Going back to stock cams (RB26)

[N155@N]

Hi SAU,

As the title states, i'm wanting to go back to stock cams on my R33 GT-R as the cams that are in the car at the moment are totally mismatched, plus i'm looking for more of a responsive setup. The cams in there at moment are HKS Step 2: INT=264 duration 10.2mm lift, EXH=272 duration 10.0mm lift. The cylinder head has been CNC ported.

Don't know to much about machining.

My question is: Will stock cams fit in this cylinder head? The HKS cams are rather big compared to stock (INT=240, EXH=236). I wasn't the one who built or commissioned the build of this engine so I wouldn't have a clue how much head work has been done. 

I'm aware that clearance work is done to fit some cams. Would replacing a larger cam with a smaller cam be possible? Or has there been to much 'cylinder head material' removed, making a smaller cam loose/not fit? (my lack of mechanical knowledge is showing lol)

Any and all help appreciated.

[WMDC35]

Should be no problem going back to stock cams, will most likely need re shimming

[djr81]

The clearancing is done to allow the larger cam lobes to rotate.  They do not have any effect for the smaller lobes.  There is no change for the caps etc.

[GTSBoy]

OP,

I see your other thread asking to buy stock cams.

If you don't have any stock cams and therefore have to pay for them.....why would you do so? Just buy some nice Camtech or other decent Aussie cams that a bit milder than what you have? There are great options available that will be really responsive, and 10x better than the stockers. Not least because you will be surrendering a LOT of lift going back to the baby stockers.

[Ben C34]

Before doing any pulling out of stuff try advancing inlet cam (go for 6vdegrees and work from there.)

[N155@N]

Appreciate the replies guys. Learnt a bit from your responses.

As for cam selection, im just going by what my mechanic/tuner (Racepace) is suggesting. Ill have a look at what other mild cam choices there are, however at $100-$200 a pair, stockies arent going to break the bank.

As for advancing timing, thatsl was pretty much already taken care off during tuning.

Thanks 

[GTSBoy]

10 minutes ago, N155@N said:

however at $100-$200 a pair, stockies arent going to break the bank

Yuh, but that's just the purchase price of the cams. On top of which you have to throw money at the workshop to open the engine up and swap them and do the clearances (and probably some tuning). Once all that is on top, the extra money for a proper cam is not actually that big an increment.

[N155@N]

1 hour ago, GTSBoy said:

Yuh, but that's just the purchase price of the cams. On top of which you have to throw money at the workshop to open the engine up and swap them and do the clearances (and probably some tuning). Once all that is on top, the extra money for a proper cam is not actually that big an increment.

Yes that's true. Head is lifting due to dodgy tune from previous owner's tuner. My mechanics certain it's just a head gasket (fingers crossed its's just that) so engine out, recondition, new gaskets, tuning etc. Thought this would be opportune time to get cams changed while heads of and dismantled. 

For a 2.8L, with hks 2530s, running e85, what cams should I have? (street driven so response is priority)

Poncam type B's are another recommendation for $1K and Camtechs lowest duration set are priced the same. My only hesitation is; will my gains from buying a new set of aftermarket cams for $1000 be even worth it? 

I want to go with my tuners advice as they are pretty much  the go to guys here in Melbourne for RBs/GT-Rs, but I'll definitely be asking him if there is worthy benefits to the cams mentioned above. 

Will also be going through dyno results forums.

 

[GTSBoy]

A ported head will really really benefit from the extra lift. You'll be stifling it and giving away a LOT of power. I'd do it (buy cams), and I'm allergic to spending money.

Camtech.....I'm a bit WTF!? at the moment. I just went to look at their site and they don't show RB26 cams. What am I missing?

If I was to use their RB25 Neo cams offerings as a guide, I'd suggest...actually nothing. I'd want a 10mm lift at least, on the 264s°.

Unigroup do an 11mm lift on 260°. They have others (less lift, but I'm not sure exactly what's on offer) too. I'd be thinking that if your head is all coming off and apart, then whatever is needed done to fit those (in case any more clearancing is required) would be worth it.

Kelfords (Christchurch) have a couple of options. This https://www.kelfordcams.com/nz/camshafts/nissan/rb26dett/182-b-camshaft-set.html is 260° & 10mm. They will also custom up a cam. So if you wanted something with 10.5 mm of lift (they have some, but with more duration than you seem to want), they could be persuaded to cook something up.

[N155@N]

30 minutes ago, GTSBoy said:

A ported head will really really benefit from the extra lift. You'll be stifling it and giving away a LOT of power. I'd do it (buy cams), and I'm allergic to spending money.

Camtech.....I'm a bit WTF!? at the moment. I just went to look at their site and they don't show RB26 cams. What am I missing?

If I was to use their RB25 Neo cams offerings as a guide, I'd suggest...actually nothing. I'd want a 10mm lift at least, on the 264s°.

Unigroup do an 11mm lift on 260°. They have others (less lift, but I'm not sure exactly what's on offer) too. I'd be thinking that if your head is all coming off and apart, then whatever is needed done to fit those (in case any more clearancing is required) would be worth it.

Kelfords (Christchurch) have a couple of options. This https://www.kelfordcams.com/nz/camshafts/nissan/rb26dett/182-b-camshaft-set.html is 260° & 10mm. They will also custom up a cam. So if you wanted something with 10.5 mm of lift (they have some, but with more duration than you seem to want), they could be persuaded to cook something up.

For camtech https://camtechcams.com.au/camshaft-search?c_association[1]=14&c_association[2]=56&c_association[3]=126&c_association[4]=127 

Will be doing some cam research in regards to everything we've talked about, before the big day.

 

Thanks GTSBoy

[DiscardTheWeak]

On 7/15/2019 at 9:31 AM, N155@N said:

For camtech https://camtechcams.com.au/camshaft-search?c_association[1]=14&c_association[2]=56&c_association[3]=126&c_association[4]=127 

Will be doing some cam research in regards to everything we've talked about, before the big day.

 

Thanks GTSBoy

Hey there, did you ever get your head sorted out. I have a similar issue, where I have an overbuilt CNC ported head with oversized valves, but am switching to 2530 ish size turbos. I have 260 10.2 procams that I can use, I’m just kind of worried about that the big power work on the head will affect low end power. The bright side was I hoping to make power at lower boost.