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Cam Gear Wont Fit.

rad100

By rad100,
in Engines & Forced Induction

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Moodles2 Grand Master

Moodles2

Posted
Posted

Tomei cam shafts are designed to be used with stock cam gears (lobe centers so you dont really need to be dialed in, unlike HKS cams for example), so should guarantee any cam gear will work (even a intake one on the exhaust side). I would be checking if you actually have a RB exhaust cam wheel, it's possible you've been sent one to suit a 2JZ, or 4G63 or something like that. Take a pic if possible.

PM-R33 Grand Master

PM-R33

Posted
Posted (edited)

Silly question but you aren't trying to put an aftermarket cam gear onto an inlet Poncam are you? Because you can't since it is made for VCT. I know you said exhaust cam gear but I thought I would double check.

Edited by PM-R33
rad100 Grand Master

rad100

Posted
  • Author
Posted

i ended up using poncams from a late rb25 (black cas) and my old stock 25 cams had a hks exh cam gear (old style)

i thought i may use the vct down the track with a switch so decided to keep it..

so went to fit it to find the bolts dont line up, hence y u need to use a tomei cam gear!

mercury, can u fit the stock cam gear to the tomei cam? exh side?

cheers

blitzxtr Community Regular

blitzxtr

Posted
Posted (edited)
strange. i am running tomei cam gears on standard cams without any issues

not very strange, just not easy to pickup unless really looking at whats going on. I had this shown to me yesterday with 4 brands of camgears and 4 different brands of camshaft. With the verniers locked after measuring the Tomei cam gear locating hole its very clear that both GReddy, HKS and Nissan gears hole is smaller. When placing the Tomei camgear on the Apexi, HKS and stock camshafts used as examples there is some quite noticable slop of a few degrees until the bolts lock the camgear onto the camshaft face. Put that gear on the Tomei camshaft that was also there and it didn't move at all with no bolts as the locating pin and recess in the rear of the camgear were a perfect fit. The HKS, GReddy and Nissan camgears would not fit this camshaft unless force was used to disform the locating hole allowing the gear to be pulled up square with the face. All the items were new or near new and both the HKS duralumin and HKS early style were the same. Paul pointed out that when running poncams a few years ago he had the same issue with OS Giken camgears. He also showed me with verniers how much larger the Tomei locating pin is. The GReddy, Nissan and HKS gears were a perfect fit on all the cams except the Tomei. He pointed out that the Tomei gear will work ok but depending on where it is positioned when tightening the bolts will affect the camshaft timing by a few degrees and if the gear is pivioting during the rising and falling of rpm will affect performance.

Im sure this is something the untrained eye would not pickup but when guys who are playing with this stuff on a daily basis using quite a range of brands these little things are easily picked up. Either that or Paul is looking harder than most.

Edited by blitzxtr
Adriano Grand Master

Adriano

Posted
Posted (edited)

How much bigger is the pin? Not doubting, but i cant see how people are fitting stock gears if the pin is bigger, any more than a 2 thou inteferance fit, and you will be smashing the gears on with a hammer, which i cant see people doing. Maybe the design of the cams has changed?

Edited by Adriano
blitzxtr Community Regular

blitzxtr

Posted
Posted
How much bigger is the pin? Not doubting, but i cant see how people are fitting stock gears if the pin is bigger, any more than a 2 thou inteferance fit, and you will be smashing the gears on with a hammer, which i cant see people doing. Maybe the design of the cams has changed?

Tomei pin is 6thou or 0.15mm larger, same as the locating hole in the Tomei cam gear. Standard pin is 6mm and Tomei is 6.15mm. Three sets of Tomei camshafts were measured to check this ranging from brand new ones out of the box, a pair 2 years old and a pair 6 years old, all the same. HKS pin is 6mm as well as Apexi. This was measured by a very experienced engine builder and double checked by a mechanical engineer with 40 years experience using Mitutoyo equipment.

Tangles Grand Master

Tangles

Posted
Posted

Ive got tomei poncams installed to RB25 with stock inlet camgear to retain VVT and aerospeed exhaust cam gear, adjustable

aerospeed cam gear was from a group buy a few years ago

installed and setup without any issues

I'll be using a pair of aerospeed adjustable cam gears with Greddy Street-Special N1 RB26 camshafts on my rb26 motor, when I build it and install into my stagea

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