GSR intake cam as exhaust cam?

BigMac88

Fat guy in a little 'teg
Ok so I saw TegSox mention a few weeks ago that the GSR intake cam's specs are very similar to the ITR/CTR exhaust cam specs, so I investigated it for myself and found it to be true. Thus I have been seriously contemplating swapping cams. But first, some questions.

I was wondering if I could put an ITR/CTR intake cam in my stock GSR head and use the GSR intake cam as the exhaust cam? Would I still be able to use the stock valves, springs, & retainers? And would I set the timing up like normal?

Thanks in advance guys, sorry for all the Q's
 

acclude

cheap bastard
hmm. I don't think I've ever heard of someone doing this but in theory I don't see why it wouldn't work.

Yes you can use the ITC/CTR cam. It is recommended to use uprgaded prings and retainers to get the best result.

As for swapping the cam over to the exhaust side, I don't see any reason why it wouldn't physically fit and timing would be the same.
 

Aussie

Zoom-Zoom
I don't think that is going to work. Timing will be off dramatically, but on top of that, the cam is keyed out for the distributor. I don't think it will fit with the exhaust caps.
 
Last edited:

acclude

cheap bastard
right, well the cam itself has proper timing, but timing on the cam gear would be 90deg advanced.
 


Aussie

Zoom-Zoom
right, well the cam itself has proper timing, but timing on the cam gear would be 90deg advanced.
Dude, what is that supposed to mean? Obviously the cam has proper timing, when it's on it's proper side. On top of that just because the lift and duration are the same on the front side of the lobe, are you sure they are the same on the backside of the lobe?
 

BigMac88

Fat guy in a little 'teg
I don't think that is going to work. Timing will be off dramatically, but on top of that, the cam is keyed out for the distributor. I don't think it will fit with the exhaust caps.
Shite good point. I was worried about clearance on the back lobes as well; I guess that's partially what I was trying to ask I just couldn't think of how to put it into words at the time lol.

Why would the timing be 90* advanced?
 

acclude

cheap bastard
Dude, what is that supposed to mean? Obviously the cam has proper timing, when it's on it's proper side. On top of that just because the lift and duration are the same on the front side of the lobe, are you sure they are the same on the backside of the lobe?
No I don't know that. But someone should take mic to it and find out.

Why would the timing be 90* advanced?
because the intake lobes are active the stroke after the exhaust lobes are active. 360 deg for all four strokes so roughly 90 deg per storke. If the intake is active from 0-90deg then the comp. stroke is from 90-180 and the ign. stroke is from 180-270, then the exhaust would be from 270-360 or back to 0 again. If you want to use the intake cam on the exhaust side, the intake activate 90 deag AFTER the exhaust cam does so you would need to rotate the cam 90 deg advanced so that it activates at the same time that the original exhaust cam normally would.

Aussie has a good point about the lobes. The lift would be the same (timing of it might be different) but duration could be different. Take a micrometer up to the cam lobes and measure them to see if they will suit your needs. Just looking at them by eye, they look pretty close but that's not good enough to know for sure.
 


Top