sr20det cam question

[mat180]

i recently picked up an s14 sr20det

when i got it and opened it up, i found tomei 270 12.5 cams, tomei adjustable cam gear (exhuast, intakle is also adjustable but not tomei), and tomei rocker arm stoppers

one rocker popped off and another snapped in half,

the rockers, springs, and retainers all appear to be oem (looking at them side by side with oem peices i have)

i dotn know about the rest of the head peices yet, but it is using a metal hg

what can i expect out of this? those are some pretty serious cams running along side some oem peices that i would have thought should have been upgraded

kinda confused

thanks guys

any input would be appreciated

[mat180]

the engine was running a pretty serious turbo aswell, a td06 upwards of 20 psi, and injectors are not oem

at the moment there size is unknown but im looking into that

[CMG]

Umm, what are you asking? If you know the parts you have then just get the parts you know you need (springs, retainers, etc.)

[mat180]

i guess im asking is it possible to run such big cams on a sotck motor?

i didnt think so, but thats what appears to be happening here?

the motor was for sale till i found the busted rocker arms. then i started to get confused with what i saw inside

[carbully]

I will ask a question-Why did all that happen??

You had better measure the tops of all the valve stems to make sure they are all the same. That thing could have been over-revved and bent a valve. If that were the case that valve is probably stuck opened partially and would have a much shorter extended height above the cyl head when looked at from the back side (valve cover side). Put each cyl on TDC and measure the heights of the valve spring retainers to the cyl head or machined surface for the V.C. You will readily see one if it is stuck/bent.

My thinking would be that something had to break the rockers. Metal fatigue from the stronger cam? Perhaps, but it's easy to check for a bent valve from under the valve cover by doing this.

If you have access to a tester, I would do a Cylinder Leakdown Test at the same time. This will send a slight ammount of air pressure into each cylinder while it is at TDC and give you a percentage reading as to how much pressure that cylinder looses. If you have a lot of loss, you can hear where the air is leaking out of. If you have it leaking from the intake, you will find a bent or burned intake valve. Same for exhaust. Hear it coming out of the oil filler or dipstick or crankcase breather and you have a damaged piston/cylinder or worn rings. All this can be done BEFORE installing the motor.

[DrifterProdigy85]

Tomei 270 cams are way too big for stock valve springs. Chances are the reason the person got rid of the motor in the first place is because he broke the valvetrain. If a Rocker is snapped, theres a good possibility the valves are F'ed up there. I had a valve spring keeper pop off already and totally destroyed my old head. Completely broke 2 exhaust valves and bent 2 intake valves. Destroyed the piston, compression chamber, and scared the stock sleeve. I think your best bet is pull the head off while the engines out, asses the damages if theres any, and fix whatever needs to. Since you have the cams, upgrade the valve springs and reuse them. They wont hurt power using a stock turbo.

[Hijacker]

My thinking would be that something had to break the rockers. Metal fatigue from the stronger cam? Perhaps, but it's easy to check for a bent valve from under the valve cover by doing this.

I can guarantee valve float killed those rocker arms. The stock valve springs are too weak for a 270 cam, and in the upper rpm range, the valves begin to experience some float, and the rocker arms typically go first.

Bending valves typically only happens when the pistons contact the valves. I have rarely seen a valve stem get bent from a cam. Especially since on our motors the cams don't directly interact withe the valves.

[sr240sx20det]

if i were to get 270 cams for both intake and exhaust side. would i need to get the double spring valve springs. and how would i figure out what cams i should get for my engine? im boring out the motor to a 90mm getting cp pistons arp studs eagle h beam connecting rods and stock turbo.

[compactfean]

It depends what you are doing with the car. If you have a stock turbo I wouldnt use the 270 because the stock turbo runs out at high rpms. I have 270's with gt3071 t25 turbo and it puts your a** in the seat from 4k to 8500 rpm! The stock turbo seams to run out at like 6k so id get some 263's. Unless your gonna upgrade turbo later. On my car anything before 4k is kinda boring.