Underdrive pulleys

[Matt Johnson]

Excuse my ignorace, but what exactly ARE underdrive pulleys, what do they do, and what are the "cons," if any, of installing them?

[chrtra1]

Basically they slow down the rotation of your belt driven accesories to free up horsepower normally used to turn them. Some downsides are that since your alternator and waterpump are now turning slower, you could have possible overheating and charging problems, especially at idle.

[jgc61sr2002]

Originally posted by chrtra1
Basically they slow down the rotation of your belt driven accesories to free up horsepower normally used to turn them. Some downsides are that since your alternator and waterpump are now turning slower, you could have possible overheating and charging problems, especially at idle. Thanks again for the good info. The charging problems were discussed, but I don't the possible overheating was. Would having the chip reprogramed to increase the idle speed rectify the situation. John

[TAF]

Mine are going in Monday...before the Atlanta Tuning Session next weekend so the chip can be tweaked to compensate for any idle increase.

[the fat bastid]

what about getting a bigger alt to compensate? or a 2nd/bigger batt? or does that just cancle the effect of the pully? i was planning on putting some audio in the mm but this may be a problem...oh the old question, sound vs power, who wins? heh

[SergntMac]

Just adding a thought here...

I don't know what March or Steeda, or any other offer in pulley kits, I didn't look into them that closely because they were more expensive than Reinhart's, plus they came with pulleys we cannot use on our MMs. (our alternator pulley is pressed on and cannot be removed) So, I bought Reinhart's pulleys, kit of two with bolts and instructions.

Both pulleys are the same diameter as what they replace, at least visually. No major change in size, but they are maybe 50-60 pounds lighter. No noticable measured power gain on a dyno, but very noticible improvement in motor spin up. Saving a little weight here, frees up the motor in the lower RPMs, and in my book, that is good.

I have a Carchip monitor too, and my engine temps did not change. I'm still holding a steady 190-192 degrees in a wide variety of driving situations. Ditto, my voltage. It stays up in the 14.0-14.5 range until I come to a complete dead stop, with a load on the motor, then it will drop to 12.5-13.0. The dash lights will dim and you can call that flicker, but the motor is resting at 550 RPM too, so I would expect this. Once I pull away from the light, voltage is normal again, and even at it's lowest, 12.5, I am not in a discharge state.

I am sure there is a history of voltage and cooling issues with aftermarket pulleys, but I haven't experienced any of them with Reinhart's kit. New cars get fresh designs. Don't throw out your personal rule book on aftermarket mods at large, but some things are not the way they used to be, with this car.

Just my .02c...

PS...I did not increase my idle when I had the chance. I like it low at the standing start. besides, turn it up too high, and you are working your breaks to death at the light...IMHO.

[the fat bastid]

fyi: in the car audio world any voltage from 12 up is ok. optimual is 14.4

most amps are rated with a 12v and a 14.4v output number and me and my friends always go with what the 12v says because 14.4v is too hard to sustain overall.

that being said, those pulleys are fine even at idle with those numbers.

[RF Overlord]

Originally posted by SergntMac

Both pulleys are the same diameter as what they replace, at least visually. No major change in size, but they are maybe 50-60 pounds lighter. No noticable measured power gain on a dyno, but very noticible improvement in motor spin up. Saving a little weight here, frees up the motor in the lower RPMs, and in my book, that is good.

OK, now it's MY turn to be confused; if the new pulleys are the same diameter as the ones they replace, then how can they be UNDERdrive pulleys? I understand that if they WEIGH significantly less than the originals, then there is less inertia to overcome and that will, as Sarge said, help the motor spin up.

Sarge, are you sure about the weights? 50-60 lbs lighter? I wouldn't have thought the originals weighed anywhere near that to start with...did you mean the new pulleys are 5-6 lbs lighter?

[martyo]

Hmmmm....do Sarge and I have the same pulleys?? You got 'em from that guy Dennis that I have seen mentioned here once or twice?

Mac, next time we speak, I wanna talk to you about the pulleys......I am confused too.

[SergntMac]

Okay, okay, I'll try to explain this better, sorry I confused anyone.

My pulleys from Dennis came in box from Dennis, not a 3rd party like the drive shaft. Two polished aluminum pulleys, very light, can carry both with one hand, I'd say maybe 20-25 pounds for both. Dealer installed, OEM pulleys in trunk. Went to put away in garage, almost broke my foot when I dropped one because the weight surprised me! Cannot carry both with one hand, can't even grip and lift. Yes, 50 pounds I estimate, maybe more, because of a known limited strength of my left hand.

As for size, I never had them side by side because the dealer did the work. However, eyeballing them as close to side by side I can get, I can't see a difference in diameters, I would have to measure them.

I see a difference in width, the OEM crank pulley looks 2 inches wider than Reinhart's. The other OEM pulley only about 1 1/2 wider than Reinhart's, again without measuring.

When I get home, I do this eyeball again, and check in here tonight.

[martyo]

Sarge: Glad you came back with this post.

I got the pulleys (two) from Dennis as you describe. They are aluminum and very light.

It was my understanding that the "heavy" pulley that you describe is/was (until you removed it) the harmonic balancer and pulley (it serves both functions on the stock motor). My read of the instructions that came with the new underdrive pulleys was that the factory harmonic balancer/pulley was removed and reinstalled in front of the new underdrive pulley so that you still have the harmonic balancer on (in front of --further away from the motor, if you will) but the belt is tracking on the smaller, underdrive pulley. The other pulley (the water pump) was a direct swap. So, when I was done I installed two new pulleys, but only had one spare part.

Does this make sense?

[SergntMac]

Oh Lord, what now...And I can't find your phone number to save my life!

Yes, what you say makes sense, Marty, as you explain it here. But, it does not jibe with my instruction sheet. RF, chime in anywhere you want, something here isn't right.

My instruction sheet says to remove the OEM harominic balancer/crank pulley assembly, and install the new crank pulley with the bolts provided.

I'm not positive, but I remember that the bolts provided looked shorter, appropriately sized to the new pulley, and not any "assembly."

The OEM crank pulley/balancer assembly I have on a shelf in my garage is very heavy, and inseparable. It's one part.

Now you suggest that both the OEM pulley/balancer, and the new pulley were to be re-installed together? I see no instruction on that.

I have two parts removed and two parts added. I did not get any bolts back and my repair order does not call for any additional bolts from LM stock, so, I presume the included shorter bolts were in fact used in my install. Using the shorter bolts provided tells me that the correct install was to remove the old parts completely.

I hate explaining my logic, I look so stupid...

Meanwhile, my balancer is clearly off my car, and your's is not. Hmmmm...

I didn't speak with the LM wrench directly, but I told the SM what I wanted, and gave him the Reinhart parts and instruction sheet.

For the moment, I must presume that the wrench understood the instruction sheet as I have, and followed it. Damm, it's going to be a long week end until we get this straightened out, eh?

Now I am the confused one, someone please call me " young grasshopper" eh?

I am really lost on this, and now I have some questions of my own.

1) A few steps on my instruction sheet are marked "N/A on Marauder," does your instruction sheet show this too?

2) Is this harmonic balancer necessary? Any potential damage or harm from removing this? I don't believe so. I clearly remember working on bow-tie motors that never had any balancer until the General stroked a small block to 400 CID in the early '70s. So, I really don't know anymore. What does this balancer do, and is it important? Anyone?

Marty, we gotta talk...soon, please?

[RF Overlord]

Sarge and Marty:

I found this on the web...

Harmonic Balancers Explained (http://members.core.com/~faldrich/harmonic.htm)

But here is the first paragraph on the page:


Crankshafts vibrate with a twisting motion due the torque variation that results as each cylinder fires. This vibration is at its worst at some critical RPM. On a V8, this RPM is typically in the 4-5000 RPM range. If you operate the engine at this critical RPM without a harmonic balancer excessive vibration will eventually BREAK THE CRANKSHAFT. DON'T LEAVE IT OFF.

[LincMercLover]

Damn, he beat me to it... I was just going to say that I've never heard of removing a harmonic balancer in an underdrive or mere pulley swap. The balancer does that itself, keep the crank in balance at high RPM's. Without this, things could become, uhh... fatal? Yah, so umm... may not wanna race anyone until we figure this out Sarge, eh?

[TAF]

Can we please come to a definative answer on this BEFORE Monday??

That's when mine are supposed to be installed....

[WolfeBros]

I have not heard of removing the harmonic balancer on underdrive installations either. Sorry I can't be of more definitive help Sarge & Todd. I never liked underdrive pullies on daily drivers. I do agree they have a benefit.

[nomad]

Don't know if this helps, it's for mustang 4.6 though.
http://www.stangnet.com/tech/pulley46.html

[gonzo50]

I thought that the purpose of the harmonic damper was to dampen any engine vibrations that can potentially harm it for a trouble free operation. :confused: :help:

[WolfeBros]

Sarge,
I just did a search on the net and came up with some info on underdrive pullies at Mustangworld since we share a similiar 4.6 liter engine. Here is a couple exerpts:

The 4.6L engine crank is INTERNALLY BALANCED (SOHC/DOHC) so there is no harmonic balancer to worry about (like on the 5.0) BUT the external crank pulley on the 4.6L acts as a vibration dampner, there is a thin rubber ring to absorb any extra vibration on the stock crank pulley. So you will still need to bolt your stock crank pulley to your new underdrive to have this extra dampening.

Further on in the installation instructions:

We now have to "sandwich" the old and new crank pullies together. You'll have the new underdrive pulley AND your old crank pulley running on your stang at the same time.
Bolt them together using locktite #242...............

Sarge........looks like your guy messed up.
Hope this helps.

[gonzo50]

13.) Now the 2 main pulleys are off - water pump and crank. The next step is to bolt the underdrive crank and the stock crank together. Why? Because the stock crank pulley acts as a dampener and is needed to smooth out crankshaft operation, that's why. Use the three bolts included in your kit to sandwich the pulleys together. Use loc-tite here. Tighten WELL.
This is from that web site nomad got.

[sailsmen]

Dennis Reinhart installed the Underdrive Pulleys on my car. I just checked under the hood and the only part that stays off is the OEM water pump pulley. Looking down at the front of the engine while facing the back of the car you should see in order from top to bottom 1) the OEM Alternator, 2) the DR Alumimum Water Pump Pulley and 3) the OEM crank pulley/harmonic balancer unit on top of, (i.e. bolted to), the DR Alminum Crank Underdrive Pulley.

The OEM crank pulley/harmonic balancer unit is one unit and goes on top of, (i.e. between the front of the car and the DR Crank Aluminum Underdrive Pulley), the DR Crank Underdrive Aluminum Pulley. The DR Crank Underdrive Aluminum Pulley bolts on first, (i.e. next to the engine block and is attached to the crank). The DR supplied bolts are shorter because the DR Crank Underdrive Aluminum Pulley is narrower than the OEM crank/harmonic balancer unit. The OEM crank/harmonic balancer unit bolts are used to bolt it to the DR Crank Underdrive Aluminum Pulley.

The DR Water Pump Underdirve Pulley replaces the OEM water pump pulley.

The only part left over that is not used is the OEM water pump pulley.

I suggest checking with Dennis Reinhart. I am not a tech, I have rebuilt several engines in the days of carbs-points-condensors-timing lites and it was always with a good tech manual in one hand and help from expert friends.

[RF Overlord]

Originally posted by sailsmen
I suggest checking with Dennis Reinhart.

D'OH!

[WolfeBros]

Todd & Sarge,
Looks like its unanimous for bolting the old & new crank pullies together. I tried calling Sarge at home to give him this info and your phone number Marty but did not reach him. He will be checking in here again I am sure.

edited because I keep getting Todd and Marty in the wrong post.....lol

[TAF]

Thank you my good friend. I'm more comfortable now that you guys provided some clarification. My guy doing it Monday is a member of this board as well. He knows how I drive the car (mostly highway, business, occasional high-speed fun) and he recommended I get them. Meanwhile he has lead me away from some other things available...once again based on how I drive the car.

Thanks again to all!

You GOT to love this place!

[martyo]

Damn, I take a couple of hours off to take my Mom out for dinner and get RF a recipe (a long story for another day) and I wreak havoc just before I leave. If anyone wants to call me my cell is 914-582-6262. Sarge my office computer which has your home number on it is down. Call me Man!!

[WolfeBros]

Ok thats it. From now on Sarge and Marty can not leave the BBS at the same time. Who is taking the first shift ?
Always leaving me and RF to sweep up.....:rolleyes:
:D

[martyo]

Sam: Thanks for passing my number on to Sarge! Here I thought he and I were going steady and he loses my number!! I sure hope all of this helps Sarge out. Now I know why I am addicted to this site. Besides the wit (RF and Todd, for example), there is wisdom to be had.....

I got Sarge's number (thanks, RF), but I am afraid it is too late to call him. If he checks in late he can call me at any hour (the GF is out of town, so I don't care if the phone rings in the middle of the night).

[FordNut]

Sounds like the DR underdrive pulleys are installed similar to the March pulleys with the sandwiching process. The Steeda pulleys totally replace the stock crank pulley/balancer with the Steeda pulley/balancer.

[LincMercLover]

Originally posted by FordNut
Sounds like the DR underdrive pulleys are installed similar to the March pulleys with the sandwiching process. The Steeda pulleys totally replace the stock crank pulley/balancer with the Steeda pulley/balancer.

Tis why I'm waiting on Steeda... :rolleyes:

[WolfeBros]

Originally posted by martyo
Sam: Thanks for passing my number on to Sarge!

Marty,
I called Sarge but got no answer. So I wasn't able to pass on your number. Hey......I tried anyway. :D
He will show up. Glad you all got to chatting about those pullies.
He needs his crank pulley put back on !!
This site is great.

[SergntMac]

Good morning y'all and Happy Easter!

Thank you all for pitching in here and helping me draw a conclusion. My DR underive pulleys have been installed wrong, and that will be corrected first thing Monday morning. This was the deciding factor;


Originally posted by sailsmen
Dennis Reinhart installed the Underdrive Pulleys on my car. I just checked under the hood and the only part that stays off is the OEM water pump pulley.

If that's the way the creator installed his own equipment, that that's the way it should be, 'nuff said on what's right or wrong.

Our friend Mad 3R's MM is presently hospitalized, metal shavings in the oil pan, and I know for sure he has DR underdrive pulleys too. I won't jump to conclusions on his behalf, but after reading all the great advice here, it's not such a grand leap, is it.

Remembering that my independent testing proved a low performance gain from this mod (3.1 HP, 9.9 ft-lb TQ) cutting back on the dead weight drag was a benefit I appreciated and highlighted here. Now that this dead weight drag must be restored, I am sure the gains will change, and I'll have to revaluate my support of underdrive pulleys as having any benefit to us MM owners.

As y'all may expect, I feel rather stupid here, but I'm limiting that feeling too. My instruction sheet is clear to me, some steps are "N/A on Marauder," and my LM certified wrench followed them without input from me. There may be others out here who made the same decisions, based on the included instruction sheet. Those of you who have the DR underdrive pulleys installed by a third party, please check your install ASAP.

Now I have to I determine if there has been any damage to my motor. I have several thousand miles of spirited driving on this motor, including a number of dyno pulls. She runs great at the present time, no symptoms of any illnesses. When I return to the dealer to remove the underdrive pulleys, I'll have the oil pan dropped and the bottom end inspected.

Again, thank you all, for the valuable input.

[Kelly]

:) The next best thing to owning the Marauder was finding this web site, a big thanks you to all you Mod pioneers for saving the bulk of us a lot of trial and errors. Kelly

[WolfeBros]

Sarge please don't feel badly about the pulleys. It is something that I think any of us could have fallen prey to and maybe some on here have. The important thing is you caught the mistake and can now rectify it. You had some help.....whoever wrote that instruction sheet can take some blame and your LM wrench fell for it as well. Surely no bad intentions from anyone. As one of the pioneer of the go-fast goodies for the Marauder here.....you stick your neck and your car out for the rest of us to determine what works and what doesn't. This willingness to do that and then report back on your efforts has endeared you to most of us here on the board. Anyone that blazes a trail and can then report back......go this way it is better, or don't step here you can get hurt.....is bound to suffer a few setbacks on the way. You unintentionally have become one of the few that I can think of that I would gladly trust and follow without a second thought.

Now that being said a thought about your car. Why not send an oil sample out for analysis? It is fairly inexpensive and will give you much 411 back. I know most large fleet operators such as PD's and fire depts do this on a fairly regular basis. I bet a shout out to someone in your motor pool could fix you up pronto.
Just a thought.

[SergntMac]

Originally posted by WolfeBros
Why not send an oil sample out for analysis? It is fairly inexpensive and will give you much 411 back. I know most large fleet operators such as PD's and fire depts do this on a fairly regular basis. I bet a shout out to someone in your motor pool could fix you up pronto. Just a thought.

Thanks for the kind words Sam, and this great advice. I don't know much about this service, but I've heard it mentioned in these threads. Maybe someone can hip me to a web site or something? Also going to have the dealer drop the pan and take a peek.

[martyo]

Sarge: I have oil analysis done on the marine engines all the time. My current diesels are Caterpillar motors and I utilize Cat's S-O-S program. I am not sure if they will do an equivalent analysis for our motors, but here is the G-2 on their process:

http://www.cat.com/services/shared/parts_n_service/09_S-O-S_program/02_oil_analysis_test/oil_analysis_test.html

There are a number of Cat dealers in Chicago and they can usually do the analysis in a couple of days (or less).

If they cant do the analysis, I bet they can send you in the right direction.

As always call me if you want to discuss further.

[WolfeBros]

Found a ton of info on the web about oil analysis. They basically look for trace amounts of metals in the oil. Here is a site that offers this service and shows a test report.
http://www.eliteetc.com/oilanalysis.html

[SergntMac]

Thanks Martin and Sam, I too, found almost too much 411 on this myself. I decided to go with Sam's recommendation, because the service was offered out front, and not hidded on page 141 of the site. I ordered 4 kits, will keep you posted on how satisfactory I find the service, as well as what they find. Thanks again, one more win for the MM.Net!

[MAD-3R]

Oh, just freaken dandy........

Have to check my install...err parts left over. I'mn a packrat, I never through things away.

[TAF]

Just got back from pulley install.

Steedas, from Dennis.

Complete replace of 2 pullies, no need to relace the third that came in the kit (same size and no cap like the OEM)

There was no bolting over the existing. Steedas came with a "balancer".

Maybe it's just in my head, but there is definately a "seat-of-the-pants" improvement off the line and no change on the volt meter at idle (still right on 12v).

Call me crazy (again) but, I like this mod so far. We'll see after she gets tuned this Sunday...

[SergntMac]

Just got back from the dealer, balancer restored. Maybe it's just in my head (right now, that's exactly where my seat of my pants resides), but the spool up to 2000 RPM seems to lag just a bit, a slight bog has returned, but still much less than OEM. Oh well, better safe than sorry. I'm sure this feeling will pass.

Believe it or not, the SM and wrench at the dealership disagreed with me about restoring the crank pulley and balancer, lots of discussion between them about "internally balanced" and "Cobra" until I reminded them that this isn't a Cobra motor. Finally, I finally called Dennis and he spoke to the SM himself. About a half hour later, I'm on my way home.

Going to do the oil testing when I get the kit, and Dennis suggested I send the filter in with it, to be section and inspected. Good Idea.

Thanks again to y'all for helping me out with this, it was along, long weekend.

[martyo]

Sarge: I was afraid that I was mistaken when I first raised this issue in this thread on Saturday and was almost embarrassed to have raised it in the first place, thinking "Did I mis-read those instructions.....". I am sure glad that I got over that feeling and made my post. The idea here is to help each other out regardless of whether we made a mistake first to find out the right way to do something (or not do something).

I am glad that everything is working out in the end with your set up and I am glad that we all benefited from the exchange of ideas and commentary. If anyone has any doubts about the value and benefit of this site, all they need to do is read this one thread, or Mad 3R's dead motor thread, and they'll instantly know just what can be gained from a great bunch of guys willing to share and pitch in. Lesson to all: If in doubt, just ask here and we are all sure to benefit from the exchange that will follow.....