Kevin Shasteen

Correct me if I'm wrong here, but are the HP formula's being bantered around just simply a spin off, and maybe a simplification, of the classic HP formula initially used to determine the old steam engines power output? From what I little I understand about Steam Engines (very, very little) accept from what I have read: is that pressure not only acted on top of the piston but also underneath it. As long as you had steam-the pressure was kept at a constant reading. The gasonline engine is an animal entirely different. not changing. It is an internal spark combustion engine. It utilizes a spark to ignite its air/fuel charge: as a result the PSI will rise/fall instantaneously preceding and following the combustion cycle. When I say classic HP formula I'm referring to the: HP = (P x L x A x N) / 33.000 P = Working Pressure measured in psi L = Length of stroke in feet A = Total Area of piston in square inches N = Number of Power Strokes per minute Because the steam engines (For the Railroads) used huge strokes & an even larger than life connecting rod L was a reference to length of stroke in feet. To make use of the formula for a stroke in inches you would use: HP = ((P x L x A x N) / (12 x 33,000))..., or HP = ((P x L x A x N) / 396,000 The problem I see w/this, as Grumpy pointed out, is that it doesnt take into account the different pressures the engine sees thru the rpm range of idle to maximum rpms. In other words it isnt a progressive formula. Instead it appears to be good for peak power & peak hp numbers only. Using the previous formula, everyone has already given, it is understood that in order to obtain HP you must know Torque & its rpm from which the measure was taken. To obtain Torque you must know HP & its rpm the measruement was taken. However, if you dont know either torque nor hp but you do know both the high psi readings and the low psi readings then you can use the classic HP formula in calculating hp & torque. I personally dont think the PLAN/396,000 formula is for anything other than peak power output: so it is kind of one sided but if you dont have anything other than psi readings then you can figure torque & hp. ...so it is not a total loss in my most humble opinion. 8) Kevin, (Yea,Still an Inliner)

Guys, dont laugh. I personally believe you have misinterpreted its purpose. Its primary purpose is a cell phone antenna it only doubles as a rear wing...this way he kills two birds w/one stone. Function & Cosmetics...can you really argue w/that? Kevin, (Yea,Still an Inliner)

Spiirit, Glad to see you making progress: if you want reading materials-just ask Grumpy, he is an excellant researcher (thumbs up Grumpy). As far as "my definition for DCR". Yes it is a calculated figure. Picture yourself in a lab room in front of a chalkboard with a lab coat on. I raise my hand and ask you to show me on the chalkboard how you determined the Static Compression Ratio of the engine you are building. You begin by drawing one cylinder of your engine: lets say it is from a 350ci SBC which has 8 cylinders. How do you go about knowing how much volume is in one cylinder? You divide 8 into 350, like so: 350/8 = 43.75ci If you wish to convert ci's to cc's then multiply your ci's by 16.387. So, your one cylinder has the volume of 43.75ci. Now you draw your piston at Bottom Dead Center and indicate the 43.75ci created after you stroke has pushed your piston to its Top Dead Center location. Now you draw your Total Combution Chamber of 4.61ci. Now you can use your "Compression Formula" to determine your SCR, like so: (43.75 + 4.61) / 4.61 = 10.49:1...or 10.5:1 SCR Now, you have an idea of what SCR is. The definition of DCR (Dynamic Compression Ratio) is: "The Volume remaining above the Piston at the moment your IVC (Intake Valve Closing) occurred. So once again-you are at the chalkboard. Now begin drawing your piston & cylinder. Picture if you can your camshaft's intake lobe rotating to the point your IVC takes place: this moment will occur on the Compression Stroke just after the piston has passed BDC as the piston begins rising towards TDC. As the piston rises-the IVC event ocurrs. Now, STOP RIGHT HERE! Now measure the amount of Volume above that cylinder relative to your Total Combustion Chamber volume...put these volumes into your Compression Forumula and you will have calculated your DCR. Let us say your IVC occurred whereby 80% of your cylinder Volume remains. Take your cylinder volume & calculate what 80% is, like so: 43.75ci x .80 = 35ci So, now you have 35ci Cylinder Volume after the IVC. Now insert this into your Compression formula along w/your Total Combustion Chamber of 4.61ci, like so: (35 = 4.61) / 4.61 = 8.59:1....or 8.6:1 DCR Hoooray, you just figured out your DCR on a cam that closes its Intake Valve in such a manner that leaves enough volume in the cylinder relative to your Total Combustion Chamber Volume that allows an 8.6:1 DCR. This engine will idle at 600-650rpm's and its torque power band will peak in the 2800-3500rpm level...a perfect street engine! As far as Duration & Overlap being a compromise-this is backwards: which most magazines imply (due to limited funds & lack of understanding of DCR). Due to lack of funds-they imply you should build your enigne and then try and pick a cam. When in reality you should build your engine based on its power needs. It is the power needs and your desired peak power rpm range that determines what cam your engine should get. Once you understand DCR then picking a cam is not a [Compromise], rather it is a Decision...and that is what it should be: a decision not a compromise. As far as a Chart existing for IVC -vs- SCR...your question should be IVC, which leads to DCR which determines your SCR. and No, there is no chart: the chart generated is the data you collect once you understand how to calculate DCR. You can then take an article in a magazine/internet and it's dyno run (which indicates the peak torque & hp) and calculate that engine's DCR. Each time you perform these calculations you will become a little more familiar with the math. You will see how the numbers begin talking to you-they really bring on a whole new meaning. Remember this: you can underbuild your engine and it will rev to 5000rpm's, you can build your engine just right & it will rev to 5000rpm's, or you can overbuild your engine and it too will rev to 5000rpm's. So, which build do you want-do you want to under build, build just right, or over build your engine? How you determine if/when you have under or over built your engine is if your peak power band occurs inappropriately to when you need it most. DCR accompanied w/appropriate secondary components will determine when your peak power manifests in the rpm range. Learn the math calculations and how to work them backwards. You need a Crank Angle Chart to determine the percentage of Stroke remaining above the piston after IVC. Dont forget to check out the books I suggested as complimentary to the URL's Grumpy gave you. Good luck & have fun. Dont press yourself too hard on your engine build-everyone makes mistakes somewhere along the line. Just try to minimise those mistakes & you will do just fine. Kevin, (Yea,Still an Inliner)

Spiirit, When looking for a cam dont look at the Lobe Separation Angle (Overlap) first as the overlap as one of the cam's functions is third to fourth on the list. First and foremost you should be looking at IVC (Intake Valve Closing) prior to anything else. After all, Duration & Lift continue well after Overlap has ran its gamut. As far as my comment, "The Point Before Reversion Occurs": well that is basically an Oxymoron-just checking to see if you were truly listening. The real question you have to ask is, "When does too much Reversion become too much Reversion?" The answer to that question is something the engine builder must answer because in any Normally Aspirated mild, moderate, or wild Performance Engine there is going to be Reversion. Understanding the Dynamic Compression [Ratio] will shed light on exactly how to determine your engine's powerband. Without going into a lot of detail, simply know that an 8.5 DCR is perfect for a street engine on pump gas while a 9.0 is considered a perfect DCR for a race engine. Once you begin working the math you will find that engiens are being built, in each category (both the street & race engines) well below their 8.5 & 9.0 DCR's. The difference in a perfect DCR and an engine that falls short of the perfect DCR is by many considered a Compromise because your engine is bleeding too much Cylinder Pressure prior to the IVC relative to SCR (Static Compression Ratio). What the perfect DCR does for an engine is it allows the engine to idle at a 600-650rpm's. Any DCR that falls short of the perfect DCR will decrease your idle quality (higher idle rpm's) and likewise so to will your Engine Vaccum decrease at the same time: thus the rumpity rump that many enthusiasts enjoy: the problem is that most enthusiast who like that rumpity rump dont know to what extent they are truly hurting their performance. By understanding DCR you will have a much deeper understanding in key knowing what idle you want prior to building your engine: this is much better than simply guessing...and guessing wrong. Once you understand the DCR issues you can choose that rumpity rump and exactly how much of it you want prior to ever touching a wrench. Before you can calculate DCR you must have a Crank Angle Chart. This chart maps the piston's location in the cylinder w/each degree of crankshaft rotation. If you wish to check out the Crank Angle Chart, I would suggest you go to your nearest Barnes & Noble or Hastings bookstore & find the book: "How To Build Max Performance Chevy Rat Motors: Hotrodding Big Block Chevy's 90's Style" by Ed Staffel (Its a Grey Book w/red print on its Binder) published by Cartech w/a Copyright of 1996. Once you have found this book go to the top of page 108 for an example of a Crank Angle Chart. Then skip over to pages 112-113 for instructions on how to use that Chart. The only problem w/this book is that it doesnt explain how to get your own Crank Angle Chart for your own engine. Each Chart will differ slightly depending on the Offset of the Crankshaft, Connecting Rod Length, Piston Compression Height: all three of these issues are then calculated w/in your Block Deck Height to determine actual piston position. If you want to create your own Crank Angle Chart then you will have to use basic Trigonometry to do so. Why Trig? Because the interrelated parts Crankshaft Offset, Connecting Rod & Piston Wrist Pin all create angles relative to the centerline of those components: specifically a Triangle-so basic Trig fits in there nicely. If you want to understand Camshaft Technology and have not purchased this book yet-I would suggest you do so: "High Performance Camshafts": the Best of Hotrod Magazine Volume 11, published by Cartech w/a Copywrite of 2000. It is a Black Book w/white lettering on its Binder. I would suggest that once you understand both Camshaft Vernacular & their functions as well as DCR's, that from now on whenever you read about an engine build up in a magazine, you calculate that engines DCR. Once you get in to this habit you will quickly realize that magazine articles rarely give you [all] the info needed to make a reasonable decision on their engine build. You will find that they rarely speak about Vaccum & Idle Quality. When they do speak about Vaccum & Idle Quality they will leave out some other issue: cant blame them too much-as there are a lot of issues to remember when not only building an engine but putting together a magazine every month. Yet if you get in the habit of Calculating DCR then you will eventually begin to recognize patterns. Understanding the Compression Formula is also invaluable as it is this forumula that allows you to work the math forwards or backwards depending on what elements your have or which elements the magazines articles have left out. Lastly, Just keep in mind that DCR, Vaccum, & Idle Quality will rise and fall based on the Duration: and that it is the Duration of your Cam relative to Cylinder Displacement that acts as the revolving door in determining if and when your DCR, Vaccum & Idle Quality moves up or down the rpm scale. Knowing when and how DCR, Vaccum, and Idle Quality are effected leads you into realizing which Cylinder Heads are best for your needs-and this leads you into knowing which Intake Manifold best suits your enigne: but as far as I'm concerned-it all begins w/DCR. GRUMPY-YOU OUT THERE? Grumpy posted not too long ago a site where someone offered a free download on a computer program for a Crank Angle Chart...perhaps he can repost that free download. Kevin, (Yea,Still an Inliner)

IMHO, I dont think you should pick a cam based on its overlap. You could have two different cams where every other spec being different while the overlap of each cam is identical. Overlap, just like any other cam spec, is not an island unto itself. Also, I think its important for us all to remember that reversion has the probability of occurring twice in a performance engine: 1) during the overlap period where the engine is trasitioning from the Exhaust Stroke to the Intake Stroke, and 2) the time preceding the IVC on the Compression Stroke. When you get into Induction Wave Tuning you are usually referencing a one of a kind custom intake manifold: which leaves most of us out in left field. If you are going to be efficient at Induction Wave Tuning & Exhaust Gas Scavenging it is best to have an even firing engine: this means a 180 crank. This too leaves most V8's out in the dark. Overlap is a function of the cam lobes in relation to one another. The cam lobes are a function of the intended performance of an engine. Therefore, Compression...both Dynamic & Static are more important of a determining measure than simply looking at Overlap by itself. As the performance of your engine will only peak at one rpm it is essential the builder knows what they expect from their engine prior to building it. The intensity of that peak is simply a "CHOICE" you have to make: I dont think it is something one really has to ponder or deliberate over. With a good 50 years of technical knowhow behind the belts of the modern (OHV Cam Tech) cam mfg's, it isnt too hard to come up w/a winning cam grind. I prefer to look at an engine build by first determining the Dynamic Compression Ratio-which leads one to the Prime Omptimum Static Compression Ratio. It is the duration of your cam that determines your Dynamic Compression Ratio and it is your Dynamic Compression Ratio that will determines where in the rpm range your peak power band will rise. It is the choice of your secondary engine components that compliment or hinder your cam choice. Your secondary engine components, which either hinders or compliments, will either move the power band upwards or downwards by a couple hundred rpms to a thousand rpms. It all depends on your intenional needs of performance and supplementary component choices. Good Rule of Thumb for Overlap & Duration: Duration: 1) IVC @ Upper 50*'s ABDC = Typical Mild Street Performanc 2) IVC @ Upper 60*'s to Mid 70*'s = Hot Street & Mild Racing Cam 3) IVC @ 80*'s to low 100*'s ABDC = All Out Racing Cam's Overlap 1) 10-35*'s Overlap = Acceptable Mileage or Good Towing Cam 2) 30-55*'s Overlap = Daily Driver & Good Low Rpm Torque 3) 50-75*'s Overlap = Hot Street Performance 4) 70-95*'s Overlap = Oval Track Performance & Auto Cross 5) 90-115* Overlap = Dragster/Comp.Eliminator Class I agree with you in that once you have an understanding of cam speak then you can narrow down your choice to three or less cams. As for when is it best to close the IVC: I'ld say just at the point which precedes reversion. This is why I like to approach the cam choice first from an IVC standpoint-for it is the IVC relative to your displacement of your cylinder that determines the Dynamic Compression Ratio which in turn determines your Optimum Required Static Compression Ratio. The Dynamic Compression Ratio approach takes your displacement into consideration whereas the Overlap spec of the cam doesnt approach the displacement issue. Dispalcement is the key into picking a complimentary cam for your power needs. Anyway-that is my .02c's worth. Kevin, (Yea,Still an Inliner)

It believe it was one of the hotrod Ford Mustang Mags: dont actually remember as I looked at about 6 different mags yesturday. Anyway-there were pictures of two brand new Focuses that a California Chassis Shop installed both a 4.6 DOHC in one and a 5.0L in the other Focus. The article called them FOCI (instead of Focuses) . The underscore stated that both the 4.6 DOHC & 5.0L swap was surprisingly simple, required no engine bay alterations & that the engine actually bolted in WITHOUT ANY WELDING. Of course the "No Cutting/Welding" doesnt count for the passenger floor board nor the install of a rear diff. Kevin, (Yea,Still an Inliner)

That would be nice if it found itself in some RWD applications; I've also read that the new DOHC V6 will have a Timing Chain instead of the dreaded Timing Belt. Hey, maybe GM is finally catching on: as in a 60k mile belt replacement is not ok w/me-just put a Timing Chain in there & let the engine go 150-200k before worrying about it). I like the Timing Chain thing...look how well the Ford 4.6 OHC engines have done w/Timing Chains instead of Timing Belts. Kevin, (Yea,Still an Inliner)

Pictures, we definately need pictures. I would think not only pictures on the entire process but specifically possibly an indepth write up on the steering rack. I can only imagine how nice an older Z would be w/power steering-regardless of which engine is in it. Umm, Austrailian Steering Rack? Dont ya'll drive on the wrong side of the road would that effect the Steering rack's installation...guess we could just use a steering rack from the States as everything on the USA WRX rack would merely be reversed from an Ausie WRX rack(?). In swapping the rack was shortening the tie rod ends all that was required? I must confess this steering rack swapping is not my strong suit Kevin, (Yea,Still an Inliner)

Looking forward to those pictures guys! 8) Kevin, (Yea, Still an Inliner)

I agree about the "reasonable power/rpm range" issue. But with the rising costs of pump fuel I dont think GM & Morpar can ignore the benefits of a SOHC/DOHC V8's much longer. When speaking of "reasonable" it is a relative term. Only relative to exp's to make the engine -vs- the market's needs. It is only a matter of time before GM will be forced to go SOHC/DOHC V8 as Ford already has, clear cross the board. Surely GM is paving the way for the DOHC engines via Olds & Cadillac. Once that is old tech the other lines will be handed that tech. Surely GM & Mopar already have their DOHC V8's waiting in the shadows, clear cross the board, as most auto mfg's usually are 10 years in advance of the RPO market. Whether the choice of DOHC V8's will be the Olds/Cad engines who can say. I would venture a guess that the gas prices have not risen enough to justify the exp's of the better breathing/better fuel mileage of the DOHC's. I like the push rods V8's as I am more familiar with them...but the power potential/fuel mileage of a DOHC V8 intrigues me. Kevin, (Yea,Still an Inliner)

I also like the Ford DOHC V8 engine, too bad it doesnt fit in the Z. I only wish someone made a DOHC V8 that would fit in the Z w/relative ease. I have searched the net for pictures of DOHC V8's; seems there are a lot of write up's on DOHC V8's but not too much in the way of viriety of actual pictures of DOHC V8's. Ok, who is going to be the first to stuff a Ford DOHC V8 in an early gen.Z? I'll provide the Z if someone else wants to provide "MY Z" w/the DOHC V8 Anyone seen pictures of Nissan's new Titan Full Size P/Up? It is suppose to be getting a 5.6 DOHC V8 w/respectable hp/torque numbers. The Titan is to be revealed in NY in April 2003. It appears the DOHC V8 wars have begun...still wondering when GM/Mopar will be using a DOHC V8 in their cars cross the board: they cant ignore Ford, Toyota, and Nissan forever. Kevin, (Yea,Still an Inliner)

Dont be gun shy: experience doesnt come cheap-that is why experienced labor cost so much....they to (the experienced ones) made their mistakes. The difference from an experienced craftsman and a wannabe is that the craftsman learns from their mistakes. Keep learning; not until you know it all, which no one on this board does, will you no longer have to worry about making mistakes. As long as we breathe we will be making mistakes: the trick is to minimize the cost of your mistakes. I bet the next time you buy an engine you will ask a few more questions about the pistons....(lesson learned-unfortunately the hard way). Sorry about the dissapointment in finding out your SCR wasnt what you thought it was. I can only imagine what a sour taste that has left in your mouth. Keep on the lookout for pistons-If you have everything you need, except the correct pistons...work, watch, and wait and when you least expect it the right pistons will show up. Call all the speed shops in your area and ask them if they have any set of pistons for your engine-you'ld be surprised what a speed shop will have on their shelves in their back closets at any one given day. Kevin, (Yea,Still an Inliner)

Those pistons do look like dish pistons w/VR's. Surely they are the factory low comp.pistons. Dont look at what you dont have instead look at what you do have. You said yourself you want an engine that runs on 87 Octane: yes/no? The only problem is that you cant make serious HP & still run on 87 Octane w/out serious mods to your engine. Serious Mods=MONEY. So, in order live in the restraints of 87 Octane that you have placed on your project...you modifications must be slight. Any Cyl.Head or Piston swap you make to take advantage of a cam swap cant to be to terribly radical, otherwise you will find yourself needing 92 or 93 Octane. What I would suggest is you upgrade to a mild cam swap and then concentrate on decreasing the restrictions to your intake & exhaust systems. This way you'll get a little more punch w/out serious bucks and still remain w/in your 87 Octane requirements. Kevin, (Yea,Still an Inliner)

I've never seen a true 'Dish' piston that also had valve reliefs. I've seen Solid Dome, Hollow Dome, and Flat Top Pistons that had piston reliefs...but never a real Dish Piston w/Valve Reliefs. I would contact the previous owner & have him confirm what pistons your actually have; get a part# and ph# of the piston mfg so you can confirm what cc's your pistons are. Kevin, (Yea,Still an Inliner)

Mudge basically said what I was trying to point out-if the engine doesnt run now it is a glorified boat anchor. If you go w/an engine that doesnt run as your rebuild project-dont pay too much...as in dirt cheep. If it doesnt run then its worthless to me; untill someone can prove to me it is not worthless...it is worthless. This should be your posturing not only for bargaining leverage but also keeps your wallet in check. Kevin, (Yea,Still an Inliner)

The Grumpster hit the nail on the head. Dynamic Compression Ratio (DCR) has become my pet-peev. Most people will always brag about their Static Compression Ratio (SCR) and have also heard that the Cam is the Brain of the Engine. But what most dont understand is exactly what Grumpy emphasized; and that is that the engine only sees DCR...which occurs only after both valves have closed. If you wish to understand camshafts then you should begin w/DCR as the SCR should compliment your DCR and not the other way around. Your DCR not only determines the desired powerband but when complimented by the correct SCR it will also determine your engine's intensity within that powerband. BTW: the 8.1:1 DCR will give your engine a choppy idle around the 800-850rpm range depending on your tuning skills. It is exactly what the old 60/70's muscle car engines did; they had a high SCR but their duration was so extensive in bleeding off extra cyl.preesure that their DCR's were brought down to respectable levels. You crane cam will work in the same manner. A must for determining the DCR's is the Crank Angle Charts (Thanks PeteP. for turning me on to that one). Kevin, (Yea,Still an Inliner)

Each Part will have a tolerance. As long as each part is within its tolerance then you are fine. The only other thing you would have to worry about would be element fatigue, as in not knowing if/when the part (metal or any other alloy) is going to snap under stress. Then it would help if you had the expertise to rebuild one...which I dont. Kevin, (Yea,Still an Inliner)

I remember when this subject came up about a year and a half ago. Mike was thinking about entering his race where his hopes are to reach/exceed the 200mph. The thread was Mike's and the subject matter was which fuel system & engine mgt control system would best fit his desire to go 200mph's. Anyways; as usual, the thread ended up going into the aero of the Z. It was pretty involved and if memory serves me correctly there were at least two maybe three pages to that thread. The only problem is I dont remember if his thread was in the High-Tech, Miscellaneous, or the EFI/Carb Forum. What are you planning on doing w/the info? Have you checked out, "Automotive Math Handbook" by Forbes Aird. His last chapter deals with the math needed to know the effects of aero resistance: regarding hp lost, drag, and lift. Pretty good stuff IMO. It is an Orange book about 6"x9" with red writing and published by MBI w/copywrite of 2000 if you decided to look for it at the book store. I too remember that the Cg to the 1st gen.Z was around the .47 to .48 range. The 2nd Gen.Z was lowered to about .38 if memory serves me correctly. Kevin, (Yea,Still an Inliner)

I'm first, hahaha ..I'm first to post on this new forum as the entire board rolls their eyes

Blown Head Gskt or Cracked Cyl Head. When the Spark Plugs are spot clean-it means they are being "Steam Cleaned" by the hot coolant as it passes through the combustion chamber. Hope I read your question/post correctly. If you are not leaking coolant, water pump is not leaking, nor your dipstick sludge-brown: and are still loosing coolant-then you have a blown head gasket or cracked cyl.head. How often do you have to add coolant: everyday? Kevin, (Yea,Still an Inliner)

If you are not mechanically inclined and your friend who is offering you the engine "Doesnt know what is wrong w/his engine" then you also dont know what is wrong w/your friends block. Unless your friend is also putting forth the money that you might waste attempting to rebuild a block for which you have no idea what is wrong-then if I were you I would go w/the crate engine. Going w/a block w/out knowing what is wrong w/it can open pandoras box-translate pandoras box as money pit. Kevin (Yea,Still an Inliner)

Even though a radio isnt currently in the car the factory radio wiring should be there. It may be laying there and unless the factory radio wiring harness has been chopped or used for another purpose it should be there. If you are running a radio and no other components you need a wire that is hot only after the key has been turned on. Grab your test light out & where the radio used to be look for the factory wiring and if you dont smoke you can wire your cigarette lighter to the power antenna. As for the fuse panel having two xtra terminals...I cant answer that one. Kevin (Yea,Still an Inliner)

It is hard to say because you are not using the factory ignition. I would start w/talkig to the previous owner on who installed the aftermarket electronic ignition...then go from there. It is hard to know what changes were made when that electronic ign. was installed: did the installer know what they were doing are did they simply mess things up(?), hard to say over the net. sorry I couldnt be more help. Kevin, (Yea,Still an Inliner)

It is not a stock Block Deck Height...it has a 9.325" BDH instead of the typical 9.025" BDH...this helps w/the larger displacement than a usual maxxed out SBC. Kevin, (Yea,Still an Inliner)

Dont forget the fuel filter at the passenger side of the fuel tank. My 240 I had in college would go thru that rear fuel filter once a year. I replaced a fuel filter at the engine initially not knowing there was a second filter at the tank....lesson learned the hard way! Kevin, (Yea,Still an Inliner)