Did compression check on my engne bad news

norcalvw · Post by **norcalvw** » Sun Mar 10, 2002 12:14 am

looks like I cylinder has low compression 85psi while the others are 123-128psi do I need new rings or is there more my mechanics suggested it could need a valve job. As well as rings he added oil to the bad cylinder then did the compression check and the reading stayed the same why did he do that? but it drives well with plenty of power on the hills so I don't get it granted I'm new to this whole air cooled world so looking for some education. Thanks,
Eric R

[This message has been edited by norcalvw (edited 03-10-2002).]

71Vdubber · Post by **71Vdubber** » Sun Mar 10, 2002 7:57 am

adding oil to the cylinder helps the rings to seal, if there was no change when it was added, then the valves are probably to blame.

norcalvw · Post by **norcalvw** » Mon Mar 11, 2002 1:36 pm

Thanks for the info

-Eric R

rich2481 · Post by **rich2481** » Mon Mar 11, 2002 1:45 pm

it is hard to have oil do any good on a horizontally opposed engine all the oil goes to the bottom, how many miles on vehicle?? might want to drive it till it craps out or do a top end, if you have to pay someone then might want to do the whole engine at some point,

why did you have it checked were you having problems with it??? as it heats up might get more compression too

good luck with whatever you decide

turbo-oval · Post by **turbo-oval** » Mon Mar 11, 2002 2:34 pm

Sound like your getting around fine just let it go if you have the money for a valve job yea you might want to get it done
I have used old tired motors for a long life.

aussiebug · Post by **aussiebug** » Mon Mar 11, 2002 10:39 pm

My worry, when I hear "just keep driving it" is that if it's a bad valve/seat (and it sounds like it is), then you risk dropping a broken valve into the cylinder and all your "savings" just went out the window.

Have the valves (especially exhaust valves ) been tight the last few times they are adjusted? If so that's a sure sign they are starting to stretch, and need to be replaced anyway. A reasonable life for a VW exhuast valve is around 40-60,000 miles, depending on how hard it's been driven.

With comrpession that low in one cylinder, I'd be removing the head and having a look.

Regards

------------------
Rob
Rob and Dave's aircooled VW pages
Repair and Maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/index.html

norcalvw · Post by **norcalvw** » Tue Mar 12, 2002 1:38 am

Hey guys thanks for the great advice I'm stillnew to this whole air cooled thing but I'm cathing on quickly. Yes I decided to pull the heads and just have a valve job done then reinstall that way I avoid trouble until I'm reay to get a serious motor I'm either going to go with a 1776 or an 1800 we shall see. Check on my progress at the URL below
http://communities.msn.com/ErickOnline/homepage.msnw

rich2481 · Post by **rich2481** » Tue Mar 12, 2002 6:59 am

just a thought but what about popping in some new rings after a light hone job, when valves are redone and seal good they tend to put lots of pressure on old worn out rings and you get lots of crankcase pressure

just a thought takes a hour maybe.

norcalvw · Post by **norcalvw** » Tue Mar 12, 2002 6:05 pm

Hey Rich,

YEah the rings are a good idea I will do both rings and valves if it comes to taking the head off.

-Eric R

dbnbde · Post by **dbnbde** » Fri Mar 22, 2002 4:53 pm

<BLOCKQUOTE>quote:<HR>Originally posted by 71Vdubber:
adding oil to the cylinder helps the rings to seal, if there was no change when it was added, then the valves are probably to blame.<HR></BLOCKQUOTE>
Ok, so I am having the same prob with my bus. Except, #4 @ 90 psi. Rest @ 120. I re-adjusted all the valves because I was having problems w/ #3 also. As far as dropping oil in to check if head or seats...how do I do that, or where? I have the pancake 75' w/dual solex 34/3 carbs. All factory. I'm new to the aircooled, but loving it. Can't wait to go get my bug tomorrow.

------------------
70 SLAMMED bug, finally, yeah!!!
75 vw bus (in project)anyone have a body, will shorten my project from 5 yrs to 2!
97GMC Sonoma ext. cab, 2wd, sprt side bed, vortec eng. all options, fully customized for show and performance. For sale going strictly european
ex owner of 82 BMW 633csi :*(

vicsvw · Post by **vicsvw** » Tue Mar 26, 2002 7:21 am

vicsvw · Post by **vicsvw** » Tue Mar 26, 2002 7:24 am

Check out this page on leak down tester -> http://www.1800vw.bizhosting.com/LeakDown.htm and this one about new rings ->http://www.1800vw.bizhosting.com/PistonRingCK.htm Vic.

dbnbde · Post by **dbnbde** » Tue Mar 26, 2002 1:28 pm

Thanks Vics...good site. I checked my compression after adding oil, and it went up to a little over 120. So...we will see.
Enjoy
Eric

------------------
70 SLAMMED bug, finally, yeah!!!
75 vw bus (in project)anyone have a body, will shorten my project from 5 yrs to 2!
97GMC Sonoma ext. cab, 2wd, sprt side bed, vortec eng. all options, fully customized for show and performance. For sale going strictly european
ex owner of 82 BMW 633csi :*(
www.geocities.com/dbnbde

VW Beetle Bug 1970 · Post by **VW Beetle Bug 1970** » Sun Mar 31, 2002 4:44 pm

<BLOCKQUOTE>quote:<HR>Originally posted by norcalvw:
Hey guys thanks for the great advice I'm stillnew to this whole air cooled thing but I'm cathing on quickly. Yes I decided to pull the heads and just have a valve job done then reinstall that way I avoid trouble until I'm reay to get a serious motor I'm either going to go with a 1776 or an 1800 we shall see. Check on my progress at the URL below
http://communities.msn.com/ErickOnline/homepage.msnw

<HR></BLOCKQUOTE>

Great lookin Ghia, take the bra off and it'll look ALOT better. Just my opinion.

------------------
Matt
1970 Beetle Bug "Putt Putt"
www.geocities.com/lambmatt85 <--Look at my project here.

mharney · Post by **mharney** » Mon Apr 01, 2002 8:59 am

That works with more than cars!

Well, most of the time anyway. The validity is proportional to your beer consumption.