I'm looking fo some cam timing recommendationsw for an all-motor build. Here's the motor specs:

Dart B20+ block, 85mm bore
95mm crank
5.967" rods
-2cc pistons
RLZ-built 35cc-38cc GSR head
.040 head gasket
(figure compression in the 12's)
Blox HSL cams
-INTAKE: Duration: 255° @ 0.050 INCHES Lift: 0.496 INCHES
-EXHAUST: Duration: 256° @ 0.050 INCHES Lift: 0.494 INCHES
TWM 50mm ITB's
running 93 octane pump gas


I looked at the spec sheet that comes with the cams, but it doesn't specify cam timing, other than saying +2 degrees on the intake. Here's the spec sheet:

http://www.bloxracing.com/prod...4.pdf

The stock cams get set to 1mm of valve lift at 10 degrees BTDC for the intake and 40 degrees BBDC for the exhaust

Should I set these to the same specs with +2 (12 degees BTDC) for the intake?

Brad from RLZ told me some other numbers, but I think he was talking about the point of maximum valve lift. Is there a universal set of numbers that work correctly? I can fine tune it on the dyno, but I'd like to get it as close as I can before then.

 

Try 102/110 lobe center in/ex.

This translates to

Intake Open 0.050 at 25.5 BTDC

Exhaust Close 0.050 at 18 ATDC

YOU MUST CHECK THAT YOUR CLEARANCES ARE OKAY AT THESE SETTINGS.

I know Don will chime in after me and say tighter lobe center for more mid.

 

Thanks, it's my understanding that the front and back side of the lobes are not necessarily identical, so could the lobe center be substituted for the point of maximum lift (or the center of that point, depending on my ability to determine the exact center with the tools that I have)? I'll definitely be checking the clearances with a dial gauge, as well as checking how much overlap I can have before the valves interfere with each other, and rotating the cam gears a few degrees in either direction to check clearances if we adjust them on the dyno. I just got my cam degreeing kit this week and am still practicing with it on a dummy motor:

https://honda-tech.com/zerothread?id=1441109

Sorry if any of these questions are completely ignorant, this is my first time degreeing cams.

 

Here are instructions from web camshafts re degreeing for you reference

http://webcamshafts.com/degreeing.html

 

Hi Bud

I am almost having the same set up as you, with the Dart B20+ tall deck block and all. Could you kindly advise as to which timing belt you are using? Preferably you could provide some details like the brand and part number? I understand that Dart specified the use of Cloyes #B-294 or Gates #T-294. But not having used them before, I would prefer some more assuring quality timing belts.

Thanks

 

I use the Gates belt, picked up one at NAPA. It appears to be identical in construction to the OE belt, just a bit longer.

 

Hi

So you are using the Gates belt. Have your engine seen track times??..drag times???...is it still holding strong the Gates belt??

 

It's still fine. I've been daily driving it, plus one weekend HPDE at the Rockingham Raceway (banked oval track with infield road course) and one drag launch in which I destroyed the transmission.

 

Hi

You destroyed the transmission?!?!....and the timing belt is still fine??

How long have you been using the belt??...is the one you currently using still the first belt used??

Do you actually have the specs of the Gates timing belt you are using??..I can't seem to fin any information regarding the belt, same with the Cloyes timing belt.

 

I knocked all the teeth off of the final drive gear and a bunch of them off of the ring gear. It wasn't too bad, I got a new final drive set in it the next day with some help from RLZ and was tracking it the following day.

Here's the Gates belt from NAPA that I bought for $48:

http://www.napaonline.com/Mast...shaft

 

Rocket, know's me too well. For 95mm crank I would start at 100 degree IN 104 EX. Or IN @.050 opens at 27.5 BTDC and closes 47.5 ABDC EX. @ .050 opens 52 BBDC and closes 24 degrees ATDC
That is the worst cam sheet i have ever seen, but I guess you get what you pay for.

 

Thanks for the input. I did finally get them degreed and they came out to:

I - 252 degrees @ .050, .490 lift
E - 256 degrees @ .050, .488 lift

For now I have it set at 100-I/110-E, but I'm going to try and get it on the dyno soon and adjust them a bit to see what works best.