Has anyone here done it? If so share your expereince. Just got an extra set of heads and was curious how easy or difficult this would be. Not sure how the big companies do it, but I've been ready up a little on the web and it can be done. Just curious to hear a little insight from you guys on how your home port job turned out.

Mike

 

Mike - hit up dave (RASilverbird) - he did his LT1 heads with pretty good results. He may be able to help you out.

 

I ported my own heads. A few tips are to leave the port walls and floor untouched but you can remove casting. Raise the port roof anywhere from 1/4 - 1/2 in up depending on casting. Do not remove swirl ramp but make blend in with the revised port roof. Also remove and smooth out the rocker boss. Just smooth out the area to the right of the valve guide and swirl ramp. Also open up the bowl/ valve seat area to accomidate the increase flow. This is what I was taught from a knowledgeable LS1 porter. Note if LS6 heads you have to take a different approach.

 

I Read Your Post And Can Relate As I Am Just Begining A Home Port Project.i Got A Sweet Deal On A Set Of 5.3's And I Have Found That I Can Use A Local Machine Shop To Clean,mill,and Install New Valves And I'll Do A Moderate Porting Of The Bowl And The Ports Mostly Around The Valve Guides.we've All Seen Some Of The Ls1's Putting Down 400+ To The Wheels With Stock Heads ,i Just Wanted To Do One Better And Have The Valvetrain To Easily Handle The Higher Stress.i Just Can't Decide If I Want To Spend The Extra Money For Larger Valve Seats To Accomodate A 2055/1.60 Setup Instead Of The Usual 202/157.

 

I ported my own heads I use the directions and kit from standard abrasives. I was able to pick up 20% increase across the board just with the porting of the intake and exhaust then I had the shop mill the heads .030. Unfortunately I have not been able to get the car running yet for numbers running into other obstacles.

 

Got a number or any contact info for standard abrasives? These were LS1 heads I take it?

Mike

 

Standard abrasive's a porting kit that has alot of the common wheels and stones used in porting and polishing. Summit used to carry them and some of the sponsors, maybe?!

If you get one, the deluxe kit's the best one~

Alan

 

Yes they were LS1 heads. You can order the deluxe kit through then 1-800-423-5444 I believe it was $64 or you can go to www.standardabrasives.com and search for the nearest distributer

 

Thanks for the "Heads" up Will. While Standard Abrasives wasn't strictly an automotive company they seemed very dedicated to their product. Even sending me to Summit to pay half as much and offered for me to call back anytime for advice even though I didn't buy directly from them. Very cool organization. So I got the kit and the video to help me threw this. I found a local bud that's done a set of LT1 heads, so that also should help.

Now through my reading I realize I need a set of crap valves to protect the valve seats during this process. My question is about the valves and valve seats. Aren't they upgraded on typical Stage II and II heads? If so what is upgraded. Not sure what can be done to a valve seat? As far as valves go what improvements should I be looking for? Quality? size? If size, how do I fit it in there.

Any advice on valves would be appreciated.

Mike

 

I couldn't tell you as far as the valve seats I was too chicken to mess with those. I can tell you that I used a digital micrometer to measure the intake and exhaust ports to make sure they were even. I think I took roughly 3mm side to side on the intake and roughly 6mm on the exhaust. Also like posted above I stayed off the floor and only went about 2 inches deep. Don't quote me on the numbers I can't find the paper, but take your time and when in doubt stop. You should see some gains.

 

The only problem I have heard with home porting is that you can get different flow numbers per cylindar causing an unbalance of power. This is what i heard and is why i didn't play with my stg2's when i got them.

 

I will post my before and after flow numbers later tonight for you. I had all 8 intake and all 8 exhaust ports flow test after and they were within 2% of each other after I was done.

 

Awesome! I'm very interested to see how they turn out compared to the manufactuorers heads. and how much you were able to pick up. What heads were you using?

Mike

 

Last LT1 heads I ported flowed 266 and 201 exhaust at 600 lift. 5 angle valve job with 2.0/1.57 valves. Last LS1 heads was 302 and 218 at 600 lift. I am presently working on a set of LS1 which should flow 320 and 240 range at 600 lift. Also working on a set of 5.3 heads which should flow really well. There are a lot of "undisclosed" tricks you need to know before big flow numbers can be reached. Just as important is velocity of flow. Which no one talks about. Porting is knowing what degrees and port volume sizes measurements need to be at specific areas according to valve size and head types. A million little changes make huge gains or completely screwing up a head.

 

Also, blend the seat to the port bowl, if you don't it crazy with removing material you should to much port to port balance. I do gsxr1000 and gsx1300 heads at my work, just my 2 cents.

 

Can you elaborate a little bit more or are these trade secrets? if so shoot me an e-mail. I got in this sport to learn about cars and less so to put up the biggest numbers or fastest times. Can't really consider myself a DIYer paying big bucks for someone else's elbow grease.

I'm also wondering what is meant by a 5 angle valve job? I hear that thrown around a lot but don't know exactly what is meant by that.

I'm glad this thread is getting some quality responces. I was worried there were too few out there that have tired this and/or didn't want to share what they know. I'm still a little worried about this, but I've tackled tough jobs before that I knew nothing about. This is just another one

Mike

 

I will be happy to share with you what I have learned. I don't have time to go into full details here but I can pm you if you want me to. The most important part of any port job is: First; machine work for your valve jobs. The correct angles are needed on the angles for proper air flow. Once your valve job and valve sizes are picked then the correct measurements can be calculated. Once you know the amount of material you need to remove then you can reach some high flow numbers with high velocity numbers. There are several tricks again that I don't have time to get into.

 

Sorry I didn't get this up last night, I had to work late. I will tell you the on thing porters don't want you to know, the angles of the valve job. intake angles on seat for my heads are 17,30,50,60,75, with 49 on valve face with 32 back cut, exhaust side was radius cut on seats, 45 valve face and 31 back cut. All the port work on my heads was blending the seats and bowls, removing some material around the guides and smoothing the area around guides, and removing the bump for the rocker bolts on the intake ports. Also DO NOT, I repeat DO NOT polish the intake ports, leave them rough. You can polish the exhaust ports and CC to reduce carbon build up. After all the port work was done my intake ports were only 207cc. Here are my before and after flow number, from the same bench, it was and old SF500 bench. By the way I have the stock valves just new angles on them.

stock
intake exhaust
.050 34 24
.100 68 52
.150 91 77
.200 122 96
.250 151 114
.300 178 133
.350 200 147
.400 214 156
.450 222 163
.500 219 170
.550 223 176
.600 227 180

Ported
intake exhaust
.050 35 25
.100 66 56
.150 94 84
.200 142 105
.250 172 125
.300 207 144
.350 227 159
.400 249 180
.450 255 198
.500 267 209
.550 275 213
.600 280 220

Exhaust port were flow test with out pipe, both stock and ported, the flow numbers would have been 15-20 cfm higher with a 1 3/4 pipe on them. I hope this info helps, I was happy with my results because I am only using an 02 LS6 cam.

 

I had bought the Standard Abrasives kit, but after it arrived, in my opinion, the size of the sanding cones were too big to complete the kind of exacting work I wanted. I used a Dremel with extension and various 60 & 80 grit drums. The head ports aren't altered, but all the flash is removed, the valve bosses are trimmed, valve bowls cleaned up, and CC's super smooth. The exhaust runners are also mirror smooth. Polishing, except for intake runners, was completed with fine compounds and various buffing disks. My engine shop guy said the job looked quite good.

 

Can someone explain the theory behind not polishing the intake ports? Also would you port a head differently for a blown car than you would an N/A car?

Mike