L24 build questions

[rayaapp2]

dont know why it keeps double posting. I only click once... grr

 

 

So Pistons: What do you guys choose to run on your builds. Im pretty set on some flat top JE pistons with the thermo sealed crowns and tuff skirt coatings(no breakin stuff on them). I would be open(and would prefer) a set of hypereutectic pistons vs forged, but no one makes them for an L that I have ever found.

 

What you guys think...

Edited December 7, 2010 by rayaapp2

[NewZed]

 

It seems to work for me, I have a DCF5-02 in my car with 17 (8.5 reported at the dist.) mechanical at 2500 rpm and 18 (9 reported at dist.) vacuum at 11.61" (295 mm) Hg. I'm running 17 static, so I'm at 52 and 34 (Edit - SHOULD be at 52 and 34, I don't have the right timing light to confirm), cruise and WOT, above 2500 rpm. I've heard not a knock or ping with 89 octane, but it is kind of cold here. I worked my way up a few degrees at a time and the engine got more responsive every time. I have a stock 1976 with EFI, but using a 1978 distributor.

 

I'm just throwing all of this out there for conversation, and might be repeating something already well-known, or maybe even wrong. It took me a while to figure out what was up with the various distributors and how the specs. were reported.

 

I put some misinformation out here and don't want to steer anyone the wrong way. With the above setup, I did get light pinging at ~2000 rpm, low-load (high vacuum). The combination probably has timing up in the low 40s at those conditions (17 static + 18 vac. + mechanical = too much). I went back to a 1976 vacuum canister (15 degrees of vac advance) and it's still there. I dropped two degrees of static advance and all seems good now.

 

15 static, 1978 mechanical advance (17 total) specs., 1976 vacuum advance (15 total) specs. Putting this out there for anyone watching, that might still be messing with distributors.

 

I'm stating to see why programmable EMS are so popular now.

[rayaapp2]

I have spoken to Dave Robello about some JE pistons for what Im planning on the bottom end. JE directed me directly to him rather than speaking with their own techs... hahaha

So I believe I have that worked out.

 

Lets talk about Cams as well,

 

First off Im going to restate that I do not have a broad knowledge base from which to make any decision here that would be anything more than a random guess as far as camshaft selection goes. That being said I have contacted 2 cam companies about my build. Delta and Webcams.

 

Delta has offered up their 272-2

Specs are as quoted

 

"225 duration int

230 exh

.464 lift

110 lobe seperation"

 

Which I must say is lacking in description, but their response in that regard was:

"those specs are what they will need to set spring pressures, and flow info.

The opening and closing events are not supplied due to too many variables. lash, follower geometry, milled head, surfaced block, all of which will move those events" So I guess its a secret... I have no idea if those specs for duration is at .006" or .050". I cant determine very much at all about this cam except for lift and it seems a bit small for my taste(again guessing here).

 

Next we have Web Cams

115 regrind

I_________E

.007"_____.011" Valve lash

.488"_____.488" Valve Lift

12.4mm____12.4mm Valve Lift

252°______252° Advertised Duration

230°______230° Duration @ .050"

108°______108° Lobe center

109.5 Separation

IO 11°BTDC

IC 50°ABDC

EO 47°BBDC

EC 8° ATDC

 

91 regrind

I_________E

.007"_____.011" Valve lash

.450"_____.45011" Valve Lift

11.43mm____11.43mm Valve Lift

260°______260° Advertised Duration

238°______238° Duration @ .050"

108°______111° Lobe center

109.5 Separation

IO 11°BTDC

IC 47°ABDC

EO 50°BBDC

EC 8° ATDC

 

I think Im still looking at cams here that dont suite what Im looking for though. Ive been comparing these specs with the stock A and C cams specs which is what I have now.

 

I have yet to contact Schneider about a re-grind. Im not sure who else other than Schneider that I could contact to see whats available.

 

Id like to set the redline at 7500rpms and start making good power at 3000rpms as long as there is something down below that to get moving from a stop sign without riding the clutch.

The car isnt a daily driver, but does drive on the street.

I have been reading through this CLICKY

 

Add this Sticky to the list as well... Very good stuff in this STICKY CLICKY "NA 3.1L=>head & camshaft questions. No shortcuts, max"

 

I have read the Racer Brown writeup several times over. Its very basic information in there, but it seams to help give a little insight into old cam designers heads.RACER BROWN

I believe Racer Brown would classify my build as "weekend warrior". For anyone still wondering what Im looking to build.

 

"It was stated earlier that small displacement engines need all the torque they can get, particularly at lower engine speeds, and if this is a factor, long duration, very high lift camshafts are O-U-T. They're great for strictly race engines. But for a street-driven vehicle they'd need a road map to fall out of a tree…and probably a push to get them started."...

"In the area of camshafts for such applications, effective duration should be in the low-to-mid-260 degree range with 44 degree - 48-degree overlap. A camshaft assembly must include special valve springs, spring retainers and lash pads of the correct thickness. Usually, this type of speed of around 7,500 RPM; but it may require notching the pistons for the required piston-to-valve clearance"

Datsun camshafts & valve timing by Racer Brown

 

I havent contacted Isky, or Schneider yet about their regrind specs or prices. I am also planning on speaking with Dave Robello about cam choices and see what he recommends, but I dont feel qualified to make a choice even if I talk with anyone about what they recommend.

 

Id love to be able to just hand these guys my specs and not rely on them to interpret my needs since they all seem to have a habit of under recommending (and with good reason as I understand it).

Edited December 19, 2010 by rayaapp2

[ktm]

Isky does regrinds. I had them regrind a P90 cam to their L490/L480 assymetric turbo grind - $125 (IIRC) picked-up. However, he does N/A grinds as well.

Edited December 18, 2010 by ktm

[rayaapp2]

I dont have any way to do the math(as in this may be a fanciful, un-realistic, un-acheivable grind), but I think what Im looking for will be something like:

.480"-.490" lift

265ish degrees duration @.006" and something like 245ish @ .050" hopefully a usable ramp angle here for L series rockers.

Lobe Seperation of 110

 

A fellow HybridZ'r sent me some info about Rebello and this is a paraphase of that quote.

 

Rebello regrinds .485" lift grind that behaves a lot like the .525†lift over the counter grinds in the upper rpms yet still produces great low end midrange grunt for pulling out of the corners pull. He went on to say that it is one of the close lash grinds.

 

So Im going to speak with Dave about cams. I wasnt aware he didnt outsource his grindings. Im almost afraid to ask price when it comes to Dave Robello's parts or work. This isnt a track car and Id like to create a reasonable budget. I was also going to speak with Dave about his crank trigger dampeners. I have already had a conversation about JE pistons with him. I have a feeling I will be dropping $1600+ with him alone just for a few parts. I am also awaiting quotes for cylinder head work.

 

Im still up in the air about changing the rotating assembly out to an L28 or keeping it as a L24 assembly. More stroke = more torque which is my focus. I was half tempted to use the LD crank, but I dont have any more of them and they are expensive to source these days. There is also the fact that they are not a simple drop in, in a P30 Block.

I checked my HKS gasket and its a 2mm X 90mm bore... It was okay for my F54 87mm flat top P90 turbo setup, but not for a 85 or 86mm bore L24 that Im trying to get 9.5:1 compression out of. I put an add up to see if I get any bites on trading it for a more reasonable MLS gasket.

[ktm]

Again, check out Isky. He has a 290 duration cam, 242 at 0.05 duration, with a lift of 490. I did not see the LSA, but if you supply him with a stock core that has a LSA within 2 degrees they should be able to get a 110 LSA cam.

[rayaapp2]

His Catalog is viewable online, I did have a look. I havent had a chance to make any phone calls yet today. Its hard to make phone calls when you dont have a land line and you sharing a cell phone with your wife cause you broke yours last night...

 

ISKY

 

GRIND L490

ADVERTISED DURATION 290°

.050 DURATION 242°

LIFT .490"

Valve Lash .010/.012

INTAKE 36-74

EXHAUST 74-36

 

Isky calls this a stage III cam... I dont know anyone that can describe this cam to me. Your obviously running a Turbo grind so it would be different lobe separation and such.

 

The ramp angle on that thing looks insane!

There is something odd about the the last set of numbers which I take to be opening and closing events.

I would be surprised if either the L480 or the L490 were refined to max potential... They look like they were plotted on paper to look pretty on a cam card. But I must again say I really dont know much of anything about cam design.

36 BTDC IO

74 ABDC IC

74 BBDC EO

36 ATDC EC

leaving you with an amazing 72 degrees of overlap on the L490 and 62 degrees on the L480. That doesnt add up correctly. There are 38 degrees of overlap on a "C" cam and 30 degrees on an "A" cam. Most of the aftermarket stuff has less overlap and the more cam you get the more overlap they seem to cut out.

 

Im really liking the tight clearance valve lash though. Im willing to bet that the Robello cam has interesting valve spring specs... like single valve springs and less spring seat pressure and still be able to function at high rpms... So far all I can elaborate is less wear on everything but the lash pads and cam surface. This would be an ideal setup with rollor rocker arms... (yes roller rockers are most definitely out of my price range)

Edited December 21, 2010 by rayaapp2

[30 ounce]

I'm using the Isky 490 cam. The idle is a little rough but it works fine around town. Isky recommended 11.5:1 compression to keep power in the lower rpm range (I live at 5280 feet elevation). There is definitley a step up in power at 4000 rpm's and it pulls strongly all the way to 7250 (probably more if I had the nuts). Rebello uses Isky springs. My engine is a Rebello 3.0 liter.

[240zip]

30 ounce ... I see you're in Milliiken. I'm down the road in Mead. I'd love to see your Rebello 3.0 in person.

[240zip]

 

It was out of my price range at $150-$200 though Im sure thats what they can go for, I was just ultra broke at the time.

 

 

 

Those Sun distributor testers can go for upwards of $2000 ... if you see one for $200, let me know. I'd be happy to buy it and let you use it.

 

http://paramountd.com/sale.html

[rayaapp2]

 

It was out of my price range at $150-$200 though Im sure thats what they can go for, I was just ultra broke at the time.

 

 

 

Those Sun distributor testers can go for upwards of $2000 ... if you see one for $200, let me know. I'd be happy to buy it and let you use it.

 

http://paramountd.com/sale.html

 

Wow, unfortunately I have lost contact with the guy that had it. He had a bunch of other junk he was trying to pedal off and that was the only thing that was worth looking into. Stuff like a BAR84 machine that was in pieces. The guy moved from down the street from my in-laws in Sacramento Ca to somewhere up in Oregon. Ill give him a call and see if I can reach him after the holidays if you want, but no promises he has it still or I can even reach him.

[Tony D]

Isky calls this a stage III cam... I dont know anyone that can describe this cam to me.

 

His name is "Ron" he works at Isky, ask for him when you call for 'Technical Assistance'...

 

Does this really need to be said?

 

As for "Lobe Center"---how do they define it. As you see on the Isky Grinds a proper assymetric grind will have some very strange characteristics, and you have to get defined what the individual grinder calls 'lobe center'.

 

Rebello uses Elgin grinds, and if you call Elgin you will be directed to Dave. Dave will not give specifics. Been there, done that.

 

Curious how much overlap Isky has huh? Matches well with what Racer Brown had to say? Street Engine?

 

Seriously, Talk with Ron, Ray. You will come away amazed. Tell him what you want, and what you have, and then listen and learn.

 

Oh, and all the Roller Rocker compnents, drawings, and technical/engineering data formerly at Malvern Racing are "out of circulation" with someone on the board who is working with several manufacturers on development of cams for some applications. FYI the Roller Rockers used at Malvern were not 1.5 ratio, either, so the numbers for that cam would in no way be comparable to anything you had for stock rockers.

Edited December 21, 2010 by Tony D

[30 ounce]

240zip: You have to drive it. It looks totally stock. (see my pics) I sent you my #. Call me.

[rayaapp2]

His name is "Ron" he works at Isky, ask for him when you call for 'Technical Assistance'...

 

Does this really need to be said?

 

As for "Lobe Center"---how do they define it. As you see on the Isky Grinds a proper assymetric grind will have some very strange characteristics, and you have to get defined what the individual grinder calls 'lobe center'.

 

Rebello uses Elgin grinds, and if you call Elgin you will be directed to Dave. Dave will not give specifics. Been there, done that.

 

Curious how much overlap Isky has huh? Matches well with what Racer Brown had to say? Street Engine?

 

Seriously, Talk with Ron, Ray. You will come away amazed. Tell him what you want, and what you have, and then listen and learn.

 

Oh, and all the Roller Rocker compnents, drawings, and technical/engineering data formerly at Malvern Racing are "out of circulation" with someone on the board who is working with several manufacturers on development of cams for some applications. FYI the Roller Rockers used at Malvern were not 1.5 ratio, either, so the numbers for that cam would in no way be comparable to anything you had for stock rockers.

 

For Racer Brown, I was looking specifically at what he had to say about street engines and "warrior weekend" engine builds. I was actually wanting to compare all the available grinds including the stock "A" and "C" cams... mostly out of curiosity.

 

Everybody's so secretive about their cam grinds with these Datsuns... I dont get it. If you want a V8 Chevy or Ford, the cam specs are available and usually included in the box with a cam card that gives info about the cam as installed "straight up". There are still aspects of the cam profile that do not show up on a full cam card so its not like they are giving up the secret sauce? Right?

 

In any case, As soon as normal business resumes this Holiday season I will be calling up Ron. Sounds like the kind of person I have been searching to talk to(fingers crossed). Ive been meaning to call Isky for a while now(before ktm mentioned them I BRAAP recommended them and I had been reading a few old threads about cams). Ive been out of town without a working phone for a while now. When I get home my sim card is going into my backup phone(yes Im that prone to doing this) and going on standby for normal business hours. lol

Edited December 24, 2010 by rayaapp2

[rayaapp2]

IGNITION SYSTEM

Crank Fire With Distributor

 

 

It looks like a crank fire ignition system is about $350 on the low side.

Ive only had about a week of messing around on the computer with non-mega squirt style EDIS systems so I may be going about this all wrong. EDIS appears to be the most inexpensive route and the most common for the average joe such as myself. Feel free to put me in my place as always guys.

 

If I go this route(which is my preference) I would like the run the L6 EDIS system. The problem is that I do not want use the coil pack. The other problem is that I will need a driver still to do timing curve and such.

 

So as with the rest of this thread this is a design it out and figure costs of the system to make it workable.

 

The best solution so far looks to be a system called Megajolt Ver 4 made by Autosport Labs(or at least sold by). This unit costs $162 plus shipping. That actually seems reasonable when comparing to others like the MSD 6AL-2 at far over $200.

 

EDIS ideas part 1

 

EDIS ideas part 2

 

EDIS Mega Squirt

 

EDIS Mounting Solution #1

 

So provided that no one has a better solution for the price here is what I can come up with.

 

Using the Megajolt system and the Ford EDIS system my 240z would require the tach adapter mod addressed here as I have a current driven tach. There are other ways of doing this as well, but I like this one. The goal here would be to retain as stock a looking car as possible.

So the big problem of using a coil pack needs to be addressed. My first thoughts here are to gut the stock distributor and weld/braze the drive shaft and rotor shafts together. Basically it will look like the inside of an 81 turbo dizzy. So this only leaves rotor to cap air gap as an ignition issue, which for what Im doing should not be an issue... I just need a good coil(which I have not addressed yet).

The next issue with using just one coil is that the Motorcraft EDIS unit has 3 outputs for the coil pack. I'm almost positive these signals are NOT amplified. The Motorcraft coils must have an internal amplifier. So the key is to rectify the 3 signals into 1 and amplify the signal. This will most likely be the hardest part, but I don't see another way to retain the stock looking distributor. I can hear everyone already: telling me to just use the coil pack. The extra work isn't worth it A rectifier bridge ran to an amplifier piggy backed onto the EDIS unit should pull this off. I just don't have specs yet to build this circuit and I don't know if I could design this one correctly. I think I could build a basic rectifier that would handle the situation, but ignition amplifiers/ignitors require a lot more thought and experience than I have. I have that MSD 6A that I could use as the ignitor/multispark, but I have no idea if thats a good idea or not. This only works though if the EDIS fires each signal wire with DCv though which I have not verified. This of course would delete the waste spark function.

 

Then there is the fact that my car is running a dealership installed AC system and Air Injection still. I dont plan on taking these items off the car. The old York compressor and a few other things will be getting replaced with a rotatory style R134a retrofit during this build as well. So the Air Pump and a AC compressor is installed on the driver side of the block(no im not running the one that goes over the fuel pump). This means my front balancer has an extra pulley on the front and and a fan clutch extender. All this adds up to a special crank trigger install. I don want to delete my timing plate to do this. Derek's balancer and sensor mounts wont work from what I have gathered. I think the reluctor wheel will need to be mounted on the backside of the balancer pulley or a complete redesign of my belt system is a must. Maybe one of those 3 or 4 groove belts would be optimal, but Im not spending a ton of money to convert over to that. I think that is going way to far down the rabbit hole for now.

 

 

My probably overly-complicated and yet still incomplete ignition circuit.

 

Edited December 24, 2010 by rayaapp2

[NewZed]

This guy's approach is interesting - http://forums.hybridz.org/index.php/topic/90889-wasted-spark-ignition-no-edis/

 

Instead of holes and Hall effect, you could drill and tap for bolts, grind the heads and create teeth on the engine side of the flywheel, so you could use the VR sensor and the Motorcraft EDIS unit. A lot of work (not too much if you went 6-1 like he did) but would allow you to stay away from the front end of the crankshaft, but get the same result.

 

No comments on wiring the three signals together and running one coil. Not my bailiwick...

[Tony D]

Everybody's so secretive about their cam grinds with these Datsuns... I dont get it. If you want a V8 Chevy or Ford, the cam specs are available and usually included in the box with a cam card that gives info about the cam as installed "straight up". There are still aspects of the cam profile that do not show up on a full cam card so its not like they are giving up the secret sauce? Right?

 

You make a statement prematurely, before talking to Ron. That conversation can take 10 minutes, or an hour and 58 minutes...

 

Cam card specifications are usually the only indication to tell you if it's installed correctly, I haven't bought one cam for a Datsun yet that did not come with that same cam card. Each person or grinder has they way they want it set up. This is from familiarity to them, and obfuscates the direct comparison with other manufacturers. If they use their own standards, then their marketing can say what they want. If everybody used the same specification, they would actually have to compete on performance or explain why their specs make more power than someone elses... There's enough theft of ideas going on in that arena now, no need to make it easier!

 

Like Frank found out on his last visit while talking to Ron: There's plenty of stuff that is NOT in the catalog. As Ron says "Don't bother with those, we have plenty of stuff bigger! Do you have a problem cutting your pistons for valve clearance?"

[rayaapp2]

I know that Im going to have to have valve reliefs. Hopefully some modeling clay and triple measurement will get it right.

 

My head, and planned piston height are to close with the gasket I think Im going to end up with(Nismo .6mm)

Edited December 24, 2010 by rayaapp2

[rayaapp2]

apparently the EDIS module has the ignitor units built into it so my idea wont work as wired above.

 

Someone have some valuable input here for setting this thing up so it looks like I have a functioning distributor?

[Dan Baldwin]

My thoughts:

 

Start with an L28. Displacement is your friend...

 

No need to spend much on ignition, a good 280Z/ZX electronic distributor or 240Z dist with Pertronix Ignitor in place of points, a good coil and you're set for what you're doing (performance street build). You might modify the mechanical advance mechanism to allow more initial advance without overadvancing. I partially filled in the advance slots in my 240Z distributor to limit mechanical advance to ~18degrees.

 

No need for forged pistons, stock will be fine for what you're doing.

 

10:1 shouldn't be a problem with a stock cam, 10.5+ with a hotter cam.

 

In the ~10.5:1 CR range with a <.5" lift cam, you shouldn't need valve reliefs machined into the pistons.

 

 

My .02...