Camshaft Spacing

FriendlyTurkey · #1 09-04-2009, 05:13 PM

I'm looking at doing billet camshafts for my EG33 with four cam gears driven off the timing belt much like the EJ205 and EJ257. Has anyone measured the camshaft spacing compared to the EJ DOHC heads? The idea behind this is to eliminate the internal gear drives.

Here is an EJ with 4 cam gears.

Regards,
FT

SilverSpear · #2 09-04-2009, 06:19 PM

Welcome to the forum. Can you please tell us more about youself?

FriendlyTurkey · #3 09-04-2009, 07:48 PM

I'm putting a EG33 in the back of a VW golf I have. Mid engine and ~2200lbs I estimate. These pictures are with a EJ18 mock up. I have the EG33 in R&D build up stage.

FriendlyTurkey · #4 09-09-2009, 11:13 AM

Found this article that was interesting. Note the four cam pulleys on this prototype for the EG33:

TomsSVX · #5 09-09-2009, 04:54 PM

I have been meaning to toy with this idea for a long time... Adjustable cam gears are always nice. Not to mention you get rid of the scissor gears. You would need to use reground exhaust cams for the intake cams.

Tom

FriendlyTurkey · #6 09-09-2009, 05:00 PM

Quote:

Originally Posted by TomsSVX

I have been meaning to toy with this idea for a long time... Adjustable cam gears are always nice. Not to mention you get rid of the scissor gears. You would need to use reground exhaust cams for the intake cams.

Tom

Have you verified the clearance between the gears Tom? I haven't had a chance to pull my head part to give this a try.

TomsSVX · #7 09-09-2009, 05:07 PM

I can check center to center spacing as soon as tomorrow. But only between the cams on a single head, not X-block

Tom

FriendlyTurkey · #8 09-09-2009, 05:17 PM

Quote:

Originally Posted by TomsSVX

I can check center to center spacing as soon as tomorrow. But only between the cams on a single head, not X-block

Tom

That would be great Tom!

Where I'm going with this is having some billet cam blanks made up, but I'd like to do a single blank to save on production cost lowering the total cost of billet cams. It looks like I can get the cost of complete billet cams down to or below the cost of web welded cams.

FriendlyTurkey · #9 09-10-2009, 10:43 AM

I checked out the camshaft spacing last night. The spacing is insufficient to use factory cam gears on the intake and exhaust. I'm tracking down the possibility to use a smaller cam gear along with a smaller crank pulley to make this possible.

So far, billet cams are pricing out beyond what looks reasonable for a small run of 20. $650-950 per cam!

FriendlyTurkey · #10 09-10-2009, 11:32 AM

The factory camshafts have 48 teeth and are about 120.5mm diameter.

Honda B series cam gears have 34 teeth. I need to get a measurement on these for diameter, but they may work. I have to verify that the EJ257 timing belt has the same tooth profile as these gears before I go to far down this path.

superru · #11 09-10-2009, 05:44 PM

wouldn't changing the number of teeth (and diameter of the sprocket)
change the timing rotation in relation to the crankshaft? then also having to change the tooth count on the crank? someone let me know if i'm on the wrong path, sounds sweet though! maybe even adapting the STI :VVT into the newer cam design ..

FriendlyTurkey · #12 09-10-2009, 07:20 PM

Thats true. You would need to go to a 17 tooth crank pulley if going to 34 tooth cam pulleys.

TomsSVX · #13 09-10-2009, 07:26 PM

Have you fitted stock 2.5l pulleys??

Tom

FriendlyTurkey · #14 09-10-2009, 09:39 PM

Quote:

Originally Posted by TomsSVX

Have you fitted stock 2.5l pulleys??

Tom

The stock 2.5 pulleys are still 48 tooth so I assumed they were the same diameter as the svx pulley. I may be mistaken.

TomsSVX · #15 09-11-2009, 05:17 PM

I will see what I can find out tonight in my spare time

TOm