Calling all Strokers (engines only)

[ArnZ]

Ready to take everything to Sunbelt for my 3.1 machine work. I have a F54, N42 and a two N47 blocks, I have a late E88, N42, P90 and a N47 head.

I have a LD28 crank, 9mm 240 rods. No pistons yet. Weber DCOE 40 18's. I plan on adding a streetable cam. I already have square, and round port headers with a good flowing exhaust. Down the road I plan having some mild head work done.

This a steet only 75 Fairlady with AC. Wanted to see what combos are on the the street now. EVERYBODY has a different opinion on what route to go. F54/N42 ,N42/P90, F54/P90, N42/N42, etc. I thought that the F54 was THE block to use, now I hear the webbing may be a not as robust for a for a 3100, and the N42 is better. Also what is the most popular piston everyone is using? 240SX , PU or aftermarket?

Thanks in advance.

Arnie

Very old picture of my car (10yrs?) minus all of the emblems that were stolen and put on a 200SX. The guy lived in my same apt. complex, IDIOT!

[Guest 280ZForce]

i was using a f54/p90 on my 1st turbo stroker engine, but now i've switched to a n42/p90 setup, havent fired it up yet.

 

i heard the f54 was the sh*t too, but then i researched and asked around and it seems the n42 will have more wall thickness so it should be more stout even after boring.

 

I'm running a 3.0L stroker turbo w/ Ross forged pistons, lightened, polish 9mm 240z rods. I hope your considering some extensive head work if you want to make the most of your stroker engine, especially since it's gonna be n/a and will depend on sucking in as much air as possible.

[ArnZ]

"extensive head work" didn't you mean expensive ?

[X64v]

ex·ten·sive - great in amount, number, or degree.

 

You will need extensive head work to make the most of a stroker, as 280ZForce said above. It could easily be expensive, but that depends on who you are and who you know.

 

And by the way, all of the questions you have asked regarding head choice, piston selection, block strength, etc., have all been discussed before.

[ArnZ]

I know they have been discussed and discussed to death, with no defiinitive answers (that I know of). I really wanted a poll, if there are numbers out there with what head is with what block . Please enlighten me with the link. I am nobody, and know nobody.

Thanks

[G.I.jonas]

Braap has taken the initiative already to tell all that needs to be known ever.

 

 

When it comes to making power N/A, displacement and RPMs are the rule. As much of both as you can financially afford is the key. The “bottom end” is where you build reliability and durability, the top end is where the power comes from. As for displacement, up to around 3.0-3.1 liters is doable on a realistic budget, but the cost curve starts a real sharp shift upwards from here, (this is where the V-8 conversions start to look real good. $$$ per HP, the V-8 swap is pretty hard to beat). As for RPM,s the weak link in the Datsun engine tends to be the crank, this is assuming that you have already installed good quality aftermarket rod bolts and the pistons are forged, not OE cast. Now if a good billet crank can be had, the rods are next in line. A good friend did some testing some years ago, (Carey M, if I misquoted you here, please jump in to clarify), and found that with as light a flywheel as possible and with a quality damper, i.e. fluid damper, the L-28 crank is good for 8500-9000 RPM, after that he was experiencing crank breakages at the rear of the crank. A billet crank should allow for more RPM.

 

Now, on to Datsun L-series cylinder heads…

The biggest air flow restriction in the Datsun L-series head is the valve curtain area, i.e. the region between the valve head and the valve seat when the valve is OFF the seat. In all my L series engine builds, unshrouding the valves is always the first place I start. Even on mild street heads, I perform moderate valve unshrouding. Next, if the head is a square port head and will be used in a race only application I’ll widen the bowl to slow down the flow of air in this region. This allows the exhausting gasses to transition from the vertical plane out of the chamber to the horizontal plane on its way to the header with less chance of loosing the laminar air flow across the port floor. In dong this, the laminar air flow across the port floor will remain, (keeps the boundary layer intact), if this laminar flow separates from the port floor you will now have turbulence and this will restrict air flow considerably. (you may or not be able to catch this on a flow bench as a flow bench doesn’t measure the dynamic air flow in and out of the ports. I’ll expand on that at the end of this post). If the head has the round exhaust ports with the liners, all I do is blend the back of the valve seat into the liner. All of the heads I do, whether for street or full race, also receive a nice 5 angle valve seat, (sometimes only 4 angles can be performed do to space constraints), that I perform in house here at Rusch Motor Sports using Sunnen seat cutters, (I’ll be offering radius seats soon), and the valves are treated to a 30 degree back cut and the exhaust valves sometimes even get a nice little 45 degree chamfer on the chamber side of the head. All this extra valve and seat work mostly benefits air flow at low valve lifts, i.e. as the valves leave and return back to the seat itself.

 

Here is my personal take on the L-series heads.

E-31 and the early E-88 heads with the E-31 chambers are decent heads. They have the same potential as the other N-series heads when rules permit extensive carving. My opinion is the best place for the E-31 and the early E-88 is for a restoration project, or for a performance application where class rules dictate no material can be added to the chambers, no carving can be performed on the head and the update/backdate rules apply to the engine as an assembly, then these heads are a great choice. Now if you are not bound by those kinds of rules, you do have other choices available and being as the E-31 is becoming so rare now, these other heads are an easier option from a financial and availability stand point.

The N-42 head is a great maximum effort race head if class rules allow extensive carving and welding to the head. In this case, weld the chambers, open the exhaust ports as described above, perform some serious valve unshrouding and “waa laa”, you now have a wonderful maximum effort race head that would SUCK on a street engine. (Side note; If you intend on having your valves unshrouded and have not done this type of work before, you are best served leaving this to a qualified experienced engine builder, preferably one that has been successful in extracting noticeable to impressive documented performance gains. If you are not sure what you are doing, do not attempt to unshroud the valves yourself. In experience can hinder the flow worse than what the heads were stock.) Of course there is more to building/machining/porting a maximum effort cylinder heading than just welding a chamber and/or unshrouding valves. There are items such as setting spring heights, clearancing the retainers, stem seals, and guides for the mega lift cam, deciding on just how far to go with oversize valves even to the extreme of offsetting the valve guides to allow even BIGGER valves if the cylinder bore permits, etc.

The Z car N-47 head is a great street head. This head becomes almost ideal for the mild to hot street engine and even the mild to moderate race engine especially if the chambers can be welded up, (pretty much turns this head into the Maxima N-47 head which is a slightly more efficient chamber than the E-31). This “peanut” or “kidney” shaped chamber when used with flat top pistons or matching* dished pistons gives the ideal quench area which makes for a more efficient combustion process. To make use of this “kidney” shaped chamber on an L-28 running pump gas you will need matching* pistons. What I mean by “matching* pistons”, is a set of custom pistons from JE or other comparable source that has CnC the dish directly under the open portion of the “kidney” shaped chamber, not the entire surface area of the piston as is the OE 1975-1980 L-28 and all L-28-ET pistons. Any how, with this ideal squish, the engines optimum ignition advance will be less than the open chamber heads optimum ignition advance due to the more efficient chamber design. This happens because the flame front doesn’t have as far to travel to consume the entire air fuel mixture within cylinder, it now is in smaller area so the flame front doesn’t have to travel all the way to the other side of the cylinder during the ignition sequence. To better understand this concept, just visualize the open combustion chamber as being a flat wide circular disc, the diameter of the cylinder itself containing the air fuel mixture with the spark plug on one side, vs a small kidney shaped ball containing the same volume of air and fuel. Ideally a sphere shaped chamber with the spark plug in the dead center would be perfect, since that isn’t realistic, tuners just try and get as close to this ideal as possible. Some engines came for the factory much closer to this ideal, ala HEMI heads, etc. As for those round exhaust liners in the N-47 and P-79 heads, they actually flow VERY well. The liners offer a nice gentle radius as the air flow transitions from a vertical flow out of the chamber to the horizontal plane where it meets the header which keeps the air flow moving undisturbed even at high velocities where as the square ports with their really sharp short side radius doesn’t allow the air to make that transition with as much ease. What happens is the boundary layer of air along the port floor can and will separate causing the air to slam into the roof of the port and tumble along the floor of the port when the velocity gets high enough. This is not a good thing in the quest for power as this turbulence is very disruptive to air flow. This why we make that region of the port, the bowl, larger in an effort slow down the air flow to keep that laminar air flow across the port floor. Of course this only happens at very high velocities. Also, all L-series heads starting in 1977 have a slightly smaller intake port volume. What the engineers did was cast one side of the intake port wall with a “flat” in it, “D” shaped if you will. This reduction in cross sectional area starts approx ¾ of an inch into the port. This port shape is supposed to help bias the air flow as it enters the chamber more towards the middle of the combustion chamber itself, steering away from the chamber walls is passes the valve head. In theory this helps to reduce some of the air from slamming into the chamber walls of the combustion chamber. I don’t have enough hard evidence to back up this theory, but I do feel that this port bias does not detract from the performance potential of the cylinder head one bit.

Now we get to the P-79 and P-90 heads. The combustion chambers of these heads are IDEAL, almost perfect once the valves are unshrouded. The only down side I see to the P-series heads, (and this down side is for the extremely radical ragged edge engines, not so much for the milder even hot race engines), is since the chambers are taller, (valves are now shorter as a result), the floors of both the intake and exhaust ports now have an even sharper short side radius and as stated previously, this is a detriment to flow as velocity increases. The transition from the horizontal plane to the vertical plane on the intake and vice versa for the exhaust, is not as smooth as the N-series and E-series heads. Now don’t take this as I am bad mouthing the P-series heads cause I’m not. I really like these heads for hot street and mild to moderate race applications. They are an inexpensive way to get the ideal squish using an OE flat top piston with a compression ratio compatible with pump gas. I have built several and will continue to build the P-90 and P-79 heads for street and mild race Z’s. What I’m saying in regards to the P-series from the stand point of building THE mega extreme N/A performance power house that is at the ragged edge of making useable power over a very narrow yet very high RPM range such as a best of the best N/A drag racing engine, these items should not be overlooked.

Maxima N-47 head. What a darling mild race head this is. For mild to moderate race engines on a budget, using flat top pistons in an L-28, or even opting for pistons with a slight dome for greater than 13:1 compression, this is my go-to head. Just have your machine shop cut out the old intake seats and install the larger seats for the 1.73” or larger valves, have a competent Datsun engine builder/tuner unshroud the valves, blend the exhaust seat into the liner, and “waa laa”, a moderately high compression ratio race engine that will perform rather well up to 8000 RPM with the right cam, induction, and exhaust system. With a set of custom pistons machined so that the dish is directly under the open portion of that gorgeous peanut chamber, this head, in my opinion, makes for the perfect street head or mild race engine that runs pump gas. At the moderate level of race and above, I tend to prefer the N-42 with welded chambers and opened up exhaust ports.

Now for that flow bench info I promised earlier on…

Since a flow bench cannot duplicate the dynamics that are happening within the intake and exhaust tracts while the engine is actually running, i.e. sound pressure waves, pressure surges, exhaust heat, fuel enriched intake charge, valve overlap extraction, etc, flow bench numbers are nothing that should be used for comparing one head to another or bragging how good one thinks their head is! The best way to use flow bench numbers is using the SAME flow bench to compare ONE cylinder head for improvement after modifications have been performed, making note of any changes in air flow whether improvements were made or lost, nothing more. Flow benches do not represent what is actually going on within the intake tract OR the exhaust tract as mention previously, i.e. Dynamic air movement, pulses, waves, heat, etc!!!!. In real life, the valves are opening and closing causing the air to stop and move, stop and move, over and over and being as air has weight and is compressible, this constant surging will cause the pressures to rise and fall FAR above and below ambient. Depending on RPM, runner length, runner cross section, port shape, number of bends in the port and radius of those bends, valve shrouding, air density, cam timing in relation to the piston movement, (this has a HUGE effect on how the air gets moving within the intake and exhaust tracts, hence lopey idles, hard hitting powerbands, etc), there could be higher than ambient pressures at a particular RPM, i.e. a natural supercharging effect, that is why intake and exhaust runner lengths are TUNED! We have all seen where almost all Nascar engine builders have achieved over 110% volumetric efficiency on a naturally aspirated 2 valve engine by tuning the intake AND exhaust tracts to a specific RPM with specific runner cross section and runner lengths. This tuning is taking full advantage of the Helmholtz principle. Your basic garden variety flow benches do NOT and can NOT duplicate this, I’m not even sure if there is a flow bench made that can do this. The only real measure of how good a port can make HP, is to mount that head on an engine and run that engine on a Dyno, (and this is what we are REALLY after right, HP! Not just some arbitrary static flow number through a head port)! An example would be if one head that on one flow bench indicates it will outflow all the others tested, when all are attached to equivalent short blocks, the high flowing head could easily make LESS power on the dyno, but then again change the configuration a little with a different cam, intake tract, piston some shape, etc, the results would get even more confusing.

Ok, I think I’m finished now.

 

[ArnZ]

I did read that thread. Braap knows his $#!* I don't know the man, and I don't know the people I talk to in person. I just want know who has what combo on the street now. Maybe there are too many varibles to ask this question and get the answer I want. I have done my homework and then some. I have scoured everything on the net. I am trying to to get a basic idea what combos are out there.

If you have a sroker L , please divulge your components. I don't need a why and how. Tell me what you have please.

Thanks,

Arnie

[Comrade_Charlie]

i was using a f54/p90 on my 1st turbo stroker engine, but now i've switched to a n42/p90 setup, havent fired it up yet.

 

i heard the f54 was the sh*t too, but then i researched and asked around and it seems the n42 will have more wall thickness so it should be more stout even after boring.

 

I'm running a 3.0L stroker turbo w/ Ross forged pistons, lightened, polish 9mm 240z rods. I hope your considering some extensive head work if you want to make the most of your stroker engine, especially since it's gonna be n/a and will depend on sucking in as much air as possible.

 

is there a link to a list of what years and what cars came with what blacks and heads like a 81 came with ? head and ? block, the search isnt working "The HybridZ database has encountered a problem." Im getting a 82 280 turbo im just trying to find out what it has...

[COZY Z COLE]

is there a link to a list of what years and what cars came with what blacks and heads like a 81 came with ? head and ? block, the search isnt working "The HybridZ database has encountered a problem." Im getting a 82 280 turbo im just trying to find out what it has...

 

 

http://www.geocities.com/zgarage2001/engine.html

 

Click on:

Performance tips for blocks.

Cylinder heads for heads.

[SUNMASTER]

N42 Block - N42 head - LD28 cranck - 9mm L16 conrods - KA24 pistons 89mm - adapter on front of the cranck with a BMW damper - ARP head , rod and main bolts - 1mm Headgasket -

 

This is what I have....

 

http://forums.hybridz.org/showthread.php?t=117468

[NZeder]

I know of 3 locally all using N42/N42.

[vegasnative]

just got mine out the machine shop 2500 dollars.p90f54 88mm ross pistons,9mm rods,ld28 crank all arp bolts,ati damper,fidannza fly wheel,head ported ferria 1mm over size intake and exhaust stage3 cam kit,gasket matched intake and exhaust, all balanced8.5 to 1 will be turbo

[ArnZ]

That's what I want to hear !

[vegasnative]

ross piston and rings 88mm 750.00,felpro gasket set 48.15,rear main seal15.13,rod bearings 23.70,main bearings45.42 shipping 26.00 these are the parts that the machine shop provided.hot tank block 48.00,mag block12.00,bore block to 88mm144.00,surface block185.00,line bore45.00,shot peen and balance rods156.00,grind crank110.00,ass short block145.00,balance short block 165.00,port head500.00,valve job210.00,surface head65.00,port ex and intake man100.00 parts i suppyed cam kit 589.00,ati damper419.00flywheel 389.00 valves289.00block and head250.00,crank250.00,rods100.00non webed intake80.00

[240zwannabe]

i was using a f54/p90 on my 1st turbo stroker engine, but now i've switched to a n42/p90 setup, havent fired it up yet.

 

i heard the f54 was the sh*t too, but then i researched and asked around and it seems the n42 will have more wall thickness so it should be more stout even after boring.

 

I'm running a 3.0L stroker turbo w/ Ross forged pistons, lightened, polish 9mm 240z rods. I hope your considering some extensive head work if you want to make the most of your stroker engine, especially since it's gonna be n/a and will depend on sucking in as much air as possible.

 

 

do you have proof that the n42 has more wall thickness?

[katman]

Before you run up to Suwanee to take your stuff to Sunbelt, you do know Sunbelt doesn't exist any more, right?

[JMortensen]

This is opinion, but your carbs are too small for a stroker. 44s or 45s would do much better. Search for threads by zredbaron. He built a stroker with a Sunbelt head and put 40s on it and I think he got 220whp out of it. Don't go too small on the cam either. You'd do yourself a huge favor to read those threads before you proceed...

[ArnZ]

Yeah, it is now Kinetic Sunbelt Engines on Holiday road in Buford. (The old Lazy Days Houseboat Factory)

I know that 40's are small. I plan on going bigger down the road.

[ArnZ]

So , no headwork with DCOE 40's, I am just pissing in the wind? I just want a little "hang on" factor.

[Mayolives]

Before you run up to Suwanee to take your stuff to Sunbelt, you do know Sunbelt doesn't exist any more, right?

 

Katman........Could this be so??? Is Sunbelt no longer in business?? Please tell us more.