how to install a T-belt on 4g64 with ajustable cam gears?

dsmstunna · 08-22-2006, 09:00 PM

Hi, I'm putting together my 4g64 motor and I'm looking at adjustable cam gears. Everyone I've talked to said just to order a set of 4g64 cam gears put the t-belt on and then the adjustable cam gears. I was just wondering if anybody knows how many degrees the 4g64 cam gears are off from the 63's and couldn't you just adjust the cam gears for this difference and put the t-belt on normal then once its on readjust the gears to the desired position??? this seems much easier then buying another set of gears just to take them off. If anyone has done this what is the degree the cams need to be set for?

Injected · 08-28-2006, 07:19 AM

There is a GREAT article in SCC about this issue with S2000 guys lowering their compression by raising the deck height in this month's (Oct.) issue, which is what you are doing. It's a simple geometry issue, but I don't want to mis-quote it or get it completely wrong, so I will wait until I get home tonight and post.

[Edit]Oh, I almost forgot, you'll need the radius of the cam gear and vertical distance between the center of the crank and the cam gears. I still haven't made it home to get the article, but I will try and remember to do that tonight.[/Edit]

[Edit2]Here's the pic, made in PS CS2.[/Edit2]

Okay, we do need either the diameter or radius of the cam gear so as to calculate how many degrees the cam rotated per unit of change from the pull of the . I still have the top cover on my Tbelt, so someone else will have to grab that measurement.

Coleman says that the difference in the hypotenuse won't really play any real affect in the calculation. Whether you agree with him or not will depend on the severity of the angle that the belt pulls on the gear. If you are a stickler, then you can compare the hypotenuses created by the 63 and 64 blocks. Our 4G engines don't have that severe of a pull, but if someone has a straight-edge and will measure the distance from the left side of idler pulley to the right side of the cam gear (top of blue triangle), and from the center of the idler pulley vertically to the center of the cam gear, I'll do just that, otherwise we can assume do the calculations as if it pulled straight down. But we still need either the radius or diameter of the cam gear.

Lunch_Box · 08-29-2006, 11:16 PM

Here's what Mitch of (Engintecs) has to say:

First you cannot use the 2.0 gears. It’s either the 2.4 or
adjustable gears. I like to retard the adjustable gears about
½ teeth which mean around 3.5 degrees on the cam gears.
However the timing marks on those gears need to be moved that
½ degree. Basically the marks that are on the peak get
relocated/remarked in the valley of the cam gears tooth the
same counterclockwise direction. Take a look at the attached
picture and you might be able to put it in better words than
me. Doing all these will make the Fidanza gears copy the 2.4
OEM ones but that’s just about it. That should be just a
starting point from where you begin degreeing the cams to get
them accurately dialed in. There are so many variables like
deck height, gasket thickness, overall head thickness, cams
grinds and their pin location that are unique to each engine
and that’s why you might end up in a different place than what
you should theoretically be so adjustable cams are a better idea.
Does this make sense?

Injected · 08-30-2006, 08:35 AM

There are those who have used the 2.0 gears because they are the same exact dimensions, but the timing marks don't line up. That is why some people go with the adjustable gears (same diameter and number of teeth). Doing these calculations will be benificial, because the change in deck height, HG thickness, etc. will only minimally impact the end result. This would allow anyone who is building a 2.4 to have a great baseline setting for their buildup.

GVR4592 · 09-02-2006, 12:23 AM

Couldn't you just get the cam card for the cams you're using and degree the cams?

GSX_Dan · 10-20-2006, 04:48 AM

Quote:

Originally Posted by Lunch_Box

Here's what Mitch of (Engintecs) has to say:

First you cannot use the 2.0 gears. It’s either the 2.4 or
adjustable gears. I like to retard the adjustable gears about
½ teeth which mean around 3.5 degrees on the cam gears.
However the timing marks on those gears need to be moved that
½ degree. Basically the marks that are on the peak get
relocated/remarked in the valley of the cam gears tooth the
same counterclockwise direction. Take a look at the attached
picture and you might be able to put it in better words than
me. Doing all these will make the Fidanza gears copy the 2.4
OEM ones but that’s just about it. That should be just a
starting point from where you begin degreeing the cams to get
them accurately dialed in. There are so many variables like
deck height, gasket thickness, overall head thickness, cams
grinds and their pin location that are unique to each engine
and that’s why you might end up in a different place than what
you should theoretically be so adjustable cams are a better idea.
Does this make sense?

Wouldn't you want to advance the timing gear and move the timing mark the same? According to what I see in the pic the 2.4 mark is advanced. http://students.washington.edu/jlhob.../excamgear.jpg

Also is it true that the location of the dowel pin is different in relation to the teeth between the 2.0 and 2.4 gears? If so simply remarking the 2.0 cam gear to match the 2.4 wouldn't place the cam straight up, it would leave it retarded. The 2.0 gear would have to be lined up with it's original marks to get the cams right, but then the 2.4 belt will never go on since it's going to be in between teeth. Even though I'm reading of a lot of people using the 2.0 gears remarked my research leads me to think the cams are retarded by a bit, which might work out but they're not straight up.

Injected · 10-23-2006, 08:34 PM

Quote:

Originally Posted by GSX_Dan

Wouldn't you want to advance the timing gear and move the timing mark the same? According to what I see in the pic the 2.4 mark is advanced. http://students.washington.edu/jlhob.../excamgear.jpg

Also is it true that the location of the dowel pin is different in relation to the teeth between the 2.0 and 2.4 gears? If so simply remarking the 2.0 cam gear to match the 2.4 wouldn't place the cam straight up, it would leave it retarded. The 2.0 gear would have to be lined up with it's original marks to get the cams right, but then the 2.4 belt will never go on since it's going to be in between teeth. Even though I'm reading of a lot of people using the 2.0 gears remarked my research leads me to think the cams are retarded by a bit, which might work out but they're not straight up.

Please explain the pic. It looks like you are saying that one gear is a 63 and the other a 64 (but neither looks like a 63) and that the timing marks are about 1/2 tooth off. The gears are the same size though, so you would just have to remark them.

I don't think the dowel is advanced/retarded however. If they were, then you would it would change a few things about the whole stuation, but doesn't mean they don't work.

DoyoFCT · 11-04-2006, 08:29 PM

GVR4592:Couldn't you just get the cam card for the cams you're using and degree the cams?

anyone going to answer that? why not just degree it with adjustable gears? i dont see how it could be off then.

Injected · 11-13-2006, 09:01 PM

One guy on ebay is selling the 64 set because he ended up just using his 63's, so according to that, they are the same dimensions.

Quote:

Originally Posted by quadrider8

Hello you are bidding on Camgears for a mitsubishi eclipse, Eagle Talon, Plymouth Laser 2.4 stroker setup. These cam gears are for the hyundai, or Galant G4CS, or 4G64 2.4 liter swap. I bought these new from Slowboyracing.com. Cost me $50 for the pair. I ended up using my old cam gears, these were bolted to the cams but never installed in the car.

Link to auction.

sensei · 02-01-2008, 06:37 AM

Sorry to bring back an old thread... I have a 2.4L with a 2.0L head with AEM adjustable gears. Getting ready to start it for the first time.... just wondering what cam gear settings other people are running with this combo. Are people retarding both gears, or retarding one..advancing the other?

alex99gst · 02-19-2008, 09:58 AM

This is how I set mine up using my stock cam gears.

Defiant · 02-20-2008, 01:32 AM

Cam differences cam identification cam ID cams camshafts camshaft degreeing timing