PONTIAC ZONE TECH FORUMS
 

Go Back   PONTIAC ZONE TECH FORUMS >
Engine Tech
> Iron D-Port Heads
User Name
Password

Iron D-Port Heads All iron d-port heads, flow number and performance results

sponser links

Reply
 
Thread Tools
Old 08-07-13, 09:42AM   #1
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default Valve jobs on iron heads - 2 angle

Reading through my old HO books I see an explanation of why the 2 angle factory valve job was superior to a newer chevy? style 3 angle. Possibly one of the "more isnt necessarily better" ideas that tends to get overlooked? or old school idea that has been surpassed? It had to do with aiming intake charge properly I believe. Was wondering if anyone could expand on this idea or list their results of actually trying it. I want to do up several sets of heads to have available and have a new shop try to get them to a basic "level". Im doing a 62 set, a 092 set and a 670.
keith is offline   Reply With Quote
Old 08-08-13, 08:22AM   #2
Mr. PBody
Registered User
 
Join Date: Feb 2009
Location: Chesterfield, VA
Posts: 819
Default

Keith,

Through extensive flow testing, we found it to be correct. While the "3-angle" valve grind (really a "seat" grind...) LOOKS logically correct, it's deceptive. But air is a fluid, and fluids don't always follow what APPEARS logical.

The exhaust benefits from a little "throating", IF there's "room". When we enlarge the seat for a bigger valve, it makes the "taper" easier. Think of the seat as a "funnel" of sorts.

The intake seat shows improved flow when the 30 deg. angle is extended beyond the valve diameter. A 70 degree throat and a TINY 45 (about .060" wide) between them will gain a little more, yet. So, in a "sense", it IS a "3-angle" job...(:- Not the tradtiional 30-45-60 deal. Of course, today, we only use that formula on stock Chevys and Fords...

It has been found at higher lifts (above .600") a 45 deg. intake face is benficial. This should be reserved for "race only" stuff, IMO. The low- and mid-lift gains from the 30 deg. face are more important.

Jim
Mr. PBody is offline   Reply With Quote
Old 08-08-13, 05:23PM   #3
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default

Im not an expert mechanic or automotive machinist but I think going after the older idea means the valve grinder must create new and different stones to grind with or possibly modify a program in an automatic grinder if there is such a thing. I tried someone out who said they did that but was unhappy with the results on a set of 092's. The valves had side play with new guides and valves. The slight rust circles I saw when lifting a valve off the seat were not perfectly centered in the seat. I have a set of 62's that were done many years prior and are still silken (no side play) and perfectly centered. Both sets will go as examples of what I do and dont want with a super rough set of 670's or 69 46's I want done. I have about 20 sets of iron heads and several motors to do. Was going to order a bag of Elgin bronze guides. Not sure if I will replace all valves. Maybe I can clean polish and reuse factory ones. I like Glyptal for the oil galleys and figure there is probably a common spring arrangement that is an upgrade maybe I can get a volume discount on. Not sure about hardened seats and stud replacement. Will likely use engine paint primer coat with oil and wrap in paper to keep them ready for use.

Apparently you are a shop that does alot of Pontiac headwork? It would benefit my effort to fully grasp, be able to communicate instruction and then verify completion of a "best flow street" valve job. If I can coordinate that with a shop that will get the basics the way I want to I will be getting somewhere. Mailing heads Id like to reserve for porting on motors nearing completion. These are "shelf heads". Do you sell a stone "set" that would acheive what you recommend?
keith is offline   Reply With Quote
Old 08-08-13, 11:36PM   #4
Mr. PBody
Registered User
 
Join Date: Feb 2009
Location: Chesterfield, VA
Posts: 819
Default

Keith,

PM sent.

Jim
Mr. PBody is offline   Reply With Quote
Old 09-24-13, 11:59PM   #5
gtofreek
Engine Machinist
 
gtofreek's Avatar
 
Join Date: Jul 2007
Location: Tucson, Arizona
Posts: 1,694
Default #47 flow sheets

Here are some flow sheets of some small valve heads I opened up to big valves.
I use a radius cutter on the exhaust and it picks the flow up about 20 CFM over the big valve heads 2 angle VJ.
Attached Thumbnails
Click image for larger version

Name:	#47Flowsheet01.jpg
Views:	451
Size:	45.2 KB
ID:	26459   Click image for larger version

Name:	#47Flowsheet02.jpg
Views:	397
Size:	52.6 KB
ID:	26460  
__________________
Paul Carter
Carter Cryogenics
www.cartercryo.com
520-409-7236
Koerner Racing Engines
520-294-5758

I was wrong once. That was when I THOUGHT I made a mistake!
Your mind determines your limits!
gtofreek is offline   Reply With Quote
Old 09-25-13, 06:20PM   #6
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default

Have a 69 350 with 47's on it was thinking of either redoing instead of doing up the 46's that are very rough I have had laying around for many years. Have an idea for a psycho 350 floating around in my head. The 350 bore has a shrouding problem and winks machined into it I believe I havent cracked it apart yet. May try to bore to 4.00 and use standard 302 chev pistons or just have JE do me up some. Have a nice set of Bill Miller 500's to use up. Have a Lunati lift rules cam with monstrous duration ... not unlike the z28 302 30-30 Duntov. Topped with a Victor I have. Will be a chore to not have a breathing problem I think. Will be a race motor for sure.
keith is offline   Reply With Quote
Old 09-26-13, 12:32AM   #7
Mb125
Registered User
 
Mb125's Avatar
 
Join Date: Mar 2005
Location: AZ
Posts: 4,224
Default

I ran big valve #16 d ports on a 30 over 350. No breathing problems, ran good for the factory valve train.
__________________
You can shear a sheep many times, but you can only skin them once.
Mb125 is offline   Reply With Quote
Old 09-26-13, 10:34AM   #8
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default

Did your 350 have the winks in the bores for unshrouding? I think not all 350's had them. Did you weigh the 350 crank to see if it weighed less than a 400 crank overall? Id like to reduce weight as much as I can without sacrificing durability. 2.100 rod journals, light pins ... if I can use 302 chev pistons .927 pins and what i take out/off the top to adjust deck height and valve reliefs. Not sure if Mahle makes power-paks for 302. Trying to have 6500-7500 be a usable area. cid about 366. Less if I don have .100 top to bottom every hole with a sonic @ 4.000. Will need some big breathers for sure tho.
keith is offline   Reply With Quote
Old 09-26-13, 12:21PM   #9
Mb125
Registered User
 
Mb125's Avatar
 
Join Date: Mar 2005
Location: AZ
Posts: 4,224
Default

6500-7500 RPM will take a great deal of work. Better off going the stroker route and making affordable power below 6000 rpm and long engine life.
Or check into the combo of the super stock 74 GTO running high 10's
__________________
You can shear a sheep many times, but you can only skin them once.
Mb125 is offline   Reply With Quote
Old 09-26-13, 05:28PM   #10
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default A new twist :)

I believe some here may have dabbled in Chevy and as a novice engine builder I have done so although not completed project number 1 yet. Similar to what Im trying to do with the 350 Poncho (a smaller displacement HP build) I thought stuff would be cheaper and most people would be more familiar for help in the various stages so I could actually finish something with a good chance of success as a learning experience. My thought was to make a late Gen1 350 into a new age old school DZ-302 that would exhibit the same or better torque and HP across the board as a stock 350 and be similar or better than a DZ at high RPM. Along with a stick in my beloved plain jane 84 Cutlass would make an interesting worker bee. Most of the magic formula would be the right CC roller (268 Mag solid) and a pair of Fastburn vortec style heads. The fastburns tripped my trigger because of the flow numbers and I noticed a new "twist" via an additional characteristic called "swirl". According to the numbers fastburns kill the larger valved Boss 302 heads up to .525 lift and have swirl all the way up wheras the boss heads only start to swirl at about .525 . I havent heard anyone mention swirl in Poncho heads and dont really understand what it is but it seems to be a positive aspect and if so maybe something acheivable with old iron Poncho heads, .... anybody ever go down that road?
keith is offline   Reply With Quote
Old 09-26-13, 11:29PM   #11
Mr. PBody
Registered User
 
Join Date: Feb 2009
Location: Chesterfield, VA
Posts: 819
Default

HSC (High Swirl Combustion) means the flame travels in a vortex, not unlike a tornado. The "kidney" or "heart" shape of the chamber will make the flame "swirl" a certain direction. Generally, the area between the intake and exhaust valves, opposite the spark plug, will have a "point" into the chamber, interfering with "traditional" flame travel, steering it across the larger area first.

From an "emmissions" POV, it helps improve the efficiency of the combustion by creating a bit of a "vacuum" (for the lack of a better word) around the edges of the flame, drawing as much unburned mixture from the quench areas (anywhere mixture can "hide" from the burn, not specifically the quench "pads") as it passes.

For performance, not only do you gain the more efficient burn, it all happens more quickly because there's not nearly as much distance to the outer edges of the chamber from the plug. While "liking" a little less timing, it resists detonation much better.

The KRE "d-port" head has a nice high-swirl chamber. So does the new Edelbrock d-port. Both are well engineered. There may be others, but those two I'm familiar with, for the Pontiac.

I've seen attempts at creating the effect in earlier Edelbrock designs, but they were more for "Hey, LOOK!" than really engineered for performance. It didn't last, the "craze".

There's another type of "swirl" involved in Chevrolet heads. In the late '80s/early '90s heads (185s, 191s, 193s), there's a "wing" in the intake runner, that creates a swirl effect with the intake mixture as it comes in from the manifold. These heads are on engines that say "Vortec" on the air cleaner. For some odd reason, "Vortec" heads don't have the wing. The theory is, the mixture will "corkscrew" it's way into the bottom of the cylinder, significantly improving low-speed power. They're not popular among the performance crowd. Guys using small blocks for "real work" like them.

Comparing the Pontiac build to the small block is apples to donuts. I've seen a hundred small blocks as you describe, including a few that use the Magnum cam. These are very good performers and no doubt, relatively inexpensive. But that's not why we're "here". This is about "the Pontiac". It's an entirely different "animal" (figuratively AND literally).

Building a 350 Pontiac for performance is not difficult at all, but one must be very careful about who and what you pay attention to. There are 350 "haters" around. Others will be plain and truthful and say a 400 or 455 will make more power for the same money. That IS true. ALL the parts are pretty much the same except the pistons and rings... It's not "safe" to bore a 350 block to 4" UNLESS it's been thoroughly sonic-tested and will allow enough meat after boring. I would say, it would have to have zero "core shift". '68 or '69 would be the best bet for that.

A good analogy would be to consider, as a "Chevy guy", is how you "see" 350. That's the "bread and butter" engine of the whole Chevy line, small block, anyway. It's the most reliable, most powerful under "stock" conditions (debatable, yes, but more torque than 327, therefore, IMO, more powerful at the same HP). Well, that's how Pontiac guys "look" at 400. IT is the "bread and butter" engine of the Pontiac line. In fact, the only V8 engine GM made in higher quantity during the era WAS 350 Chevy ('67-'79).

So forgive those that say "go bigger". That's the way "we" think. Ever heard of a 3,000 lb. car with a 406 small block in it going 6.30s over 210? We know a 400 Pontiac that does it.

PM me for a good recipe for 350.

Jim
Mr. PBody is offline   Reply With Quote
Old 09-28-13, 12:53AM   #12
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default

Thanks for your input Jim ... do you do valve jobs chamber mods and porting on Pontiac heads as a business? Forgive me I think you may have told me before. I used to spend more time on this forum and have always enjoyed my time here. I have 3 different engines on my table Im trying to work at this point but keeping my worker bees going and life in general continually interferes. The Chev 302 concoction a Poncho 350 concoction and an 87 Sportster concoction. Solid rotating assy's lightened as possible, great heads matched to appropriate cams cams with quality valve-train. Have used track Fastburns for the Chev - CC Mag 268 solid , NOS 86 1100 bathtubs - Andrews .536 for the sporty. For the Poncho ... I need heads to match up with a Lunati lift rules RL-067 cam .256 I, .262 E @.050 , 108 lobe separation 2 degree advance... intake open/close 22 54, exhaust 61 21. Victor and Hooker Super Comp with 800DP carb or Holley Q-jet DP, the large one. Motor will feature BillMiller 500 aluminum rods and a nitrided factory N-crank slightly destroked to make 365ci if I can go the 4.000. Manicured fillets for the 2.100 rod journals.

One of the things I liked about the Fastburn/302 combo was the the super low-lift flow numbers as well as the swirl and would be trying to emulate that with the Poncho. I have read the 670 head is noticeably better at low lift than other iron d-ports and was wondering if the closed chamber might be a better choice for my project as the cam is not going to be high lift (close to or under .500) I have one set of rough 670's but they were the original set on my best 4-bolt 428 block Id like to save. Cam range is 4000-7000 supposedly do have a set of Rhoads lifters. Might go for the newer version of these, the cam is hydraulic although a solid might be more appropriate. This motor will most likely need ported heads. The block is 69 ... hoping it will take 4.000 bore. What would be your min sonic wall thickness? I was thinking .100 ??? Is there a way of porting or modifying a d-ports to make it swirl?
keith is offline   Reply With Quote
Old 09-28-13, 12:49PM   #13
Mr. PBody
Registered User
 
Join Date: Feb 2009
Location: Chesterfield, VA
Posts: 819
Default

Yes, we do this for a "living"...(:- See the ad on the side bar for Central Virginia Machine Service.

For 7,000 RPM, a hydraulic ain't gonna make it... Not for very long, anyway. Solids are the best way to make upper RPM power. According to Charlie Reichardt (Cam Craft), fast-bleed lifters are a "patch for choosing the wrong cam". I realize they're popular among some of the Pontiac people, but not here. Our performance "record" speaks for itself. (Dirty Bird, Galopin'Goat, Jolly Green II, etc...)

PM me and we can talk about this out of the spot light.

Jim
Mr. PBody is offline   Reply With Quote
Old 09-29-13, 12:17AM   #14
screamingchief
Registered User
 
screamingchief's Avatar
 
Join Date: Jan 2007
Location: Austin,Tx.
Posts: 251
Default

Quote:
Originally Posted by keith
Not sure if I will replace all valves. Maybe I can clean polish and reuse factory ones.
Bad idea,OE intake valves are 2 pc. welded variety,known to fail by dropping the head off the stem and imbedding the valve head into the top of the piston.

Especially true with higher spring pressures like is typically needed with those "lift rules" stocker cams you mention.

Quote:
Originally Posted by Mr. PBody
It's not "safe" to bore a 350 block to 4" UNLESS it's been thoroughly sonic-tested and will allow enough meat after boring. I would say, it would have to have zero "core shift". '68 or '69 would be the best bet for that.
Agree,I seriously doubt you'll find a 350 block that'll be able to go out to 4" bore.

I would'nt even bother trying.

The "restrictive" 350 bore shrouding thing is most folks showing a lack of knowledge on the subject.

Sure the 2.11"/1.77" valves become shrouded on a stock 350 P bore,but the truth is there is no good reason for using that big of a valve for a 350 P in the first place.

These days,knowing what I know,I probably would'nt use any big valve head for the small bore 350 P myself.

Just use some 2.05" or 2.08" SBC valves for the intakes and the OE 1.66" (-or- a 1.71" cleveland exhaust) valve and that's all a serious 350 P should ever need,just look up Ace's 350/383 build in the "proven engine combinations" forum and read up on what SD did with those heads.

http://www.pontiaczone.com/forum/showthread.php?t=15973

That was with the OE port opening too,not opened up to the RAIV port like most ported iron heads use.

And those valve sizes wont be shrouded in a typical .030" over 350 bore (3.905").

Dave @ SD knows his craft.

Matter of fact,that whole build of Ace's is pretty solid,very good study material for any 350 P fan.

I'm gonna build one kinda like that ^^^^ fairly soon,Ace's SRS forged pistons,3" main 4" stroker crank,long rods (6.800"),PPR/Isky flat tappet solid cam,ported iron heads,should easily be able to wind it up some should I choose to.

Good luck with this,but dont overthink the whole thing,it's not nearly as complicated as you seem to be making this out to be.

Start with a good foundation and a strong understanding of the fundementals and work from there,dont be tempted by the "trick of the week" stuff that some tend to be drawn to.

Slightly tweaking the B/S & R/S ratios aint necessarily gonna be the key to making a combo like this live significantly longer @ higher RPM,IMO a well thought out plan w/proper parts selection,top notch machine & assembly work,and proper tuning is what it'll take to make it all happen as intended.

Also,if staying with the stock stroke,you might wanna use a set of #18 heads off a '68 350 H-O as they have the smallest chamber of all the small valve heads,that will give you plenty of "virgin" seat material to allow for 2.05"/2.08"/1.71" valves,and that's gonna save some trouble of getting a decent CR for serious power while using a longer duration cam for higher RPM power,now granted you'll have to convert them to screw in studs among other concerns,but that's just SOP for small valve heads.

Good luck with this.

Bret P.
screamingchief is offline   Reply With Quote
Old 10-02-13, 12:00AM   #15
keith
Stubborn old goat
 
keith's Avatar
 
Join Date: Mar 2008
Location: Pittsfield NH
Posts: 666
Default

Well this 350 is an experiment. It doesnt belong to any one of my cars in particular so Im going learn what I can from it and shove it in something. Im modifying a factory crank, using aluminum rods, starting with a crazy cam and most likely new Rhoads lifters, a Victor intake and my trusty 800DP trying to make a smaller Poncho grow big wallies then as the local Hawaiians used to say when someone asks, "hey brahda what you got in there" I can say ... "Get one da kine 3 half Poncho brahda, nevah like da kine bowtie li dat. Get one kine beef? "
I have to get everything apart clean weigh and log it. Then get a crank that I like ... hopefully the one in it unless its the thin weight one which I dont .(What is the difference between 400 and 350 crank by the way? just how much is drilled out of the counterweights for the smaller piston ??) Im
going to chase R/S and B/S ratios by destroking as much as possible up to .140 with perfect index and nicest fillets I can on new 2.100 rod journals after grooming oil holes and whatever dimension that needs to be to fit the BME's right. They are reducing weight, eliminating a weak point and adding a significant measure of strength as long as I can get them right ... in my estimation. They're American made too I will find pistons to adjust or just order custom to get the CH I need once the crank is modified. I have to decide on main-bearings I guess cross-drill if using half-grooved or dont if using 3/4 or full-grooved. Once everything is done and has been mock-up "fitted" I will send the crank for nitriding.
One way or another I will sonic the block and bore to a minimum wall thickness of .100-.125 hoping for the 4.00 bore but taking whatever I get ... will be custom pistons most likely and I like JE stuff. Does anyone have a hand held sonic tester they would like to rent or would anyone like to buy shares in a new one? They are about 2 grand. 4 guys 400 a share I buy 2 to hold it then call when need it and return as soon as done ... all express mail to minimize waiting maybe ?? Once I have how many cubes Ill be feeding Ill decide on the heads. Im going to get the short block done over the winter hopefully. My target rotating assy weight reduction is 25% and I will move the redline that much higher from 6000 to 7500.
Will be thinking about head flow. I did make a little chart showing different displacements at different rpms. My destroked 350(352) @ +.060/3.61 stroke at 7000rpm is moving more more air than a 6000rpm 400 , over 90% of a 6000rpm 455. Im not sure staying with the smaller valves is the best idea ... it would only be if shrouding was causing more of a hindrance than the larger valves helped. Smaller valves might help low end torque tho. Well I will read and try to digest the material in the provided link maybe get a clearer picture.
keith is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
High revving Pontiac gtofreek Engine Tech Discussion - Street or Strip 49 10-19-13 04:46AM
building a 499 e-headed race motor badbird68 Engine Buildups in progress 403 01-26-11 09:46PM
Port Volumes vs. cfm Gach Engine Tech Discussion - Street or Strip 128 01-27-10 12:26PM
Aftermarket Cylinder head stack ranking discussion Bruce Wilkie Engine Tech Discussion - Street or Strip 119 12-15-08 01:51PM
csa v cfm 7t2cv Engine Tech Discussion - Street or Strip 36 11-04-07 09:06PM


All times are GMT -3. The time now is 12:29PM.

Featured Ads
Ken's Speed & Machine
Mayhem Turbocharging

Carter Cryogenics.  What can we freeze for you?

Pacific Performance Racing

Central Virginia Machine Service.  Home of the Injun Engine!

All Pontiac Engine Kits

Larry's Auto Machine.  Full serivce auto, marine machine shop, domestic and foreign.

Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
2001 - 2007 PontiacZone.com
Page generated in 0.14539 seconds with 46 queries