Weber Hyd Camshaft specs

[dweller]

anyone want to try to translate this data that came with my camshaft?

Grind 520H

Cam Duration Intake 250(deg) Exhaust 250 (deg)
Cam Lift Intake .315 Exhaust .315
Valve Lift Intake .409 Exhaust .409
Valve clearance Intake .000 Exhaust .000

Duration checked @ .020

Valve timing
INOP 17 BTC EXOP 53 BBC
INCL 53 ABC EXCL 17 ATC

and some handwritten notes on the back include: tightening torques, and this bit that i'm hoping someone would know details - Timing Advance
2 deg more than stock.

This is a new cam i bought on Ebay during the buildup of parts needed for my 77 Westie last year. The seller said his dad worked on VW's (out of Cali) and this was a new Weber complete setup for Hyd. lifter conversion on the 77 2.0L. Came with everything, camshaft, gear, hardened springs and hyd lifters, mushroom tip pushrods. I spent $50, and considered it a deal. It was new, not a ding/scuff, etc. anywhere, and in the original packaging, etc.

Mostly i need to know about the timing advance info listed above. Since i'm set for 7.5 deg BTDC, what am i looking for at " 2 deg. more than stock" ? 9.5 or 5.5?

as for the other stats, any stab at the info what be a cherry on the top. I don't know what this cam was set to deliver (more lower end? stock? added power??) so if you know, chime in.

thanks, i'd like to utilize it to full potential, whatever that may be.
dp

[germansupplyscott]

that cam is very mild, not more than a tad over the stock hydraulic cam, i would say. the specs for the stock cams are something of a mystery, since they were never published as far as i know, but if you look here at grind # 107i:

http://www.webcamshafts.com/pages/volkswagen-auto.html#1

you can see how the cam specs of your cam compare - lower lift, shorter duration. the 107i is a mild performance hydraulic grind, so not knowing the exact specs of a stock grind, we could still assume that your grind is somewhere between stock and the 107i. i believe the lift at the cam of a stock hydraulic bus cam is close to .250, but this is only taken from measuring cams.

if you wanted an opinion on the grind itself, i'd say find a better cam to use. you can do a lot better than that one.
_________________
SL

[dweller]

[Bleyseng]

that would mean more advance at 3500 rpms so 30 degrees of advance total not at idle cuz who drives around at idle?
_________________
70 Ghia Black convert-9/69 build date-stock w/133k 1600 SP-barn find now with a rebuilt tranny and engine
77 Westy 2.0L w/Ljet, Camper Special engine-95hp and with LSD!(sold)
76 Porsche 914 2.1L L20c, 120hp Djet (sold)
87 Syncro Westy Titan Red 2.1L 2 knob 100k miles

[dweller]

[dweller]

okay, so i set the idle, point gap, and the timing at idle to 7.5*BTDC.

advancing to 3500 RPMs i pass 30* at about 25-2800 rpm, and at 3000 rpms i'm off the scale (past 36*).

am i missing something here? is there something else i should be adjusting?

the engine appears to idle fine at 850-900rpms. The timing was off, as were the points (from the rebuild, mechanic's settings). The points were at ~56* dwell, and timing was about 12* or more. I reset everything to correct dwell, gap, and timing. Just the advanced appears to be wrong?

i'm heading for a test drive 'round the blocks. will check back shortly w/any observations and see if anyone has a tip.

thanks
dp

[dweller]

maybe i'm missing something here, but i'm just trying to find out if i'm doing this correctly.

Either i set the timing at idle, and then it advances past 30* at 3500 rpms, or am i supposed to run it up to 3500 rpms and then set the timing to 30* , and then lock it down, regardless of where it sits on the scale at idle?



dp

[Randy in Maine]

Set that dwell angle to 47º +/- 3º.

I am not sure what distributor you are running, but you would time this SVDA as you would any distributor that has a centrifical advance component. Put your timing light on it.

Take the vacuum hose off at the distributor. Wind the engine up until all of the centrifical advance is "in" at about 3500 RPMs. You want that to be at about 28º BTDC on the timing scale.

Then re-hook up the vacuum line and rev it back up to about 3500 RPMs and back off the thottle until you are at about 1/3 throttle. YTOU want the total advance (centrifical advance + vacuum advance) to be no more than 42º.

Here is what it looks like by means of the graph (pretend you are a 205P)

Then let it loaf back to idle. You should be around 7.5º BTDC at correct idle speed of about 850 RPMs. Hang tight with the 28º of centrifical advance setting. See how it runs.

[dweller]

thanks for the replies, i'll work on making sense of the instructions and apply them on my next day off.

i appreciate it.
dp