[Them Witches]

Have you thought about taking the cams in to be polished or will that not save it ?

In the Helm manual it says if I can feel it with my fingernail replace it.

 

[Lotus]

can you post a picture? After a polish they might be fine.

 

[Them Witches]

I can do that later. I have never had someone polish a camshaft for me so I am unaware of the procedure and cost.

 

[Lotus]

DIY with a polishing wheel and polishing compound.

 

[KBuilt]

I can do that later. I have never had someone polish a camshaft for me so I am unaware of the procedure and cost.

What lotus said or if you rather trust a machine shop to it I would imagine it’s a similar process to having a crankshaft polished. I have never needed the service personally but I have had friends that sent cams in to be polished up before use , it’s great for getting surface rust off the lobes from sitting.

 

[KBuilt]

I can do that later. I have never had someone polish a camshaft for me so I am unaware of the procedure and cost.

 

[LotusElise]

Have you thought about taking the cams in to be polished or will that not save it ?

My assumption is the depth of those erosion spots is bigger then the polishing process can do. Polishing goes down to 0.1 µm roughness or so. Those erosion spots are typically around 100-300 µm. This would be a de-shaping polishing process, which only get done right if you have a master lobe contour and an adequate aperture to grind it properly. Cam lobe stuff is most sensitive to valve acceleration as an de-shape of only 100 µm can cause a damage of the valvetrain.

Maybe this is my personal risk assessment outline, but I wouldn't polish those erosion spots out.

 

[Them Witches]

My assumption is the depth of those erosion spots is bigger then the polishing process can do. Polishing goes down to 0.1 µm roughness or so. Those erosion spots are typically around 100-300 µm. This would be a de-shaping polishing process, which only get done right if you have a master lobe contour and an adequate aperture to grind it properly. Cam lobe stuff is most sensitive to valve acceleration as an de-shape of only 100 µm can cause a damage of the valvetrain.

Maybe this is my personal risk assessment outline, but I wouldn't polish those erosion spots out.

The Z1 cams are $150-$300 used and typically they come with the cam gears. At this point in the game, investing $879 for RR3 cams seems like a deal. To buy new PRC cams 010,020 profiles are $800 new for both cams.
I paid $300 for the K20z1 (PRB-1) complete head that the Z1 cams came from. If it all works out and I can get a trade in on the head, I will surpass my original investment of $300 for the entire head assembly.

I maybe able to sell the Z1 cams (PRC-030's) to someone that wants to polish them or invest in someone to polish the cams for them. I have little to no interest in polish the cams, I do not want to damage my valvetrain or valves.

 

[Lotus]

I“d not estimate depth of corrosion without at least some pictures, ideally before and after some manual buffing.
yeah, 300 microns is bad, but fingernails can catch at depths of as little as a 100 nanometers.

 

[Them Witches]

I“d not estimate depth of corrosion without at least some pictures, ideally before and after some manual buffing.
yeah, 300 microns is bad, but fingernails can catch at depths of as little as a 100 nanometers.

I am going to post pictures of the cams shortly. I have some morning appointments I have to make, when I get back on the forum I will post pictures of the cams for everyone to see.

 

[BlackNDecker]

Greetings everyone,
After many years of a slow build, I finally had my k24 engine dyno’d with disappointing results. I am hoping you all can help me trouble shoot. It seems to fall apart around 7200 RPM.

K24a4 block
4Piston ported head (pro 156v2)
Nippon racing pistons 88 mm, 12.5:1cr
BC lightweight rods
Prayontoo Racing stage 3 cams
J35 (68 mm) throttle body
RRC intake manifold (inlet port matched)
ASP 4:1 header with reverse cone and 3” exhaust
E85 gas

The tuner mentioned the possibility of a stuck valve and we will recheck the valve train.

 

[LotusElise]

After many years of a slow build, I finally had my k24 engine dyno’d with disappointing results. I am hoping you all can help me trouble shoot. It seems to fall apart around 7200 RPM.

A great welcome back @BlackNDecker. I am very happy to read from you, but I am sorry for your disappointment. I have some ideas to discuss, but before I would like to see the calibration and stuff I pm'd you. Do you still have the modified RSP IM?

Did the tuner finish his job or did you brake up the session? The 25 wftlb dip between 5.5 and 6.0 krpm indicates there is some potential left in the calibration. Anyway, did you guys do a leakdown test and a proper engine brake-in on the dyno. As well did you do a compression test?

 

[K4NEB]

Greetings everyone,
After many years of a slow build, I finally had my k24 engine dyno’d with disappointing results. I am hoping you all can help me trouble shoot. It seems to fall apart around 7200 RPM.

K24a4 block
4Piston ported head (pro 156v2)
Nippon racing pistons 88 mm, 12.5:1cr
BC lightweight rods
Prayontoo Racing stage 3 cams
J35 (68 mm) throttle body
RRC intake manifold (inlet port matched)
ASP 4:1 header with reverse cone and 3” exhaust
E85 gas

The tuner mentioned the possibility of a stuck valve and we will recheck the valve train.

View attachment 106728

What injectors and oil pump are you using?

 

[BlackNDecker]

A great welcome back @BlackNDecker. I am very happy to read from you, but I am sorry for your disappointment. I have some ideas to discuss, but before I would like to see the calibration and stuff I pm'd you. Do you still have the modified RSP IM?

Did the tuner finish his job or did you brake up the session? The 25 wftlb dip between 5.5 and 6.0 krpm indicates there is some potential left in the calibration. Anyway, did you guys do a leakdown test and a proper engine brake-in on the dyno. As well did you do a compression test?

Thanks Markus. I will send the info after we check the valves and then dyno the car again. The car is being dyno tuned in another state and being handled by a friend. Some of the details I don’t know but will try to get the info ASAP.

I do not have the RSP anymore, sold it to a user here about 6-7 years ago.

 

[BlackNDecker]

What injectors and oil pump are you using?

Deatchwerks dw300 pump and ID1050 injectors

 

[Lotus]

the engine cannot breath anymore at high revs. My suspicion is that the RRC manifold holds it back.
The NPR pistons are cast pistons, so 7500 is a sensible rev limit anyhow.

 

[Them Witches]

welcome back to the forum brother

 

[LotusElise]

I will send the info after we check the valves and then dyno the car again

Sounds good 🆙. Good luck for the dyno session.

I do not have the RSP anymore, sold it to a user here about 6-7 years ago

Ok. Would have been an interesting thing comparing these two. Your plenum design was very interesting candidate for more power above the typical OEM IM torque break down.

 

[BlackNDecker]

the engine cannot breath anymore at high revs. My suspicion is that the RRC manifold holds it back.
The NPR pistons are cast pistons, so 7500 is a sensible rev limit anyhow.

Hmmm…not trying to argue, but I’ve seen so many dyno graphs of the RRC intake manifold making power out to 8000ish RPM (and consistently beating virtually every aftermarket manifold under 8000 RPM). That makes it hard to believe that the RRC would be such a huge bottle neck on my fairly mild k24 build.

 

[BlackNDecker]

welcome back to the forum brother

Thank you. Happy to see this forum still has some life.