3.0 Compression Results Advice

[911gilley]

Hello,

I am currently looking for a 3.0 engine for my project car. This past weekend I went to look at one (an '82 3.0 with a reported/documented 77K miles, Carerra tensioners, turbo valve covers) and did a compression test on it. The seller said engine has been sitting for approximately 1 year (out of car). The results of the test are as follows:
#1 175
#2 165
#3 40-50 (highest after 3 tests)
#4 145
#5 158
#6 135

Seems like left bank higher and better but with #3 very bad, as opposed to right side lower but within 15% of each other.

Tested #3 3 times, after first time shot small amt of oil into cylinder and results did not improve.

I do own and have read Wayne's book and section on copression/leakdown but it does not completely answer my questions on reading this type of result.

I have an idea of what the very low #3 may mean, and can anyone explain why the drastic difference between left and right hemispheres/banks? Can these results be accurate or at least some indicator of engine health without starting and running engine prior to test (which might be difficult to have done in this case)?

I would appreciate any views on what people think of the general condition of this engine. Does it look like a rebuild here and to what extent?

Thanks

[aigel]

Ed:

#3 is bad news. Keep looking, unless you want to rebuild it and it is a cheap core. Of couse, after sitting, there may be carbon stuck under the valve, or some other lucky deal, but it won't run right with that compression and you would have to dig into the engine to know what's up.

Why does the engine not reside in a vehicle? Usually there is a good reason...

George

[Wayne 962]

Right - no real way to tell on an engine that has been sitting for so long. Sometimes they have 100% leakage, only to fire right up and cure themselves when running. Sometimes...

Unfortunately, there are no definite answers...

Side to side differences can be caused by misadjusted carbs (if it has carbs on it), or other clogs in the fuel injection system.

-Wayne

[911gilley]

The engine is from a front-end collision '82 Targa. Owner bought it as spare parts car for his '83 SC restoration. Used some parts, parted out rest, and this engine remains. Owner also stated he never ran the engine due to the fuel tank being heavily damaged and was afraid of causing fire with jumper pack.
Engine is complete original with fuel injection. Would clogs in fuel injection cause compression result variations like this if engine has not been run? Would it be wise to try a retest with fuel injection system off of engine? Is the only way to get accurate comp test results to try to "bench run" the engine first?

[Rot 911]

Ed the fuel injection system isn't going to affect the compression readings. I have to agree with the others, I would only buy this engine as a core fully expecting to do a full rebuild. If I wanted a running engine, I would be looking elsewhere.

[911gilley]

Thanks. Seems like that is the general consensus. What is it worth as a core (engine is complete).....around $1800?

Also, since I am still looking, anyone with any leads on a later 3.0 feel free to chime in.

[john walker's workshop]

get it cheap while you can. there aren't that many around. it may be fine, being that it's been sitting, and carbon may have fallen between valve and seat on that cylinder. it may need a valve grind, but we can walk you thru that.

[Porsche_monkey]

At $1,800 I would buy it right away.

[911gilley]

Well, he wanted $4700 for the complete engine, tranny still attached. I have not made him an offer, but I am asking what everyone thinks it is worth (the $1800).

[john walker's workshop]

considering that a valve grind done at a shop could go $3000, the price should reflect the repair costs. that leaves $1700. less than $2k, without the trans would be good for a rebuildable core.

[Porsche_monkey]

On the ther hand, how many rebuildable cores have you seen lately for under $2K? Around $3,500 is lowest I've seen.

[Wayne 962]

Originally posted by john walker's workshop
considering that a valve grind done at a shop could go $3000, the price should reflect the repair costs. that leaves $1700. less than $2k, without the trans would be good for a rebuildable core.

Yikes, I didn't even pay that much to have my heads done by Walt. I think the total was about $1100, of course, I didn't need new valves.

But $3K, is that a a typo John?

-Wayne

[john walker's workshop]

that would be take the engine out, teardown, go thru the heads, reassemble and install. new valves, guides, springs, filters, tuneup parts, etc. 30 hours labor plus parts. heads only $1000ish. rings, rod brgs, chains, sprockets, etc, would be extra.

[911gilley]

I think $3500 for a core is a bit high. $2K ish is more in line.
So it seems that you guys are saying pay around $2K for the engine and assume around $3K in addional rebuild costs? John, what do you mean by "teardown, go through the heads?" Does the 3K include you taking engine out and reinstalling?....I'm not seeing the whole picture. What would it cost for an "I ship you engine, you rebuild and ship back fixened" scenario?

[Wayne 962]

Originally posted by 911gilley
What would it cost for an "I ship you engine, you rebuild and ship back fixened" scenario?

I depends upon what is wrong with it...

-Wayne

[911gilley]

That's what I thought. I guess John was generalizing when he said for $3K he would "teardown, go thru heads..." I now assume that he means if he finds anything wrong during the teardown other than what he stated he would replace in that scenario, it will be additional $.

[john walker's workshop]

they're all a "pig in a poke" until you have it spread out in front of you.
yes, the $3K includes taking it out of the car and reinstalling. and that's limited to just doing the valve grind. it's time consuming, and time is money as you know. you could do it yourself, and just farm the heads out for much less. get wayne's book.