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Camshafts, Camshafts And More Camshafts

N1GTR

By N1GTR,
in Engines & Forced Induction

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N1GTR Grand Master

N1GTR

Posted
Posted

Hey guys,

Ive put tomei cams in my current motor, and to my suprise had to buy new buckets as i didnt realize they have a different base circle to stock cams. Turns out im not the only one who's fallen for this trap.

As an example, i thought cams would cost about 1k, but then add the buckets and thats 2k. Now, if HKS (for example) cams are 1400 but dont require buckets then you're about 600 infront overall. Make sense?

So, this thread is to hear peoples experiences with cams - who's had success with what etc but more importantly; Do JUN cams require bucket/shim/whatever changes? I know springs should be changed to match lift - but other than springs, what else needs to be changed?

I need to get cams for the next motor im building, which is underway currently (starting from bottom end first) and would love to just get the right cams this time without spending huge amounts of coin

Thanks everyone :wave:

Swiper the Fox Grand Master

Swiper the Fox

Posted
Posted (edited)
Hey guys,

Ive put tomei cams in my current motor, and to my suprise had to buy new buckets as i didnt realize they have a different base circle to stock cams. Turns out im not the only one who's fallen for this trap.

As an example, i thought cams would cost about 1k, but then add the buckets and thats 2k. Now, if HKS (for example) cams are 1400 but dont require buckets then you're about 600 infront overall. Make sense?

So, this thread is to hear peoples experiences with cams - who's had success with what etc but more importantly; Do JUN cams require bucket/shim/whatever changes? I know springs should be changed to match lift - but other than springs, what else needs to be changed?

I need to get cams for the next motor im building, which is underway currently (starting from bottom end first) and would love to just get the right cams this time without spending huge amounts of coin

Thanks everyone :wave:

The base circle dictates what size shim you require to get the clearance right...JUN like to tell you to use a really thick shim to make this clearance right...i dont recommend this...the thicker bucket is always the better more reliable way to go, which is how Tomei do it. PM unique1 and ask him what happens when you run a 'tall' shim instead of the thicker bucket and a reasonable size shim...it will cost you a lot more than doing it right once. Please don't take short-cuts mate...id hate to see you bitten again.

Edited by DiRTgarage
Swiper the Fox Grand Master

Swiper the Fox

Posted
Posted (edited)
I have held off on cams due to this same shim/bucket issue, cam upgrades dont seem to be such simple "drop in" jobs as the kits suggest.

32mm base circle cams are a 'drop in' nothing else. Id suggest anyone putting 32mm base circle cams in to do a quick bucket clearance check just to make sure its ok.

Edited by DiRTgarage
Tangles Grand Master

Tangles

Posted
Posted

rb25: Tomei 256deg cams and 8.8mm Tomei springs are a good fit ! :(

rb26 - dunno sorry, but something like the above would probably only be "mild" on a built rb26. 272's then, perhaps.

what turbos, bottom end combo will the head be utilising, plz ?

Swiper the Fox Grand Master

Swiper the Fox

Posted
Posted (edited)
yeap i've been bitten by using JUN cams with standard buckets and big shims. Destroyed the entire head when the sim popped out of the bucket. Had to do it all again. :)

yeah...another one eh...bummer.

if you look on the JUN website it lists the 'tall' shims they advise you to use. In my opinion this is a dangerous practice and has been proven so with many shim 'pops'. Did you use the JUN offset retainers as they have 2 offset types that take up 0.5mm and 1.5mm clearance respectively?. With a 29mm base circle camshaft if you use the 1.5mm offset retainer and the 1mm thicker Tomei bucket you only have to use around a 0.5mm thicker shim than standard. This is the best way to go if using 29mm base circle cams.

Edited by DiRTgarage
N1GTR Grand Master

N1GTR

Posted
  • Author
Posted
I have held off on cams due to this same shim/bucket issue, cam upgrades dont seem to be such simple "drop in" jobs as the kits suggest.

Exactly

From further investigation it looks like JUN sell a package including buckets etc

rb25: Tomei 256deg cams and 8.8mm Tomei springs are a good fit ! :)

rb26 - dunno sorry, but something like the above would probably only be "mild" on a built rb26. 272's then, perhaps.

what turbos, bottom end combo will the head be utilising, plz ?

HKS GT-RS's

Full built RB30 bottom

unique1 Mentor

unique1

Posted
Posted (edited)

i wasnt the person who had issues Dirt it was Public Enemy i think u were thinking of. I run the biggest lift cams Jun make and never had an issue in 2 years+ of over 550rwhp and 8500rpm+, i recently bought a set of Tomei buckets though after hearing of the possible dramas, just to keep my mind at ease.

Edited by unique1
N1GTR Grand Master

N1GTR

Posted
  • Author
Posted
i wasnt the person who had issues Dirt it was Public Enemy i think u were thinking of. I run the biggest lift cams Jun make and never had an issue in 2 years+ of over 550rwhp and 8500rpm+, i recently bought a set of Tomei buckets though after hearing of the possible dramas, just to keep my mind at ease.

So until then you used standard buckets?

unique1 Mentor

unique1

Posted
Posted
So until then you used standard buckets?

yes standard buckets and bigger shims from precision shims. the shims are pretty damn thick due to the small base circle so it isnt ideal at all, but it works none the less, but im changing them over just to save a disaster arising after hearing about Public Enemy's dramas.

Public Enemy Community Regular

Public Enemy

Posted
Posted

yeah i used the JUN cam package that includes cams, Titanium retainers and type 2 springs. My understanding was that this package would be put together to be compatible with the base circle of the JUN cams. The shims were huge from memory and destroyed the retainers when they came out and then the retainers cracked the standard lifters which messed up the casting of the head. Lotta $$ porting and polishing that head and it went in the bin :P

Ah well live and learn.

Anyway now using Tomei 272 10.8 cams, Tomei buckets and Tomei type C springs.

So far so good but only a 1000 odd Kms on this step up.

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