Stroker Poll

Tech tips and how to's

Moderators: notoptoy, garth, S Allen

Any interest in gathering stroker data to share with all?

Yes, I will submit information soon.
30
65%
Maybe, let me get back to you.
14
30%
Naw, a big waste of time-move on.
2
4%
 
Total votes: 46

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peter
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Re: Stroker Poll

Post by peter » Tue Mar 25, 2014 5:20 pm

The cam came from Dean and he didn't gave me special valve adjustments. I adjust the cam like the original one on the dots on the both gears.
I didn't try to make the settings tighter.
Hitting the valve seals, I will look at that tomorrow too, thanks.
Daryl Smith wrote:Peter,
One of the Cams I tried recommended .012" - .015" Valve clearance setting in my stroker.
Did your cam come with a recommended valve clearance?
I set it at .015" cold, and it is reasonably quiet with an iron head, and stock rockers.

Also, if you have the valve cover off again, check that the valve retainer is not hitting the valve seal, as this happened to me once upon a time...... :roll:
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Gregs672000
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Re: Stroker Poll

Post by Gregs672000 » Tue Mar 25, 2014 7:44 pm

I'm glad that others who have more R engine experience are chiming in!
Greg Burrows
'67 2000 #588
Tacoma, WA

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peter
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Re: Stroker Poll

Post by peter » Wed Mar 26, 2014 8:46 am

I checked today my valve springs and found out that under maximum opening only 0.0098" have left between every coil.
I can't press the valve deeper.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Solex68
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Re:

Post by Solex68 » Wed Mar 26, 2014 9:43 am

SLOroadster wrote:I'd love to see the same thing done for the U20 but since hot U20s are few and far between, I don't think its really worth it.
I'd like to see something similar with U20 Solex Jetting.
Greg a.k.a SOLEX68 - http://www.datsunvents.com/
Laguna Hills, CA
68 2000 U20
Always willing to help another Datsun Roadster owner
Pending installs: SS brake lines, Stan Stealth Dizzy, Denso TT plugs

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Gregs672000
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Re: Stroker Poll

Post by Gregs672000 » Wed Mar 26, 2014 12:00 pm

peter wrote:I checked today my valve springs and found out that under maximum opening only 0.0098" have left between every coil.
I can't press the valve deeper.
I really don't know at what "spec" a valve spring is considered to be "coil bound" but I would THINK that having any clearance would be enough. I'll ask my machinist... Left a message for him...

So you're saying that when the cam is on the maximum height of the lobe and the valves are adjusted to spec, the spring has .0098" between each coil, correct? What valve lash or adjustment spec are you using?
Greg Burrows
'67 2000 #588
Tacoma, WA

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peter
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Re: Stroker Poll

Post by peter » Wed Mar 26, 2014 12:25 pm

I use now 0.40mm hot for both, I saw somewhere that the coils must have a space of 0.70mm.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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spl310
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Re: Stroker Poll

Post by spl310 » Wed Mar 26, 2014 12:45 pm

If you show some space, but cannot push the valve down any further, then perhaps the retainer is bottoming out on the guide.
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Gregs672000
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Re: Stroker Poll

Post by Gregs672000 » Wed Mar 26, 2014 1:12 pm

Ok, talked to Steve; minimum is .050". With the rocker fully depressed by the cam you should still be able to see through the spring. Are you sure you didn't mean .098"?

Also, here is an easy way to adjust the valves on a pushrod engine. It took me a bit as I'm usually focused on watching the cam etc like on a U20. First, write out 1, 2, 3, 4, 5, 6, 7, 8 on a line to represent the valves in the head. Then, draw a line between 4 and 5. This splits the head in two, fore and aft. They are a mirror of each other. Now, spin the engine (if needed) until one valve/rocker is clearly fully depressed down, let's pretend it's #2. The valve to adjust then is its mirror, in this case #7. Continue on, let's say the next valve depressed is #6; it's mirror is #3, and so on. Put a mark next to each valve you adjust and you'll be sure to do them all. He also suggests about .012-.014" for valve lash, and you can go a bit tighter if they remain noisy.

If you have coil bind, see if there are too many shims under the springs or valve seals.
Greg Burrows
'67 2000 #588
Tacoma, WA

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peter
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Re: Stroker Poll

Post by peter » Wed Mar 26, 2014 1:27 pm

no I really saw that it is 0.0098" is what left when the valve is down, you can't look true the valve spring.
I do it like this: when cylinder 1 both rockers want to change in and out to tumble, cylinder 4 both valves are free to adjust. this is correct isn't it? and the same for cylinder 2 and 3.
I spoke to dean too, and he told me that the stem seal could influence it, but I let the stem place milled around the stem.
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Gregs672000
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Re: Stroker Poll

Post by Gregs672000 » Wed Mar 26, 2014 4:20 pm

Well, if that .0098" is accurate, and you cannot see through the spring, you have a coil binding situation that must be addressed immediately! Hopefully you have shims under the spring or stem seal (if using "sombrero" or hat style seals, which are typically used). Unfortunately, if you don't have any shims, then the head has to come off and machining done to fix the problem. That's why I wanted to confirm that number. Perhaps you can post some pics showing the spring compressed before you tear into it. I want to be sure before you start disassembling things on my long distance advice!

Steve mentioned that any clearance work would require removing the head. I assume the head would need to be machined on top where the spring sits to gain some clearance.

Was this a stock head? Custom valves or stock? The cam didn't sound that radical, but actual specs are hard to come by unless they reference lift at "50thousands". Others must have run this cam from Dean before; what's been their experience regarding stock springs?
Last edited by Gregs672000 on Wed Mar 26, 2014 4:28 pm, edited 2 times in total.
Greg Burrows
'67 2000 #588
Tacoma, WA

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peter
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Re: Stroker Poll

Post by peter » Wed Mar 26, 2014 4:28 pm

I have used the sombrero seals, and there are no shims under.
I need probably new springs, but where to buy???
Image
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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Gregs672000
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Re: Stroker Poll

Post by Gregs672000 » Wed Mar 26, 2014 4:41 pm

So there's no shim under the spring or under the seal eh? I assume these are stock springs? Spring height/number of coils and seat pressure are the two main specs I think. That, and physical dimensions of course. Again, I'm sliding outside of my knowledge base. You don't want a spring too stiff as it will wear things, too weak and the valve can float at high RPM. I really don't have any suggestions as you're going to have to factor in the lift of the cam, spring height and seat pressure of the spring. Unless you know how to do all this, I think you'll be talking to a machinist!

Perhaps someone like Isky will have some suggestions on springs? I think they list cams for the U20 at least. Others who race R engines may also have some suggestions... Try a separate post (?).
Greg Burrows
'67 2000 #588
Tacoma, WA

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peter
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Re: Stroker Poll

Post by peter » Wed Mar 26, 2014 4:45 pm

This is the original spring size, I hope a machinist can tell me more.
I contact catcams.com

Valve spring free length - outer - 49.0mm (1.93in.)
- inner - 50.0mm (1.97in.)
Valve spring pressured length (valve open)
- outer - 30.4mm/61.1kg (1.19in./134.4lb.)
- inner - 28.7mm/21.3kg (1.13in./46.9lb.)
Valve spring assembled height (valve closed)
- outer - 39.0mm/30.0kg (1.54in./66lb.)
- inner - 36.9mm/13.1kg (1.45in./28.8lb.)
Valve spring effective turns - outer - 5
- inner - 6.5
Valve spring wire diameter - outer - 4.267mm (0.1822in.)
- inner - 2.8mm (0.11in.)
Valve spring coil outer diameter
- outer - 33.734mm (1.328in.)
- inner - 23.95mm (0.943in.)
Horsepower is how hard you hit the wall,torque is how far you take the wall with you.
Datsun Roadster '66 #7000 Sora Blue, restored 220 Hp and 340 Nm

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msampsel
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Re: Stroker Poll

Post by msampsel » Tue Jul 15, 2014 6:42 pm

A little rusty on all the info on this pushrod 2 liter (or stroker) completed in 1975. I'm older now :lol: :)

I still have the car too. A friend rebuilt the engine for me (he had a 67.5 2 liter with Solex carbs and factory cam) and I was able to pull away from him after he rebuilt my car. Maybe the cam maybe the fly wheel maybe the gear ratio I do not know.

2 liter crank cut and key ways machined.
Aluminum head from 67 1600
Bought a 5 main bearing short block
Racer Brown Cam grind 266 duration 0.475 lift (0.12 intake 0.14 exhaust) to be adjusted running and hot. I am too old for the running part I just check them when car is hot

Bigger radiator made in 75 added electric fan much later in the 90's with on switch (no thermal switch).
160 degree thermostat
Added the plastic fan later after I exploded the metal one racing up a hill (before I added the electric fan)
Aluminum flywheel
Racing oil pump from Datsun comp
Racing oil pan Datsun comp(7.5 QT finned aluminum)
Stewart Warner mechanical oil pressure gauge
Stewart Warner mechanical temp gauge
1600 stock SU's changed the jets not sure which ones I have now
Headers replaced the stock manifold and added a bigger exhaust and glass pack mufflers in 1975
Redline in 8000 RPM hence I added the 2 liter tach goes to 8000 and 160 speedo
Not sure what the builder did for the valve springs but I recall they are stiffer than the stock ones
Balanced flywheel, rods pistons and crankshaft
Standard 67 distributor and points
Domed racing pistons (I believe they were Jans at the time, but there is not a Company or Jans pistons now) no paper work on them.
Four speed transmission and 68 rear end with traction bar
Low top 67 body
Konis shocks
One my third electric fuel pump
Had racing suspension springs but my wife refused to ride in it so I went back to stock still stiff with the Konis.
I still have the rear spring in my garage they are like railroad ties!
Added halogen headlamps
Window wipers suck use Rainx and drive fast!
I have exploded the clutch under fast acceleration up hill (an interesting sound) :x

~ 26 K miles since changes, been on some long trips with it. Rear wheel bearing broke free and the axel popped out tore up the tire but car went straight down the road.

Fixed both wheel bearings since. The stiff suspension caused some battery acid to leak which ate through the washer on the original alternator and burned up my ameter it glowed bright red when the hot line shorted to the alternator case. Fortunately I had a cutoff anti theft switch at the time (in the main wire) and was able to stop the short before the car caught on fire. So beware of super stiff suspension and battery acid leaks.

When some one added wheels to my car the wheels rubbed the brake line and no brakes.
Careful when adding wheels too especially without dual master cylinder

Had the car towed once on the rear wheels (big no no) countershaft in tranny burned up.
This car has been in the family a long time.

67 Low top 2 liter Amethyst Pearl, gold letter roadster
78 911 SC Targa
2000 Toyota Avalon

Location is Tucson AZ
Here is the registry link
http://www.311s.org/registry/1967/spl311-08207.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Last edited by msampsel on Mon Jul 21, 2014 7:43 pm, edited 1 time in total.
67 1600 (Mods only a mother could love)
78 911 SC Targa (Severe Oversteer but still loved)

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Gregs672000
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Re: Stroker Poll

Post by Gregs672000 » Wed Jul 16, 2014 10:39 am

She sounds like quite the runner! Post your location!
Greg Burrows
'67 2000 #588
Tacoma, WA