Ross Metal Jacket Harmonic Balancers For Rb25Det Neo's

[JustinP]

Has anyone used a Ross Metal Jacket harmonic balancer for a Neo yet?

I contacted Ross a while ago and he said they had a new part to suit the Neo (#306204) which is not yet listed on their website. I ordered one but the box I recevied said part number #306517 on it (Neo with 10% under driven alternator and 7% under driven power steer). However when I opened the box the part number on the balancer is #306200 (RB20DET) and is missing 3 of the 6 bolts.

I rang them last week (Ross has been away for a while) and they didn't seem to think that they did any parts for the Neo. Then they worked out that they did do a Neo part, but they only did an under driven model for the Neo, and that it is made out of parts of other balancers (i.e. RB20DET, hence the wrong part number printed on it). They said that one was normal to be missing the 3 bolts. They seemed pretty confused and unsure about what they were saying.

If anyone is familiar with Ross balancers for Neo engines could they please have a look at the pictures and let me know what they think? I have the OEM and Ross balancers side by side for comparison. I have also attached a picture from the Ross website of the R33 RB25DET for comparison too, it looks completely different again.

I will call Ross next week and I'm sure I will get it all sorted out, but I just wanted to check to see if anyone else has used these before for a Neo.

Also one more question, have people had problems with under driven pulley's before on cars that are used for a mix of street and racing duties?

Cheers

Justin

[JustinP]

Oh and one more thing, I weighed both balancers and the OEM one is lighter!

OEM - 4603 grams

Ross - 4818 grams

Seems strange?

[kitto]

Interesting.

Myself, along with Garage 7 were the people who organised ROSS to start making a balancer for the NEO. I sent my old original balancer to them and then they designed one to suit.

The only difference between a standard RB25 and NEO harmonic balancer is the power steering pulley. Different offset and the NEO uses a 4PK belt where as the normal RB25 uses a 3PK. They make the NEO balancer by using a standard RB25 off the shelf under driven balancer and fitting up a power steering pulley they the would have designed.

When i received mine i was very much like WTF in regards to there only being 3 bolts holding the power steering pulley and timing disc on. I rang ROSS and spoke to Ingrid. She told me they had employed a new head designer and that he believed 6 bolts for the timing disc and power steering pulley was overkill. They may well be overkill but honestly i'd prefer they use 6.

Your NEO balancer does look very different to mine. Mine has a specific NEO part number engraved as well as 'RB25 NEO' engraved as well.

I can also see that the engraving stating the Torque for the balancer bolt is incorrect. Thats the torque spec for an RB26. RB25 balancer bolts are torqued to 152Nm. The stuffed the engraving up on mine as well. They engraved 235Nm on mine, Ingrid confirmed this was wrong. Apparently the operator typed it in wrong into the laser engraver.

I can't take any photos of mine to show you just yet. Its currently back at ROSS getting some modifications done to it to make it correct and the way it should be.

If i was you i would ring up on Monday and ask. Speak to either Ingrid or Ross himself (if he is back) and complain. I am getting a bit frustrated with them. They are SO vague and not really sure whats going on. Their products are good and at the end of they day i'm hoping this will turn out to be a good thing. But its just a bit all over the shop at the moment.

In regards to the weight of the ROSS vs Genuine i'm not sure i can't help you. Havn't weighed mine, i would ask as well. To be honest i dont think its much of a deal.

[kitto]

Oh, to add. under driven is really good for flat out race cars, or cars that spend a lot of time at the track at really high revs.

Street car, hmm you might notice the power steering is a bit heavier at idle.

Hopefully the balancer spins the alternator and water pump quick enough.

[JustinP]

Thanks Kitto - your info is much appreciated!!!

I will speak to Ross next week, hopefully I can get some clearer info and get this sorted out. And yep I noticed the printed on RB26 torque setting for the main bolt too, which worried me further!

In regards to the under driven pulleys, I'm not worried about steering effort at idle but I am a little worried about the alternator. I won't be running a mechanical water pump, but the extra load from the electric water pump, thermo fans, WMI etc is a bit of a worry.

[kitto]

Well an alternator doesn't put out bugger all current at idle, let alone if its under driven.

For your setup, this could not be good.

Speak to ROSS, find out if they are doing a 'standard' type balancer yet. Did you order an under driven or a standard? Or you were under the impression you were getting a standard balancer?

If they don't do one yet and you'd like to use a ROSS balancer still, you could fit a larger alternator pulley.

[JustinP]

I did order the standard, non under driven one, which was supposedly part number #306204.

Seeing as your's actually has RB25 Neo printed on it, do you remember if the part number printed on it #306504?

Cheers

Justin

[kitto]

Well if you ordered a standard then you should receive a standard.

I had a look on my phone and i took two pics. Mine has 306517 engraved on it.

What you can do is check the circumference of the alternator and power steering pulleys on the OEM one and compare it to the ROSS unit.

See if the ROSS pulleys are slightly bigger.

[kitto]

Ok so i just compared an OEM NEO bskancer with an OEM R32 RB20DET balancer.

The offset of the power steering pulley is identical. Both being 4PK.

The NEO ever so slightly under drives the P/S pump.

The NEO drives the alternator and water pump a fair amount quicker. R32 alternator pulley has a circumference of approx 465mm where as the NEO is approx 515mm. I measured this by wrapping 1mm2 wire around one of the belt grooves.

Air con pulley has the same circumference on both.

Circumference of the P/S pulley on the NEO is approx 375mm.

If the ROSS balancer underdrives the P/S pump by 7% i would exoect thr ROSS bslancer to have a circumference of around 349mm. If the ROSS balancer underdrives the alternator by 10%, i would expect a circumference of 464mm.

I think the reason the OEM NEO balancer has a larger circimference alternator pulley is because the RB25 doesnt rev as hard or need to rev as hard as an RB20.

[JustinP]

Thanks for checking kitto. I finally got in touch with Ross. He has assured me it should all work well, so I will give it a go. Also the idea of the under driven pulleys has grown on me. I will make it work one way or another