Kevin Shasteen

When it overheats-is it really overheating? Have you touched the radiator cap w/your fingers (only for quick second) to confirm the readings are correct? Possibly your radiator is beyond normal cleaning & may need to be hot tanked by a radiator shop. Does it always run hot-or does it only run hot when you are in stop/go traffic or slow speeds like 15-30mph for extended periods of time....have you replaced the fan clutch? Have you replaced your radiator cap, heater hoses or their clamps? Definately need to have a radiator shop do a pressure test-this should only take 5-15 minutes & this will determine a pin-hole leak if one exists; unless its really a small one. Once you know there are no leaks then you either have a sticky thermostat, defective temp.sender or temp gauge; or the wiring somewhere between the two is defective. Start w/the pressure test first; then the thermostat; then if it persists & your sure it actually is running hot/you may have a radiator that needs to be hot tanked or replaced. Your fan clutch is only an issue at low speeds; if the engine is actually running hot all the time-consider a pin hole leak somewhere, stuck thermostat or a stopped up radiator. Dont let it get the best of you; this is something that everyone goes thru a few times in their lives...you'll figure it out & after you figure it out-you will be that much smarter! Kevin, (Yea,Still an Inliner)

The site Lone gave for the 434 kit offers the engine w/4" stroke...this means a bore of 4.155 is required to obtain 433.89 cu in. All SBC blocks have a Block Deck Height of 9.025; deduct the 6" rod & the 1/2Stroke of 4" (this equals 2") then you only have 1.025" for a piston comp.height; they list the use of a JE piston w/dome but doesnt say how large the dome is. Chances are their machine shop has removed .010 from the block deck height just to square the block-so its possible the piston comp.height may even be less than 1.025"....the only way to know for sure is to call them & inquire. They do give the 76cc combustion chamber a 11.6:1 comp.ratio. If durability is in mind/you may want to rethink your choice as their advertisement does read "Racing Engines"...not Street/Grocery Getters! Now-as Lone mentions if a race only engine is what you're looking for...go for it; just remember-the closer you get to the exotic displacements the more maintenance is required & sometimes this means a daily/weekly/monthly rebuilding of said engine-depending on how exotic you get. I'm sure if you wanted a streetable 434 you could use a 5.703 rod & this would leave a more reliable piston comp.height of 1.320 w/.002" to sqaure up the block if it were needed & maybe a flat top piston to lower comp.ratio & a milder cam...but then you're back to a mere performing SBC & might as well go 383, 406, 408(?)...something to think about. Then again there's nothing wrong w/a 9.5:1 or 10.0:1 comp.ration 434 stroker!!! Its all about what you personally want-so weigh your options & then make an educated decision...then dont worry-& be happy! Kevin, (Yea,Still an Inliner) PS: I like that site Lone gave-their "Engine Building Tips" is a book unto itself...I always appreciate an engine building business/shop that isnt afraid of edjucating their customers by divulging trade secrets. [ June 09, 2001: Message edited by: Kevin Shasteen ]

Does anyone know of any site/books where I can find actual figures for airflow in a DOHC cylinder head. I'ld like to know how mfg's determine what size valves are required; also what comp.ratio is needed based on the size of their valves -vs- expected output of an engine w/multiple valve cyl.heads(?) I'ld also like to know what math/formulae are used in making those determinations. Any response would be appreciated.

That alone is the very issue that keeps me leaning toward the whole idea that there is something to the rod/stroke ratio (longer rods being better) & why I like the article "The Small Block Chevy Should've Built". I'ld just like to know (I guess only a piston mfg knows this) is exactly how minimal a piston compression height is considered too minimal for an engine on the street where durability is an issue/as opposed to a race engine that will be rebuilt on a weekly/monthly basis(?). Kevin, (Yea,Still an Inliner)

Okay, so Rod Angularity only comes into play at higher RPM's(?); then this is one more piece of the pie to the Rod/Stroke Ratio theory. I agree that most 400's were put thru the ringer w/heavy foot drivers that usually didnt own the vehicle (employees driving tow trucks/service trucks..,ect,ect). Looks like the controversy continues-where will it end? Kevin, (Yea,Still an Inliner)

Lone; I think you're correct on his trans; do you know what his tire size is (his most recent swap and are those the tires he gonna be racing with? I'm pretty sure on his rear gears being 3.7. Kevin, (Yea,Still an Inliner) [ June 09, 2001: Message edited by: Kevin Shasteen ]

Racnoth, The previous suggestions are "realistic". I'm not an Inliner expert so I can only go with what the books say about the engine. The books say you already have that "165Hp"...the only problem w/that is the books go on to say the 165HP doesnt come into play until @ 6000rpms. With that in mind & the fact that Mfg's usually like to s-t-r-e-t-c-h the hp/torque readings...I couldnt honestly tell you if those are true numbers. So you need your Peak HP to come into play a little sooner. Also the factory books list the I6 as having a miniscule 8.3:1 Comp.Ratio. As you stated in an earlier post-you want a 1/4mile ET = 15.9/86mph & need the 165HP-yet you need it to come into play @ 4235rpms. This means to me, IMHO, that what you need is a higher comp.ratio & a better breathing engine-which means upgrading your intake/exhaust as well. Make this a slow methodical transition-dont rush into anything. First and easiest to change would be a better breathing intake & exhaust. Look to the aftermarket premium headers & premium intake (K&N for the intake-as mentioned earlier by Richard). Once you've opened that restriction-then you can concentrate on the cylinder heads/pistons and deckign the block if that comes into play. Remember-you already have the 165hp-you just need it an lower RPM; so a mild performance cam is also in the picture; but do the exhaust & intake first; what good is all the performance add on's to your engine if the intake/exhaust are the primary restrictions? Before your engine can perform-it has to breath..then after it's capable of breathing it can become a performance engine. Take the suggestions you have thus far & find a local engine builder that specializes in performance building Datsun L6's; go talk to the local Nissan Dealers-they always have a few shops they sublet to when a customer wants performance. Take our suggestions & offer them to that shop & weigh their answers w/what you already know! Kevin, (Yea,Still an Inliner)

Mike, Not knowing the exact * (Degrees) ABDC where the Intake Closes nor the Area (Sq.In.) of the Cylinder Head's Intake Port Opening will force us to guess; but not all is lost....going w/current known cam's & cyl.heads we can make a pretty good "Edumacated Guess" & get you in the ball park. Keep in mind-I'm not that Fuel Injected savvy but I have read up on airflow regarding the cyl.head & their required comp.ratio's w/a given choice of camshaft. What I'll do is list three possibilities of a cam's Intake Closing-that being 50*, 60* & 70* ABDC...then give you what compression you will need to run that engine on Pump Gas/Race Gas. The cylinder head issue; well all Dart's Website offered were the Iron Eagle, Pro1 & the 220 heads.....I went w/the Pro1 as it had the 2.05 intake valve & was an alluminum cyl.head; it offered three intake port flow spec's: 200cc, 215cc, 230cc. I went w/the 215 & 230cc heads. These are the knowns: 383 V8 Bore x Stroke = 4.030 x 3.75 265/50/15 Tires = 25.4" Diameter 3.7 Rear gears 6spd trans: 1st = 2.97 2nd = 2.07 3rd = 1.43 4th = 1.00 5th = .80 6th = .62 Cylinder Head's Potential Peak Power 1) 215cc = 462.79 2) 230cc = 495.08 *This figure's is determined by the camshaft you have chosen (Hydraulic Roller) & the port volume it flows. Cylinder Head's Potential Maximum Peak Power/RPM 1) Intake Port Area 1.9 sq.in. = 5744rpms 2) Intake Port Area 1.99 sq.in. = 6017rpms 3) Intake Port Area 2.05 sq.in. = 6197rpms 3) Intake Port Area 2.13 sq.in. = 6439rpms 4) Intake Port Area 2.18 sq.in. = 6591rpms 5) Intake Port Area 2.20 sq.in. = 6651rpms *This figure was determined by the area of the cyl.head's port entrance multiplied by a conversion factor of camshaft choice another cnoversion factor determined by the Displacement of the engine. Compression Ratio Required if Intake Closes at 50*, 60* or 70* ABDC: 50* ABDC Pump Gas = 9.6:1 Race Gas = 10.2:1 60* ABDC Pump Gas = 10.2:1 Race Gas = 10.8:1 70* ABDC Pump Gas = 11.0:1 Race Gas = 11.75:1 I think from these numbers & the fact that you've ran your 1/4 mile in the past w/larger tires & shifting at 6300rpms that a safe cruise speed would be @ 6000rpms; I dont know how long you can continue that cruise speed (but we are just theorizing here). T-56 6spd Trans & 3.7 rear gears 3rd= 1.43 x 3.7= 5.291 @ 6000rpms= 85.72mph 4th= 1.00 x 3.7= 3.7 @ 6000rpms = 122.59mph 5th= .80 x 3.7= 2.96 @ 6000rpms =153.23mph 6th= .62 x 3.7= 2.294 @6000rpms =197.72mph I purposely figured about 300-500rpms on the low side; so you theoretically may hit that 200mph. It all depends on what the Intake Closing ABDC is & what the Area (Sq.In) of your Cylinder Head's Intake Port Entrance equals. Once you've determined what the unknown variable are-you should be able to come up w/some absolute answers....Ala-no more guessing (theoretically speaking-of course)! Hope this helped & not confused. Kevin, (Yea,Still an Inliner) [ June 08, 2001: Message edited by: Kevin Shasteen ]

MikKZ; that sounds like a killer small block! What I cant get out of my mind/discount; is the article (I forget who found it first)-it was about "The Small Block Chevy Should Have Built" where the engine was build to alledged impossible spec's then ran on cheap pump gas & w/high comp.ratio w/out detonation. To me that proves there is something to longer rod's & their ratio; but then why all the fuss about it? Either there is irrefutable evidence or someone has pulled the wool over the eyes of a lot of people....including myself! Kevin, (Yea,Still an Inliner)

Nosz, When it comes time for any of us to put our money where our mouths are; only the individual can make that decision! When making that decision you need to decide if you want a mildly warmed over Z (which is really not that mild since the z is so light) or a weekend warrior that is barely streetable. Unfortunately this is a question only you can answer; congratulations on making it to this point....now the real fun begins! Dont forget the brakes & suspension! Kevin, (Yea,Still an Inliner)

Those are always so cool; I'm too too jealous/nice! Kevin, (Yea,Still an Inliner) PS: Cute Jim-got a kick out of your signature in parenthises; One of these days my "Yea,Still an Inliner" is gonna read "Yea,No longer an Inliner"...we'll just have to see who catches that & who doesnt! For now-no worry/it's a good ways off. [ June 08, 2001: Message edited by: Kevin Shasteen ]

Racnoth, My calculation puts your 86mph 1/4mile time at 4235rpm's. Kevin, (Yea,Still an Inliner)

Racnoth, I've recently worked out the kinks to my new toy (Crank/Slider Mechanism) which allows me to know what comp.ratio is needed w/any given camshaft chosen based on location of piston in relation to the rotation of the crankshaft degrees (sounds fancy-not really once you understand it). Before I begin-when milling any OHC engine-regardless if it from the block or the cyl.head-if too much is removed then you will have to use Cam Tower Shims (just a reminder). Anyho; the L28 engine has: Bore x Stroke = 3.385 x 3.110 -or- 168 cu.in engine You have two choices-The Stock Set up or the L28 w/L16 con.rods: (all spec's taken from How to rebuild your Nissan & How to Hotrod your Datsun books) Stock Set Up: Block Deck Height = 8.183 Stock Connecting Rod = 5.125 Piston Compression Height = 1.496 1/2 Stroke = 1.555 Add this up: 1.555 + 1.496 + 5.125 = 8.175 *NOTE-This leaves you .008" piston deck to block deck clearance or you may wish to mill a portion of this for squaring up your block. The L16 Rod/Piston Comp.Height: Block Deck Height = 8.183 L16 Connecting Rod = 5.236 1/2 Stroke = 1.555 *Note-This leaves you .014" piston deck to block deck clearance to mill for squaring up your block (or more room for using pip-up pistons) To maintain a 9.0:1 Comp.Ratio you will need a camshaft whose Intake Valve Closes 38* ABDC ("*"=Degrees) or less 37*, 36* or 35* ect. To maintain a 9.5:1 Comp.Ratio you will need a camshaft whose Intake Valve Closes 47* ABDC or less. Any cam w/Intake Closing later than 47* & you're enterine the world of High Octane Fuels! So keep that in mind. For the life of me-not one of those previous mentioned books listed combustion chambers for the L24, L26, L28 engines for comparison with the numbers I came up with-they only listed comb.chambers cc's for the 4bangers(?). My numbers indicate you need a 53 to 54cc Combustion Chamber for the 9.5:1 Comp.Ratio set up. You'll need a comb.chamber of 57/58cc for the 9.0:1 Comp.Ratio set up. Remember-the actual combustion chamber in the cyl.head can be less than listed above-after you factor in the cc's from the dish in your piston, the deck/block clearance in cc's and the head gasket crushed thikcness in cc's....all this will add to the actual combustion chamber/tell your machinest what you want & let him discuss the final measurements required. Hope this helped-I'm not a 6 banger guru/so maybe someone else can chime in about the piston's Dish/Dome & the actual combustion chambers required to make a performance engine run. I almost forgot: Your 280Z-if its weight is @ 2800lbs w/you in it requires 165FWHP to run the 1/4mile ET = 15.9/86mph. I dont know your tire size or I'ld give you your RPM's as well. Good Luck & have fun. Kevin, (Yea,Still an Inliner) PS: IM ADDING THIS AFTER THE FACT, I MADE A MISTAKE ON RACNOTH'S HP NEEDS. THE 165HP IS ACTUALLY RWHP...SO HIS ACTUAL HP NEEDS ARE 195 FWHP. ANYONE READING THIS MAKE NOTE-RACNOTH ACTUALLY NEEDS 195 FWHP & IF HIS ENGINE IS AT .85% VOLUMETRIC EFFICIENCY THEN THAT TRANSLATES INTO 165 RWHP. MY MISTAKE-SO SORRY. [ June 10, 2001: Message edited by: Kevin Shasteen ]

Mike, Which T-56 trans do you have? I forgot you swapped wheels/tires; which size tires are you going with...I went with the tires you had previously forgetting your most recent swap. I also thought you had 3.7 rear gears; did that change or am I just losing it (wouldnt be the first time)? So: 1) Which T-56 do you have? 2) What is your tire size? 3) Which rear gears are you running? Kevin, (Yea,Still an Inliner)

Mike, Give me the lo-down on your set up. Is your engine still a 383? I'ld like to see what info I can come up with-merely by you giving me your known spec's? I) What is the maximum RPM you'ld like to maintain? Also-what is your: 1) Bore x Stroke 2) Camshaft Type (Hyd/Mech Flat Tappet/Roller? 2a) I need the Intake Closing ABDC in degrees-get this from your cam's tech line! I need the Seat to Seat closing (maybe the same as "Advertised" but we wont know till you ask your tech line. 3) Which Cylinder Heads have you chose? 3a) What is the width & heighth of the intake port opening on those cyl.heads 3b) What is the advertised cfm they flow? 4) What is the Con.Rod Length & Piston Comp.Height? 5) Still have the 6spd trans? 6) Rear Gears? 7) Tire size? Remember that peak airflow in an engine usually occurs around 78* to 82* ATDC. Depending upon where your cam's Intake Closing will need to compliment your static compression ratio as the moment where your intake valve closes will determine how much cyl.volume remains to be "Compressed" during the "Compression Stroke"; thus I need the Seat-to-Seat" Intake Closing (in Degrees ABDC) which your cam's tech line will have on hand. The connecting rod length & piston compression height will affect the location of the piston in the cylinder/so dont forget that info also! If you can get me the above requested info...I think I could get you a whole slew of results (sounds like fun). Kevin, (Yea,Still an Inliner) [ June 07, 2001: Message edited by: Kevin Shasteen ]

Like David sayd; I too am "NOT" a datsun expert. However; since you cant idle it down-maybe you have some vacuum leaks & there is {unmetered} air entering the engine-thus giving your engine the sensation of "Its Time To Accelerate" now. Unmetered air will make your engine act like is should under acceleration. Put a cloth rag in front of the air intake to clog the engine's incoming air...if it speeds up then you have an air leak somewhere; if it chokes & then tries to die/then you have no air leak & this means you have other problems. Sorry; but this is the extent of my tune-ability expertise/good luck & hope someone else chimes in here! Kevin, (Yea,Still an Inliner)

I've read quite a bit on this rod/ratio stuff & it seems there are some good points & then there are those who get miffed about it. http://www.headsuperview.com/gklass012101.html is an article written by George Klass...FFW Tech Director. He recounts the actions of Reher-Morrison Racing Engines who built a 500cu in engine for the puropose of testing different engine combo's whereas the only variables were different connecting rods & piston comp.heights....the outcome was that there wasnt any difference on hp/torque. I've also read where the old rule "There's no substitute for Cubic Inches" makes the rod/stroke ratio argument a moot one(?). So why did Reher Morrison choose to argue his point by building a large displacement engine to make his point(?) when large cubic inches allegedly counters his countering of his test??? I've also found an excellent article on the web where as the writer gives all the arguements: timing, cyl.pressures, dwell time and piston accel (well worth reading); it is: http://www.chevytalk.com/tech/engine/rod_angle.html In that article he makes a valuable point on rod length regarding its angularity in relationship to the piston/cylinder. He claims that any rod angle more than 18* ("*" being Degrees) is hazzardous to an engine and will result in excess cyl.wear due to ecess thrust to the piston. He also gives a formula for calculating piston angle-it is as follows: Stroke/2 = Answer/(Sin(Con.Rod Length)) Take a 350; its stock stroke is 3.48 w/5.703 rods...working the above formula gives you the answer of: Rod Anlge = 3.48/2 = 1.74/(Sin(5.703)) Rod Angle = 1.74/.09937 Rod Angle = 17.51* Now take Davy's 355/6" rods; it works out to be: Rod Angle = 3.48/2 = 1.74/(Sin(6.00) Rod Angle = 1.74/.10452 Rod Angle = 16.646 Now take the 400; its stock stroke is 3.750 w/5.565 con.rods...this gives you an angle of: Rod Angle = 3.750/2 = 1.875/(Sin(5.565)) Rod Angle = 1.875/.09697 Rod Angle = 19.33* (Note-This explains why many engine builders talk about the 400's excessive cyl.wear) Now lets take a stock 454 w/6.135 con.rods & working the formula gives us the following: Rod Angle = 4.00/2 = 2/(Sin(6.135)) Rod Angle = 2/.10687 Rod Angle = 18.741* Now, for you Ford guys; take the 5.0; it has a stock stroke of 3.00 w/5.090 con.rods: Rod Angle = 3.00/2 = 1.5/(Sin(5.090)) Rod Angle = 1.5/.08872 Rod Angle = 16.907 Take the 5.8W block that has a 3.50 stroke w/5.956 Con.Rods; this gives us... Rod Angle = 3.50/2 = 1.75/(Sin(5.956)) Rod Angle = 1.75/.10376 Rod Angle = 16.865* As always-I've enoyed this thread! Kevin, (Yea,Still an Inliner) [ June 07, 2001: Message edited by: Kevin Shasteen ]

I'm glad this came up; I personally have no experience in owning/building nor using a 383 but have always wondered about choice of rod/pistons w/the 3.750 stroke. Of all you guys that are using the 383, 400, 406, 408's which incorporate the 3.750 stroke...which rod/piston choices have you made & what kind of durability have you found. My questioning arises from specifically from the 6" rod which will require a piston compression height of 1.130 after a .010 Block Deck Height clean up that still allows the piston to remain .010" below Block Deck Height. To me that 1.130 piston compression height is rather thin/pushing the brink; but then again I've never ran w/a 383(?). The 5.7" rod in a SBC w/3.750 stroke requires a piston comp.height of 1.425 which allows .015" removal from the block deck height & your piston would still be .010" below block deck height. The 5.565" rod which is the factory rod for the 3.750 stroke uses a piston comp.height of 1.560 and also allows .015" removal from the block deck height and again allows the piston to remain .010" below the block deck. So; again-everyone out there using a SBC w/the 3.750 stroke; what rods/pistons have you chosen & what kind of durability have you seen....also I'ld like to know what your compression ratios were along w/the intended use of the engine (street only or street/strip or strip only?). Thanks for the thread-good info! Kevin, (Yea,Still an Inliner)

Doug, Car looks nice; I also like the air inlet & I'm partial to the 2+2...looks great (my car is a 78 2+2). Kevin, (Yea,Still an Inliner)

I used to have a Toyota Corolla whose blower motor would quit whenever it wanted to; I usually would grab my flashlight, while driving, & tap on the motor without ever missing a beat & then the motor would start up again. If that didnt do it then I would tap on the dash where the fan switch was-usually one of those two would get the motor running again....car had 260,000 miles on it/amazing little car! Your real culprit is either the switch, wiring or the motor itself or a bad ground to any one/or a combination of the three. Kevin, (Yea,Still an Inliner)

Alright, who started this; you guys are getting me going again-talking about dealers. The 12 years I was w/MIC I did nothing but deal w/dealers. All the way from the the janitor to the owner & everytone in between. I've seen their paperwork on the deals they made which went sour for whatever reason & I've seen their scheme's for salaries on their salesmen-it aint a job for everyone. The dealer as a whole is only going to be as good as its owner; if the owner sets the ground rules & is firm in enforcing those rules then the dealer as a whole will be a good one. However, what I noticed when dealing w/claims against dealers is that the salespeople will circulate dealers; in other words they'll work for a dealer for a few months-if nothing big happens then they'll quit & move on down the road to the next dealer only to return back to the first dealer in a few months or they move on down to the next dealer. Very few salespeople stay w/one dealer for extended periods of time. If they have been there for awhile its usually because the dealer is a good one or the owner doesnt trust anyone else other than that person. Its definately a strange game the dealers play & a very shrewd one at that. Kevin, (Yea,Still an Inliner)

Yea Lone, I tend to agree w/you; it all boils down to the outer dimension/measurements (size) of the L x W x H of an engine; still its an interesting concept to ponder(?). Kevin, (Yea,Still an Inliner)

Thanks for the responses everyone; but for clearification purposes only-I'm not considereing a BBC for my Z. I intended for this thread to be something that determines or differentiates a BBC from a SBC. The reason I posed the question is the result of my reading on perf.engines of Mopar, Ford & GM; wherein, each displacement of their V8's have ben honed, bored, stroked/blown & turbo'd to the max as we now have small blocks surpassing the displacements of the typical big blocks...so my question was more of a phylosophical question which usually leads to factual/reality type answers. Since there are small blocks stroked to the hilt utilizing con.rods from big blocks which yield amazing torque.....at what point does a small block become a big block/or is the differential between the two merely one of outward dimensions? I liked Mike's trip down the history lane & found it insightful. What I found interesting is that the crank journals are not that much larger nor are the connecting rod journal thickness of the crank that much different when going from a small block crank to a big block. The stroke/rod length ratio is however quite a leap when looking at stock small blocks & stock big blocks; as are the valves to port ratios & the valve to piston deck area ratio's. My quesiton was hopefully posed from the angle of this: If we were able to shrink ourselves & enter the inside of a small block & walk around (no, I'm not on mind altering drugs!)...what would we find different from a big block if we did the same? Just attempting to get all of us thinking; I like challenging questions; So again, what differentiates a Big Block from a Small Block-is it merely the engines ability to breath complimented w/a longer stroke & larger connecting rods because if that is the only thing we are going on, then there are a lot of stroked small blocks which could be considered big blocks(?). Kevin, (Yea,Still an Inliner)

No Guys; not for me/sorry to get your hopes up as I'm still an Inliner. My question tho & this is merely for fun is this: With all the hotrodding of every Amercian Push Rod V8 since its inception, all the parts swapping & all the stroking of each & every engine Detroit ever put out.., what constitutes a Big Block from a Small Block? I have my own ideas but wanted to lure all the thinkers in here to giving their opinions; doesnt matter how simple or complex..I'ld like to hear you thoughts! Kevin, (Yea,Still an Inliner)

Ross, Those dyno slips & itemized lists of items added w/their gains in hp/torque obtained per each dyno slip would be a nice thing to have on the site somewhere!! Kevin, (Yea,Still an Inliner)