Oversize Valve Selection - Rb26dett

[Blitz]

Hi guys,

Im in the process of planning some head work and looking at the available options in the way of a 1mm oversize valve set for my RB26 head and im hoping someone can shed some light on exactly what is available and from where. Ferera, Nitto and Naprec are the only brands I have heard of, are there any others worth looking at?

Also on this subject, what other components in the head will need to be changed to facilitate the larger valves?

Thanks

[Faid]

Hey dude i had my oversize valves made by manley in the US. they fabricate head components for muscle cars but they do custom orders. the valves have exelent alloy propertys and havent shown a sign of wearing, even using my 10.35mm lift cams. youll need to change the retainers, the springs, the lifters, the valve stems need to be complety reworked, and your head will need a nice port and polish job to suit the rest of the components. if you have any questions feel free to pm or mail me. ill do my best in helping you setup your head

[legend01]

Hi Nick

Give proengines a call he makes his own valves and gets some after market types as well check this out might explain more, http://proengines.com.au/perhead.html might help

Cheers Peter

[Duncan]

Or talk to nas at thornleigh he did 1mm oversize valves for us, not sure of the brand of valves. Apart from the valve seat nothing else had to be changed for the valves, although we did get the head releived to clear the cams at the same time, and porting of the inlet (and a clean up on the zorst side)

[Adriano]

Fitzpatric speed works has a set of 1.5mm o/s for sale for $600, but im sure you already know that

[Adriano]

Or talk to nas at thornleigh he did 1mm oversize valves for us, not sure of the brand of valves. Apart from the valve seat nothing else had to be changed for the valves, although we did get the head releived to clear the cams at the same time, and porting of the inlet (and a clean up on the zorst side)

Curious why they would port the inlet and only clean up the exhaust side, when it is common knowledge that the exhaust side is where rb's need the most work

[r33_racer]

any good workshop should be able to make custom oversize valves from blanks.

[BOOSTD]

Curious why they would port the inlet and only clean up the exhaust side, when it is common knowledge that the exhaust side is where rb's need the most work

retain boost response

[Fitzpatrick Speed Works]

Nick having used a few different brands over the years heres a little wrap up I have made

FERREA are far and away the best....

NAPREC are bigger being 1.5mm oversized but the trumpet angle is the same as standard, around 16 degrees, now this is far from optimal and something nissan could have done better, as the greater the angle, the more flow. They are still good though and do as well as the FERREA's in flow testing just a hassle to order them.

Haven't used Nitto or whatever, but I have used Ferrea's a few times and they are good quality at a good price and have 20 degree angle.

Manley are awesome but you can only get them in blanks, getting them to make customs for you is like having a baby, it takes a long time there is a lot of pain in the arse and crotch but you get a good result at the very end!!!

Hope this helps

[Duncan]

yeah I don't want to get too far off topic but mine is a fairly low reving race motor where i need boost early. will be interesting to see how it performs

[proengines]

I've currently got 2 heads here that I'm doing, one using 1.5mm o/s Naprec valves and one using 1mm o/s Ferreas and personally I would go for the Ferreas. They have a better finish, for example the raduising on the valve heads. The Naprec valves use a 6mm stem on both intake and exhaust which require custom exhaust guides while the Ferrea uses a 7mm exhaust stem, the same as standard so you don't require different guides or seals.

Another option is the Pep Pro valves, these are sold by Austral distributing. They are Taiwanese and are a top quality valve and a little cheaper than the others, definitely cheaper than a genuine Nissan valve. They are made by Shin Ichi which distributed in the US as SI Valves. I have used them in a lot of different engines without any failures.

After saying all that, the standard valves dont have issues. I have a head here that made over 700 RWHP with standard valves and they look like new.

[Tim_zenki]

Hey dude i had my oversize valves made by manley in the US. they fabricate head components for muscle cars but they do custom orders. the valves have exelent alloy propertys and havent shown a sign of wearing, even using my 10.35mm lift cams. youll need to change the retainers, the springs, the lifters, the valve stems need to be complety reworked, and your head will need a nice port and polish job to suit the rest of the components. if you have any questions feel free to pm or mail me. ill do my best in helping you setup your head

what exactly has to be done to the valve stems? if they needed to be modified, i would think the valve keepers would need to be as well?

[PranK]

what exactly has to be done to the valve stems? if they needed to be modified, i would think the valve keepers would need to be as well?

Hey Tim,

Might be worth starting a new thread as this one is from 2007 and info is bound to be out of date now.