Milling the Heads... How much to Mill?

[drumsbh]

Guys,

Patrick spec'd me out a cam and Im having Rick (G8-4-Speed) to the port/polish/mill. rick is suggesting milling 0.025", what do you guys think? I'm just worried as this is my DD on nice days and gets put away in the winter. I thought about taking just 0.010" off, but since this is most likely the last thing I can do to the car ( Thanks to my Wife) I really want it to be worth it. I want everything to go smooth on install ,and no surprises

Cam Spec's: 222/226 .597”/.605” 114 LSA +2 advance

Static/Dynamic compression with new cam: 10.5:1 SCR, 8.24:1 DCR

i laso have new stock Head Gaskets and 7.400" push rods.

any insight would be great. Patrick and Rick feel free to post.. please.

[gmpower]

I wouldn't mill em, just do a valve job and some porting especially since you're gonna dd it.

[drumsbh]

Its not a normal DD. It rarely gets driven. If their is a chance of rain the car doesnt leave the garage. I talked to Geoff from EPS about the milling after talking shipping of my parts and he said just make sure that their is wiggle room for milling, he said I dont want so much compression and have to retard the engine. I do want the most I can get for power out of my setup...

[todds87ss]

Pat G should be able to tell you the amount of milling to improve CR with that cam. Send him a PM.

[drumsbh]

Pat G should be able to tell you the amount of milling to improve CR with that cam. Send him a PM.\

Sent

[G8-4-Speed]

.025" will give you 10.9 comp. Stock LS3 is 10.8 comp. Go for the power....even if its just a little

[laserred]

10.9 compression is nothing on an LS-series motor. While there is some difference, professionals like Katech routinely build LS engines with between 11.25-11.5 compression and they run happily ever after on pump gas. is 8.24 DCR with the .025 mill? I'd say that would require 93 octane, but nothing special. The heads I bought from Roy (edmanet) are milled to 10.9 and I am sure he had no issues either, and went 11.60s with them and a cam comparable. From what I've seen here, I doubt Rick would do you wrong...

[drumsbh]

10.9 compression is nothing on an LS-series motor. While there is some difference, professionals like Katech routinely build LS engines with between 11.25-11.5 compression and they run happily ever after on pump gas. is 8.24 DCR with the .025 mill? I'd say that would require 93 octane, but nothing special. The heads I bought from Roy (edmanet) are milled to 10.9 and I am sure he had no issues either, and went 11.60s with them and a cam comparable. From what I've seen here, I doubt Rick would do you wrong...

is 8.24 DCR with the .025 mill? No I think thats is with a 0.010" mill if I went that route. I'm not saying Rick would do me wrong... I just want to know if I should go for the 0.025" mill and chance it they I dont have to take the heads off any time after and would have to mill again for any reason. I also thought well maybe if I just did 0.015"?

[drumsbh]

and the pump gas up here in MN can get pretty crappy. As of now I run 91+ non oxy. I found I get more power and better MPG vs. the 92 octane. No 93 octane in my town...

[Crazy Paul]

I also thought well maybe if I just did 0.015"?
Keep in the back of your mind that there's an optimum pushrod length to ensure proper valvetrain geometry, which has an effect on component life and noise.
For your camshaft grind with stock GM head gaskets and stock head thickness there'll be length X pushrods required. Mill Y amount off the heads and now pushrods need to be X minus Y in length.
They don't make an infinite range of lengths, so don't get caught in no-mans land by plucking a random milling thickness out of your butt.

[drumsbh]

Keep in the back of your mind that there's an optimum pushrod length to ensure proper valvetrain geometry, which has an effect on component life and noise.
For your camshaft grind with stock GM head gaskets and stock head thickness there'll be length X pushrods required. Mill Y amount off the heads and now pushrods need to be X minus Y in length.
They don't make an infinite range of lengths, so don't get caught in no-mans land by plucking a random milling thickness out of your butt.

Good call... thanks Paul. this is why i posted... I do have new stock gaskets and 7.400 push rods... thanks again Paul.

[G8-4-Speed]

Keep in the back of your mind that there's an optimum pushrod length to ensure proper valvetrain geometry, which has an effect on component life and noise.
For your camshaft grind with stock GM head gaskets and stock head thickness there'll be length X pushrods required. Mill Y amount off the heads and now pushrods need to be X minus Y in length.
They don't make an infinite range of lengths, so don't get caught in no-mans land by plucking a random milling thickness out of your butt.

You can get the right pushrod length no matter what gets milled of the head. Its a guess to buy pushrods with a cam in the first place, there is no guarentee what the base circle will be. It should be "x" based on the lobe lift but that isn't always the case. If it was I would not have been from a 7.500 pushrod down to a 7.325 on different cams with close to the same lobe lift. The geometry will not change, only lifter preload. The only time you mess up geometry with an LS is with valves, valve jobs, and adjustable rockers. None of which are changing. If you are milling the heads, then go for as much power as you can get without the hassel. You can take .040 off the heads and be fine. It would be better to go with a .040 gasket and .030" but he already has the head gaskets. The higher the elevation, the more compression you can get away with. Heck, these motors are setup to run on 87 with 10.4 comp and a stock cam that has a higher dynamic compression. Thats why there is a low octane timing map. Depending on the lifters being used for the delete, the 7.400 might not be right for anything....

[familycaronROIDS!]

My heads are milled .030 and I am happy with the performance. No port or polish though. My cam is a 224/234 custom grind.

[drumsbh]

Here is the spec sheet for cam info from Patrick. He recommends the 7.400" push rod with up to a .025" mill. Rick, I believe I ordered LS7 lifters.

Info:
Cam recommendation: 2008 G8 with stock L76 6.0L short block, .010” milled 68cc L92 heads, .054” gasket, ported L76 intake, 6L80E trans with stock stall, 3.45 gear, 1 3/4” long tube headers with dual cats, 6400 shift point, 6600 rpm rev limiter.
222/226 .597”/.605” 114 LSA +2 advance (with 1.7 ratio rockers)
Comp EPS/LXL lobes 54-000-11 3 bolt cam core
13116R/13158R HR114 LSA +2 advance (112 installed intake centerline)

Recommended valve springs: PAC1518 beehive or TEA .660" dual.
Recommended pushrod length: 7.400” chrome moly with up to .025” mill.
Static/Dynamic compression with new cam: 10.5:1 SCR, 8.24:1 DCR.

[laserred]

Rick, how are the E38 ECMs with ICLs tighter than 110? I know from my Ford days even the A9L had fits coping with tight cams. BTW what's the DCR on the stock cam?

Drumsbh, 2 things: 1, .025-.030" is nothing to be afraid of, and 2nd, you can always get a brand new pair of LS3 heads for under $700, complete. Half a point compression ratio should be worth about 1.5% additional power plus some torque, in addition to better part-throttle MPG from the increased efficiency. Don't be skeered! :)

[1ChargedG8]

I just got my heads from the machine shop. They got milled but not by much, maybe .007"

[G8-4-Speed]

DCR for a stock G8 is 9.06.
My Thumpr was on a 103 ICL on a 109 LSA without issues. Tune needs to be right for it to work good.

[drumsbh]

Sounds like .025" it is!

[G8-4-Speed]

Here is the spec sheet for cam info from Patrick. He recommends the 7.400" push rod with up to a .025" mill. Rick, I believe I ordered LS7 lifters.

LS7 need different length pushrods, you'll have to measure them. The cup placement is at a different height. You will need a .050 shorter for a LS7 lifter compared to stock. Just make sure to check at install.

[drumsbh]

I'll have to check tomorrow when the rest of the parts show up. Geoff at EPS put the kit together for me, not 100% sure what lifters are with it. This is really going to suck if I have to buy different rods already.

[johnbell2]

LS7 need different length pushrods, you'll have to measure them. The cup placement is at a different height. You will need a .050 shorter for a LS7 lifter compared to stock. Just make sure to check at install.

7.400 w/ LS7 lifters sounds right... that's what I run w/ the 0.040 gasket and stock heads so should be in similar ballpark.

[drumsbh]

7.400 w/ LS7 lifters sounds right... that's what I run w/ the 0.040 gasket so should be in similar ballpark. I believe the stock gasket whch I have is .054"? sound right?

[laserred]

.051" is stock.

[drumsbh]

Just received the rest of my parts today... I think I have the stock (for us minus the afm crap) lifters and the head gasket compressed is .051".. I took pictures of them in hoping someone could tell me if I need to change the push rods length. Thanks guys

http://dl.dropbox.com/u/6643521/IMAG0044.jpg

http://dl.dropbox.com/u/6643521/IMAG0045.jpg

[drumsbh]

Looks like these... http://www.summitracing.com/parts/NAL-12610046/

and

http://www.summitracing.com/parts/NAL-17122490/

[drumsbh]

I don't see a timing chain dampener in my parts... Do I need one?

[G8-4-Speed]

I don't see a timing chain dampener in my parts... Do I need one?

yep, need to replace the stock one before it ends up in your oil pan.

Should have went .040" on the head gaskets, and 7.400 sounds long. You may need 7.375-7.350. Depends, they will have to measure it with a pushrods tool. The 7.400 will work but might be noisy if they are not in the target preload range.

You have two choices:

Throw the 7.400's in and see if it works ok. Or check the preload turns when tightening the rocker bolts. It is all just "best" guess, whether you mill the heads or not.

Or, measure it and install what it needs. The cam and heads will have to be installed to check.

My current cam takes two different size pushrods for the lifters to work best, blame Lunati.....

.070-.100" preload has worked best for me. Have heard LS7's will work with less preload.

.025" off the heads will be fine. Your best to ask Pat about the pushrods and LS7's, he has sold this grind several times so if anyone knows how this cam generally installs with "x" lift, it would be him.

[drumsbh]

yep, need to replace the stock one before it ends up in your oil pan.

Should have went .040" on the head gaskets, and 7.400 sounds long. You may need 7.375-7.350. Depends, they will have to measure it with a pushrods tool. The 7.400 will work but might be noisy if they are not in the target preload range.

You have two choices:

Throw the 7.400's in and see if it works ok. Or check the preload turns when tightening the rocker bolts. It is all just "best" guess, whether you mill the heads or not.

Or, measure it and install what it needs. The cam and heads will have to be installed to check.

My current cam takes two different size pushrods for the lifters to work best, blame Lunati.....

.070-.100" preload has worked best for me. Have heard LS7's will work with less preload.

.025" off the heads will be fine. Your best to ask Pat about the pushrods and LS7's, he has sold this grind several times so if anyone knows how this cam generally installs with "x" lift, it would be him.

So the lifters I got which are - http://www.summitracing.com/parts/NAL-17122490/ are LS7 lifters? I researched the LS7 lifter and it was a different part number. I did sent a PM to Patrick and he said the push rods I have will work with a .025" mill...

[drumsbh]

Anyone know where to get just the chain dampener and bolts for it?

[-Ray-]

Greg at Pace.

[drumsbh]

Greg at Pace.

Thank you

[drumsbh]

So I just did some research and I do have LS7 Lifters... Instead of all 16 with part gm#12499225 I got 2 boxes of GM#17122490... Rick, you ssaid these lifters are shorter than the stock ones and the head gasket is thicker, does that mean possibly the 7.400 push rods will work? Sorry I'm just trying to understand all this and make sure I have the correct parts if possible.

[SS DAVE]

firstly i wouldnt make the mistake of listening to too many people,everyone has thier own opinion.you have pat g specking the cam ,so listen to his advise.he knows his shit.as for the push rods ,7.4 should be on the money but you still need to measure preload on assembly,and be prepaired to get different length if required.you wont know till its checked on assembly.

[drumsbh]

Thanks SS

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[08G8V8]

I am doing a dod-delete with linkbar lifters instead of the LS7 lifters and trays, and Patrick could not give me a recommended length based on these, but he did give me a length based on LS7 lifters. My builder is going to just measure at time of install, and then order the proper length, which he says is about a 1-2 day turn around. I ordered all my parts except for pushrods, this way I won't get stuck with the wrong length.

[drumsbh]

I am doing a dod-delete with linkbar lifters instead of the LS7 lifters and trays, and Patrick could not give me a recommended length based on these, but he did give me a length based on LS7 lifters. My builder is going to just measure at time of install, and then order the proper length, which he says is about a 1-2 day turn around. I ordered all my parts except for pushrods, this way I won't get stuck with the wrong length.
Like me most likely... I'll just exchange them when I know what size for sure if these don't work.

[laserred]

Always remember that Trend Pushrods, one of the industry leaders, has shelf stock in about every length you could ever need. In the off chance they don't, they will make anything your heart desires.

trendperform.com

[drumsbh]

Good to know, thanks laserred

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[gtp6515]

12822
I was told I did not need to install this. Geoff told me this as well when I was looking into his kit Came with Livernois stage 1c kit. Is this not accurate? Car runs fine.

[G8-4-Speed]

12822
I was told I did not need to install this. Geoff told me this as well when I was looking into his kit Came with Livernois stage 1c kit. Is this not accurate? Car runs fine.

:oops::nutkick:
Well, technically you have one. Just likes to break and end up in your oil pan. Which is why you install that one. Wanna sell it cheap?

[drumsbh]

I just ordered one from Pace... I don't want anything in the pan.

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[laserred]

Oil is usually a requirement. Unless you've got Slick 50, ZMax, or Prolong. Then it's optional.

Good luck with the conversion... I'm sure you'll like it.

I keep wanting to do it, but my brother is getting ready to pull his 404 and put a stock motor back in his Camaro SS, maybe I will get it from him.
I'm thinking 238/250@.050" 113+4 w/ .621" is probably a tad big for a stock converter in a G8 :)

[gtp6515]

I hope this one lasts the winter as I will be doing another cam swap. This stage 1c isn't cutting it. I will use this one I have then. I assume this is why I did not have to mess with the pick up tube.