
> : bye the way the engine vill only be used for bracket racing
> : any answer appriciated
> : d-racer
--
"The Road To Hell is paved with unclaimed stuffed dogs.."
-Ernest Hemingway, "The Sun Also Rises"
Rob E. Zwissler
stretch... tho I was also under the impression that a stretched timing
chain was more of a high mileage problem. Will a good double roller
stretch significantly enough for a measurable difference? What kinda
rpms are we talking before this becomes a problem?
Later
Rob
In alt.autos.rod-n-custom Le Grande Raoul <ra...@olympus.net> wrote:
: Again, *I'm* no expert on these matters, but I always thought that the
John Kunkel
>
> hi i'm about to rebuild my 454 iand I wonder if the gear drive give any
> advantages over a good quality timing chain or if its better to put my
> buck's on something else
> bye the way the engine vill only be used for bracket racing
> any answer appriciated
Gear drives do rob HP but the exact number depends on variables. One
thing they also do is transmit nasty harmonics from the crank to the
valvetrain and, since the valvetrain has its own harmonics, the two
together can have a damaging effect. A timing chain or, better yet, a
belt drive tend to dampen the harmonics.
John
Larry Heath
As to power losses I have seen some cost power and some gain power.
The question is, are you a "class racer" that 10 hp is a big deal to?
If not I would take the advantage of stable timing and no ware, chain
stretch ect.
I don't care whose chain you use if you run a racing roller cam you are
going to stretch the chain.
Disadvantages are they are more costly and may require some machine work.
Let me leave you with this thought, do you see many chain drives on pure
racing engines?
Later Larry
"Rob E. Zwissler" <ro...@masu.wwa.com> wrote in message
news:sBta4.1770$h3.6...@ord-read.news.verio.net...
> I was under the impression that a good quality timing chain would not
> stretch... tho I was also under the impression that a stretched timing
> chain was more of a high mileage problem. Will a good double roller
> stretch significantly enough for a measurable difference? What kinda
> rpms are we talking before this becomes a problem?
>
> Later
>
> Rob
>
>
> In alt.autos.rod-n-custom Le Grande Raoul <ra...@olympus.net> wrote:
> : Again, *I'm* no expert on these matters, but I always thought that the
> : advantage of a gear drive was that the cam timing was more stable- no
> : problems with chain stretch, worn cogs, etc., etc. Also, since the
timing
> : with gears was so stable, small amounts of timing changes could be made
> : for performance gains.
>
> : 10-15 HP loss gear to chain sounds like quite a bit but, as with
> : everything, it could be. Anyone seen a side-by-side dyno test?
>
> : Jeff
>
> :> I'm no expert on this, but I was told by a Comp Cams tech that the
higher
> :> weights (or friction?) of a gear drive can rob 10-15 hp over a double
> :> roller. I believe a lot of gear drives require some machining to the
> :> block (don't know to what extent)... I went with a nice Crane chain...
> :>
> :> later
> :>
> :> Rob
> :>
> :>
> :> In alt.autos.rod-n-custom d-racer <drag.r...@spamswipnet.se> wrote:
> :> : hi i'm about to rebuild my 454 iand I wonder if the gear drive give
any
> :> : advantages over a good quality timing chain or if its better to put
my
> :> : buck's on something else
> :> : bye the way the engine vill only be used for bracket racing
> :> : any answer appriciated
Grape Ape
transmitted through it. Use a good damper to limit vibrations.
--
Grape Ape www.ulster.net/~nubb
"Bob Hoffman" <bhof...@adaptivemerchant.com> wrote in message
news:khta4.9961$fH.4...@news1.rdc2.tx.home.com...
Lifespeed
<lgh...@sunline.net> wrote:
> Let me leave you with this thought, do you see many chain drives
> on pure racing engines?
No, but you don't see many gear drives, either.
Belt drive is the ultimate, but impractical for the street.
A good chain is ideal for the street. The gear-drive harmonics issue is
very real. Most street rollers won't stretch the chain that quickly,
either.
When my big block gets to 80K miles, I'll change out the true-roller
for a new one. I tore it down at 30K, due to a cylinder head issue, and
found little stretch. Not maintenance-free, but reasonable.
- Lifespeed
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
The fastest and easiest way to search and participate in Usenet - Free!
Jim Harvey
to take advantage of the gear drives inherent positives. For an average
bracket motor , a gear drive will not add anything more than noise ( which
can be the desired effect anyway). The added expense fo a gear drive isn't
going to provide enough of a benefit to you to justify the cost. Modern
double roller chain setups are adjustable and will last longer than the
motor probably will.
JIm Harvey
Harvey Racing Engines
Frank Williamson
advantages over a good quality timing chain
Well.. built a canadian block '454' ..velasco crank, titanium rods and
boring took it to 529ci.. .717" Crane roller.. Mondello Nascar heads ..
..Team 'G weiand intake with two 1050 dominators.. and port injected Nitrous
.. it was a 'good' motor..redline was 7k RPM..had a limiter so it wouldn't
break itself if something came apart in the drivetrain..
..used a crane double roller chain on it.. ran fine for two years.. built
it for a customer long ago.. first thing it did in a caged '68 camaro was
blow up a Ford 9" rear (LOL .. told the owner he would need a Dana with all
the toys to hold it)
..and it was a 'powerglide' car.. bracket 1 racer.. consistent as the day is
long.
I left the area .. dunno if the owner still runs it or not.
Was a real hoot to race the motorcycle boys in.. just annihilated 'em.
(primer gray '68 camaro .. looked like any backyard hot rod project car. .
snuck up on a *whole* lotta street racers :)
-GE
Tascarella
Lifespeed <life_...@hotmail.com> wrote in message
news:00844d40...@usw-ex0101-005.remarq.com...
> In article <84dqn...@enews4.newsguy.com>, "Larry Heath"
> <lgh...@sunline.net> wrote:
>
> > Let me leave you with this thought, do you see many chain drives
> > on pure racing engines?
>
> No, but you don't see many gear drives, either.
>
> Belt drive is the ultimate, but impractical for the street.
>
If Belt drive is so impractical for the street, then why do almost all new
engines come with a belt driven cam? Not a flame, but an honest question.
Grape Ape
poor dust covers, which isn't a problem at the track. On the street dirt and dust can get in there,
and belts don't like foreign objects very much. Jessel makes a nice unit that clears the stock
cover, but the $700 figure still makes it impractical.
--
Grape Ape www.ulster.net/~nubb
Josh Lee
Grape Ape wrote in message ...
To convert a big block Chevy to a belt drive would be about $700. Most
aftermarket belt drives have poor dust covers, which isn't a problem at the
track. On the street dirt and dust can get in there, and belts don't like
foreign objects very much. Jessel makes a nice unit that clears the stock
cover, but the $700 figure still makes it impractical.
-
If Belt drive is so impractical for the street, then why do almost all new
engines come with a belt driven cam? Not a flame, but an honest question.
I would go with a belt drive, if I had the cash, just use the ones with a
cover. A lot of new production cars come with belt drives. Even the best
double roller chain going to stretch, but its usually a predictable (and
therefor you can compensate for it, advance the cam) amount, about 3 to 5
degrees. And from what I've found its stretches early on in the motors life.
Then it doesn't stretch much more after that. A gear drive is accurate, and
it really will not move. But on a street driven car it will kill the
valvetrain a lot faster then a chain or belt. Harmonics are killers, even
with the best harmonic damper a gear drive are harder on the motor. Though
if you want your car to sound likes its got a blower, go for a noisy gear
drive. I think but am not sure, chains make more power than gears, belts are
even better.
Jim Harvey
Completely different animal. Stock OEM belts are differeent from Race Belt
Drives ( usually a Gilmer type belt) OEM do not allow for adjustments to the
degree that race units do, Race units are designed to be serviced frequently
while OEM units are designed to be forgotten about for at least 50K miles.
Run race equipment on race cars and something else on daily drivers and
you'll be much happier and have more money in your pocket and you car will
be exactly as fast as it would have been with all the trick shi*.
Jim Harvey
Josh Lee <g...@qnet.com> wrote in message news:386c1...@news.qnet.com...
Lifespeed
aftermarket Jessel-type belt drives, but I've not used one, so I'm
unsure.
An then, there is the whole accessory mounting issue.
Grape Ape
They are thin belts (about 1/2 as wide as the average 4 cylinder belt). Jessel says that they reduce
the amount of vibration transmitted to the cam at higher rpm (4000+), but they do not help any at
lower rpm. So there really isn't much of a benefit for a street car.
--
Grape Ape www.ulster.net/~nubb
Larry Heath
tilt pro/str car with a 540 motor that uses a Jessel belt and he drives the
thing all over hell and gone and has for the last three or four years. Lest
you think that this is a wimpy motor with lots of N2O for the go, it aint.
Engine made just a tad over 1000 hp on Oddys dyno, without the juice and
1330 with the first of two 300hp stages. I freshened the heads about 1 1/2
years ago and set the springs on this jewel at 265 on the seat, full boogie
.720 lift roller can in this deal. We made some cam timing changes at that
time and the Jessel belt was tight and right. Having seen the way this guy
flogs on this deal I can say that I am pretty sure that the Jessel stuff
will, at the very least, work "OK" on the street. Better than a chain for
sure, in my opinion.
Again I personally prefer gear drives set it and forget it, no worries.
Later Larry
"Grape Ape" <Grap...@ulster.net> wrote in message
news:s6puodg...@corp.supernews.com...
Grape Ape
don't know how they'd hold up. How many miles do you think he puts on that car a year? I know that
the belts are better than chains for accuracy, but can they last 60,000 miles? I don't know, but I
wouldn't want to be the one to try it.
--
Grape Ape www.ulster.net/~nubb
"Larry Heath" <lgh...@sunline.net> wrote in message news:84j4m...@enews4.newsguy.com...
Larry Heath
That's exclusive of trips to the track, which he doesn't do much of anymore,
8.50's just don't get it anymore in that deal. But that's a major lot of
miles in my mind with the full race valve train he runs. I guess that he has
somewhere around 20000 and 30000 on the engine since new. When we went
through the heads a while back they looked pretty good seats had widened a
bit, but not significantly.
I really don't think that it would be a problem to run the Jessel stuff on
the street in a 100000 mile engine if the valvetrain was a bit more
realistic street type unit, still racy but not full racing roller.
I'll talk to Bob and see what he has on the car for sure the next time I see
him.
Later Larry
"Grape Ape" <Grap...@ulster.net> wrote in message
news:s6r1r1...@corp.supernews.com...
Grape Ape
adjustments would be great. Since the motor is built for nitrous, ultra high lift and high spring
pressures are not needed, it might last a long time. It's also a stroker that makes all it's power
under 6000 rpm.
--
Grape Ape www.ulster.net/~nubb
"Larry Heath" <lgh...@sunline.net> wrote in message news:84ks7...@enews4.newsguy.com...
Massey
427 chevy truck engines (tall block) almost exclusively use gear drive. I
am rebuilding one now that has over 300,000 miles on it. According the
fleet service manual it had a valve job at 115,232. Other than routine
maintenance, I see no other entries for engine problems. Now these only use
two gears, a crank gear and a cam gear. Probably more durable than three or
four gear setups (IMO). Inliners usually use a two gear setup and get very
good life out the gears and valvetrain. Admittedly these are stock engines
and seldom see more than 4000 rpm in regular duty.
So my question then, is it the three or four gear setups that are causing
the bad valvetrain harmonics or the higher lift cams or the higher rpm's
associated with performance engines?
Massey
Josh Lee
I prefer a belt drive over a chain, and a chain over a gear drive, but thats
my opinion. I am talking about a Street/Strip car not just a everyday
rebuild. Where I would get about 20 to 30 thousand on the motor and would
want to build a faster motor anyway, so longevity isn't a big factor.
Scott Herring
Josh Lee wrote in message ...
Robert McCord
heads and a 660 lift roller, and I am running a donovan gear drive that came
off an old fuel car. I have had no valve train problems due to harmonics as
a result of it and when I changed it over from a chain I definently had no
E.T. loss, or M.P.H. loss for that matter, so at least in my experience, I
can't see any drop in horsepower. If it is a bracket car, I wouldn't sweat
the little stuff. At least on my motor, I would take the longevity and
accuracy over sweating the possibility of slight hp loss any day.
Larry Heath
belt or what have you that connects the valvetrain to the crank. Some of
these are better at dealing with "bad harmonics" but this is just a Band-Aid
in my opinion. If you have a badly designed valvetrain or run the valvetrain
outside of its design limits then nothing is going to save the situation,
something in the valve train is going to give up. Most likely while in the
process of giving up the harmonics are going to get worse and worse until
failure occurs. Chains are a weak point in racing valvetrains and will go
first, belts absorb much harmonics and are I am told stronger than chains
and gears are vastly stronger than chain and will not be affected by
harmonics but will readily transmit some frequencies depending on the
natural frequencies characteristics of the unit.
Chain is relatively cheap and fairly weak, gear drives are in some cases
nearly as cheap as chain, most are moderately more expensive, and belts are
the very expensive. I use single idler gear drives, there very strong and
last dam near forever, moderately priced in comparison to belts and work in
the engines I build without problems. I would prefer to use two gear setups,
but sometime cam companies can be a problem with getting reverse rotation
cams of the required specs. This also brings other sets of problems as well.
Later Larry
"Massey" <dned...@willmar.com> wrote in message
news:Scsb4.24$ib1....@news7.onvoy.net...
Dan Timberlake
<drag.r...@spamswipnet.se> wrote:
>hi i'm about to rebuild my 454 iand I wonder if the gear drive give any
>advantages over a good quality timing chain or if its better to put my
>buck's on something else
>bye the way the engine vill only be used for bracket racing
> any answer appriciated
>d-racer
>
Bill "Grumpy" Jenkins - circa 1976, in "The Chevrolet racing engine"
"As far as we are concerned, there is never any reason to drive the
cam with anything other than a stock-type chain..........A chain acts
as a damper to isolate the valve train from all the rattling and
banging in the crank............"
He does talk about which sprockets NOT to use, and changing the chain
as a precaution every teardown. 9500 rpm, 0.700/0,730 inch lift small
block Chevy.
Smokey Yunick - circa 1983 in Power Secrets.
"I see no reason to ever use a chain to drive a canshaft in a racing
engine!.........I can see no reason to use a gear drive in any sort of
high performance street engine."
Sometimes there are 2 good answers to a question.
Dean Wagenmann
stop by your liabray and see what he says about chain/gear drives in his
book .Condensed: he hates gear drives and has nothing good to say about
them.
d-racer <drag.r...@spamswipnet.se> wrote in message
news:kKra4.8266$W33....@nntpserver.swip.net...
TedHarbit
>>What a can of worms you started here.>>
I've been reading all these comments back and forth so here's another view. I
run a car that has a stock factory cam gear. It is not the multi gear set up
and is very quiet so can't comment on those. This is in a 38 year old 289 cu.
in. Studebaker V 8 engine. Now before you completely double over laughing, it
has the stock forged crank, stock camshaft, stock heads except for some porting
but does have a tunnel port intake with dual stock AFB carbs (except for
reinforced floats), and dual turbos. The car is 3600 pounds with driver and
runs low 10's at 132 mph. I have to say the gear works at least as well as a
chain (in this case).
Ted
Big Dog
and has not been mentioned as of yet, is that I just love the sound
BP
Larry Heath
Smoky says as follows and I quote from his book circa. 1983 ISBN 931472-06-7
page 90 and 91 under CAM DRIVES.
"I see no reason to ever use a chain to drive the camshaft in a racing
engine! In my opinion, the only sensible way to turn the cam is with a
two-gear drive."
"Next to a two-gear drive, I suppose the best selections is a three-gear
drive."
"The best advice I can give with any sort of chain drive is to make certain
the chain has some slack when you first put it in place. After it's been run
a while in a racing engine , any chain will stretch quite a bit - so you
should change it fairly often - but don't start with it very tight or I'll
give up real fast."
"I can see no reason to use a gear drive in any sort of high-performance
street engine."
What I hear being said here is to use a gear drive in race engines and
chains in street engines. I also would like to point out that as drag racers
we use a lot more valve spring pressure than the typical track racer of
1983. Smoky also says that they used chains way back when, when stock cars
were really stock, and that they would last 500 miles most of the time "but
never really knew when one might come apart in the middle of a race" and
that's with stock springs and max r's probably in the 5500 to 6500 range.
No where in 16 paragraphs do I see anywhere that Smoky says anything about
hating gear drives.
So if your going to quote or paraphrase at least try and get it close to
being what was actually said.
Later Larry
"Dean Wagenmann" <ts...@mcn.net> wrote in message
news:s7520nn...@corp.supernews.com...
> What a can of worms you started here.If any of you put trust in Smoky
Yunic
> stop by your liabray and see what he says about chain/gear drives in his
> book .Condensed: he hates gear drives and has nothing good to say about
> them.
> d-racer <drag.r...@spamswipnet.se> wrote in message
> news:kKra4.8266$W33....@nntpserver.swip.net...
Bob Hoffman
If you can't afford a blower, at least get the sound of one!
Big Dog <bpa...@netcom.ca> wrote in message
news:3872EF65...@netcom.ca...
> The influencing factor that made me go with the gear drive over a chain,
> and has not been mentioned as of yet, is that I just love the sound
> BP
>
> d-racer wrote:
>
Dean Wagenmann
MoparNut
Dean Wagenmann wrote in message ...
Eric A. Coberly
transmit harmonic vibration from crank to cam and visa-versa. I have no hard
evedence to support this however it might be best to be safe and not sorry.
Good luck
Eric
Matt@MCCR&C
construction co.. This truck has over 650,000 miles on it (definitely long
lived, I belive maintenance is everything).
There has been none of the harmonics problems that you speak of.
Matt @ Matts Custom Cars, Rabbitry, & Construction.
Eric A. Coberly <eac...@bellsouth.net> wrote in message
news:KWvd4.4478$ps.4...@news4.mia...
Grape Ape
--
Grape Ape www.ulster.net/~nubb
Matt@MCCR&C
slammer
pros and cons ,i haze seen some chains come apart if your lucky minimal
and repairable damage , if the belt drive breaks just go get another
belt which is under 15 bucks usually you can't just buy a chain you
have to buy the whole assembly ,the nice thing about the belt drive is
you can switch it from one engine to another i wouldn't recommend it tho
and the maintenance is probably negligible and there is a kit that you
can run the distributor off the front of the engine where by your
timing is going to be as precise as it's going to get
this is just my two cents
good cruising
d-racer
pistons will hit the valves with big damage results or am i wrong?
sttill i dont got 700 bucks to a belt drive so the choises are chain or
geardrive
d-racer
slammer <dunkel71...@in.epix.net.invalid> skrev i
diskussionsgruppsmeddelandet:1761dd4a...@usw-ex0101-007.remarq.com...
Grape Ape
the Pete Jackson quiet gears are ok, but the noisy ones make vibrations. I also heard that Dynagear
drives make vibrations. What ever you choose, just make sure you use a good damper to limit the
vibrations to begin with.
--
Grape Ape www.ulster.net/~nubb
"d-racer" <drag.r...@spamswipnet.se> wrote in message
news:9q6e4.7047$yn3....@nntpserver.swip.net...
Bill
>
> hi i'm about to rebuild my 454 iand I wonder if the gear drive give any
> advantages over a good quality timing chain or if its better to put my
> buck's on something else
> bye the way the engine vill only be used for bracket racing
> any answer appriciated
> d-racer
I can't think of a reason to use a gear drive on a BBC. The last gear
drive I saw on a serious engine was a Wegner BGN Buick V6 I freshened
for a guy in Houston back in early 95. Even then it was a tradeoff
because 9000 rpm V6's are really hard on chains. The other guys are
right about harmonics transferring from the crank to the cam via the
gear drive. The problem here is there is no damper on the cam. I might
use one if it was free and I didn't have any hard core plans for the
engine.
Wheeler
cents worth......... Well....... O.K....... It has cost me a hell of a lot more than 2 cents to get to
where I am at today............ A good gear drive is going to cost you a hell of a lot of money because
of the good damper that you have to have to go with it........... The belt drives will break just like
the chain drives will break..... If you want to put in a gear drive you are going to have to have a
damn good damper to take care of the vibration and if you want a belt drive you are going to have to
spend am arm and a leg to get a good one....... SO for me........ I will stay with my proven time and
again double roller chain set up.......
Wheeler
Mark Davis
slammer <dunkel71...@in.epix.net.invalid> wrote in message
news:1761dd4a...@usw-ex0101-007.remarq.com...
> yeah it may be expensive now to put on a belt drive but consider the
> pros and cons ,i haze seen some chains come apart if your lucky minimal
> and repairable damage , if the belt drive breaks just go get another
> belt which is under 15 bucks usually
[snip]
If the belt breaks and the motor is spinning 7000 RPM at the time, you are
going to need a LOT more than a new belt. How about pistons valves etc.
Mark.