Tony D
-
Posts
9963 -
Joined
-
Last visited
-
Days Won
74
Content Type
Profiles
Forums
Blogs
Events
Gallery
Downloads
Store
Posts posted by Tony D
-
-
I use the Tomei from Japan, they have a nice etched degree wheel and are accurate.
A couple of degrees makes a big difference.
Our torque band went from 6000-7500 flat and level when the cam was 'straight up' compared to a 2 degree change resulting in that SAME LEVEL OF TORQUE being available from 4500-7500. It just opened up the bottom end and didn't seem to change anything up top.
Having your torque plateau widened by 1500 rpms would be classified as a 'Big Difference' in my book. If you want to dispute that is not a 'big difference' we will have to agree to disagree. It was the difference between not being able to 'pull the spread' at speed and breaking records.
Before the change when doing drag strip testing we would shift to third and you could literally count 1...2...3 before the wheels broke free and the car started accelerating again, passing through the traps at 13.08 at over 100mph and spinning the wheels all through the end of the 1/4 mile (3.36 gearset, and stock diameter street radials.)
-
It takes all of maybe 5 minutes to install it. I can't imagine any easier installation. It plugs into the factory harness in three places (light place for each bucket and the body harness going to the right headlight), and provides a plug for the no-longer used factory body harness to the left bucket. Attach the power lug to either the alternator B+ stud, use a sheetmetal screw to ground the relays and mount them in one fell swoop.
Come to think of it, it was more like 3 minutes...
It goes on my list of 'must do when buying a new 240Z to drive' right up there with 'replace lights to 55/100 H4 Beams and new water pump'...
-
But that costs $240, now doesn't it? And some dyno time to get it 'just right'. It's not just a retardation, the opening and closing events are slightly different as well. A couple cam degrees makes a big difference even though it doesn't seem like much.
There is someone making nice replacement spraybars now out of billet aluminum, with 'cooling grooves' on it.
-
Wow, I was out of the loop. Was that on WCR forums?
-
Some grinders balk at regrinding drilled cams, the solid one will likely be a better bet. While the head is off, don't forget to open up the oiling restrictions in the top of the block to the recommended size (in the Blue Book) for good top end lubrication. With the crap oil these days, this helps.
With the holes opened, you will have plenty of oil up top as long as your oil pump is in good condition. If you haven't installed a turbo/auto pump, now would be a good time to do so for additional flow capability.
-
"BTW, I have a P90 that I shaved and I'll suggest something in the middle that picks up on some of what both Tony and Jon say. The cost to shave and shim the head was in hind sight, not worth it. But it's rather cheap and easy to put a reground cam in while you have the head off. I used a Delta Cams regrind of a stock L28 cam (don't remember which one) that makes great power from 3500 to 6500 and still idles great. Plus, with the lower compression you can be sure to run full advance without detonation, something that's iffy with a CR in the 10:1 range, especially on hot days."
This is more along the lines of what I was getting at: the CR increase will give you nothing but problems running regular gas, in addition to rendering a head useless for any other use.
You didn't say the head was ALREADY OFF and NEEDED PLANING. In that case: shave AS LITTLE as possible. If you didn't port the head ($$$$$) it's coming off AGAIN anyway to have that done, so if you shave it now and anything happens between now and then, you're in the market for a new head...
The "A" cam is better than the later cams. Notwithstanding JM's comment on them all being 'dinky' or whatever, they do have timing which promotes higher rpms than a pedestrian L28. Drive an original L24 and an original L28 powered anything and realize the 'zing' above 4000 just isn't there in the late models. The key is in the cam.
And speaking of 'incrementals'---you will change to a solid cam and spraybar ANYWAY so why not do THAT instead... and like suggested have that early cam reground to something that will be slightly better than an early cam.
That will pay LOADS more dividends than ruining the head by shaving it 080.
Which, I think I said in the beginning...
-
Google "GM SERVICE MANUALS" and Fifth Suggestion was Helm, Inc
Couple of clicks got me here:
Enter what the JY told you the year and model was and you have the order blank online for the appropriate service manual.
Like this one, only $150 for the SET!
I revert to my original statement regarding easy access of manuals for domestic vehicles in today's market. Though I was amazed to realize that Helm did ALL the domestics. Imagine that...
-
The point is that it's better to leave the damn thing alone than start going after 'incrementals'---if you really think an 080" cut is worth the effort, then so is swapping to the "C" cam, and blah blah blah...
You want an incremental increase from a P79, throw it in the dumpster and stick a properly dressed N42 on it.
Why cut a turd? To get one that doesn't smell quite as bad.
Sometimes absurdity does not come across well on the internet. But I am also at work and couldn't really put a lot of effort into making it really over the top.
Given the choices given originally, I think I said it more than once that 'leaving it alone' would be the best thing to do. And that Aluma-Seal was a better remedy for an 'all stock' engine as opposed to pulling the head for a gasket change.
If you are going to do it, do it right (not all at once, but for gods sake why waste time on a P79???????)
-
Sad day indeed. Best wishes to Floyd and the rest of the Family.
-
Good Point, the L24 cam is solid and not particularly applicable to the later cam tower setup without a spray bar being added. I always run internally oiled cams with a spray bar anyway...
I guess in that instance, my recomendation would be just "leave the head alone and Aluma-Seal it!"
The P/N is all over the internet. They are NLA from Nissan I believe, but they are in engines all over the place. The early cams in an L28 get rid of the 'slow to rev' complaint people blame on the longer stroke.
-
I never said it was a blown head gasket... more like a coolant weeping head gasket =)
I would do everything at once if I could, but time and money situations force incremental improvements. Porting and increasing compression ratio by itself might not gain much now, but can set the foundation for other improvements down the road.
I don't have any big resistance to cam tower shims, I just can't afford them, new valves, and the time to source it all at the moment. I do have access to an earlier cam though...
Nobody said do it all at once. What do you realistically think you will gain by bumping the compression? You will still have an L28 cam, which peaks at what...5300rpms?
Finding an earlier stock cam from an L24 will change the way the engine reacts, allowing more useable rpms, and I posit a more effective horsepower increase.
Do you really intend to port and polish a P79 head? And if you do, what will your long term plans be, do they include rpms over 7000? If so pistons are on the horizon and then you are stuck with a shaved custom head with a strange combustion chamber requiring custom cut compression increasing pistons.
I'd suggest you skip the planing of the head. I think there is some thought down the road this will be something other than a waste of money. But the head will come off for porting, so why do the head shaving now? Why not wait?
The cost of the shaving will not net much IMO. Other than a higher than stock compression ratio meaning now you can run premium gas all the time instead of regular.
Whereas a stock early cam that lets that L28 pull to higher RPMS will keep you on pump gas, increase your power, not require shims, valves, nothing (I mean the rocker arms are supposed tobe resurfaced, but if you get that cam from another older head...might find those matched rockers as well...
If this is a question of "should I do this now?" I'd say skip it until your plans solidify more. You are polishing a turd. When's the last time you heard of anybody buying a 'performance P79'?
OH, BTW....if money is a concern....I'd try half a tube of Aluma-Seal on the head gasket to stop the weep first. Ford would put that much in every car off the line at the factory (Volvo as well) so that is something to seriously consider if the engine is running well and has no other ills other than weeping a little coolant. I've done this one on several engines myself!
-
A solenoid or 'bump switch' to open a small orifice venting air around the throttle bodies is a scab fix. They were used on some cars (a late model Corvair, for instance) when emissions at idle needed enleanment but transition needed a lot of fuel...
Small spring-loaded arm set to be tweaked and crack a rubber stopper over a hole in the base of the carbuettor straight to the manifold. Soon as you cracked the throttle, the spring put the stopper over the hole and vacuum sealed it tightly.
-
Stock linkage is not linear.
It is impossible for it to be linear through it's near 90 degrees of throttle shaft movement.
On the 280zx throttle body linkage, it starts out with the minimum authority and gains authority in relation to the throttle pedal movement the further it is opened.
Argh, you completely missed the point!
OK. ASSUME the SAME linkage on both TB's. 60mm and 50mm.
Now, calculate throtle plate opening area.
NOW, from a 0% rotation to 10 Degrees rotation, calculate the RELATIVE THROTTLE OPENING CHANGE between the 50mm and 60mm T/B.
Because the 60mm flows an appreciable figure more (and knowing what that number is will allow you to 'pair that' with an equivalent 50mm T/B opening) you need LESS throttle angle on the 60mm body for the same 'modulation'...
By using that formula, you will know EXACTLY how much to alter the linkage to give similar tip-in characteristics between the two.
When you look at the valve flow coefficient the non-linear response to a linear rotation characterized in degrees may be plotted, and valves of different flow characteristics may be made to feel as though they are identical. This is what happens with fly-by-wire.
For all intents and purposes the TB opening is 'linear' as you use the 50mm as your baseline to compare with a 60. You manage the DIFFERENTIAL CHANGE to make modulation similar. And to do this you need FAR MORE non-linearity on the 60mm TB than you do on the 50 to get the same 'feathered throttle' feeling.
If you want to split semantic hairs fine, but you're throwing out the baby with the bathwater arguing a moot semantic point. Throttle opening is in degrees, and THAT IS LINEAR and comparable between the bodies.
The flow given per angle of throttle rotation is not linear, and far mor dramatic at low throttle angles on the 60 relative to the 50.
Don't loose sight of what is being discussed. You will miss the forest in all the trees. You've already been discounted in the discussion as not being able to 'feel' the flow difference with identical linkages (a physical law at work there, BTW) kind of means stating the obvious (not linear throough 90 degrees of motion---who said it was?) is not contributing anything to the thread.
-
Motors Manuals were the choice of independent garages for years. They directly copied many of the sections of the Factory Manuals.
I would put them right next to Factory Manuals---they were tools for professionals.
Rarely, if ever, will you find a Haynes, Chiltons, etc in a real car shop unless it's a really obscure thing and they need a specification.
I mean hell man, some of them can't get the FIRING ORDER CORRECT on a Datsun L-6!
-
Gasoline will expand about 10% by volume. If you fuel up and then drive, chances are good you will go the 19-20 miles required to give you space in the tank to then stop and eat and let the diurnal variation cause your fuel to expand.
Venting of the tank is crucial to proper pump operation and getting a full tank when at the pump. It needs a high point to bleed the air out of the captive parts of the tank. JDM cars had a 1/4" overboard dump (my 73 for instance...) and that works just fine.
See the other comments about using nylon adapters to convert the larger vapor recovery hoses to something smaller, more managable, and cheaper.
a 1" band will not give you much capacity. Expect 22-27mpg if the car is running properly and you keep the speed below 80. That's about 3 hours at a stretch driving before you want to think about getting a tank of gas. It's a nice interval to stretch you legs.
If you want capacity, cut out the spare tire well, and put in a 77 - 78 gas tank, they are 16 gallons.
You CAN fit a 100L (32 Gallon) tank back there. No spare tire. Stock Datsun Part, NLA. Needed a special sender and dashboard gauge anyway. No, you can't use mine. I plan on using it in my Diesel Conversion. At 40mpg conservatively, I'll go 1200 miles between stops. Just about a days drive the way I do it.
Forget about that kind of range with a petrol car, you will stop six times and waste 20 minutes a stop each time, so at the end of the day a petrol car will have to drive 2 hours longer per day to keep the same daily pace as I will be able to in my Diesel Z.
Yeah, been across the country a couple of times...
Yeah, I use a stopwatch and write stuff down...
-
Do the mass-flow calculations, and you will see preturbo is 'no free ride'---the mass of the air, while increased....also contains water. You can preinject before the turbo to the limit of 100% R/H on the outlet of the turbo. It must then go DIRECTLY into the engine as if any cooling of the charge air occurs condensation and liquid water will form.
The density increase from latent heat offsets the loss of air due to water displacing it, so you get more power.
If you had something that burned (methanol) then the latent heat issue is AIDED by the 'carried along' anti-detonant as it is burning as it goes.
In either case, your cylinders stay really clean.
Spearco Water Injection (2 Stage) on the car since 1979...
You know they made them for N/A's back then as well?
-
Question is, what do you gain by the CR bump. Is it worth trashing a head that can then never be decked again without more shims, longer valve stems, etc etc etc...
What realistic gains can be expected from this?
I posit a cam change from an earlier engine might benefit him more than the bump in compression would.
-
ECU doesn't see injectors, they are an output device. The only thing it 'sees' is RPM, AFM, CLT, TPS, etc...
You can put 370CC injectors on there and the ECU won't know the difference, it will just run pig rich as it has no method for pulsewidth alteration. It doesn't know 370 from 280 from 160 from 550 from 720CC injectors. It fires the same pulsewidth based on the input signals from the above input devices. There isn't even an O2 sensing loop to know that you're rich and to taper off the pulsewidth.
It is a dumb ECU.
-
Try a set of FLAT TOPS.
They idle on a SEPARATE CIRCUIT from the needles, so the IDLE mixture can be adjusted SEPARATELY AND INDEPENDENTLY from the power circuit (ever wonder why all the Flat Tops have the needles savagely removed---perhaps because they have a more agressive taper for the larger L26 that made more HP than the L24???)
Sure, the power valve isn't the greatest for the progression, but unless you are willing to taper your own needle you are experiencing EXACTLY what Nissan did when trying to get emission compliance, and came up to the same conclusion that spawned SU's invention of the HIF-6 Carburettor.
Separate the idle on it's own circuit, leaving WOT and High Load on the needle.
But remember, "Flat Tops Are Boat Anchors"...
-
Hose Size / Velocity is valid. The larger the hose, the slower the velocity, the more surface for coalescing.
Also remember this stock hose is CONDUCTIVE for static dissipation, and has a flame arrestor (metal tube brush) stuffed in there as well.
People can make plenty of stuff look great, but it doesn't mean it's engineered to provide the same safety margins or functionality as the stock parts. You shouldn't sacrifice safety for flash in this instance, a crankcase explosion is not a fun event.
"BOOF!"
-
Yep, my 1960 Corvair still has the card that says to write to Helm to get the domestic stuff GM wise... So does my 1990 dually, so chances are if they were doing it from 1959 to 1990, chances are they are still the place to look today.
Just a guess...
-
If it's the connector for the EFI Relays, the Fairlday Z has it on the same side as LHD cars, it will NOT be by the steering wheel on the RHD Dash, it will be up near the glove box. My 76 and 77 are packed away now, but if you still can't find it I can go look where it is on my car and give you a general location with a photo or two.
I put a 76 280Z EFI harness into my 76 Fairlady Z, and the EFI relay plug from the LHD Car was a perfect fit to wherever the connector was on my Fairlady. The plug configuration was EXACTLY the same, and there was NOTHING nearby that had a plug even remotely close to plugging into it.
You may want to look for an Australian or UK Spec FSM (if such a thing exists separately) as I have not had much success finding mush service manual information on the FZ.
-
What massive gain do you expect for all this work and use of now non-standard parts?
Realistically?
Think about that aspect long and hard. I suspect the gains will be minimal in the real world, and neglible in real performance quantification.
And the increased CR....
What was that you said, you have a blown head gasket?
-
Nonstop 16 hour days since the beginning of the month, plus getting some sort of Canadian Crud which causes hacking, snot production in my lungs, a headache, and sinuses which feel like they will explode may be affecting my memory. I can see the bearing and when we installed it...but can't clearly see the "NTN" number afterwards...
And all I have to look forward to is 12 days in the freakin' desert when this is done.
Not any desert, the freakin' desert, A.K.A. "The Sandbox and Environs Therein"
Head Shaving Question
in Nissan L6 Forum
Posted
It was 1999. I would have to look at the dyno sheet from our testing, we both advanced and retarded the cam up to 4 degrees in each direction and took the position that gave us the best torque. I remember for our application that 2 degrees was the ticket.
This DOES NOT mean that 2 degrees is some magic number and this is where you set every cam. We spent $200 in dyno time testing the cam in various positions and took the one that gave us the best torque/HP split. Subsequent testing with different induction systems on the car gave similar results.
The only way to know is buy a sprocket and try it on your particular build. Someone said: 'Big difference? By whose determination?' so this was illustrative of such an instance. Best $200 we spent in 'performance modifications' to that point. $200 for Dyno Time. Until you do that, you're just guessing. The torque and HP we picked up from that change allowed us to pick up our first record at ElMirage.