Is 10 lbs compression below normal too much?

Oracle · 07-20-2003, 07:38 AM

Hi,
My mechanic told me the compression is about 10 lbs. below normal but equal in all cylinders.

Is this something serious, am I looking into a rebuild?
Oil consumption is normal.

Thanks
-J

stealthn · 07-21-2003, 08:40 AM

Others might disagree, but if they are all close I don't think it's an issue. Have you had a valve job done on the car? It might make a difference.
What did your mechanic think?
My two cents.

Barber Dave · Barber Dave's Garage

What about a leak down test to determine if it,s the valves or rings.
My understanding is ,put compressed air to each cyl.
Listen at the T.Body or carb and exhaust if you here hisssing then it's the valves
If you don"t and the compresssion slowly goes down it's rings

I am not a expert ,this is my understanding, others will jump in if I'm wrong. I need to do this to my 1.7 as a check of general condition of my engine. Dave

mike_the_man · 08-26-2003, 04:09 PM

You can also pour a teaspoon of oil in each cylinder and do a compression test again. If it increases, then your rings are going, if it doesn't increase, it's a valve problem. I'm no expert either, this is just what I've heard, but worth a try.

Oracle · 08-26-2003, 06:47 PM

Thanks a lot for your ideas and suggestions.
I will definitely talk to Marc B. (Alpine Autowerks) about all these suggestions and most likely I'll try them regardless since they're all a lot less expensive than a not-really-necessary engine work.

Thanks!
-J

Doug Zielke · 09-02-2003, 07:19 PM

Quote:

Originally posted by Oracle

My mechanic told me the compression is about 10 lbs. below normal but equal in all cylinders.

Depends on what he considers "normal".
What are the numbers?

Oracle · 09-02-2003, 08:26 PM

I wish I could answer that question but I have not seen any formal report, this was from the previous owner and verbally from the mechanic, he mentioned that it was OK. regular wear but still 100K more miles to go if I take good care.

So I'm relatively relaxed but I guess as everyone else would like to predict or preview any major issues with the car just to be prepared (or call it quits

)

Bye
-J

Doug Zielke · 09-03-2003, 07:29 AM

In that case, I'd get a compression tester ($50) and do some tests myself. That way you'll know what you have, lest any shyster mechanic tries to BS you into needless work.

Oracle · 09-03-2003, 01:30 PM

I didn't know a compression tester would be that low in price. Do you have any particular brand/model in mind I can buy? I really like the idea of testing this by myself...

Thanks!
-J

Barber Dave · Barber Dave's Garage

Oracle:
Go to your local friendly FLAPS they should have a selection.
My advice don't buy the cheapest or the most expensive. this is a tool you buy once and have for life. Dave