Anyone try making Crawford power blocks out of plastic?
 

Was curious if anyone has tried to make the crawford power blocks out of plastic? I was interested in getting them however I've heard a few instances of the materials actually causing the engien to heatsoak due to them soaking up heat at a much higher rate than the plastic intake manifold.

Was curious if there was a reason for this or not.. Either way I'm interested in possibly scanning a set and making them from a 3D printer, unless someone has a reason as to why that may not work?

Don't worry about the heatsoak. I find it really easy to heatsoak my engine and I even wrapped my intake in that gold foil tape... but it did not do much for my AIT's. I am sure if you have a sutable plastic they will work just fine, but why bother. That little bit will not make much difference to be honest. If you really want to stop any extra heatsoak wrap the blocks in headerwrap, I am sure that will help a bit?? :iono:

Air moves through so fast the transfer of heat is negligible. Your intake ports are longer and made of aluminum.

I know I'm replying 10 days late, but I do 3D printing as a side gig with friends. We have a fully established business in the Nerf community (yep, that kind of Nerf... for children). I fear that the ABS or PLA would get too close to the glass transition temp and get messed up. Nylon might not be an issue.

Edit: For fear of not appeasing the all powerful admins, I will not talk about charging machine time for a test. Should someone contact me outside of the publicly visible spaces of the forum, I might be able to say otherwise. Private messages are not allowed for this sorta thing here, but I shouldn't be too hard to find online.

I would be amazed if it made any sort of difference. We have a plastic manifold, that's a great place to be in this respect. I have never seen the manifold get to hot to touch, my old sti you could not touch that thing at all.

I wouldn't worry about plastics for heat, but there certainly would be cost benefits.

Nylon is what I was thinking. A friend of mine makes various bits and pieces using nylon for some local BMW guys. Just need to get my hands on some of these blocks or find someone that has a CAD render for them.

I saw this type of commentary in the original Crawford BPB threads but they are so long to track now. Do you have any evidence of heat soaking logs, dyno, etc?

I can supply the base shape without the oring groove.

If you had that available as a CAD file, I might be able to draw up some full powerblocks. I would just need to know how tall to make them. My intake is currently off for an engine rebuild so I can measure things like the o-ring gasket.

They are DXF all you would need to do is create a LOFT of what ever the height you need it to be.

For best print results, it should be calibrated for the extrusion size (print resolution). I'll see if I can work with it this weekend.

Nylon requires temperatures above 240C to extrude, but it melts under stress at a much lower temp.

3d printed nylon significantly softens at 155-165C (will deform to the touch) and starts to significantly deform, discolor, and melt at around 170-180C. (even though the published melting point for nylon 6,6 is 256C, 3d prints will break down at a much lower temperature.)

That's a pretty low melting point for something bolted to bare metal on the cylinder head. These will be in direct contact with the intake ports.

Naturally aspirated, they have to withstand a theoretical maximum differential pressure of 14.7 PSI at operating temperature. (closed throttle, high revs, decelerating.) normal idle in neutral sill generates almost 10 PsiD (vacuum) At that differential pressure, it will likely deform well below 155C... That's (optimistically) going to put you down into the high 200's F for a max temperature. That seems really really low. Does anybody know how hot that bare aluminum gets at the intake ports?

I'm not saying don't do it, just cautioning and encouraging research before somebody has to chip nylon glop out of their intake ports. There's a reason they don't 3d print these manifolds. They pay a Sh*tload more money to injection mold them... There's more factors that go into it, I know, it might be fine, but that temp looks low enough for me to worry about.

Oh, forgot to mention its glass transition temperature is below 100c (70C dry, lower wet). Oh, and it's hygroscopic, it can absorb almost 10% of it's mass in water. It's really not going to like heat cycles. Especially when those heat cycles always exceed the Glass transition temp, and the boiling point of water, and come dangerously close to melting point. The above mentioned temperatures were determined experimentally at 0% humidity. Those temps are probably going to come down even further in the real world.

P.s. for the pedantic people out there. 14.7 psi vac assumes standard pressure at sea level in a perfect vacuum.. That won't happen but it's close enough to be a good number.

Either way, This topic has been addressed before on the forum (several times), and by my recollection, nobody has been able to come up with a suitable material to 3d print these things with. I have suggested unobtanium, impossibrium, AND hardtofindium but nobody takes me seriously

The closest anyone has come to a viable idea is to mill them from plastic. That may work if you pick the right plastic, and your machine's milling bit doesn't melt it, but you sacrifice the cost savings (as the billet blocks are milled as well, and the difference in material cost in negligible) making it a useless thought experiment.

Warning: opinion: If you want to make real power with this engine NA, there is no way around ITB's on the intake side, tuned (runner length/diameter and horn size) to make peak power at a specific RPM, matched to what your (EL) header is tuned for (or tuned to make peak VE @ the torque peak of your UEL header, if you're a low-end torque guy). Everything else is a compromise, and a sh*tty one at that. The stock intake manifold is good for one thing: efficiently shoving forced induction into the cylinders, and nothing else. Support for this argument is, despite its many significant technical advantages, this engine has a garbage specific output NA compared to any other high-performance NA 2 liter in the last 20 years. And that's stock. The disparity only gets worse when comparing tuned NA versions of these motors. The most immediate example is the Toyota 3s-GE which literally shares the same 86 bore and 86 stroke, and makes more NA power with a lower compression, no DI, and the SAME FACTORY REDLINE. Other great examples include the f20c by that one company everybody hates.. Yak it up about emissions controls, but the disparity only grows when both engines are tuned, and all emissions controls are removed.

Q. E. D.

So let's scan a product someone else made, and print it with plastic and sell it for profit... haha am i missing something?