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Now it "Majically" makes sense. I don't know about the back cut. will it reduce the seat surface enough to cause early wear or un reliable sealing? If not I say go for the back cut and be done. This type of thing is kinda like remodleing a house, "you know Honey for just a bit more>>>"
next thing you know your 20k over budget. If your comfortable with where you are sit down. BTW congratulations on a very informative and entertaining thread. Thanks |
Herb - Thanks for the compliment. There's sure a good crew providing support. These guys know their stuff.
All - I'm headed back to my home town tomorrow where the machinist-friend is. Am taking the heads awa the pistons. (If you got in after the piston discussion go back 2 or 3 pages.) Turns out the new, hypereutectic/eye-browed pistons have floating pins. Eric, the flow bench guy, said he thinks those require a mod to the rod. So, I'll ask my machinist. And, I'll ask him to look the valve seats over to see if any need touched up after the alleged "porter" did his thing. :o I'll also ask him if he has any SBF heads I should consider. Dunno what he might have sitting around. But, back to the pistons. I'm not convinced that the "new" pistons are better from a quench standpoint. Yes, they'll sit .020" higher in the bore, but they don't quite have as much flat area out of the combustion chamber to serve as the bottom of the quench zone as the dished pistons do. And, at first blush they may have more volume lost to the valve reliefs than the "dished" pistons do. I did get the burette in yesterday but have yet had time to answer that question, but will. So, please chime in with regard to pistons and quench area. And, btw, Eric said to go for a .039" thick quench area, and get there by zero-decking the piston and using a .039" head gasket. |
I agree with Eric.
Deck the block, and keep quench under .040". But who knows, those pistons might be there already??? (I mean, that is the point of them) I thought I had suggested this before. Dish or no, the quench keeps detonation at bay by (A) creating turbulence, (B) offering too much relatively cool metal for the intake charge to burn in that area. What you don't want is a taper where the flame front can force the remaining charge into the corner and the rising pressure will set off an explosion, instead of a controlled burn. |
Originally Posted by ArdWrknTrk
(Post 10915237)
I agree with Eric.
Deck the block, and keep quench under .040". But who knows, those pistons might be there already??? (I mean, that is the point of them) I thought I had suggested this before. Dish or no, the quench keeps detonation at bay by (A) creating turbulence, (B) offering too much relatively cool metal for the intake charge to burn in that area. What you don't want is a taper where the flame front can force the remaining charge into the corner and the rising pressure will set off an explosion, instead of a controlled burn. My plan is to ask today how much it would take to change from one piston to the other. And, I'll ask how much to deck the block awa if he remembers how far in the hole the pistons are currently. Then, when things settle down here I'll mock up the engine and measure, awa cc the pistons and heads. Btw, a guy responded to my WTB with GT40 heads that have been pocket polished and have double valve springs mounted. Will call to find price, but am thinking the springs are too much. But, I have new springs on my heads, so.... OTOH, another guy called saying a certain salvage did have 3 vehicles that should have those heads and they are ~$100/pair. |
Originally Posted by Gary Lewis
(Post 10912716)
As for preaching, in what way? Seriously, everything you said was constructive and not at all like preaching or ranting. And, btw, was the B&S a Model N? No, couldn't be, surely it was much later. I'm giving away my age, but I will say I spotted one of those 50' away in the museum across the street from the Dover Mile one day while waiting on the race to start.
and I actually had to look up what an N model briggs was! a bit before my time! :-X03 if the rods are full floating it means that they don't have to be pressed onto the rod, however you will need pistons that have grooves cut for the circlips that keep the pin from taking a journey into the cylinder wall. i agree with eric as well about zero deck and 0.040" quench |
RE: porting heads - what to document
Originally Posted by ArdWrknTrk
(Post 10913391)
There is a big block guy in Tacoma Washington who offers port templates and tutorial online for a fee.
Re in"Car"nation High Performance, BBF information / porting index I wonder if this sort of information isn't available elsewhere for Windsor engines? |
I didn't want to plug Scotty for his porting and head work, Valvetrain components and custom cams.
Nor, his incredible recurved DSII distributors. I just wanted to point out that the information is out there for just a few bucks. Not that anyone would expect him to give away all his secrets. With his templates and sectioned heads anyone with the time to grind iron can improve the flow of their D0VE's or D3VE's, in fact I think he even has some E7 (EFI) heads to show as well.
Originally Posted by 85lebaront2
(Post 10916328)
I have already run across him on the big block forums.
|
Originally Posted by Gary Lewis
(Post 10915889)
When you say "those pistons might be there already" I assume you mean the dished ones, the ones that are on the rods currently?
I meant the ones you say you stole that have a .020" lower wristpin in them. If you have already mocked it up with your current pistons you would know if +.020" compression height would get you to zero deck or not. |
The rods will have to be bushed if you go with pistons that are full floating.
|
I'm back from the machinist's and I was wrong about the pistons I "stole" - the pins can be either floating or pressed so they'll fit my rods with no mods.
So, when I can I'll cc both pistons awa the heads and mock up the engine. That'll tell me how much would have to be taken from the deck to zero-deck either piston. And, I'll be able to calculate compression ratio. Which leads me to heads. I've gotten one response to my WTB craigslist post and have two other leads to follow up on. The guy that responded has a pair with polished ports, new larger valves (he thinks), and dual springs. When I asked him how many miles were on them he said ~12, and followed that with "between 12 and 20 passes". They are still on the car and he wants $300 for them. How much CR can I reliably run with iron heads and a .039" quench area w/o problems? On 87 octane? |
:-wink Ok, I fear I obscured my question by "laying it between the lines", to borrow a lyric from Peter, Paul, and Mary. (PETER, PAUL & MARY - I DIG ROCK AND ROLI MUSIC LYRICS) I say that because I know that I've not stumped you but yet no one has responded. Ergo, the question was obscured.
So, here 'tis again: How much compression can I run on 87 octane gas? Remember, the goal is MPG, so I don't want to retard the timing too much. And, although somewhere I think I still have an Edelbrock VaraJection water injection system, I'd rather not resort to that. Also, assume I'll get that .039" quench area and that I'll be running iron heads. MuscleTruck, my copy of Engine Airflow came in yesterday (roughly 30 hours after ordering - scary) and it looks like a very good read. I'm getting ready to go back to see the Grins (Grandtwins) again and that'll give me something to pass the quiet time with. Thanks for the tip. |
Like I said before, I would build for 9-9.5:1 compression and run crap gas. Just back the timing if it starts pinging. Would gain more in performance from the compression increase than the loss of timing(so long as it is only a couple degrees). Keeping the compression under 9.5 should prevent all pinging under load. I have run over 10:1 on pump gas but that was when premium was $1.20 a gallon.
If you don't like those heads you ported, send them to me. I would have no problem putting them on my motor. Looking at your average tq and hp, your had the highest average, or did I read that wrong. I would put the backcut valves in them, and call it a day. Now, about the flowtests. What inches of vacuum were the tests run at? All of them the same? Running the test at 10 inches versus 20 inches will make a major difference in flow numbers. Even just a few inches of difference throws out any comparison you could do. Using a different bench with the same heads will usually show different numbers. My summation: You have done everything I would do to a set of heads. I would probably run double springs, but that may just be a carryover from my days running circle track and high rpms. And water injection is not a bad thing in my book. |
Stang - Thanks! I was starting to think I was alone in considering running the ported heads. At least I didn't really hurt anything on the intake and the exhaust is noticeably better at higher lift, which should help the MPG situation - I think.
Speaking of flow, all readings were taken at 28" +/- .0X". Eric says the software he is running will correct to 28.0", but he has a series of valves that he adjusts to get the reading to within +/-.0X" before hitting GO on his keyboard. The system then takes 10 readings and averages them. I'm guessing the valves are "dump" valves that divert excess vacuum to get the reading very close to 28. And, he has a series of switches that bring in more and more vacuum motors as the need arises. So, he gets the flow above 28 with the valves closed and opens the right one partially to get very close to 28. And, I did get the best average HP and torque, but not by much. (Btw, I called Comp Cams to find out over what range CamQuest averages, but that guy couldn't tell me. However, given how much smaller their #'s are it looks like they must go up to 6000.) But, Thumper's heads get significantly better average #'s. Which leads me back to heads. I put stock GT40 flow #'s into Desktop Dyno and CamQuest last night and both say those heads will give almost exactly the same HP & torque #'s, including averages, that Thumper's do. I don't understand that because Thumper's heads flow a bit better, but that's what they show. And, btw, all these #'s are at 8.5 CR, but go up nicely if the CR goes up into the 9's. So, I'm still following leads on GT40's. As said, one set is available for $300 and may be ready to run save for changing out the springs to my new ones, as my machinist urged; Another guy says he thinks he has a pair in storage; A 3rd guy doesn't have any but thinks his friends may and didn't seem to be put off when I told him I was thinking maybe I could get a pair for $200. Again, thanks for the input. I'll be out of the shop for almost the next two weeks and won't be able to carry on much of a back-and-forth here so want to get some feedback to cogitate on. |
Originally Posted by muscletruck7379
(Post 10912646)
Amazon.com: Engine Airflow HP1537: A Practical Guide to Airflow Theory, Parts Testing, Flow Bench Testing and Analyzing Data to Increase Performance for Any Street or Racing Engine (9781557885371): Harold Bettes: Books
not sure if you have seen or read this book before, but it might help. it has alot of theory in it and alot of math, but its a good thing, by far the most in depth that I have seen. I bought it on kindle and liked it enough to buy the hard copy. there is even some math for building your own flow bench. http://reviewastore.co.uk/image/y/R.gif |
Corrections
Guys - I've found some minor errors in my software dyno runs. They stem from both DD and CQ having 2 places to input valve size - one on the airflow page and one on the overall engine page. Apparently you put the actual size of the valves that were tested on the airflow page, and then try changing the valve sizes on the engine page to see what difference that makes.
I've now gone through and input the correct data, including that for stock GT40 heads, below. Also, I played like I had a head with just the exhaust portion of my porting and stock intake. As it turns out, that gave a result neatly 1/2 way between stock and my ported head #'s, so that seems to say both the intake and the exhaust porting I did worked. So, my observations now are that the porting got me from 8 to 20 HP, partially by allowing the engine to wind more and partially by getting rid of the burned gas better. However, stock GT40's are good for another 26 - 34 horsepower. And, while Thumper's heads do flow better and give even more power it comes at even higher RPM, where I'll never run. But, with all that said, the peak torque #'s don't change much although the average #'s do come up, which indicates to me that the engine will be able to maintain speed while pulling a load better. Anyway, let me know what observations you draw from these #'s. <style><!-- BODY,DIV,TABLE,THEAD,TBODY,TFOOT,TR,TH,TD,P { font-family:"Arial"; font-size:x-small } --> </style> <table frame="VOID" rules="NONE" border="0" cellspacing="0" cols="9"><colgroup><col width="100"><col width="90"><col width="90"><col width="90"><col width="90"><col width="90"><col width="90"><col width="90"><col width="90"></colgroup><tbody><tr><td align="CENTER" height="19" width="100">Head</td><td style="border-top: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000" colspan="2" align="CENTER" width="180">D8OE w/stock valves</td><td style="border-top: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000" colspan="2" align="CENTER" width="180">Gary's ported D8OE</td><td style="border-top: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000" colspan="2" align="CENTER" width="180">Stock GT40's</td><td style="border-top: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000" colspan="2" align="CENTER" width="180">Thumper's ported E7TE</td></tr><tr><td align="CENTER" height="18">Source</td><td style="border-left: 1px solid #000000" align="CENTER">DD</td><td style="border-right: 1px solid #000000" align="CENTER">CQ</td><td style="border-left: 1px solid #000000" align="CENTER">DD</td><td style="border-right: 1px solid #000000" align="CENTER">CQ</td><td style="border-right: 1px solid #000000" align="CENTER">DD</td><td style="border-right: 1px solid #000000" align="CENTER">CQ</td><td style="border-left: 1px solid #000000" align="CENTER">DD</td><td style="border-right: 1px solid #000000" align="CENTER">CQ</td></tr><tr><td align="CENTER" height="18">Peak HP</td><td style="border-left: 1px solid #000000" align="CENTER">227</td><td style="border-right: 1px solid #000000" align="CENTER">239</td><td style="border-left: 1px solid #000000" align="CENTER">248</td><td style="border-right: 1px solid #000000" align="CENTER">247</td><td style="border-right: 1px solid #000000" align="CENTER">274</td><td style="border-right: 1px solid #000000" align="CENTER">281</td><td style="border-left: 1px solid #000000" align="CENTER">279</td><td style="border-right: 1px solid #000000" align="CENTER">303</td></tr><tr><td align="CENTER" height="18">At RPM</td><td style="border-left: 1px solid #000000" align="CENTER">3500</td><td style="border-right: 1px solid #000000" align="CENTER">4000</td><td style="border-left: 1px solid #000000" align="CENTER">4000</td><td style="border-right: 1px solid #000000" align="CENTER">4000</td><td style="border-right: 1px solid #000000" align="CENTER">4500</td><td style="border-right: 1px solid #000000" align="CENTER">4500</td><td style="border-left: 1px solid #000000" align="CENTER">4500</td><td style="border-right: 1px solid #000000" align="CENTER">5000</td></tr><tr><td align="CENTER" height="18">Avg HP</td><td style="border-left: 1px solid #000000" align="CENTER">188</td><td style="border-right: 1px solid #000000" align="CENTER">56</td><td style="border-left: 1px solid #000000" align="CENTER">206</td><td style="border-right: 1px solid #000000" align="CENTER">58</td><td style="border-right: 1px solid #000000" align="CENTER">231</td><td style="border-right: 1px solid #000000" align="CENTER">71</td><td style="border-left: 1px solid #000000" align="CENTER">232</td><td style="border-right: 1px solid #000000" align="CENTER">82</td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18">Peak Torque</td><td style="border-left: 1px solid #000000" align="CENTER">385</td><td style="border-right: 1px solid #000000" align="CENTER">393</td><td style="border-left: 1px solid #000000" align="CENTER">386</td><td style="border-right: 1px solid #000000" align="CENTER">393</td><td style="border-right: 1px solid #000000" align="CENTER">401</td><td style="border-right: 1px solid #000000" align="CENTER">397</td><td style="border-left: 1px solid #000000" align="CENTER">391</td><td style="border-right: 1px solid #000000" align="CENTER">399</td></tr><tr><td align="CENTER" height="18">At RPM</td><td style="border-left: 1px solid #000000" align="CENTER">2000</td><td style="border-right: 1px solid #000000" align="CENTER">2000</td><td style="border-left: 1px solid #000000" align="CENTER">2000</td><td style="border-right: 1px solid #000000" align="CENTER">2000</td><td style="border-right: 1px solid #000000" align="CENTER">2000</td><td style="border-right: 1px solid #000000" align="CENTER">2000</td><td style="border-left: 1px solid #000000" align="CENTER">2000</td><td style="border-right: 1px solid #000000" align="CENTER">2000</td></tr><tr><td align="CENTER" height="18">Avg Torque</td><td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000" align="CENTER">289</td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER">104</td><td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000" align="CENTER">311</td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER">107</td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER">341</td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER">120</td><td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000" align="CENTER">341</td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER">131</td></tr></tbody> </table> <table style="width: 14px; height: 5px;" frame="VOID" rules="NONE" border="0" cellspacing="0" cols="5"><tbody><tr><td align="CENTER" height="19" width="100"> </td><td style="border-top: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000" colspan="2" align="CENTER" width="180"> </td><td style="border-top: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000" colspan="2" align="CENTER" width="180"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td><td style="border-left: 1px solid #000000" align="CENTER"> </td><td style="border-right: 1px solid #000000" align="CENTER"> </td></tr><tr><td align="CENTER" height="18"> </td><td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000" align="CENTER"> </td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER"> </td><td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000" align="CENTER"> </td><td style="border-bottom: 1px solid #000000; border-right: 1px solid #000000" align="CENTER"> </td></tr></tbody> </table> |
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