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-   -   compression/leakdown results, 3.0L (http://forums.pelicanparts.com/porsche-911-technical-forum/620090-compression-leakdown-results-3-0l.html)

Christien 07-19-2011 04:26 AM

compression/leakdown results, 3.0L
 
150k on the engine

135/10
140/8
140/7
135/8
135/7
135/5

Thoughts?

1990C4S 07-19-2011 04:28 AM

Track car? Weekend driver?

Christien 07-19-2011 04:30 AM

3 or 4 track days a year, daily driver in the summer, 8-10k km per year. Would be a replacement for my 2.4L.

dad911 07-19-2011 04:37 AM

Where is it leaking from? with 10% you should hear it out the exhaust, intake, or case, which would tell you if it's from valves or rings.

Christien 07-19-2011 05:56 AM

Don't know, just got those #s from the seller.

Christien 07-19-2011 07:23 AM

Would 10% on the one be anything to be overly concerned about? I'd like to get at least 4 or 5 years and 30k miles out of this engine before opening her up.

Brad394 07-19-2011 07:49 AM

Chris - is the engine local to you? 10% is up there, but like everything in life its who is doing the testing. Maybe you could go and check it out yourself ???

dad911 07-19-2011 07:50 AM

IMHO that test is incomplete and should give you more info. 7-10% is showing wear, which would be expected on a 150k mile engine. If I was buying/checking this out, I'd be more comfortable knowing it was leaking through the valves, and if so, I'd think about freshening the heads while the engine was out, or at least monitor the compression/leakdown annually looking for change.

As to a 30k mile guarantee, I don't think they were that long when new.... but I'd give it even odds of lasting 30k miles if I was a gambling man.

Christien 07-19-2011 07:54 AM

Not local, no - about 4000 miles away. The 30-40k mile/4-5 year is based on when I think I'll actually be able to get around to a DIY rebuild :) I've had my 2.4 on my garage floor for 2 years now, with no free winter in sight, until my kids are a bit older. I've got a 2.0L hot-rodded engine in there, but still only making about 135hp, and I'd like to get a bit more power in there. Price on the 3.0 is good, and I could likely sell the 2.0 for what I pay for the 3.0, or close enough.

Brad394 07-19-2011 08:02 AM

oh that is a hike. I did a quick google for the numbers - as I said - numbers alone are no real indicator. One quote form Wayne Dempsey -
The following is a quote from Wayne Dempsey's "How to rebuild and modify Porsche 911 engines". A book I regard highly.

"Good running engines will typically have leakage less than 10%. Engines with significant problems will exhibit leakage of 30% or more."

Also in checking - temp of test, as said hearing a leak, etc have a bearing on results and money to be spent. That 10% may be significantly lower on a running engine.

Hey, your kids are old enough - I have had my youngest in the garage with me since she was 5 months old... and now she has been bugging me lately that she has only had one track day this year and no seat time. cayuga will let you drive on track with your kids over 6 ( junior dragster waiver ).

Brad

Christien 07-19-2011 08:04 AM

Funny, I asked them when I was there last week, they said 16! I might just try to sneak her out for a few laps... :)

I know it's a bit of a gamble, and I'm trying to weigh the risks and benefits. In the end, it's not like it's huge money, but still, I'd hate to get a year out of it then need to rebuild it.

mholbrook38 07-19-2011 08:30 AM

I would drive it a while, adjust the valves and re-test. In any case, 3.0 engines are great.

Brad394 07-19-2011 08:30 AM

The engine - check to see if a Pelican can check for you ??? I did that when I was looking at a 3.2 in Philly back in '06.

as for your daughter, I was taking Holley out in the car for 2 or 3 events ( evenings ) then I was confronted by staff (female) about not doing it ... after I discussed things with her - she had me sign the junior dragster entrant form/waiver. Hey they are on track racing. I drive different with her in the car - she is only 8 - but she watches the data and tells eveyone she likes going "G speed" which is anything over 1.? g.

we should meet at cayuga one wednesday/friday evening

Brad

Christien 07-19-2011 08:32 AM

You bet - I plan on going at least once a month for the rest of the season. It's so close, and so cheap. I wish Mosport was that close!

Brad394 07-19-2011 08:39 AM

ya I know - for me its less than 30 minutes away -

yelcab1 07-19-2011 08:56 AM

I would not pull the engine for a rebuild just on 10% leakage. But, that is me.

BK911 07-19-2011 09:33 AM

10% does not scare me, but one at 10 and one at 5 is a little concerning. As others have stated, you need to know where the leakage is from. If a valve, you could pull a head and lap a valve. That may drop it some. If rings, nothing you can really do without a tear down.

As a reference, my 914 is about 12% across all 4 and runs great.

dad911 07-19-2011 11:10 AM

Quote:

Originally Posted by yelcab1 (Post 6145294)
I would not pull the engine for a rebuild just on 10% leakage. But, that is me.

Neither would I, but it's out and OP is buying it. It's out now.

Would you buy an engine with 10%, take out a good motor, install the 10% motor, and expect it to last 30k miles? Not sure I would......

yelcab1 07-19-2011 01:43 PM

10% leak in one cylinder = a lower price.

You pay your money you take your chances.

1990C4S 07-19-2011 01:51 PM

I would drive for a season as is, and be prepared to fix it. A nice winter project.


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