Crower 404 owners... Little help here

I finally got my project done. Here’s my mod list…

P&P Head
Crower Valvetrain
Crower 404 cams
PR3 Pistons
Shotpeened rods w/ ARP rod bolts
New Bearings
New Rings
New GSR Oil Pump
New Water Pump
usual bolt ons

I’m still breaking in the motor but ever since I started the rebuilt engine I’ve been having trouble between 1,000-2,000 RPMs. The engine stutters when it’s in that range, but when it hits 2,000 it stops doing it. Is this normal for the 404’s to do? Thanks for the help people.

have you checked ur timing?

that might be part of if not the whole reason.

That’s part of the problem. The idle is so uneven, I can’t set the timing correctly on the engine. Should I rev the engine to 2,000 RPMs and then try to set the timing or do you know of a way to set the timing with lopey cams like the 404’s? Thanks for the help.

Other things I left out…

FPR set to 35 psi
Cam Gears set to 0 (both in. & ex.)

you going to need to raise the idle to about 1,500 to even out the lumpiness at first. Get it wideband tuned, it will stutter like crazy becuase of the out of wack a/f mix. My advice to you-get a hondata. S100, its only 245 or so.

My friend has a new LM-1 unit that I’m going to use to tune the engine on Friday. What should be a good number to aim at? I know 14.7 is the ideal mixture but I’ve heard that I should tune it to 12.X, is this correct? Also, any help on the timing? Should I rev it to 1,500+/- to keep the rev’s steady and then set the timing? Thanks a lot for the help.

shoot for a lean-but very safe mix down low, and let it run a tad rich up in higher (6k+) RPM areas to avoid detonation. As for the timing, I dont see why you wouldnt be able to set it while the engine is revved slightly. remember, 16 degrees BTDC.

ALSO, I see you’re running 10.8:1, make sure than you tune for premium gas. The best thing you can do is pull off a baseline, look and see where you need work (I can tell you right now its going to be the Air/Fuel chart) and just fine tune from there. Setting the LSA (if you dont know what that is, search) wide will give you a smoother idle, more low end power but it will sacrifice your peak power output. Narrowing the LSA will make the idle worse, and shift the powerband upward as well as increase your peak power. Its all up to you, good luck.

on a side note, try 37 or 38psi.

Get a rising rate FPR if you can find one, and lower the idle pressure to improve idle a little bit.

Thats odd, u should check ur timing belt, it might be off by a few teeth, 404s dont idle THAT bad. mine idles rock solid even without the SAFC

Hi I was wondering if I should also get a new set of crower valves for my setup or could i just reuse my stock ones?

my setup:
crower 404
crower ti retainers
aem cam gears
b&m fpr
b&m fpr gauge
pr3 pistons
port n polished head ( soon )

stock will work fine, unless you plan on running oversize valves like me.

do you need some stocks? my old ones are available fairly inexpensively. :wink: