I'm looking for your guys opinions on gear drive in BB, good or bad Thanks
Opinions on gear drive in BB
- Thread starter sabre67
- Start date
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dart_68
Well-Known Member
I ran a Milodon. Worked...whined like a blower! I'm not sure they are worth the extra bucks over a good timing chain.
yellow rose
Overnight Sensation
If you use a good, fixed idler gear drive and it makes noise you did something wrong.
I don't waste my time anymore. I use a gear drive and forget it.
They don't make noise if they are installed correctly, and you cam timing will be the same 500k miles from now.
I don't waste my time anymore. I use a gear drive and forget it.
They don't make noise if they are installed correctly, and you cam timing will be the same 500k miles from now.
Pete Jackson (quiet)
Makes timing dead on especially when you're running straight advance and run
Above 4500rpm occasionally on street.
Some modifications on my b block with the grinder no big deal.
Dave
Makes timing dead on especially when you're running straight advance and run
Above 4500rpm occasionally on street.
Some modifications on my b block with the grinder no big deal.
Dave
72Dart6pack
Harder Better Faster Stronger.
Is there a reason why you think you need it?
If you are running a large spec solid lift cam, it takes internal timing questions out of the equation.
I don't have any interest in running a gear drive. I've had them in the shop before but never put them on an engine. They just seem too crude to actually use so I switch the customer over to a belt drive.
I know the supercharged guys (Roots type anyway) run gear drives but hardly anyone else runs a gear drive anymore. Most of the serious race engines use a belt drive while the bracket guys stick with timing chains.
440dartsport
Well-Known Member
Gear drives transfer a lot of harmonics to the valve train. Don’t spend the money on one.
The harmonics thing has been proven a myth from the 70s. Gear drives work well. If you can stand the noise, they hold timing very stable.
Strong and solid.
yellow rose
Overnight Sensation
Am I the only one who can use a gear drive and not have it make noise? I've installed probably close to 50 if you count the chevy and other GM stuff. Not one ever made noise.
yellow rose
Overnight Sensation
My father, brother, and myself exclusively used Summers Brothers gear drives on all our race motors before switching to Jesel belts. I can't ever recall any making any noise whatsoever.
EchoSixMike
Well-Known Member
The harmonics thing I think stems from the use of gear drive on the Cosworth DFV, which did have an issue with harmonics causing breakage problems...at 10000rpm. Duckworth came up with the quill drive, where the drive gear was driven by mini torsion bars IOT get rid of vibrations. This was actually an invention from an earlier engine, probably a WW2 aircraft plant or something similar. If you do the research, most automotive engine "developments" come from the old warplane piston engine world. Ie the Offenhauser from some French indycar engine which itself was development off some WW1 aircraft plant. S/F....Ken M
Theres a little noise initially then wears in. Solid lifters alone drown it out regardless.
Penstarpurist
Well-Known Member
Are you looking to run it on a drag only car? I have never run gear driven as every time I've mentioned it to the parts guys or car guys they say it's a drag only set-up as they wear out and grind down leaving metal shavings in the oil. Which of course takes its toll on the engine. Like I said I have never run one and going by what I've heard and been told. So I guess I'm asking if that info is correct.
The guys you talked to have no idea what they are talking about. Gear drives have pretty limited use in drag racing (usually blown fuel cars). Their primary application is dirt and super modified oval. Also they can run damn near forever without any wear at all. They are probably only familiar with those Pete Jackson gimmick things.
The primary reason gear drives are used actually has nothing to do with valve train accuracy (that's just a bonus). Gear drives are used to handle huge loads on the timing set. Oval and fuel motors don't look anything like what the average gear head is used to. To eliminate belts most/all accessories are direct driven. Fuel pump(s), magneto(s), water pump, oil pump, power steering pump, hydraulic ram pump, coupled with extreme valve spring pressures will stretch and snap belts and chains. Technology has caught up and now we can use belts. Much wider belts that are kevlar reinforced.
440outlawdart
Well-Known Member
all i run is milidon gear drives,they say chain drive is not good for transbrakes racing
Penstarpurist
Well-Known Member
I think I am going to have to do gear drive on my next engine build.
Bighead440
Well-Known Member
We run one on our 471 B front engine dragster. I wanted a Milodon fixed-idler system but my partner wouldn't go for the increased price over a PeteJackson "noisy," because the engine was originally built for his '62 Valiant gasser. Car Craft or Hot Rod had recently run an article that disproved the myth that the dual-idler gear drives were "power eaters." It made zero difference over the Milodon on the BB MoPar they did the testing on. We ran this engine several years and then decided to try a Racer Brown tight lash roller cam, replacing a Howard's solid roller. Broke it down and everything looked brandy-new, no wear discernible on anything, just shiny contact areas. Gained basically zero swapping the cams, BTW, except a little better "cackle" from the zoomies!!
I will say this about gear drives.. If you have ever had a Mechanical 3406 caterpillar motor or any other big rig diesel apart then you would see they all have gear driven cams and injector pumps. Comparing apples and oranges here... but they are built for precision timing, durability, and longevity in mind. However they are designed to run at mostly max rpm of 2200 in most cases. I couldn't see a timing chain or belt lasting any amount of time in diesel applications.
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