Polishing, ported LS6 heads
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Polishing, ported LS6 heads I'm just about to purchase some Patriot Stage II LS6 heads for my LS1. I dont think they come polished. I wont be putting the heads on the car right away. So I have time to polish the intake/exhaust ports. The polising will be done using some very fine abrassive, not going to take too much off, but will get an almost mirror finiish. Is it wise to polish the intake ports aswell as the exhuast? should the intake be left as is (does rougthness help mike fuel/air)
I liked the look of these heads as they come preassembled with dual springs, cam, rockers etc... from one of the sponsers.
My next qeuation will be is chamber size. I have a choice of 59cc or 64cc. I have gone for 64cc as its near stock. I'm not going forced induction, and I'm worried about PtV clearence. I run on Shell Optimax/V-Power fuel all the time, I guess there is gains using 59cc, but whats the disvantages?
I liked the look of these heads as they come preassembled with dual springs, cam, rockers etc... from one of the sponsers.
My next qeuation will be is chamber size. I have a choice of 59cc or 64cc. I have gone for 64cc as its near stock. I'm not going forced induction, and I'm worried about PtV clearence. I run on Shell Optimax/V-Power fuel all the time, I guess there is gains using 59cc, but whats the disvantages?
if you are going to polish anything just do the exhaust and maybe the combustion chamber... i am about to put a set of Patriot 243 heads on my LS1 and i am not going to polish anything. the gains from polishing are going to be minimal.
if you get the LS6 "style" heads i would suggest the 59cc heads, the way patriot does it you will not lose any PtoV clearance.
if you get the LS6 "style" heads i would suggest the 59cc heads, the way patriot does it you will not lose any PtoV clearance.
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From: England UK
Originally Posted by 2000TransAmWS6
if you get the LS6 "style" heads i would suggest the 59cc heads, the way patriot does it you will not lose any PtoV clearance.
I'll give them a polish on the exhaust/combustion area, not expecting much gain, its just feels like I'm doing something when they arn't on the car.
I asked about this on my patriot heads. Gunnar said they don't offer this. WCCH said they "could" do it, but don't recommend it. So, on those two notes, I left mine alone. Patriot does awesome work!
I have the stage 2 243 head and if I could do it all over again...I'd still go Patriot. GREAT bang for the buck.
A few tips though: Don't bother doing anything to the intake runner. It's fine as is. If you really want to, you can take out the ridge that's around the valve guide. It seems to be caused by the CNC machine not being able to port the whole thing in one go (from one end to the other). Keep it a rough finish though. You will benifit from making the exhaust port smooth, so I'd suggest doing that.
They'll mill the 243's to anything you want. I had them mill mine about .010 and I'm somewhere around 11:1 static compression. If I milled any more I would have had PTV clearance problems since I got the upgraded valves to 2.02 and 1.57. I'm right within spec with those valves, a 224/224 cam, and a .045 gasket. Bigger valves will really eat up PTV clearance. Check out this post: https://ls1tech.com/forums/showpost....5&postcount=69
A few tips though: Don't bother doing anything to the intake runner. It's fine as is. If you really want to, you can take out the ridge that's around the valve guide. It seems to be caused by the CNC machine not being able to port the whole thing in one go (from one end to the other). Keep it a rough finish though. You will benifit from making the exhaust port smooth, so I'd suggest doing that.
They'll mill the 243's to anything you want. I had them mill mine about .010 and I'm somewhere around 11:1 static compression. If I milled any more I would have had PTV clearance problems since I got the upgraded valves to 2.02 and 1.57. I'm right within spec with those valves, a 224/224 cam, and a .045 gasket. Bigger valves will really eat up PTV clearance. Check out this post: https://ls1tech.com/forums/showpost....5&postcount=69
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From: England UK
So if I went 59cc chambers with 2.02"/1.57" valves I wont have any PtoV clearence with 226/226 .585/.585 112LSA and using Stock Head Gasket.
What sort of compression would I be looking at? I tried entering it in a engine package, and its ways 11.42 which I think is higher than what I would expect.
I wont do anything on the intake side, I'll get the exhuast shiny ports though.
This is the head/cam package I'm getting Head/Cam
I@m ordering other parts from the same place, so I wanted to get the heads and cam package from them too.
Trying to decide on 59cc or 64cc chambers. I'm not going FI, and dont want to fly cut, so is 59cc going to benifit me more?
What sort of compression would I be looking at? I tried entering it in a engine package, and its ways 11.42 which I think is higher than what I would expect.
I wont do anything on the intake side, I'll get the exhuast shiny ports though.
This is the head/cam package I'm getting Head/Cam
I@m ordering other parts from the same place, so I wanted to get the heads and cam package from them too.
Trying to decide on 59cc or 64cc chambers. I'm not going FI, and dont want to fly cut, so is 59cc going to benifit me more?
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I think you will be fine with the 59 CC heads. Get them and then do a clay test to see what PTV clearance is with a stock head gasket, then if you have plenty of PTV you can buy a smaller head gasket according to the clearances.
I would NOT polish those heads. It takes a fair amount of port work (unless it's fixing the short side radii) to see a difference on a dyno when you're PORTING a head. Polishing them will do nothing aside from some theoretical gains. The reality is, it's not an appreciable gain. Customers just like to see shiny ports when they buy heads.
If you mess up and hit a set when you're polishing them, you might really regret it then if you have to get a new valve job.
If you insist on cleaning them up by hand you can actually do it all with sand paper and a lot of elbo grease. You can reach all of the exhaust ports and do the chamber with sand paper and your fingers, but it's not fun at all.
Ben T.
If you mess up and hit a set when you're polishing them, you might really regret it then if you have to get a new valve job.
If you insist on cleaning them up by hand you can actually do it all with sand paper and a lot of elbo grease. You can reach all of the exhaust ports and do the chamber with sand paper and your fingers, but it's not fun at all.
Ben T.
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From: Austin, Texas
Originally Posted by RedWS6 00
I'm just about to purchase some Patriot Stage II LS6 heads for my LS1. I dont think they come polished. I wont be putting the heads on the car right away. So I have time to polish the intake/exhaust ports. The polising will be done using some very fine abrassive, not going to take too much off, but will get an almost mirror finiish. Is it wise to polish the intake ports aswell as the exhuast? should the intake be left as is (does rougthness help mike fuel/air)
I liked the look of these heads as they come preassembled with dual springs, cam, rockers etc... from one of the sponsers.
My next qeuation will be is chamber size. I have a choice of 59cc or 64cc. I have gone for 64cc as its near stock. I'm not going forced induction, and I'm worried about PtV clearence. I run on Shell Optimax/V-Power fuel all the time, I guess there is gains using 59cc, but whats the disvantages?
I liked the look of these heads as they come preassembled with dual springs, cam, rockers etc... from one of the sponsers.
My next qeuation will be is chamber size. I have a choice of 59cc or 64cc. I have gone for 64cc as its near stock. I'm not going forced induction, and I'm worried about PtV clearence. I run on Shell Optimax/V-Power fuel all the time, I guess there is gains using 59cc, but whats the disvantages?
I've done a bunch of flow testing with cnc heads, don't polish them you'll lose cfm. Just run them out of the box, if you want more flow have it done by a shop with a flow bench.
You don't want a polished surface on either side, if your running forced induction using a finer finish on the exhaust side is a good idea but I won't advise trying it if you've never done port work before.
Good luck with you project.
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Okay I'll probbly leave the polishing, no point touching a job thats already been done well.
Now as the Cam is failry high lift, but not massive. Does the 59cc bring the valves closer to the piston more than the 64cc? I believe the diameter of the valves are the same in both Head packages. 2.02" intake. I guess the difference in the combustion chamber is that 64cc has a little more material removed, but the position of the valves is still the same space, therefore PtoV would be the same on both? am I correct?
Just out of interest what it the thickness of the of the stock LS1 head gasket?
With the heads off and you have the piston right at the top, is it level with the top of the block?
I guess the top of stock pistons are flat? or are the dished? if so how many cc's?
Sorry for all the mechnical questions
I have come from the PCM tuning side of things, and now require to change mechanical stuff. The mechanic that is giving me a hand to do this dosn't want to do fly cutting, well we both dont. Of course we will check by hand rotating the engine to make sure nothing hits.
Thanks for every ones help so far, its giving me more confidence in every reply.
Now as the Cam is failry high lift, but not massive. Does the 59cc bring the valves closer to the piston more than the 64cc? I believe the diameter of the valves are the same in both Head packages. 2.02" intake. I guess the difference in the combustion chamber is that 64cc has a little more material removed, but the position of the valves is still the same space, therefore PtoV would be the same on both? am I correct?
Just out of interest what it the thickness of the of the stock LS1 head gasket?
With the heads off and you have the piston right at the top, is it level with the top of the block?
I guess the top of stock pistons are flat? or are the dished? if so how many cc's?
Sorry for all the mechnical questions
I have come from the PCM tuning side of things, and now require to change mechanical stuff. The mechanic that is giving me a hand to do this dosn't want to do fly cutting, well we both dont. Of course we will check by hand rotating the engine to make sure nothing hits. Thanks for every ones help so far, its giving me more confidence in every reply.
Last edited by RedWS6 00; Jan 23, 2007 at 03:55 AM.
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From: BFE
With 59cc your DCR will be too high (8.9x), so I would go with 64cc and have them milled t0 62cc (.010 mill), or run .045 Cometic head gasket with the standard 64cc (I prefer that route)
Don't mess with the heads unless you know what you're doing. You can deburr imperfections and such, otherwise if you are set on polish, bling bling the outside.
Don't mess with the heads unless you know what you're doing. You can deburr imperfections and such, otherwise if you are set on polish, bling bling the outside.
Joined: Apr 2006
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From: Grand Rapids, Michigan
Polishing won't do much mainly because there's a "boundary layer" of air that for all intents and purposes is stuck to the walls of the port. Polishing an intake runner is a bad idea because it can promote fuel dropping out of suspension. The reason for polishing an exhaust port is to inhibit carbon buildup in the port. The reason for polishing a combustion chamber is also to inhibit carbon buildup, but it also reflects heat which puts more power down.
The RIGHT person polishing your intake side will not hurt anything, probably not help either for that matter. Patriot has a great bang for the buck thing going, but it seems from my experience that their tooling marks can be a bit wide. Polishing with an 80 grit roll is plenty "rough" to keep a/f mixing in line.
FYI, patriot is one of the favorite CNC heads to get hand finished because of their low price and staright forward port job. Its a great base for some of the high end porters to pick up.
FYI, patriot is one of the favorite CNC heads to get hand finished because of their low price and staright forward port job. Its a great base for some of the high end porters to pick up.
Originally Posted by xfactor_pitbulls
The RIGHT person polishing your intake side will not hurt anything, probably not help either for that matter. Patriot has a great bang for the buck thing going, but it seems from my experience that their tooling marks can be a bit wide. Polishing with an 80 grit roll is plenty "rough" to keep a/f mixing in line.
FYI, patriot is one of the favorite CNC heads to get hand finished because of their low price and staright forward port job. Its a great base for some of the high end porters to pick up.
FYI, patriot is one of the favorite CNC heads to get hand finished because of their low price and staright forward port job. Its a great base for some of the high end porters to pick up.
Originally Posted by RedWS6 00
Okay I'll probbly leave the polishing, no point touching a job thats already been done well.
Now as the Cam is failry high lift, but not massive. Does the 59cc bring the valves closer to the piston more than the 64cc? I believe the diameter of the valves are the same in both Head packages. 2.02" intake. I guess the difference in the combustion chamber is that 64cc has a little more material removed, but the position of the valves is still the same space, therefore PtoV would be the same on both? am I correct?
Just out of interest what it the thickness of the of the stock LS1 head gasket?
With the heads off and you have the piston right at the top, is it level with the top of the block?
I guess the top of stock pistons are flat? or are the dished? if so how many cc's?
Sorry for all the mechnical questions I have come from the PCM tuning side of things, and now require to change mechanical stuff. The mechanic that is giving me a hand to do this dosn't want to do fly cutting, well we both dont. Of course we will check by hand rotating the engine to make sure nothing hits.
Thanks for every ones help so far, its giving me more confidence in every reply.
Now as the Cam is failry high lift, but not massive. Does the 59cc bring the valves closer to the piston more than the 64cc? I believe the diameter of the valves are the same in both Head packages. 2.02" intake. I guess the difference in the combustion chamber is that 64cc has a little more material removed, but the position of the valves is still the same space, therefore PtoV would be the same on both? am I correct?
Just out of interest what it the thickness of the of the stock LS1 head gasket?
With the heads off and you have the piston right at the top, is it level with the top of the block?
I guess the top of stock pistons are flat? or are the dished? if so how many cc's?
Sorry for all the mechnical questions
I have come from the PCM tuning side of things, and now require to change mechanical stuff. The mechanic that is giving me a hand to do this dosn't want to do fly cutting, well we both dont. Of course we will check by hand rotating the engine to make sure nothing hits. Thanks for every ones help so far, its giving me more confidence in every reply.
stock head gasket is right at .051 compressed thickness.
the stock pistons are flat, and i would think that they would come out of the bore a couple thousandths, but i am unsure how much.
