Building a 350 Vortec motor

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

http://www.nastyz28.com/forum/showthread.php?t=56505&page=2


First off, a warning: This post is a sig-hunter?s dream. I will be using phrases like ?pinning the rocker stud,? or ?studs pulling-out? or even, ?I prefer tapping the stud-bosses.? Please get all of your chuckles out of the way now .


- Stand back, look at the bruises on your hands and ask yourself why you didn?t just pay a machine shop to do this for you........
__________________

I'll stand back and let you tap those studs yourself... HAHAHAA...

Machine shop is doing whatever work i need done. I wont be touching it other than to put the heads on when they're finished.

 

[greg82255]

Re: Building a 350 Vortec motor

I'll stand back and let you tap those studs yourself... HAHAHAA...

Machine shop is doing whatever work i need done. I wont be touching it other than to put the heads on when they're finished.

Comp cams makes a special tool that allows you to tap the holes yourself, but after buying it and trying it a few months ago, I'd definitely recommend letting the machine shop do it. Anyone who reads my 383 thread knows the amount of time and $ I spent getting everything to work correctly with the vortec heads. I tried to remove the studs and tap the holes myself and eventually just gave up. I ended up going to 2 different machine shops to get all the work done. In addition to the standard surfacing and valve job, they machined the valve guides for higher lift, machined the stud bosses for the ARP studs (I believe it was .350"), tapped the holes, and installed/torqued the studs for me. If you install the studs yourself make sure you use a thread sealer.

 

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

-Retainer, steel http://www.summitracing.com/parts/CCA-774-16/
Comp Cams 774 $59

-Keepers, 7-degree http://www.summitracing.com/parts/CCA-648-16/
Comp Cams 648-16 $28
http://www.summitracing.com/parts/NAL-12499224/

For peace of mind: 1-330-630-0240 summit tech support

Just inform them you are using the ls6 spring's yellow in color or blue with comp retainers on vortec heads for increased lift with no maching done to the heads. This mod is extremely popular and very old.

Thank you for all the links! While there, i can get my fuel pump push rod as well. I still havent heard from the guy who ordered my cam as to whether or not it's in. Should've ordered it myself and told him to keep his discount so i could avoid the hassle of trying to track him down.

 

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

Alrighty... I just finished ordering suggested springs/retainers/locks from summit along with my bronze tipped fuel pump push rod and stainless intake bolts. Should be here by Thursday or Friday. Hopefully Thursday so i can get the stuff to the head shop and they can get the heads done. Now if i could just get my hands on my cam and intake....

 

[John_S]

Re: Building a 350 Vortec motor

Did you get the GM LS6 springs?

 

[Tail_Gunner]

Re: Building a 350 Vortec motor

Here's a good data sheet they will work fine...GM's stock rev limit is 6600 on those springs...plenty of margin

http://www.s10planet.com/forum/showthread.php?t=14790

 

[John_S]

Re: Building a 350 Vortec motor

http://www.jpmagazine.com/techarticles/engine/154_0911_jp_350_part_1_400hp_chevy_engine/viewall.html

Not sure what they did wrong.

 

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

Did you get the GM LS6 springs?

I did. I purchased everything tailgunner sent me links to... after i checked into it of course. The order has already shipped and is projected for Thursday afternoon arrival.

 

[John_S]

Re: Building a 350 Vortec motor

I did. I purchased everything tailgunner sent me links to... after i checked into it of course. The order has already shipped and is projected for Thursday afternoon arrival.

I am interested in the success of using them. They are very cost effective compared to the beehive. It was just some of the links, it wasn't exactly clear if it was 100% successful. ie I might change my cam and or rockers in the future, and looking for the most economical way to do it.

 

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

I am interested in the success of using them. They are very cost effective compared to the beehive. It was just some of the links, it wasn't exactly clear if it was 100% successful. ie I might change my cam and or rockers in the future, and looking for the most economical way to do it.

I spoke with the man at the head shop a little while ago. He has done the LS6 springs multiple times with positive results. Though he did say my stock retainers and locks would work ok. Oh well, i spent the $$ for a little extra reassurance.

 

[Tail_Gunner]

Re: Building a 350 Vortec motor

http://www.jpmagazine.com/techarticles/engine/154_0911_jp_350_part_1_400hp_chevy_engine/viewall.html

Not sure what they did wrong.

With the heads, intake, and camshaft sorted, that only left the valvespring issue to deal with. And that's where I hit a wall. Standard high-performance valve springs require machining of the Vortec's valve pocket and valve guide. It's no secret that you can skip the machine shop by installing LS-style beehive valve springs over the uncut 0.900-inch spring seat of the Vortec heads. In an effort to avoid costly aftermarket springs, I first tried a set of factory LS6 springs. On paper they should have worked, but the LS6 springs went into coil bind at about 1.30-1.34-inch, which is earlier than spec'd, so that was out. Then, Lunati sent a set of its new 74881LUN springs and its 75787LUN retainers that delivered a seat pressure of 100lbs at an installed height of 1.750-inch. These springs worked great up until about 5,300rpm, at which point the aggressive Voodoo profile began manhandling them. Some Lunati 74818LUN springs should fix the instability issues, but we won't know until the engine takes another ride on the Westech Performance dyno. Tune in next time for the complete engine specs, part numbers, prices, and dyno

Read more:http://www.s10planet.com/forum/showthread.php?t=14790

All of the above springs will fit the 4.3L Vortec spring seat perfectly. They all however will require a different retainer. You must use Comp Cams retainer number 787 this will give you the correct size retainer and also the correct install height. It will work with your stock locks.







Above : The retainer on the left is Comp's 787 retainer. The one on the right is a stock LS1 retainer. This retainer looks right but it will give you an install height that is far too low. Also your locks will not fit in the retainer correctly. DO NOT use it.


seems they missed that trival part of the mod.

 

[John_S]

Re: Building a 350 Vortec motor

With the heads, intake, and camshaft sorted, that only left the valvespring issue to deal with. And that's where I hit a wall. Standard high-performance valve springs require machining of the Vortec's valve pocket and valve guide. It's no secret that you can skip the machine shop by installing LS-style beehive valve springs over the uncut 0.900-inch spring seat of the Vortec heads. In an effort to avoid costly aftermarket springs, I first tried a set of factory LS6 springs. On paper they should have worked, but the LS6 springs went into coil bind at about 1.30-1.34-inch, which is earlier than spec'd, so that was out. Then, Lunati sent a set of its new 74881LUN springs and its 75787LUN retainers that delivered a seat pressure of 100lbs at an installed height of 1.750-inch. These springs worked great up until about 5,300rpm, at which point the aggressive Voodoo profile began manhandling them. Some Lunati 74818LUN springs should fix the instability issues, but we won't know until the engine takes another ride on the Westech Performance dyno. Tune in next time for the complete engine specs, part numbers, prices, and dyno

Read more:http://www.s10planet.com/forum/showthread.php?t=14790

All of the above springs will fit the 4.3L Vortec spring seat perfectly. They all however will require a different retainer. You must use Comp Cams retainer number 787 this will give you the correct size retainer and also the correct install height. It will work with your stock locks.




View attachment 143035


Above : The retainer on the left is Comp's 787 retainer. The one on the right is a stock LS1 retainer. This retainer looks right but it will give you an install height that is far too low. Also your locks will not fit in the retainer correctly. DO NOT use it.


seems they missed that trival part of the mod.

In the one JP picture showing the LS6 springs installed on the V8 vortec heads, it does look like the stock LS6 retainers. But, not sure that is the issue, since they said coil bind vs retainer to oil seal clearance. If the stock LS6 spring installed height is suppose to be 1.8", that says the retainer is only buying you an additional 0.05" in the JP article. That probably wouldn't be enough in their application/cam.

What I have heard that can happen is that the LS6 springs can bind on the vortec head valve pocket tower. Maybe scrub the tower is a better description than bind. Part of the inner diameter hits the upper part of the tower prior to coil bind. Not all towers and not all LS6 springs. It sounds like a mfg tolerance issue. ie if you have a tower toward the max diameter tolerance, and a LS6 spring diameter at the minimum.

In the OP's case, the head shop should test each valve, and resolve if there was a problem.

 

[Tail_Gunner]

Re: Building a 350 Vortec motor

Good points John...there are some tolerance issues or control issues but i believe that's probably from some vendor who is tagging his product wrong. I am still confused over a few details such as yellow vs blue spring's apparently yellow allow for 550 lift and blues for 525 while GM seems to say they are now both the same...One thing to note that if those are ls6 retainers and it sure looks like it...ls6 valves stems are 8mm and vortec are 11/32. How does that work. Just not enough complete info there. I can tell you on the v6 heads there was no issues with my setup

You learn all the time that article states vortecs have a 5 angle factory valve job...Thats new

It's tough to see, but the factory Vortec heads feature a complicated 5-angle valve job that some machine shops can't duplicate. If you can't score a set in the boneyard that doesn't need refurbishing, it's usually better in the long-run to simply buy a new set of heads from GM Performance Parts since often times a standard valve job will actually hurt flow.

 

[joewithaboat]

Re: Building a 350 Vortec motor

Good points John...there are some tolerance issues or control issues but i believe that's probably from some vendor who is tagging his product wrong. I am still confused over a few details such as yellow vs blue spring's apparently yellow allow for 550 lift and blues for 525 while GM seems to say they are now both the same...One thing to note that if those are ls6 retainers and it sure looks like it...ls6 valves stems are 8mm and vortec are 11/32. How does that work. Just not enough complete info there. I can tell you on the v6 heads there was no issues with my setup

You learn all the time that article states vortecs have a 5 angle factory valve job...Thats new

It's tough to see, but the factory Vortec heads feature a complicated 5-angle valve job that some machine shops can't duplicate. If you can't score a set in the boneyard that doesn't need refurbishing, it's usually better in the long-run to simply buy a new set of heads from GM Performance Parts since often times a standard valve job will actually hurt flow.

I just briefly looked at this video i have no idea who it is only grabbed it to show the machine and the process. Go to the very end and you will see the seat being cut. They can do a 5 angle all at once. I'm sure the one GM uses is fully automated and as big as a building LOL, but you get the point.

http://www.youtube.com/watch?v=RK0djZ2Ha_Y

Most race shops still use stones after cutting and then hand lap to finish off.
Most places would laugh at you if you asked for a 5 angle valve job.

 

[John_S]

Re: Building a 350 Vortec motor

The merc V8 gen+ service manual only shows them as a 3 angle valve grind.

 

[John_S]

Re: Building a 350 Vortec motor

..ls6 valves stems are 8mm and vortec are 11/32. How does that work.

They would need new locks or used the ones from the vortec valves. I believe the conical angle are the same for the LS6 and vortec spring retainers.

 

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

Well, i'm not exactly sure what they will end up doing to mine since the heads were practically new to begin with. I told him to do whatever he thought would be in my best interest. He did like the LS6 choice for springs though and has done that mod many times over with good results.

I got in touch with they guy who did my parts ordering and am a little nervous. He ended up ordering me a Lunati cam instead of the original comp cam we had discussed. Hoping he didn't order wrong for my application. I pick up my intake and whatever cam he got tomorrow afternoon sometime. Keeping my fingers crossed for now. Hopefully i can get some work done soon. My patience is getting thin.

I do need a tip on somehting. Since i've never put a motor back together, how do i get #1 set at TDC, and get the cam lined up appropriately before putting on the timing gears and chain?

 

[Maddoxsdaddy]

Re: Building a 350 Vortec motor

They would need new locks or used the ones from the vortec valves. I believe the conical angle are the same for the LS6 and vortec spring retainers.

From what i've read, you are correct.

 

[Tail_Gunner]

Re: Building a 350 Vortec motor

http://www.pacificp.com/forum/viewt...&start=0&sid=72a2f10f8cac040856d21288c9eebedd


Found a old thread..good one.

 

[John_S]

Re: Building a 350 Vortec motor

Changing from a 1.7 to 1.8" install height gives you an extra 0.100" for retainer to seal clearance. In the JP article, they should have been good for 0.510 lift. You think they would have examined and explained what was happening, vs just order a bunch of new parts.