Built HR *Broken Cam* Part 2
jay when we drove around on it , it didnt sound like it was leaking.. good thing you found it tho..
Regarding a leak..non fi.. how much power can be lost due to a leak? Major ? minor?
Regarding a leak..non fi.. how much power can be lost due to a leak? Major ? minor?
Actually Ehsan its always sounded like a leak at idle. I as reassured it was not leaking after having it looked at. Obviously it was lol
^ That's what is troubling and suspicious about this. It makes absolutely no sense from a technical standpoint to put aftermarket springs on stock cams, and according to the car owner's posts here on page 1, he didn't ask for them. He stated that it was the suggestion of the shop and that springs were the last thing on his mind. He also stated that the redline remained stock after the springs were installed.
The shop involved hasn't addressed these points and has yet to explain why they recommended aftermarket valve springs.
The shop involved hasn't addressed these points and has yet to explain why they recommended aftermarket valve springs.
1. The customer (not being specific to the OP) saying that he/she may want to do cams in the future if their power needs increase or as budget allows, so they opt to do the springs while the motor is out to save future labor cost on install
2. The shop makes the offer to the customer either in good faith, expecting the customer to upgrade cams soon, or as a way for them to get more money out of the initial build process knowing that once people have their wallets open for an engine build they are more likely to dump a few hundred extra dollars on ancilary parts, especially if they are sugested under the guise of "safety".
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Joined: Aug 2010
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From: Tampa, FL
those leaks that he found are actually after the primary O2 sensors, so no, this would effect anything... also, since these are catless downpipes, the tuner would have turned off the secondary O2's so those wouldnt be sending back crazy signals, either.
This is incorrect, our ECU's (gen2 at the minimim) do in fact use the lower sensors in closed loop corrections -- I've done all my own tuning and have logs to prove this; I'm no armchair tuner. And sensors aren't 'turned off', the DTC is simply disabled.
Last edited by djamps; Apr 11, 2011 at 07:01 AM.
Even not considering the performance aspect but where they are located would cause alot of fumes in the cabin
You guess? ...So the lesson wasn't learned.It's foolish to leave the BC springs in there with the stock cams. Nobody has provided a good or valid reason to exert higher spring pressures on stock cams with a stock rev limit.
Last edited by RudeG_v2.0; May 15, 2011 at 07:14 PM.
I think i've heard of this happening on aftermarket cams also where the installer used an impact gun to tighten the bolts. That obviously caused a weak spot and the cams cracked.
well considering I did this in my spare time I didnt feel the need to re assemble the head nor take the heads off and have to buy a new hks head gaskets. If it snaps again I will be the one removing the cam again. So, yeah call me foolish. We will just have to see. If after zdayz jay ( owner ) decides to get cams I will tackle that then. I understand your concerns though and thanks.
JWT have a set up so you can change springs with heads on the engine, you push air into the cylinders so the valves dont drop. I think they are fairly cheap he just gave me one after my cam broke and I decided to change the springs and cams at the same time.
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no, you would be surprised. OEM cams can be pretty weak compared to aftermarket bits.
knew a guy localy that did a cam shootout for SR20s years ago. dyno tests, etc... the final element (which is retarded, but i *did* learn something) the cams had to endure was whacking them across a bench vise. for him, it was just because 'he could'. obviously, i would never do something like this. any route, the OEM cams snapped immediately. one of the aftermarket cams (couldnt tell you which one, i had no idea) took one hell of a beating and just wouldnt snap, so forth and so on. HAHAHA it's just one of those things where, well... i would never even have thought to subject a cam to, but damned if i didnt want to watch it and see what would happen.
knew a guy localy that did a cam shootout for SR20s years ago. dyno tests, etc... the final element (which is retarded, but i *did* learn something) the cams had to endure was whacking them across a bench vise. for him, it was just because 'he could'. obviously, i would never do something like this. any route, the OEM cams snapped immediately. one of the aftermarket cams (couldnt tell you which one, i had no idea) took one hell of a beating and just wouldnt snap, so forth and so on. HAHAHA it's just one of those things where, well... i would never even have thought to subject a cam to, but damned if i didnt want to watch it and see what would happen.
I have a Tomei 268 in the garage...severed just like yours. my first broken cam...happened back in 2007 with about 500 miles on my build. after everything was taken out, checked by the machine shop, and new cam put in...no problems since. retuning for 1000 hp soon.
Last edited by Old School; May 18, 2011 at 10:16 PM.
If the valve happens to fall down it won't go far because the piston is in TDC therefore the valve will rest on the piston.