Pressure testing the intake system .......Chapter 3
cpcycle at earthlink.net
Wed Aug 4 22:10:54 EDT 2004
Thanks for the info Derek.
Derek Pulvino wrote:
> Look for some posts I sent in a couple of months ago on the topic. I
> don't remember what the "subject" said, probably something about oil
> leak, but that's where all the discussion I'm aware of wrt to oil
> leaks, leak down, and compression testing should tie back to. It
> shouldn't be too hard to find though, as I haven't posted much
> lately. So if you do a search for my email/name, you should find it
> within about 20-back.
> In a nutshell, the data I picked up seemed to point towards high leak
> down in the block which is causing increased crankcase pressure and
> thus forcing more air/oil out the breather hose to the intake. The
> worst offender was cylinder-three. Though I was informed the numbers
> I got are in the "rebuild" range, the car still runs fairly well. I
> thought about trying to compare the % leak-down to the "good" range
> given for our cars in the Bentley under "compression testing," but
> nobody really knew if that would work. IE range in the Bentley for
> good from say 190-130 psi would equate to a "good" leak down to 68%
> (ie 130/190=0.68). Ah hell, it works for me, and I pay the bills so...
> Some people I've talked to have talked about the turbos leaking, but
> not a lot of data there either. The other thing I thought of with the
> leak down test...not sure leaking valve stems and guides would show up
> in the test UNLESS those leaks/loss of tightness also result in the
> valves not seating correctly. Also, I noted that your consumption is
> fairly close to what I've observed in the past.
> In other news (on the consumption) I haven't checked again recently,
> but for some reason ever since I did a t-belt and made sure ALL of the
> intake plumbing was snug, my car runs smoother, and it seems like the
> consumption has gone down. First makes sense, second...not so much,
> but I'll confirm over time. At any rate, I've not been a quart down
> since I did the belt and changed the oil...?
> Derek P
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