bortous

You owe me an LS9 engine block!

With the trunion upgrade you are not upgrading the whole assembly.
This is more of a budget job.
We don't do this down here.
Yella Terra Rockers free up hp because there is much less friction in the rollers themselves and you get a complete kit.
Because they are lightweight it can help your engine rev quicker too.
They are very strong too with the ultra lite pros being able to handle up to 480lb of open spring pressure,
Then they have a pro street version which can handle 600lb and the platinum series 900lb
I have the pro street on mine

bortous

You can get away with ultra lite pro rockers for sure but if you ever plan on fitting a heavier spring in the future use the pro street version so you have room to move.
I'm using the PAC 1209X spring which has 510lb of open pressure

bortous

You end up ordering the camshaft Andy?

AndyTA

I'll be sure to look for one that I can actually afford (like in a junkyard...if that's ok ;-)

Thanks for the education on this! Holy smokes these things aren't cheap. It's just another one of those things I will add to the list... every bit counts!

Sorry for the lack of updates here! I last second changed my order to the one with 10 degrees of overlap. But yes, I did order it :-) It will arrive to me probably by Friday of next week. I'll post the cam card once it arrives ;-)

Since I have you here:

Obviously I will be checking for PTV clearance - but of course, I'd like to learn more about this.. How are you/Darth able to say with confidence that there won't be clearance issues? What quick back-pocket knowledge are you referring to, that gives you the ability to do this? Again, genuine learning question. I have no clue about how this works.

I know how to measure the clearance using clay, I just don't know how to....know what would "potentially clear" just by cam specs alone!

Y'all are doing some magical guru stuff, which is what I'd love to learn.

Thanks,
Andy

bortous

Hi Andy, you made the right choice.
The 10 degrees overla camshaft is the best compromise of the three as you will still have a decent note.
And yes I would like to see the camshaft card once you get it.
How much lift on the intake and exhaust and how many degrees of ground in advance did you specify?
We know you will not have clearance issues due to the fact that we have a fair idea on how big you can go on your engine.
a 236/252 camshaft with cathedral heads on an Ls7 will be all good. You will of course need to check just like you do with any size camshaft.
You are more inclined to have issues with ls3 heads unless you have valve reliefs in your pistons and then the sky is the limit on camshaft size.

bortous

I have 60 thou shaved off my LS3 heads which makes my combustion chamber size 60cc and my compression 12:8.1
On stock pistons you will not be able to even fit a 223/231 duration camshaft without clearance issues all because of the shaved head and valve.
Because my engine was rebuilt and my pistons have valve reliefs, even a 268/280 camshaft can now fit without clearance issues on my combo.

AndyTA

Hi Bort,

1) The final cam specs I ordered are: 236/252 .629/.615 117 LSA +3 - I'm sure that they haven't begun grounding this cam just yet, so if I need to make a change to any of that, let me know. I'll call'm up ;-)

2) That makes sense! Thanks for the explanation. So, if you were to take a "shot in the dark" sort to speak, just speaking in theory here where Andy went crazy and said "f*** you" to "drive-ability", what would be the "biggest" I could go given my specs and borderline destroying my engine from lack of PTV Clearance? Again, I would never do this. This is for learning experience.

3) I assume Valve Relief is the "-cc" dishes that are CNC'd in to the piston heads? In my case, would that be referring to the -20cc piston?

Thanks for your interest and time!!
Andy

bortous

I'm liking the specs. I would advise, get Texas Speed to ground in 1 degrees of advance into the cam so you have a bit of wiggle room to move in case the specs end up changing a little once installed.
Make sure you tell the person who degrees the camshaft in to your engine to ensure it is advanced by 2 more degrees so it's on a 114 ICL so your valve events are where they need to be.
You can advance it either 1 or 2 degrees.
I wouldn't go 3 as you will not have room to move if you need to.
If you advance it 1 degree the installer will need to advance the camshaft 2 more degrees.
If you advance it 2 degrees the installer will need to advance it one more degree.
Make sense?

The valve reliefs are cut into the piston heads.
All after market forged pistons have them by default.

If you wanted to say FU to driveability you would fit something like a 246/262 112 LSA +3.
This may fit but cannot be sure.
Same valve events as other camshafts but 3 times more overlap at 30 degrees.
This will be mental up top though.

AndyTA

1) So wouldn't the "+3" tell them to ground 3 in advance? (236/252 .629/.615 117 LSA +3)

2) I will be the one installing the cam as I did the first time, however... I installed mine "Dot to Dot" method without a degree wheel. I'm assuming you would advise against this?

3) I think to understand this, I would irst need to understand #1

All of that makes sense :-)

Thanks Bort,
Andy

bortous

Andy don't worry about advancing the camshaft. It's too much to explain.
Just get the 3 degrees of advance built in which will mean you will need to install it straight up at 0 degrees.
Degreeing the camshaft is important so you know you have been given the right spec and that it was ground right.

JakeFusion

iTrader: (7)

That's not far off from what I'd suggest as a street friendly cathedral port 4" stroke grind.

I would have said 237/254 115+5. The earlier the exhaust opens, the more power you'll make up top. And a slightly lower IVC would be better... that cam still would peak at 7000. But you lose probably a good 30-50 ft-lbs throughout the range with the later IVC. The supercharger will continue to push peak higher and higher as long as the exhaust can keep up. IVC becomes almost moot.

Also, overlap makes power. Even on a blower combo.

bortous

That might be true but Andy did want something more focused in the mid- top end with not too much overlap.
He has cathedral port heads so torque won't be an issue in a 427 in the low end.
I was going to specify something at about 50 IVC but he wanted something more focused on top.
Original spec was a 234/252 117+4 but once I saw what he wanted it was altered to be more focused up top.
Your spec is good too though Jake although too much overlap for what he is wanting.

JakeFusion

iTrader: (7)

The difference between 10 and 15 degree overlap in terms of drivability in a 427 with a Gen III PCM is completely unnoticeable.

bortous

There would be a difference but it would be small.
As I said, Andy wanted to lose the least amount of boost possible.

Darth_V8r

iTrader: (4)

18 degrees on mine I can drive fourth at 20 mph.

Much bigger and I am sure you would start to pay a price.

bortous

What size engine have you got again Darth?

Darth_V8r

iTrader: (4)

428.

Ls7, honed our to 4.130 bore so I could call it a 428. Because Pontiac and Murica

bortous

That explains it.

JakeFusion

iTrader: (7)

*technically a 429. You Ford lover!

AndyTA

Looks like they ground the 14 overlap one before I got a chance to update them with the 10 overlap cam - and actually, I'm totally content with this. :-)

Thanks again Bortous and Jake for chiming in with your invaluable input! Here's an update:

1) Cam is ground and shipped, arriving Saturday (I'll still be Out of town, wont return home until the 11th)
2) Machine shop has my engine torn down completely, they'll probably call me today to let me know what all went wrong
3) If I can get my engine back by the 13th or 14th, I'm hoping to throw the engine back in the following day
4) Dyno tune probably two weeks after engine is in, or sooner.

Thanks,
Andy