| Author |
 Topic  |
|
| |
Current Topic Rating:  | Join the Forum to Rate this Topic at: www.VNCommodore.com Support Forums
|
|
|
VN91SX
Fully Licenced
344 Posts
 |
 Posted - 07 Dec 2008 : 10:49:18 PM
|
Hi everyone! This question is kind of a "part two" to the cam upgrade forum i started. I just got the latest edition of Street Commodore Magazine, and have been doing a bit of research on performance roller rockers. The article, and a few websites claim a 15rwkw gain through the simple application of a set of higher ratio roller rockers, as they increase cam lift. I am curious as to what options are available for a V6 VN Series 2. I have replaced the standard rocker covers with Kilkenny polished rocker covers, which are the same height as the standard rocker covers. Will this effect the application of higher ratio roller rockers? Any recommendations regarding this topic would be appreciated! 
|
|
Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 08 Dec 2008 : 4:31:36 PM
|
You can gain quite a significant power increase with roller rockers because of 2 reasons.
1) The lift is increased, so you get more air and fuel into the combustion chamber. Simple.
2) Because of the pivot point of the rockers is now a roller, rather than just metal on metal, there is less friction, so more power can be outputted to the flywheel, rather than being lost in keeping the motor moving.
As for 1.95, I doubt you can go that high. I'm not sure how different the S2's are to the S1's, but the highest you can go on an S1 VN is 1.8. But that's using Yella Terra.
|
Report to Moderator  |
|
|
trizo
Forum Moderator
3091 Posts
|
Posted - 08 Dec 2008 : 5:02:51 PM
|
| would a thicker gasket make a diff? eg: more lift height under the covers, ( this is of course if you are going to change rockers ) |
3 can keep a secret if 2 are dead |
Edited by - trizo on 08 Dec 2008 5:07:43 PM |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 08 Dec 2008 : 5:12:01 PM
|
I'm not really sure.
Possibly. But you'd probably need a REALLY thick gasket.
But the gains from a set of 1.8 Ratio Roller Rockers will be noticeable, definitely. |
| Report to Moderator |
|
|
leebo
Fully Licenced
495 Posts
|
Posted - 08 Dec 2008 : 7:34:14 PM
|
| how much is this vn series 2 V6 upgrade your doing costing as i might look into it. |
I'll show you the Rick James cell. It's superfreaky!. |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 08 Dec 2008 : 9:05:55 PM
|
Me? I'm not doing an upgrade. The S2 motor is worse than the S1 motor. Put's out a worse torque curve.
The VN S1 is a much quicker motor. |
| Report to Moderator |
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 09 Dec 2008 : 09:44:45 AM
|
The series 2 motor had a "little" 2kw more than the series 1, but slightly less torque. Apparently you can use two gaskets to increase the rocker cover height. I wouldnt mind going a set of 1.7 or 1.8's. From Yella Terra they will cost about $800, and between $200 to $300 to install. They are a "simple" bolt on that they estimate should take less than 2 hours to install.
A final question. Would you guys recommend Yella Terra? |
| Report to Moderator |
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 09 Dec 2008 : 09:52:08 AM
|
| I have a question for crazybiker. With 1.8 being the highest that you can with the series 1, is this because of the rocker cover clearance, or the design of the motor? Im just keen to find out as much information i can about this mod before making any purchase decisions. Thanks mate |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 09 Dec 2008 : 3:05:27 PM
|
@ Your first post; Yes the S2 motor made 2kw more, but the torque curve was drastically different. They're about $600 and you can pretty much do them yourself
@ Your second post;
"1.8 is the maximum ratio we do for the early 3800's
VN S1 prior to eng no 1274843 uses 3/8" mounting bolts.
Set number is YT6657"
That's the post I got back from the Yella Terra guy at JC.
I'd recommend YT because they're a well known brand...and many people use them.
Note: When you do the rockers, it'd be a good idea to replace the valve springs too. |
| Report to Moderator |
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 09 Dec 2008 : 5:38:10 PM
|
Apparently the torque curve was changed because morons were losing it going around corners because of heavy wheel spin lol. The series 2 motor still has a nice amount of torque on tap.
Crazybiker: Would you replace the valve springs with firmer springs, or brand new standard one's? And who did you address you question to regarding the Yella Terra roller rockers? I sent an email to their sales people 2 days ago, and no reply yet. My motor was built July of 1991 (S2), making it one of the last of the VN's. Also, i appreciate your last post, as it was very detailed. Thanks mate.
|
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 09 Dec 2008 : 5:52:28 PM
|
That's exactly why Holden changed it...and up to about 100km, the VN S1 was quicker than the SS too :P.
Holden couldn't have their six beating their 8 :P.
Valve springs? Just replacement standard ones. The old ones would be worn and all, so while you've got the rockers off, it'd be just as easy to replace the valve spring.
I got the info from one of the Yella Terra boys at Just Commodores. He's the rocker specialist, so he was able to give me that chunk of info.
Glad I could help |
| Report to Moderator |
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 09 Dec 2008 : 8:02:58 PM
|
| Thanks for the help Crazybiker! Can i ask a big favour? Would you be able to get in contact with the guy from Just Commodores and ask for the info you got from him, but for a series 2 motor? Have you done the mod yourself buddy? |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
|
|
leebo
Fully Licenced
495 Posts
|
Posted - 10 Dec 2008 : 11:45:59 AM
|
I'm probably going to just save up a lot of money and dump it on the motor all at once instead of bit by bit cos you don't notice the performance out come every time you add 3KW if you know what i mean.
you can have the engine rebuilt with high performance cams for $3700
twin 70mm throttle body manifold for $1200
dual cold air intake $500
exhaust $269
Turbo $2100
I'll just do it all at once while of got the motor out to make it worth my time.
I'll have to save for many months though. |
I'll show you the Rick James cell. It's superfreaky!. |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 10 Dec 2008 : 11:59:14 AM
|
LOL.
See, I'm doing **** like Rockers and stuff now, and a year before I get onto my unrestricted licence, I'll start buying all the gear I need for my Supercharger kit, and I'll bolt it on once I've changed my licence over. |
| Report to Moderator |
|
|
leebo
Fully Licenced
495 Posts
|
Posted - 10 Dec 2008 : 12:59:42 PM
|
yeah that sounds good just with these p plate retractions you can't do much and since it's my weekend car and if i get defected i have another car to drive so I'll still mod it up.
|
I'll show you the Rick James cell. It's superfreaky!. |
| Report to Moderator |
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 10 Dec 2008 : 5:47:28 PM
|
| Crazybiker, you are a legend mate!!!!! I really appreciate the link that you attached. 1.9!!!! Sh!t. Imagine the difference that would make. |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 10 Dec 2008 : 9:05:10 PM
|
| Looks like I will have to give Yella Terra a call and enquire about the 1.9 and 1.8 ratio, and also find where I can get new valve springs. |
| Report to Moderator |
|
|
leebo
Fully Licenced
495 Posts
|
Posted - 30 Dec 2008 : 1:38:42 PM
|
quote:
Originally posted by VN91SX
The series 2 motor had a "little" 2kw more than the series 1, but slightly less torque. Apparently you can use two gaskets to increase the rocker cover height. I wouldnt mind going a set of 1.7 or 1.8's. From Yella Terra they will cost about $800, and between $200 to $300 to install. They are a "simple" bolt on that they estimate should take less than 2 hours to install.
A final question. Would you guys recommend Yella Terra?
I can actually find that easy to believe because my '89' VN is much much quicker off the line than my brothers '95' VS ecotec which has 17 more kw from factory, i can hold off a non-SS VN V8 off the line till it builds up some power about mid 3rd gear which leave's them pissed off if i get the next lights. |
I'll show you the Rick James cell. It's superfreaky!. |
| Report to Moderator |
|
|
trizo
Forum Moderator
3091 Posts
|
Posted - 30 Dec 2008 : 2:59:09 PM
|
| it is common knowledge that the s1 motor was quicker than the s2 motor for the fact of the torque,, hence y all the stupid mods were made to the s2 cause clowns couldn't control them and the s1 motors break very easily,, they had a bad habit of twisting of the engine mounts under high torque and snapping from the gearbox! Mind you that was 20yrs ago when they were new. I'd like to see 1 twist the engine mount now days, but back when they were new this was the problem they had with the s1 motor,, in saying that you really wont notice any difference between the s1 and s2 stock motors! Just a bit of random trivia! |
3 can keep a secret if 2 are dead |
| Report to Moderator |
|
|
leebo
Fully Licenced
495 Posts
|
Posted - 30 Dec 2008 : 4:21:42 PM
|
yeah i notice that alot of the after market performance parts made by various different manufactures are mostly for the s2 motor as bolt on easy fit items and tend to have in brackets (with modifications to the s1 motor) this part will boost performance....etc.
|
I'll show you the Rick James cell. It's superfreaky!. |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 03 Jan 2009 : 12:07:43 PM
|
quote:
Originally posted by trizo
it is common knowledge that the s1 motor was quicker than the s2 motor for the fact of the torque,, hence y all the stupid mods were made to the s2 cause clowns couldn't control them and the s1 motors break very easily,, they had a bad habit of twisting of the engine mounts under high torque and snapping from the gearbox! Mind you that was 20yrs ago when they were new. I'd like to see 1 twist the engine mount now days, but back when they were new this was the problem they had with the s1 motor,, in saying that you really wont notice any difference between the s1 and s2 stock motors! Just a bit of random trivia!
It's true, but not to that extent.
We rebuilt the motor in my VN, an S1 motor, and we've done one engine mount, but that was it was an older engine mount.
They've got quite a nice torque curve on them for a V6. |
| Report to Moderator |
|
|
trizo
Forum Moderator
3091 Posts
|
Posted - 03 Jan 2009 : 3:13:33 PM
|
| From new the vn s1 motors were smashing mounts left right and centre, weather holden did a recall on some of the first vn's Im not sure, but that was the biggest drama they had with them. |
3 can keep a secret if 2 are dead |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 03 Jan 2009 : 5:51:04 PM
|
| Well, I'm just telling you what ours is/was like, with a completely rebuilt motor. |
| Report to Moderator |
|
|
trizo
Forum Moderator
3091 Posts
|
Posted - 03 Jan 2009 : 8:15:08 PM
|
yeah thats cool m8, I understood what u were sayin  I know you have fully rebuilt yours , I wasnt saying you were wrong! |
3 can keep a secret if 2 are dead |
| Report to Moderator |
|
|
crazybiker
Fully Licenced
141 Posts
|
Posted - 03 Jan 2009 : 9:24:21 PM
|
Cool.
As a matter of fact, that reminds me. I've gotta get under the car and check my box mount, I think that's JUST starting to go.
My engine mounts are good, but my box seems to be bouncing a little more than normal.
GRR. Always something. |
| Report to Moderator |
|
|
VN91SX
Fully Licenced
344 Posts
|
Posted - 07 Jan 2009 : 8:41:05 PM
|
| Ordered a set of 1.8 Yella Terra roller rockers yesterday. Hopefully I will have them before the end of the week, so that I can put them on the car. Excited! |
| Report to Moderator |
|
| |
Topic |
|
Topic Locked
