Air Care Help?

New posts disabled. Archived technical discussion about the Datsun PL510
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Turn7
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Postby Turn7 » 04 Oct 2004 07:45

Thank Byron
spray bar it is! We actually tried the first one without and it didn't make it. I actually did get this can through air care... but after checking my records, it was with my single sidedraft Dellorto not my Dual webers. I am not too sure how well the dual Webers would do.
Brent

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jason
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Postby jason » 04 Oct 2004 08:03

banzai510(hainz) wrote:If this is a true Solex roadster then it will have the bigger cam. Maybe thats why is failing smog test. If a tuely Solex motor cam ect...
But my L18 with 44mm Mikunis and bigger cam passed no proplem in the day when I had to do it.

Good luck!!!!!!!


Yep, true solex roadster with a "B" cam. Not failing by much yet and it ain't over yet!

Thanks

Jason

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jason
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Postby jason » 04 Oct 2004 08:07

Byron510 wrote:The Solex version of the roadster had a bigger cam. Nissan labeled the cams A, B, and C, C being the biggest and the original one on the Solex version. Tuning the carbs is a bit of an acquired art. If Toyo can't help you out, I would suggest Andy at Specialty Engineering in New West. He is a magician at these things.
Byron

PS The key to passing air care is a smooth running engine. If the motor is stumbling or tripping, then this means a miss in a cylinder and that equals unburned fuel going out the exhaust - and you emission readings go through the roof.


Thanks for the tip off for Specialty, I was wondering who in town beside Carl could work on these carbs. I still haven't found much on tuning them either, any books to suggest? I knew that the carbs weren't synched properly though before I went in, the engine does run a little unevenly after the tune up. Ah well off to work.

Thanks

Jason

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jason
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Hah, I passed with Toyo's help!

Postby jason » 07 Oct 2004 20:57

Got a clean pass after Bob at Toyo tuned the solex's and retarded the ignition slightly. Didn't have to use any of that Mohawk 94 either, just the real canadian superstore 91 octane premium! All readings are down by 50%. Boy thank god for those guys at Toyo.

Thanks for all the help.

Jason

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Byron510
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Postby Byron510 » 07 Oct 2004 21:15

A little tuning can do wonders, this is where that last 5% of the power comes from on race cars. We tend to foget this on our street cars, but all that fussing around really does make a diffrerence.
BTW, set the timing back to where it should be now that you have passed air scare!! Get that few extra HP.
Byron
Love people and use things,
because the opposite never works.

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jason
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Postby jason » 07 Oct 2004 21:28

Byron510 wrote:A little tuning can do wonders, this is where that last 5% of the power comes from on race cars. We tend to foget this on our street cars, but all that fussing around really does make a diffrerence.
BTW, set the timing back to where it should be now that you have passed air scare!! Get that few extra HP.
Byron


Timing is now set for 16 degrees, should be ok, now I'm gonna get the cheapest 1 yr insurance possible (then I'll upgrade it in the spring) because the beast is gonna be in the garage for most of the winter! Now I get to figure out how to tear down the U20, anyone got a cheap engine stand for sale?

Jason

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Postby 510rob » 08 Oct 2004 00:43

...can you explain...the difference between the 445 and the 780?
...As a side motive, i am thinking about going with less cam...


To pickup where Byron left off, and just for the record, so it's available to everyone who may ever want to see any of it...

The following notes are the result of my chat with Barry at Shadbolt Cams, August 20, 1998

With regard to the L-series Datsun...
Streetable Regrind : $120
Track Regrind : $160
Extreme Regrind : $200
The price reflects the amount of material to be removed from the base circle. i.e. even just the 445 profile requires 0.060” to be taken out of the base circle on the backside.

445 Profile:
Duration: 280 degrees (30-70-70-30)
Overlap: 60 degrees
Lift: 0.507” at the valve
"Good for about 7200 rpm max"

449 Profile:
Duration: 256 degrees
Overlap: xx degrees
Lift: 0.492” at the valve
"...?..."

651 Profile:
Duration: 296 degrees (38-78-78-38)
Overlap: 76 degrees
Lift: 0.487” at the valve
“...this never worked as well as it should have worked; Andy said if you already have a 445, don’t waste the time of putting one of these into your head; it isn’t worth much more” - Barry referring to Andy from Specialty Engineering
NOTE - From a conversation years later (late 2003) with Geoff Bardal from Colt Cams said, "I never liked the 651, because it's numerically almost identical to a worn out 445 with it's lobe tip worn off, so pick either a 445 or a 780 instead"

780 Profile: The Datsun Radial Challenge Cam (DRC)
Duration: 304 degrees (44-80-80-44)
Overlap: 88 degrees
Lift: 0.522” at the valve
"Should be good for more than 8000 rpm easily"

The mild TURBO Profile: 445 Intake, 449 Exhaust
Intake = 280 degrees @ .507 lift
Exhaust = 256 degrees @ .492 lift
Total Overlap : 48 degrees (VERY low overlap)
Lash: 0.008” Intake, 0.012” Exhaust
"...has very low overlap, early exhaust opening and intake closing..." - Barry

"...there is not much growth in those motors (L-series), maybe 0.001”...Give it 0.009” & 0.013” respective & then check it when it has warmed up..." - Barry

Also, for those of you who don't know the Colt Cams story, after well over a decade (maybe even two decades, but I don't remember what number he said it was) of service at Shadblot, Geoff Bardal broke out on his own to start Colt Cams in Langley BC (http://www.coltcams.com) and is the guy who ground most of the Datsun L-series cams while Shadbolts were cranking them out in the Datsun's heyday because after all, Geoff used to run a L-series himself.

Barry’s (from Shadbolt) version of cam theory with respect to turbocharging...
"...you don’t want too much overlap because the cool intake charge will blow right through the motor and cool off the turbo..."

Later note - Sean Kearny had a “721” grind (45-81-81-45) which he says is 0.582” lift with 306 degrees duration which is purported to be a copy of the Racer-Brown model 391-R from page 54 of the later Steve Smith book.
Last edited by 510rob on 17 Oct 2004 23:03, edited 1 time in total.

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bertvorgon
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Postby bertvorgon » 09 Oct 2004 16:03

Yup!!!! I am going back to my original turbo cam. I lost more than I gained. If I want top end...I have the bigger TURBO to put on. Then look out..........WHOOOOOSSSSSHHHHH

(Professional driver, closed course!) My legal dept says I should put this on now!
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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bertvorgon
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Postby bertvorgon » 16 Oct 2004 09:00

Hello Rob, I was wondering what he meant by this statement...did he mean adjust the valves COLD? I know I always adjust valves hot. Also, what did he mean on the 651 that it is just a 445 with the lob tips worn off. As I head back to my original cam, I am just wondering about a few things.
"...there is not much growth in those motors (L-series), maybe 0.001”...Give it 0.009” & 0.013” respective & then check it when it has warmed up..
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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bertvorgon
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Postby bertvorgon » 18 Oct 2004 07:12

Hi Rob,
I dragged out the 510 Bible and re-read the Racer Brown section on cams. ( not that I understand all of it) but, I think he is spot on on the Turbo cam. I really think I am doing the right thing going back to that original grind. Note to everybody out there...DO NOT OVER CAM YOUR MOTOR!!
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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rnorrish
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Postby rnorrish » 18 Oct 2004 07:42

did something happen?
richard norrish
'68 'goon resto / '71 ice racer / '72 'goon project / '70 4-door rust pile / '67 520 project
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shardik wrote:My swap will be made of solid gold and it will run on puppy farts.

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supersportsedan
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Postby supersportsedan » 18 Oct 2004 08:24

I think the problem was that nothing was happening..... until 7000rpm! :o

510rob
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Postby 510rob » 18 Oct 2004 08:51

Richard
The new cam that Geoff made up for Keith had waaay too much overlap, and the intake closed waaay too late - ergo, too much duration, ergo, totally overcammed. The late intake closure relies on intake mass to develop cylinder filling rather than just atypical cylinder pumping action - you don't get proper intake resonance until you are well above the lowrpm to midrpm... and until you get up "on the cam", you will have terrible standoff, and as Keith said, with the turbo box off, there were 6" fountain sprays of fuel misting out the top of the carb when they tested the really bad cam...
RF

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rnorrish
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Postby rnorrish » 18 Oct 2004 17:36

oh, i see.
i must have missed some other story.
i thought everything was a-okay this summer...

and i'm assuming boost is too low at this point to overcome this problem... but when it does, weeee!
richard norrish
'68 'goon resto / '71 ice racer / '72 'goon project / '70 4-door rust pile / '67 520 project
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shardik wrote:My swap will be made of solid gold and it will run on puppy farts.

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bertvorgon
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Postby bertvorgon » 18 Oct 2004 20:04

What Rob said! I think I was WISHING everything was ok! The Wheee factor was great, But, the ARG factor was greater. I never did have any real problem getting to redline in 5th..it may not have been EFFICIENT..but redline in 5th is still redline in 5th!!! When I found I could NOT launch my car, at what I would call a normal SOLO start, that was the final straw.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer


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