Adding weight to the roating assembly

[DesertSasquatchXploration]

I bought a 12.6 extended M20 flanged bolt for the crank pulley. I'm working on a 4.3inch X 5/8 thick (washer) if you will. Weigh in at 2.5 LBS. Looking to extend the low rpm hill climbing power in my baja. This will either work great or beat the hell out of the crank bearings and or explode the engine at higher RPM.

Thoughts? Have you tried something like this? Have I officially lost my mind

[Brian_e]

It won't do much. Too close to the center axis. You need the weight as far out on the diameter as possible. Make a thick ring to add to the outer diameter of the flywheel, and then you will feel it!!.

We used to do this in the manual transmission rock crawlers. It works amazing, and it will really let the engine lug down before it stalls. BUT... it also will take longer to rev up, and it reacts much slower to quick throttle inputs.

Since its in a baja, just attach another flywheel to your crank pulley.

Brian
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-Modok

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[DesertSasquatchXploration]

Ok yea Would like to build a Bolt on option that can be modified start big, turn down the Dim till it suits my fancy. A removable weight I could bolt on for off road and remove for the highway. Hmm
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Key is to have downward travel Preload keep both wheels on the ground at all times once you lift a tire your DONE. Guys worry about clearance instead think of the opposite you want the suspension to drop that tire in the hole and keep you going. A spider for example they keep their body low but their legs can reach pretty far so they don't (bottom out)

[Schepp]

How about a heavy berg pulley? That's an easy way to add rotating weight.
I've got a hand-me-down berg pulley, though the engine blew up before I could feel its benefits.
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Bandit #19
1972 Baja Rallycross Bug

[94touring]

I was going to suggest the 6.5lb heavy pulley too. I also just added a steel trigger wheel to a different pulley and was surprised by the weight of it. Once I add that to the heavy pulley I'll probably have 8lbs up there.

[Alstrup]

A heavier pulley along with a stock weight flywheel will make the engine behave more like f.i. a 5 cylinder Audi 100/200. Good at lugging, but slow to pick up rpm. As Brian notes it will increase the kinetic energy at low rpm, but once its "out" its out. There is less coming back from sub idle rpms as the engine will not be able to creat the energy to spin the heavier rotating assembly. So there is a trade off.

Some 20 years ago I had a request from a dragon flyer club which used 181 Things to pull the Dragons up. They needed "maximum" torque from idle to 1500 rpm. They even field weighted the cars up with 200 kg extra in the back seat area to have enough traction. First time around I built a 1600 higher compression 1600 sgl port. It was better than the stock 1600 dual port, but noot enough. I added a Berg 3½ lbs achiever to have more energy stored for the yanks. Didnt really help much. There was simply not enough energy behind it. Second engine became a stock cammed 1776 sgl port. 8-1 CR etc etc. and I added an Achiever on that one too. SIGNIFICANTLY better. Now the engine had the torque to actually spin the tyres at 1100 rpm (on grass)
They ran the Things like that for some years, but eventually swopped to FJ40 Land Cruisers. 4WD and more weight.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[Brian_e]

I swapped from a standard aluminum pulley to a 6lbs heavy pulley, and you could barely tell a difference.

Get the weight out as far as possible. It will require less weight, and be even more effective.

Brian
_________________
So more or less the lazier and stupider you want to be, the nicer quality parts you need to buy.
-Modok

Narrowed beams, Drop adjustable spring plates, Bus disk brake and IRS kits.
www.type-emotorsports.com

Type E Engine Parts and Supplies
https://type-emotorsports.com/collections/engine-parts

[oprn]

Or you could swap a diesel engine into it. That sounds like the effect you are looking for.
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Our cars get old, we get old but driving an old VW never gets old!

[DesertSasquatchXploration]

Well a 3/16 10x10 steel plate is 8 bucks at my local metal yard. Yield 4LB, with 3 inch's hanging out should do something.

Yes the Gene pulleys are cool but 250$? I can make a heavy washer for a few bucks. I like to test ideas for myself before believing the aftermarket. If you can sell a promise to someone that cant prove it works, great happens daily in the aftermarket world. Millions made every year selling BS parts.
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Key is to have downward travel Preload keep both wheels on the ground at all times once you lift a tire your DONE. Guys worry about clearance instead think of the opposite you want the suspension to drop that tire in the hole and keep you going. A spider for example they keep their body low but their legs can reach pretty far so they don't (bottom out)

[94touring]

There's an empi or ebay knockoff version of the berg that wasn't crazy expensive. I think I got mine from CIP.

[Brian_e]

[esde]

Careful with the cheap pulleys.
I had an EMPI heavy pulley that fit a little loose, and it beat the key side to side in the keyway, till the pulley was jammed onto the crankshaft. Took a giant puller and every swear word in the book to remove it.
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[ZEKE65]

I have been running the Empi 33-1090 pulley for a few years. It weighs 3.5 lbs., is steel, and 6 3/4" in diameter.
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1965 VW Sedan, 1968 C10 Step BB, 99 C5

[oprn]

From all the discussion about heavy pulleys on this site the consensus is that the best results are adding weight to the pulley not the flywheel. That tends to even out the dynamic balance issues better.

As far as a heavy washer... if it's at least as big as the pulley or bigger then it will take less weight to do a better job than something small on the crankshaft center line. Get the mass out there where it can have maximum effect.
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Our cars get old, we get old but driving an old VW never gets old!

[redhot]

An easy check of effect for symmetric shapes per the linked table;

https://en.wikipedia.org/wiki/List_of_moments_of_inertia

Guess you are something along either of these depending on layout; '

[chrisflstf]

Stock weight flywheels and the added weight with a counterweighted crank make a very stable cruiser on the freeway. It just keeps on going when you take your foot off the gas

[stealth67vw]

I run a Gene Berg 7 1/2 pound power pulley on my street/strip car. I put it on to help with my 60 foot times at the dragstrip.

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John Bates
JB Machining Services
1967 street Bug 2276 w/ 48 IDAs, 2050lbs with driver
7.76 @ 89.55mph 1/8 mile
12.27 @ 109.56 mph 1/4 mile

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[modok]

[mikedjames]

Its an energy store. Good if you launch at high RPM because it slowed down the acceleration of the engjne as you wound it up and stored the energy.
If you dumped all the energy in that heavy plulley going from 5000 rpm to zero over 5 seconds it works out about 3HP .
Or 12HP from 10000 rpm to over the same 5 seconds.

It will hinder accelerating from the next gear change as it absorbs HP by storing energy that is not pushing the car forwards.

So it makes standing starts better and 60 foot times better but overall will do less once a gearchange is involved and RPM rises while driving the car from the engine.

By making engine acceleration and deceleration gentler: on soft ground it may help reduce wheel spin induced by being heavy on the throttle,.

But a heavy flywheel does the job better as it has a larger moment of inertia from a larger diameter and more mass.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[BFB]

I say fuck it, try it. add the weighted pulley and see if theres a way to add weight to the flywheel too.
theres not alot of room between the case & flywheel but I bet theres enough that a person could weld an 1/8" plate to the backside of the flywheel, maybe 3/16? weld the edges and plug weld it, turn it so its flat & pretty and have it balanced.
I had wondered if holes could be drilled in the flywheel and filled with lead but considering leads low melting point, not sure if the flywheel would get that hot or not, depends on if your a clutch slipper or not I reckon.

does the 6v 180mm clutch weigh more than the 200mm flywheel since its machined for a smaller disk? but then the disk & PP are smaller so they might make up for it if the flywheel was heavier...
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