Fw: Broke exhaust valves and 4ktq's (fwd)
orin at WOLFENET.com
Sun Mar 4 18:40:07 EST 2001
As he says, please copy replies to mardkins at email.msn.com
> From mardkins at email.msn.com Sun Mar 4 15:18:12 2001
> Message-ID: <006301c0a502$13579b40$fae00b3f at pattywack>
> From: "mardkins" <mardkins at email.msn.com>
> To: "Orin Eman" <orin at wolfenet.com>
> Subject: Fw: Broke exhaust valves and 4ktq's
> Date: Sun, 4 Mar 2001 15:23:07 -0800
> Organization: Microsoft Corporation
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> Orin, could you forward this to the main list and see if anyone has any
> ideas. I am not subscribed so they will need to reply direct.
> We finally got Seans car taken apart tonight and yet anouther broken
> exhaust valve. This time #3. This makes 3 confirmed valve breakages in
> 4ktq's that I know about. All seem to happen the same way. 2 of the 3 had
> good intercoolers 1 even being a stock 5kt intercooler.
> So it begs the question why? They were all running less than 15lbs of
> which 5kt's dont seem to have a problem with. The other 2 were in cylinder
> 4. They all apear to have broke near the base of the stem. So does
> know if the 10v turbo's in 5kt's have had problems with valve breakage? If
> they do I have never heard of it.
> I do have a couple of theory's though.
> 1: Fuel volume. One of the things they all have in common is they are
> using stock 4k fuel pumps. Is it possible that these fuel pumps arent
> supplying the volume to keep things cool. Sean did have an EGT guage but
> sadly was not watching it when it gave up. There does not seem to be
> problems with knocking and it does not show up on a oxy sensor reading as
> lean. Orin seems to think that they typically do not show enough detail to
> be worth much valuable information.
> 2: Transmission. With the stock 4kq transmission we are spending alot of
> time right near redline. This is true on PIR, Bremerton, and SIR.
> Could this be the problem. I have honestly not been watching 5ktq's
> tachometers on the track to see where they are running but I would guess
> they could run a bit lower in the rev band for 2 reasons. Longer gearing
> and better aerodynamics which helps them pull a little better at higher
> speeds without stressing the engine as hard.
> So please shoot these theories down if you think they are not valid or let
> me know any additional theory's you might have. Are there any solutions
> that could be had reletively easy. Sean needs to put his car back together
> and we both would like to feel better about pushing are cars.
> Thank you for listening and I cant wait to hear your suggestions/theories.
> Pat Martin
> 86 4000csq turbo, 2 1/2 cat back, H&R-Boge holdin it up, MC and loving it.
> Drilled and stopping it. Yokohama Avs intermediates turning it, K&N and uh..
> 84 4000sq AKA: The beater.
> 95 subaru legacy
> Bothell, Wa
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