Hemi Predator Build #2

[bob58o]

I flipped the engine over so that gravity is pulling the cam towards the crank.

Cam clearanced to block.
Cam clearanced to crank.
Head clearanced to piston.
Valves clearanced to piston.

I think I'm good now????

Here is a video after grinding with an electric die grinder and sanding drum.

https://www.youtube.com/watch?v=Fv-KlOp4K9k

 

[Noseoil]

Just make sure you check it with the side cover in place as well, to make sure it's still not hitting anything. If you have about .050"-.060" to be safe, it should be fine & looks like it's there now.

Curious how your crank journal was on this build. Mine was out almost .005" when I checked it (1.189" to 1.194") on the 60363. Not good, since ARC wanted .0005" or less for their rod. I got it within about 1 thousandth, but that's all.

 

[bob58o]

Without cutting up a side cover, how do I do that?
Just going off of feel??? I couldn't feel it hitting before I ground it. But I wasn't looking for it.
I think that is what KF was asking as well.

 

[bob58o]

I had to go back to page 4.

Rod was right on the money with the cheap HF calipers. It measured right around 1.188" everywhere I checked. My guess is that the calipers are only good to about +/- 0.0025" anyway. I don't take the last digit on my calipers too seriously. Maybe they are better? I could measure my feeler gauges if I was so inclined.

Oil clearance was a little tight when measured with plastiguage. 0.002", which is the minimum. Shooting for 0.0025" to 0.0030" (no less than 0.002", no more than 0.004").

 

[bob58o]

Just measured again. Always 1.187(5)" to 1.188(0).
So maybe the calipers are good enough?
I like when my tools give me the answer I want.

---------- Post added 08-02-2017 at 12:13 AM ---------- Previous post was 08-01-2017 at 11:18 PM ----------

Without actually measuring, you can have a look if you don't have the rod or piston installed.
https://www.youtube.com/watch?v=uk_0FM21hX0

 

[bob58o]

Made a valve cover gasket.

 

[ezcome-ezgo]

Maybe you should check the clearance with the connecting rod installed also. You've got a tight spot there.

 

[bob58o]

Maybe you should check the clearance with the connecting rod installed also. You've got a tight spot there.

That is the issue. I can check with the side cover off or I can check with the con rod/piston out.

With the side cover on and piston installed, I cannot see or measure inside. Kart Fab had to cut his side cover up. I don't have an extra side cover. Or do I? I have a spare block, but don't think it came with a side cover.

 

[ezcome-ezgo]

I didn't say the piston, just the rod.

 

[bob58o]

Here is an example of how the ignition timing retards with RPM with standard coils.
http://www.fastermotors.net/PVLTIMINGCURVE.html

 

[rk970]

So Bob,, why does the timing retard with increased rpm?

 

[ezcome-ezgo]

RPMs bend time?

 

[bob58o]

RPMs bend time?

No 3 K&N style filters bend space and time.

 

[rk970]

No 3 K&N style filters bend space and time.

The time it takes for the coil to saturate and create a spark is relatively constant. As an example say it takes 6ms for the coil to charge/discharge with a spark. At idle the amount the crank moves in 6ms is very small then when at 8,000rpm..
Points or a transistor trigger sometimes are not such a bad thing to have.

 

[bob58o]

So Bob,, why does the timing retard with increased rpm?

Just cause I studied Physics doesn't mean I understand electromagnetic induction. E&M I and II were tough classes. They were graded on a curve. 50% was like a "B".

If you are testing me, I really don't know the correct answer. Coil design and the principles of electromagnetic induction???

If you really want to know the answer, this seems like more of an itsid question. He's a smart guy, I just play one on TV. But I don't think he reads too much of my threads, or at least doesn't post.

EDIT: Nevermind I was too slow to draw.

 

[ezcome-ezgo]

Who you calling a retard?

 

[bob58o]

I made another mod to the block.

I saw this on the internet so it must be good!
The little hole between the pushrods. I drilled it bigger. I think it allows oil to return to the crankcase. I used the smallest drill bit that was long enough to reach it.

 

[bob58o]

The time it takes for the coil to saturate and create a spark is relatively constant. As an example say it takes 6ms for the coil to charge/discharge with a spark. At idle the amount the crank moves in 6ms is very small then when at 8,000rpm..
Points or a transistor trigger sometimes are not such a bad thing to have.

Which is the same reason why you need more advanced ignition timing at high rpm. Just as you say the time it takes for the coil to charge/discharge is constant, the speed at which the intake charge burns is constant too (given CR and air/fuel ratio stay constant). The crank spins twice as fast at 7200 RPM as it does at 3600 RPM. So if timing is optimized so that peak combustion pressure happens at 20 degrees ATDC at 3600 RPM, when spinning 7200 RPM, the piston will be too far down the cylinder to get the most out of the combustion.

Starting the ignition sooner so that peak combustion pressure happens at 20 degrees ATDC when the engine is spinning 7200 RPMs means that at 3600 RPM peak combustion pressure is happening sooner than the optimized time. The piston to connecting rod angle would be less than ideal and if advanced too far the combustion could try to push the piston back down while it's still coming up.

I know you already knew that, but was sharing for those who might not know.

 

[rk970]

Yes and No... Quench, swirl, tumble can increase the speed of burn. Sometimes you have to pull timing back near the rpm limit.. The only way to optimize timing is during a constant load on a dyno..

Which is the same reason why you need more advanced ignition timing at high rpm. Just as you say the time it takes for the coil to charge/discharge is constant, the speed at which the intake charge burns is constant too (given CR and air/fuel ratio stay constant). The crank spins twice as fast at 7200 RPM as it does at 3600 RPM. So if timing is optimized so that peak combustion pressure happens at 20 degrees ATDC at 3600 RPM, when spinning 7200 RPM, the piston will be too far down the cylinder to get the most out of the combustion.

Starting the ignition sooner so that peak combustion pressure happens at 20 degrees ATDC when the engine is spinning 7200 RPMs means that at 3600 RPM peak combustion pressure is happening sooner than the optimized time. The piston to connecting rod angle would be less than ideal and if advanced too far the combustion could try to push the piston back down while it's still coming up.

I know you already knew that, but was sharing for those who might not know.

 

[ezcome-ezgo]

I made another mod to the block.

I saw this on the internet so it must be good!
The little hole between the pushrods. I drilled it bigger. I think it allows oil to return to the crankcase. I used the smallest drill bit that was long enough to reach it.

Now you've broken it.