Rocker arms

[mfp4073]

I was considering a trunnion upgrade kit for my LS1. That progressed to a set of new performance rockers probably 1.8.1 ratio, I believe you really need to upgrade the valve springs and push rods at the same time.
So is this worth the effort and how much power and torque would you likely gain out of this.
I don't plan to do this until next year so if it's a bad idea let rip
I was hoping for a genuine 450 HP and around 440 torque so nothing too outrageous.

[SturdyHSV]

The stockers with a trunnion upgrade are pretty bullet proof and well designed, and although a 1.8 ratio will allow more airflow, it's a relatively small gain for the cost, as it'll really need a remap to make use of it.

I would imagine springs would also be a good idea, although you'd only be increasing the lift a small amount so may not be necessary...

Pushrods if you went aftermarket rockers then you'd likely want to get a pushrod measuring tool and then order a set to the right length, again, time and money there :/

It's a tough one, are you going to do the work yourself?

Also, 450bhp / 440 lb ft is a decent jump for an LS1, assuming it's starting at around 380ish? Realistically a 70bhp jump probably isn't going to happen with a few small changes, for those sorts of figures NA I'd guess you'd really need a cam

Edited by SturdyHSV on Friday 31st May 21:12

[mfp4073]

SturdyHSV said:

The stockers with a trunnion upgrade are pretty bullet proof and well designed, and although a 1.8 ratio will allow more airflow, it's a relatively small gain for the cost, as it'll really need a remap to make use of it.

I would imagine springs would also be a good idea, although you'd only be increasing the lift a small amount so may not be necessary...

Pushrods if you went aftermarket rockers then you'd likely want to get a pushrod measuring tool and then order a set to the right length, again, time and money there :/

It's a tough one, are you going to do the work yourself?

Also, 450bhp / 440 lb ft is a decent jump for an LS1, assuming it's starting at around 380ish? Realistically a 70bhp jump probably isn't going to happen with a few small changes, for those sorts of figures NA I'd guess you'd really need a cam

Edited by SturdyHSV on Friday 31st May 21:12

Thanks for the quick reply,
I would not be doing the work myself so I realise I need to factor in the fitting cost.
Mind you if it really needs a remap I won't entertain that one. I would only remap the car again if I went the whole hog and put a cam in there which is fair enough.
It looks like 450hp can wait a while longer, I've got a few other things to sort out first anyway.
Thanks again for the info.

John

[Boosted LS1]

Trunnion upgrades are good. You can also use bushes instead of needles.

Have you considered piston to valve clearances with the extra lift from 1.8 rockers? Correct length pushrods will be a must.

[SturdyHSV]

Regards trunnion upgrades, either keep the stock ones or go for the bushing kits, Straub do one and I believe there's another brand doing it now too.

I'd suggest avoiding the comp cams trunnion upgrade as there are quite a few reports of them failing and dropping lots of lovely needle bearings into the engine.

[fred bloggs]

I may be wrong, but I doubt you'll see 450 on stock heads/cam/intake.

[chris-y]

I'm just assembling my LS2 following the original engines valve spring failure.

I learned about the trunnion bearing problem, and the originals sometimes loosing rollers which are then moving around the engine.

In the end after considering solid bushes I instead went for Brian Tooley Racing needle rollers that are retained, basically the benefits of needles but they cant get out like the standard ones can.

I think needle rollers should have a much longer life, the only problem seems to be needles getting out so this seems to be a good solution.


I'm no expert but I wouldnt think changing the rocker ratio will give much benefit, OK its going to increase maximum lift, but it wont change duration, overlap etc.

I would also think that the extra forces on the pushrods would definitely mean an upgrade to those and as everyone said you need to be measuring the length and choosing the correct rods if you have changed anything else.
I wouldnt consider any valve lift changes without upgrading the springs. In my opinion, and I believe other peoples too, any change to valve operation needs a good quality dual valve spring swap.

I'd suggest this is all not worth it at all unless you are changing the cam, you would have to start again with the rods when you did that anyway.

[mfp4073]

Thanks for all the advice guys, I was hoping for a quick cheap mod with a usefull power increase.
You would think at my age I would know better.
The trunnion upgrade sounds sensible, so that will be put on the to do list.

Thanks again

Edited by mfp4073 on Saturday 1st June 17:32