20V cam gear differences?

[Sam_Q]

From what I hear a Blacktop has different cam gears to a silvertop as such:


- larger diameter
- different tooth profile

what I want to know is that has anyone ever tried swapping the gears between engines for various reasons? Are they differenty offset or move different amount with the vvt actuation?

I am just building a hybrid engine and I have to either change the top gears off my spare head or somehow find the bottom gear.

[Mr Revhead]

i dont think the tooth profile is different.. il check it out

its true they have different VVT pulleys..... memory failing me as to if they move different amounts though.... im pretty sure they do

[Sam_Q]

if you could that that would be great thanks

[bobob]

The table at the bottom of this page may give you some idea of the differences in the VVT / cams between the 2 heads

http://www.billzilla.org/4agstock.htm

[Mr Revhead]

the ifnfo there on vvt switching isnt accurate

[bobob]

The RPM points for the VVT actuation? Or all of the data?

How would you measure the "throw" of the VVT?

Take the pulley off, turn it by hand and measure?

[Mr Revhead]

yeah, VVT is not rpm switched.
its load and TPS.

[bobob]

I remember reading that! Which is funny because normally I do not remember much!

I also remember it being Temp controlled as well, as in it does not 'activate' until operating temp has been reached. Fairly clever! What ever engine control is used should manage that.

The belt for the blacktop, taken from http://www.rollamods.com/ae111_20v_part_numbers.htm did fit for me:

13568-19185 BELT, TIMING 01.05.1995-01.08.2000 4AGE..AE111

I do not know if this part differs to the silvertop part at all.

[Mr Revhead]

silver top belt is 13568-19035

yeah once the engie has reached 1/2 normal temp and anything over about 1/4 throttle VVT is on. untill about 6200-6500 rpm when its off

[Sam_Q]

I do know that the belt is longer by a few teeth but the difference in profile isnt confirmed. I might take a picture of me holding a silvertop belt onto my blacktop head to see the differences and post a pic of it here.

[JP]

the genuine blacktop and silvertop belts I've got in the garage both have the same profile. There's also a BMW gates timing belt that fits the blacktop, it's 0.3mm thinner though. T910... 110 teeth, 20.7mm wide

The silvertop belt is 111 teeth and 19mm wide

[Mr Revhead]

yeah black top one is longer, they run a hydrolic tensioner whereas the silvertop is just spring tension

[Sam_Q]

I guess regardless of the belt type I still need the bottom gear because it would be bigger than a silvertop one right?

Jp: thanks for that I will get one from Repco, why would the silvertop have 1 less teeth when its shorter?

[JP]

The silvertop belt is 111 teeth and 19mm wide, it's one tooth longer than the AE111 belt.

The 16V belt is 113 teeth and 19mm wide

[clubagreenie]

Therefore not interchangeable as they either wouldn't meet or overlap depending on which way you went.