cwin

Hi Guy's

I am new on here and from sunny UK

I run a Mazda RX7 Track car with a Stroked LS2 fitted,the engine has all the forged internals Trick flow heads ect,ect,it made 674 fw hp.

My problems are with cam chains,just broke the 3rd one in 12 months,what are we doing wrong or do they make a cam gear set that will do away with the chains?

1 of the chains we broke was a duplex one the other was a ls2 factory one not sure about the 3rd will need so speak the the engine builder?

I am not bothered about the whine or noise as it is just for trackwork we run a straight cut box anyway just need some reliability with the engine.

Here is the car............

PLEASE HELP

Regards

Craig

jay_lt4

iTrader: (4)

i think this is what you aree looking for, this is the ls1,6 version they dont know if they make a ls2 version with the cam reluctor or not?






http://www.hardcorels1.com/vbulletin...ead.php?t=1448






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Disturbed Bird

iTrader: (9)

have you tried a ls2 double roller timing chain? i dont think you will break one of these!

dubrado

iTrader: (20)

try a c5R chain, I haven't seen anyone break one of those.

T/AWS666

iTrader: (7)

+1 for the c5r

tinker-27

it had a dual chain fitted first which broke then a comp cams chain broke then a std one, i dont think a c5r one is that much better (and they are not avaliable at the moment) we are after the reasons some of these motors snap chains any ideas ????????, ps all the valve train is correct,and we have changed the underdrive,

Disturbed Bird

iTrader: (9)

if your braking a double roller then you need to check out that motor you have something wrong

Haans249

iTrader: (24)

I agree, something is not right. What transmission are you using?

DrkPhx

iTrader: (15)

Are you using the LS2 timing chain damper that bolts to the block between the crank sprocket and cam gear? That definitely helps, though you may have other issues going on. How high are you spinning the motor and what crank pulley are you using?

sixpack_2_go

iTrader: (1)

i have been wondering about LS gear drive too. i haven't heard of anybody actually producing one, but i have keeping my eye out. you might try a good double roller timming chain.
p.s. badass car man!

vettenuts

iTrader: (4)

Two things, harmonic damper and timing chain damper. What harmonic damper are you running? Do you have the timing chain damper in place?

jay_lt4

iTrader: (4)

http://cgi.ebay.com.au/HOLDEN-GEN-3-...228148001r6780

sroach20

iTrader: (31)

i thought gear drives had a problem with producing false knock?

drz

iTrader: (3)

Broken timing chains in road-race applications are typically caused by cheap/ineffective crank dampers that allow bad harmonics to pass into the chain. Get a REAL damper designed for sustained rpms and you shouldn't have any problems.

You can call up ATI and have them spec you a custom damper specifically for your engine. They can juggle damper shells, inertia weights, and rubber ring durometers to match your engine and application.

http://www.atiracing.com/products/da...ting/index.htm

tinker-27

it does have a chain dampner inbetween the chain and its a slp damper as recomended by one of ls1 techs sponsors to cure this problem (it had a spi-sfi cant remember) one on it before i do agree there is something wrong thats why we are asking for help, the first chain lasted for a whole year of racing and track days and this last one lasts 4 hours !! we are reving it to 7,000 but it goes mid corner on part throttle every time !!! its a t56 box,

drz

iTrader: (3)

This only reaffirms the damper as the most probable source of the problem - sounds to me like the crank is hitting a harmonic resonance in the mid-range somewhere. If the resonance is really bad, you may have simply hit a bad combination of parts (flywheel, rods, crank, damper). Seriously, call up ATI and see what they have to say about the problem. It's only a phone call, and even the secretary there will know more on this subject than 98% of all the ls1tech sponsors.