Rocker Trunnion Upgrade

[Redline457]

Very nice , 12 pounds that would wake it up alright. Getting me excited 408 cube stroker kit with a blower on top would be interesting. My baby attached

 

[Redline457]

I’ll contact them this week, HPF did the WP upgrades for me. The whole package has been very reliable over the years

 

[Skylarking]

@Pollushon, what sort of torque you pushing through the drive line and what have you done (if anything) to the gearbox and diff to ensure longevilty?

@Redline457, now i'm in more disbelief that the rockers weren't upgraded...

 

[Redline457]

Approximately 700 nm atw, OEM trans cooler fitted pre delivery.

 

[Skylarking]

@Redline457 & @Pollushon

A bog standard LSA pumps out 430Kw & 740Nm but comes with 6L90E auto or MG9 TR-6060 manual, a much bigger diff, lots of extra cooling for both auto, diff and engine and (i think) a higher rated fuel pump (as compared to standard LS3) so as to feed the monster engine with good fuel pressure and volume... It's a $$$ package.

Oddly I had a look at HPF and they don't mention gearbox & diff upgardes and surprisingly don't mention fuel pump upgrades at all within their VF packages.

So, as a minimum, maybe you need to keep an eye of fuel pressures if hammering your beast as going real lean can kill it quick. Not relevant if you don't wring its neck and only take it easy with an occassionally short squirt easing the throttle down and reving to 4.5K-5K RPM (if that).

Don't take it the wrong way, not baging what you've done (it's impressive) but just curious as to what must give when GM/HSV engineered their LSA's in a very different way...

 

[Pollushon]

That's nice mate, the LSA is a really well made unit. To be honest I think the engine is going to wake the blower up, it's a full fruit build made for big boost

@Pollushon, what sort of torque you pushing through the drive line and what have you done (if anything) to the gearbox and diff to ensure longevilty?

Hasn't hit the dyno yet, hoping this week I can tee that up. I'm told tuned for a daily it should see 550hp and 1200nm atw safely. Ensure longevity is not a term I associate with a build like this, things are going to break I'm not going to flog it, that's my best chance long term. Short term there's a Mantic 9000 dual organic on a mildly toughened T56. Trutrac in the rear

Is a good call mate. Fuel pressure is life. I'm running a 465lph @ 40psi non surge system. Good for 800hp. Factory builds do fine on half that. LSA injector is only a 600cc squirter at 80% duty cycle

 

[Redline457]

Hi Skylarking , I know and understand where your coming from, I’ve queried the fuel pump issue with HPF some time ago I was assured the stock pump was okay for this package, I’m not wringing it’s neck or flooring it every set of lights, gets the occasional full on squirt. Back on topic would you recommend the bronze bushing over the caged bearing for the trunnion upgrade ?

 

[Skylarking]

Like anything, mods can sometimes be influenced by fashion or fad.

Back in the day, all rockers were originally on shafts, then a manufacturer moved to post mounted rockers on their new engines.
Post mounts were new so those who modded their engines modded what they had... in a cost constrained way... as we all do...

Shafts were supposedly more solidly supported but pedistal mounts probably cheaper to make.
So pedestal mounts can flex and high spring force can pull the bolts out, supposedly.. who knows the truth...

It's the same with bearings, originally bronze bushes were widly used and each has it's pro's and cons.
Bushes supposedly have higher parasitic loss but needles through an engine are no fun.
GM even say an oil pump can't suck them up, others say it's not a big issue... yet it's an issue solved by the aftermarket...
Who really knows the truth as there is no one truth.

Even if one has day job designing and engineering combustion engines, you'd also suffer from fassion and fad in your job....
As is, everyone will have a view though it always comes down to money, otherwise we'd all drive ferrari's...

Me, I've always liked the simplicity of a long shaft supporting all the rockers which run on bronze bushes.
Reliable, last forever but maybe don't make highest power in heavily modded engine.
Only thing better IMHO is over head cams with solid buckets (cam followers) but that's a different type of engine.

Either will work well with LS engine.... the issue with the OEM D trunion is fully resolved by a round trunion with circlips but bronze bush will also fully resolve the problem... it's sort of blue pill red pill dilema.

Not helpful i know so i'd talk to HPF as they have done your mods and it's worked well for you so their opinionand what they are more comfortable with will probably be more valuable to you..

 

[Redline457]

Thanks Skylarking appreciate your input

 

[Dirbatua]

I'll throw my 2 cents in for what its worth.

It's a known thing that the rocker bearings where cheaped out on with the LS engines against the engineers wishes, this is less of a problems in the VF's compared to the VE and earlier models but still an issue none the less.

I've used the comp cams trunnion kit in a lot of cars I've built over the years, some of which have 150k plus on the engines since they were installed without an issue.

Its a simple installation process to push out the old bearings and install the new ones, don't even need a press if you dont have one as a bench vice will do the job just fine.