Tony D
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Posts posted by Tony D
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I try to stay out of China, it's not worth my time and aggravation until management decides to listen and act upon suggestions of field personnel. Multiple field personnel.
Technically, I'm based in LA. My company doesn't do shit for me living here in Philippines now. I just figures by saving the $26,000 in airline flights every year (153,000+ commuting miles) that something could be worked out... Instead of that, the MBAs decide to "leverage" my investment in a houseful of furniture and vehicles to "save" more money availing of the flight savings anyway since their bet is I won't pull a George Costanza and start maliciously flying back to LA for a day to get on another flight.
Hey, my 500 hours a year on a plane flying over the Pacific can be spent productively....or flying. Their choice, right?
New Year, new attitude. It's the year of the Sheep. "Baa Baa Motherf-ers!"
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I considered adding "against a spec of what"--if your diameter is good per piston and ring specs, then you look good as long as they are found and not tapered top to bottom, etc.
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Make sure your starter system allows the jets to return to where they're supposed to be.
If one is down further, or stuck "on" partially it will act like a Rev limiter. Regardless of float levels one bowl will eventually be sucked dry, and you flatten out in power...like a Rev limiter.
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Bore mic to what diameter now?
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What's a "dizzy"?
Same thing as a "dissy" just spelt wronglier.
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Heat rejection capability.
Look what size JeffP has on his 700+HP S130. During 5-Minute Oil Temperature Testing Runs where we held the engine at peak torque at WOT for five minutes (just add throttle and load till you run out...) the note temperatures on the engine Dyno never exceeded 40C at a 30C Ambient with three small pancake fans sucking air over it. That indicates that for at least that airflow sizing was fine. We noticed the same thing making passes at over 650hp on the chassis Dyno. The "heat soak" most seem to experience baffles us.
Look at what air cooled compressors get by with and you realize most of this stuff is either grossly inefficient or blown up to make a statement of some sort.
You really need to work backwards from you power goals. Jeff originally sized his for 500 hp, and it's working fine at 650+.
Same with his exhaust,, he expected he would see problems over 500, but none yet... He thinks it may be diminishing returns over 700hp, we haven't checked exhaust abc pressure while dynoing so we don't know what part restriction plays in the hp bumpers flattening...but suspect more the turbo is in stonewall than exhaust restriction since the turbo graph seemed to point in that direction as well.
You need hp. Hp tells you fuel and air. Air in pounds per hour, combined with turbo compressor map and efficiency will calculate discharge temperature at pressure used...
From that you can calculate the required sizing of the core to reject that heat to whatever rise over ambient plus reserve capacity you so desire.
It's just math. Math is your friend. Think of it as a "story problem"--except this one is in REAL LIFE like your teacher warned you would happen!
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JeffP wrote up his experiences with the Melling Pump on his webpage, he wanted some big number at idle... Don't recall where it tapered off to on the top end.
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"I have a mechanical autometer gauge"
Is it me...or does this say he's already GOT a mechanical gauge?
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Jeff used the ITM stock turbo pistons on his blown piston replacement.
For their cost hard to beat!
A note on sealing.... The diameter really doesn't matter, it will seal just as well at bore size as over sized 5mm, the fire ring effectively causes a super-high pressure clamping area which affects your sealing surface. The flat copper gaskets distribute that clamping force out quite a bit due to them being non compressible. They won't "creep" like a fire ring only clamped by the bolting forces...but that's more a function of how they are constructed. Same for MLS which have a very narrow fire ring backed up with a lot of metal to stop the fire ring from moving at all.
O-rings are considered "blowout proof" simply because you machine a hole they fit into...when detonation occurs they move outward slightly in their groove similar to hydraulic o-rings, which then hits the shoulder of the groove, & can move no further. At this point bolt clamping forces are concentrated onto about a 0.040" wide sealing ring area resulting in extreme face pressures compared to conventional gaskets which may spread that clamping force over 0.080" or even 0.120"+ face! resulting in less face pressure....so the head gasket blows....let's combustion gases above face sealing pressure by....bang! The stock FelPro may have "X" face pressure, a wire O-Ring at the same head bolt torque may have 3 to 4X face clamping pressure...it still may move, but once backed by it's groove stops...it's either blow past that face pressure, or sink the rings on your piston!
When you pull your head gasket, pay very close attention to, or hold it to a new gasket and look for the fire ring having moved. If it did, and your head/block is flat within spec: YOU ARE DETONATING! You may not hear it, and as I have said for a long time "the detonation you hear isn't breaking your parts, it's all those miles when you were detonating and NEVER HEARD IT!
Anybody can lift when you hear that pinging. Everybody just stays in it if they don't hear it. Always check those gaskets during tear downs.
JeffP's build with blown #5 cylinder showed similar deformation on 3/4. Going back through his dead gasket bid, he realized EVERY head gasket he had that was blown went on 5/6, or 3/4. This revalation in conjunction with talking to John Knepp of Electramotive and other experienced Datsun a Builders in heavy competition when currently a new model, pushed us towards the coolant-temperature detonation susceptibility realization.
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Didn't let that HEI lose ground while you're powered on, or it's toast if you don't have a robust aftermarket unit with current limiting. Stockers fry with the snap of your fingers!
Chances are good you weren't "losing power" while cranking, you were getting a pulse and your meter was auto ranging and too slow to catch it. Set it to 20 V or lower manually (5 or 10 ideally) and you should be able to see the pulses from the ECU. If you use a NOID Light or LED of proper voltage it wil "pop pop pop" light on that wire when cranking if you got the polarity for + & - right...
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What weight oil are you running and is it the weight Rebello recommends?
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I will agree with TimZ on this, I've run a stock Cherry Head Gasket on my L28 since 1985, set between 325-350 HP. You aren't "getting" the source of blown gaskets is detonation, not BMEP.
Jeff P is running 475+ on his stock L28ET, with a standard FelPro head gasket...which I insisted he try because he's half deaf and driving a fully sound isolated S130, the only way he knows it's detonating is when the HG blows.
Head gaskets don't blow from boost, they blow from detonation.
Get your fuel and timing right and a stock Nissan L28ET or Fel Pro will be just fine as long as you aren't detonating.
Jeff went through three head gaskets and one set of pistons before he got fueling correct. He conceded finally I was right: "run the stock bottom end because forged is just more expensive when it breaks." Get your tuning done to 350-400HP on stock stuff. By then you will know the fueling characteristics of the engine. As Jeff P found out it IS important to make a full rpm pass at "only" 8 psi. You need to determine power and torque peak. From that curve you can extrapolate fueling needs and potential as you raise the boost. The curve won't change, it will just move higher on the chart. First thing Jeff will do with his forged bottom end THIS TIME is make that pass at 8 psi first. Optimize it. Then calculate it out to see if everything is up to snuff before even trying higher HP runs. He's running to 7,400 now on cast pistons and hasn't found the power peak yet...
But 475 at 7,200 at 17psi ain't bad on a stock L28ET bottom end with a FelPro head gasket, no?
The power is in your head porting, cam, and turbo selection. Fueling properly prevents detonation and blown/broken things.
You run an MLS on cast pistons, you just break them instead of blowing the head gasket when you detonate tuning the engine, and you WILL detonate.
At 300 or even 350 HP, there is positively, absolutely no reason to piss money away on a piston breaking "seal all that pressure when you detonate" MLS head gasket!
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That was a short run, sounds like peak power is at lower revs than you would expect.
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Just needed to get the right perspective on it!
Forged pistons suck 1qt every 1,000 miles right? So do worn stockers....
But if you got 186psi of compression, and drive 10,000 miles a year, you spend ten quarts of oil worth per year (say 40$ a year...)
I love guys that use "excessive oil consumption" to justify and overhaul ($3500 paid, how many miles you gotta drive to get that back?) then complain their new, tight engine is down on power and they just can't figure it out!
BMW did testing showing some of their engines were still gaining in HP at 30,000 miles. In other words, those tight clearances and rings wearing in/sealing results in progressively more power and takes a LOT longer than the 1,000 miles most people think!
Porsche, on the other hand just said "buck up"--they service with Synthetic from day one, and say "live with the oil consumption" (easy to do with a 21 qt dry sump admittedly...) on the philosophy the gave round bores, and the sealing is accomplished on the motoring Dyno to "sufficient" levels...so the engine may not be perfectly sealed, but will progressively seal better and better the more mileage it accrues.
When you really start "thinking" about automotive paradigms and work out the cost-benefit-analysis to YOU and not the OEM Aftermarket Parts Division you go "Ooooh those dirty...."
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Classic line that took on COLOSSAL irony not 6 years later, as Mark Hammil fight through the crowd to get to the rotating display and sees a RHD Fairlady Z done up as hideously as he mangled the Vette and exclaims "A DATSUN?!?!"
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And Dude, "ass-painer" is no longer the preferred terminology, "Whino-American", please!
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Why are they NLA from a dealer?
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Do you want to loose horsepower for the next 150-200,000 miles for those bearings to "loosen up" or do you want to give away that mileage for the horsepower immediately and live with an engine that may only have a bottom end capable of going 200-250,000 miles between bearing attention?
That's really the only question you need to ask yourself. Engine building is a series of decisions, made and weighed against payback and potential downsides.
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Seems like a cagey way to go about it...
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"They're a commodity, to be bought and sold!" I first heard that here:
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Coal?
That's not PC Mike.
We must now offer Coal, Alabaster, Sulphur, and Amber depending on the identified racial component of the ass-painer.
It's in the new FEDREGS... CFR somethingorother... I'm sure some consultant can point it out to you for a fee, before you are in violation and have fines, penalties, and interest retroactive to this first post!
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I'd trash the carb and put a TBI injection unit on there and forget the headaches of 30's technology.
There is a necroposting penchant of late, so we wanna talk EFI vs 4 bbl, the 4 bbl we used was idling at 2,200 rpm, the 45 DCOE's at 1,700, and 45 mm ITBs at 500 if we wanted it to. Lightning fast, crisp throttle response from as low as 400 rpm idle, but we moved it to 900 just because. Started right up on 35 degree mornings, fast idled and etc just like a factory car.
Horsepower gain on the ITB's over Webers was 40Hp at 8,250 rpm, and 45DCOE's were at least 20HP more over the Four Barrel at 7,500.
NASCAR went EFI, time you did so too.
I got a four barrel intake on my 72, it's been running an EFI setup now going on 23 years.
23 years.
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There's an old saying "they run their best before they blow!"
Generally if oil clearances are under 0.003" you're good. Anything much closer and there is an issue getting proper oil flow through the journal and rod side clearance. You want oil flowing through there removing heat. That's why factory clearances were as low as 0.0015, and higher, but the performance build recommends higher clearances.
In high speed centrifugal compressors you can pick the bearings or pin ions run with close tolerances and mineral oil as they always have more varnish built up on them due to added heat from lack of flow. We use instrumented bearings in some machines, and you can see the difference in as little as 0.0005" difference in setup clearance and corresponding bearing temperatures (both oil throw off and actual bearing backshell temperatures.)
The flow from the oil pump has to be up to the task. If you start building excess pressure with that flow, the oil pump will start sucking horsepower as well. You need oil pressure/flow to get oil into that bearing area in sufficient quantity to maintain an oil wedge under rod reversal and peak cylinder pressure.
L28 Dyno Results - Bad Cam Timing?
in Nissan L6 Forum
Posted
It's external. The levers only push your jets DOWN they have a spring to return them up to adjusted height.
If it sticks down, you suck the float bowl dry and run on one carb.
If that doesn't cause lean starvation, I,don't know what would!
Lift off WOT and the engine pulls higher... Sometimes...