max valve lift on hks 3.4 stroker ?

its a long shot but im wondering if anyone has experimented with high lift cams and a hks 3.4 stroker, at what point does piston - valve contact become an issue assuming pistons are stock hks items with no extra pocketing ?

the biggest cams hks list is 272d 9.1mm lift which i currently have but want more for the new head. i dont want to remove pistons for machineing just head and cams change. id like to order the cams if i can find out maximum lift and duration i can run.

Have you tried asking on supraforums...!

Titan 280 10.4 mm lift gets nowhere near the piston but is interferance.

Does running interference (sounds like American Football) mean that the timing options are limited then?

Does running interference (sounds like American Football) mean that the timing options are limited then?

it means if your cambelt snaps pistons will hit valves.

Titan 280 10.4 mm lift gets nowhere near the piston but is interferance.

thats handy to know cheers fella, what rpm limit do you run at ? hks state 7600 rpm max.

it means if your cambelt snaps pistons will hit valves.

I know that. When the timing belt snaps the timing is lost so when the valve is down there is a chance that the piston will be up.

This is why I asked if the timing options are limited. Ie, if you add to much timing do you risk the piston being at TDC while the exhaust valve is out fully.

Does running interference (sounds like American Football) mean that the timing options are limited then?

No not at all.

No not at all.

do you know upto what lift that is mate ?

thats handy to know cheers fella, what rpm limit do you run at ? hks state 7600 rpm max.

9200 at the moment, 10,000 if im losing a race !!!!!!!

I know that. When the timing belt snaps the timing is lost so when the valve is down there is a chance that the piston will be up.

 

This is why I asked if the timing options are limited. Ie, if you add to much timing do you risk the piston being at TDC while the exhaust valve is out fully.

this is the exact question im asking the limit of cam lift / duration on a 3.4 hks stroker, just considering cam options.

it means if your cambelt snaps pistons will hit valves.

Correctomundo

9200 at the moment, 10,000 if im losing a race !!!!!!!

have you had extra balancing done ? does it proove reliable at that rpm ? fair play fella

do you know upto what lift that is mate ?

We put a thick slab of plasticene on a piston and I set the pulleys at TDC, full retard and full advance and the valves never touched the plasticene, I can't see why you would want to go more than the 280 10.4's which will pull way past 10,000 rpm. My car was still idling at 1000rpm with a 4" TB and no IAC.

have you had extra balancing done ? does it proove reliable at that rpm ? fair play fella

Yes I balanced the crank and rods and pistons my self, I could not get them any better with the scales we were using and the machine I have acsess to, to be fair they were very good as they were. I also balanced the flywheel and clutch cover.

Correctomundo

Can you have a look at my query John. Not really got an answer on it.

I know that interference means that the piston and the valve, at different times, occupy the same space. Surely if you altered the timing too much one way, too much the other way or increased the lift by too much there would be a chance of them hitting?

Can you have a look at my query John. Not really got an answer on it.

 

I know that interference means that the piston and the valve, at different times, occupy the same space. Surely if you altered the timing too much one way, too much the other way or increased the lift by too much there would be a chance of them hitting?

If a cam belt snaps with an interferance cam the motor is toast, if it jumps a few teeth the point of contact is far more likely to be the valves hitting each other and not pistons !!!! Re the timing check my other post in this thread.

If a cam belt snaps with an interferance cam the motor is toast, if it jumps a few teeth the point of contact is far more likely to be the valves hitting each other and not pistons !!!! Re the timing check my other post in this thread.

Cheers mate, so potentailly the valves could touch the pistons if you went to far with timing and had really long/high duration cams. But in this particular scenario you have tested full retard and full advance with no touching.

Not sure how I missed those replies, must have been in quick succession lol.

Cheers

Titan 280 10.4 mm lift gets nowhere near the piston but is interferance.

Is that with the stock head gasket thickness and pistons?

The 10.8mm lift JUN cams are suppose to make the engine interference.

I was running a BC 3.4 stroker with my own 280 9.9mm lift cams and had plenty of clearance to. When my timing belt tensioner sheared off I bent 12 valves(from memory) so had to rebuild the head, everything else survived. I used to run it to 8500rpm on the race track without any revs related problems anyway, revs wise it depends on what turbo setup you have, no point in revving it if the power is dropping off.

I was running a BC 3.4 stroker with my own 280 9.9mm lift cams and had plenty of clearance to. When my timing belt tensioner sheared off I bent 12 valves(from memory) so had to rebuild the head, everything else survived. I used to run it to 8500rpm on the race track without any revs related problems anyway, revs wise it depends on what turbo setup you have, no point in revving it if the power is dropping off.

its on a t51r spl bb but power does start dropping from 7k rpm mainly due to cam timing i think as both cams are 4d retarded, im not sure on exact spec of current head but i have an andy @ amt head ready to go fully ported with 1mm bigger valves.

its on a t51r spl bb but power does start dropping from 7k rpm mainly due to cam timing i think as both cams are 4d retarded, im not sure on exact spec of current head but i have an andy @ amt head ready to go fully ported with 1mm bigger valves.

Why are they both retarded?

Why are they both retarded?

i honestly dont know its how it was when i bought the car 8 weeks ago, its been on the dyno and is safe but more power and better spool should be available with better cam timing, i think id rather wait til the new head is on then have cam timing optimised. i may be going bigger cams aswell.

i am going by the hks cam pulleys i havnt actually checked it, but seeings as the whole engine is all hks im assuming there quite accurate.

i honestly dont know its how it was when i bought the car 8 weeks ago, its been on the dyno and is safe but more power and better spool should be available with better cam timing, i think id rather wait til the new head is on then have cam timing optimised. i may be going bigger cams aswell.

i am going by the hks cam pulleys i havnt actually checked it, but seeings as the whole engine is all hks im assuming there quite accurate.

Yeah probably best to wait until the head goes on. If you need some cams, my 280 9.9mm lift version will work a treat on your setup.

Is that with the stock head gasket thickness and pistons?

 

The 10.8mm lift JUN cams are suppose to make the engine interference.

There is no question the engine becomes interferance Nic, Scott means if clearance is fine at TDC is it still fine when retarded or advanced.