R32 Rb26 Camtech 272S?

[Dauntess]

Does anyone have experience with the Camtech CTRB26 445B cams in an R32 RB26DETT? They claim to be drop in, can the stock valve springs be reused safely and no other mods required?

[ahh 33 s2]

it would depend on the lift to some degree, i have just installed tomie 270s, but with the 10.8mm lift i needed springs and the head to be resessed to allow th cam to turn with out fowling

[Beer Baron]

honestly, I would not upgrade cams in an RB26 to anything without doing valve springs. valve springs get tired and the last thing you want is your 100,000km old springs now having to deal with more lift. so yeah, if doing cams (regardless of the lift - they all have more lift than standard) do springs at the same time.

[Dauntess]

Thanks for the info. They are listed as 272 degree duration and 9.7mm lift. Is any machining of the head required to run these?

[Piggaz]

Yes. Poncams are considered the largest lift you can go without machining the head. They are 9.15 mm.

[T04GTR]

unless they use a smaller base circle

[Dauntess]

Though if they used a smaller base circle they wouldn't be a direct drop in either. Can somebody link me to what is involved in clearancing a head for bigger cams? Sorry for the newbie question.

[GTRNUR]

Unless you want to pull the head off the engine so you can clearence it without worrying about debris falling into the engine, then forget about high lift cams. If it requires clearencing, its far from a drop in affair.

Unless as TO4 says, the cams might use a smaller base circle, which means re-shimming the valves. Not a task for the typical back yarder. A reduced base circle cam runs the same peak lobe height as a 9.15mm cam, but runs the back of the lobe (base circle) at a reduce diameter. Thicker shims are added to raise the bucket further off the valve. This translates to more lift at the valve, with no need for clearencing.

But I really agree with beer baron. 272's should have a step 2 spring and are typically used in engines that rev to 9k. The whole point of longer duration cams is to move the peak torque point further up the rev range. Running 272's with standard springs will give you 2 results.

1. A reduced usable RPM power band

2. A wonky idle.

Add any meaningful level of boost and you start getting valve float with standard spring/standard 8.7mm cams at around 7500. Higher lift and duration will bring that RPM level down considerably.

Edited July 29, 2011 by GTRNUR

[T04GTR]

new valve springs should be used. id recomend supertech. cheap and really good. also not hard on the valve train. tomie do +1mm buckets for the 30mm base circle cams. (putting to thick a adjusting shim can have issues)

either way its a $1300 exercise just for the bits, but a nessesary expence) if you are not chasing huge power just get pon cams.