Datsun Roadster Forum-311s.org

Okay, my stroker has about 200 miles on it so far so I thought I would share some of my info for the group.

1. head. ported early head with intake work to match them up
2. U20 crank that was rekeyed/shortened
3. lightened flywheel approx. 14 lbs.
3. cam. 280 duration and 457 lift.
4. valve lash. .18 intake and .20 exhaust
5. carbs. 40 mikunis, still tweeking the jets
6. dizzy distributor
7. 3 row champion radiator
8. 1 5/8 header going into 2 inch exhaust with megaphone tipe and o2 sensor.
9. 5 speed and stock rear end. 3.9 ( I think)

I don't remember how my car drove before the stroker so I cannot compare how it drives. It idles lumpy at around 750-800 when it warms up. I have not taken it above 4000 rpms so I don't know how it feels beyond that or how far I can push it. MPG: it seems like Im getting in the low teens mpg. my speedo is off. Overall I like it.

My 1600 engine (not a stroker)is restored and the compression is increased to 10:1 with a faster cam 442 Lift at the valve / 270 Duration and higher pressure mahle dome pistons.
my question is if I have to change the valve springs with this lift and duration.
I ask this because my engine is ticking like you hear the rocker on the valves, not on low rpm, than it sounds smooth, but when I bring the rpm’s to 3000 or 4000 rpm the ticking sound is louder if the rocker distance to the valve is larger than normal.
what can be the problem.

Peter:

Have you considered that you may have a bad rod bearing?

Shannon

I don't know much about pushrod engines. However, I don't think you would be getting valve float at 3000rpms. Did you check the springs for coil binding (coil compresses fully?). Loose valve adjustment setting? Rod knocks usually sound off in a particular way; it knocks on acceleration, stops while you hold rpm, then knock on deceleration again.

Peter:
Have you considered that you may have a bad rod bearing?
Shannon
The rod and piston bearings are new and the pistons too.

today I first adjust the valves, and made a video, when the engine runs at idle it sounds not bad at all, but when I increase the throttle to 3 a 4000 rpm you hear the sound, listen and try to give me a indication.

My opinion only, kind of sounds like a chain ratteling, like little or no oil getting to the tensioner or sprockets in general.

Again, not super familiar with R engines. However, how tight are your valves adjusted? Even at idle they sound loose to me. First, I would set them cold, then bring the engine to full temp and recheck them, noting the direction they go (tighter or looser. On a U20 they actually loosen as they get hot despite what the manual says). You have to have some clearance, but as long as the valves are allowed to seat fully into the head and thusly transfer heat, any extra clearance is just slop, right? Too tight and the valve can't seat, won't transfer heat and can burn, so have some degree of extra clearance to account for wear and settling. But I might try tightening them while leaving say 6-8mm of clearance and see if it quiets up. If not, then one has to wonder about other issues like a loose tensioner, coil bind on the valve springs (not likely, and not sure on what that would sound like) or too weak (again seems unlikely unless something's missing from the assembly). You went slightly higher compression but nothing radical. However, if the cam timing is off maybe you're tapping a valve on a piston? If so, a leak down test might reveal it. But I'm thinking it's gonna be a loose valve adjustment.

Just to be sure, you do have good oil pressure, right?

I spoke to richard and he told me to first check the distance between the piston and valve on bdp.
oil pressure is good(I think), at 800 rpm 20psi, at 3000 rpm 45 psi,

Good on the oil pressure. You may be able to look inside the cylinder with a good light, or maybe a camera? Still, I'd adjust the valves first and see what happens. You won't hurt it as long as you have clearance.

But I might try tightening them while leaving say 6-8mm of clearance and see if it quiets up.
You mean 0.6 or 0.8 extra looser?
The are normal on 0,43 mm hot, and 0.50 cold. now I did set them on 0.40 mm.

thinking out loud here.....

Do you have stock rocker arms or by any chance have the roller rockers? I have the roller rockers and my top end is loud as well...maybe not that loud (it has been a while since I've heard it...last fall) but still loud.
tim

I have stock rocker arms with new valves new followers and a new faster cam and new special pistons.
What I see now is that when the valves on there lowest point the coils have only 1mm clear-ens between the coils.
Tomorrow I will look if the valves have space between the piston and if I can press the valve deeper so that I be sure it have enough free space to work and don't hit the piston.

My J13 pushrod engine called for .014 valve clearance. One valve would tick loudly until I tightened it to .009. At this seting the idle was a bit off so I eventually reset it back to factory spec and lived hith the tick.

Quote: "The are normal on 0,43 mm hot, and 0.50 cold. now I did set them on 0.40 mm." Is it just me or these numbers either way to loose at .43 or .50 or too tight at .0043 or .005. I would try tenthousandths of an inch (.010) and see how it sounds.

0.017 " = 0.43 mm warm for the inlet and outlet.

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...... (stock rebuilt head, then added higher lift cam....)
I don't know what kind of lift the stock valvetrain will accommodate??