Strange compression readings x_X

[TynoPrime]

Hi guys.

My engine has been running like... Well it's fair to say I could probably choke my girlfriend as she'd sound smoother than the engine on my bug does.

I replaced the HT leads, spark plugs and distributor cap, changed the oil (which was below the LOW line! )and reset all my valves to .006 (exhaust on cy 2 and 4 were literally closed completely. I couldn't even fit the smallest feeler guage i have in there)

Cylinder 2 however... Doesn't seem to fire properly. I only know this because when I pull the lead to cy 2 from the dizzy, there's a barely noticable change. Whereas on every other cylinder the engine really struggles once the leads been pulled. So I did a compression check (on a luke warm engine, about 2 hours after a long drive) and got;

Cyl 1: 120
Cyl 2: 90
Cyl 3: 116
Cyl 4: 118

Aha! So I'd found the problem! I unfortunately had nothing to inject oil into the engine so left it there for the day.

Today, having a serringe in hand and the engine stone cold, I pulled the HT lead off, took out the plug and plugged in the tested. I thought, I'll do a test before the oil and after it, and see what difference it makes..
I turned over the engine and....

Cyl 2: 120

So I took it and and redid the test...

Cyl 2: 118

So, confused, I put the oil back into the pot - I didn't need it now!

And so here's my issue! Could you first test have been wrong? Maybe I didn't have the tester in correctly? Or didn't turn it over enough?

Could it be that the (low) oil that is now full and new has sorted it out? The issue I still have is that it still doesn't seem to play much part in the engine actually WORKING! It still doesn't make much difference if that cylinder is running or not.

Why?

Could it just be something simple like timing/advance/points?


Any help would be much appreciated!

Thanks~

Gordon

[65'1300Deluxe]

Did you do the test at wide open throttle each time?
_________________
1965 Deluxe Beetle "Camilla"
1972 Super Beetle Barnfind "Roland"
2001 GTI 1.8L Turbo

[Relyt]

Check the compression when hot again. Maybe the valves are tightening up.
_________________
69 Beetle - Daily driver
1600 SP (unknown history)
30 PICT 1 w/power circuit (Volkzbitz)
205T (Bill)

[Q-Dog]

[JerryMCarter1]

Can you rephrase your statement?

"The issue I still have is that it still doesn't seem to play much part in the engine actually WORKING! It still doesn't make much difference if that cylinder is running or not. "

I am not sure what you are saying ?

Jerry
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[TynoPrime]

[LeviMan2001]

Well it sounds to me like your compression is fine. You probably just didn't have it threaded in quite right or something like that. So you've made sure your spark is good, your vavles are good. What else is there? There's timing and fuel. Check to make sure your timing is right and your carb is adjusted properly (first timing, then carb). I imagine youve attached the #2 cyl spark lead to a plug and made sure that it's getting spark? I wouldn't be to bothered by the #2 cylinder thing. It could be that there is a specific issue with it, but without the unknowns being eliminated it could just be that number two is showing off a more general issue.
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http://www.thesamba.com/vw/forum/viewtopic.php?t=366056 - My '73 Super Build. 2332cc, 16" Fuchs

[TynoPrime]

Could timing affect just one cylinder though? I'm just about to change my dizzy to svda so I'll retime and reset the idle/fuel straight after.

[JerryMCarter1]

But that is supposed to be your low compression cylinder.
Doesn't make any sense to me!
I would now go for a valve adjust --
Jerry
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[TynoPrime]

Rechecked all my valves - still at .006. Took out ALL the spark plugs and did a compression check on full throttle -

Cyl 1: 122
Cyl 2: 122
Cyl 3:120
Cyl 4: 128

So they seem fine in regards to compression. Put the spark plugs back in, and really tightened them this time, as before I didn't want to tighten them too much (but when I pulled the plugs the copper washers wern't crushed, so i guess they weren't tight enough) I didn't go TOO overboard but made sure they were nice and tight.

And...

It's firing perfectly. Sounds sweet and pulled the no2 ht lead and there was a big change! Guess that solved it!

Onto the plugs though - all 4 had alot of black soot on them. Guess I'm running too rich?

I'm changing my dizzy to SVDA tomorrow morning so I'll retune and change the fuel/idle screws to the correct settings (as per vw-resource)

Edit: I don't know if I'm just being an idiot, but when using my multimeter on Tach 4cyl setting, and putting the COM wire to the green terminal on the coil and the other to ground; It reads RPM of 3500-4500 at idle! x_x I can hear it's no where near that - more like 900-1200! So am I just doing it wrong?

Thanks,

Gordon

[JerryMCarter1]

To rich or not enough spark, maybe even not enough advance.
You new svda will help!
Something must be wrong with your meter!
900 is a good number
When you put in your new dist you will have to re-time it -

Great to hear the good news -- this is what the Samba is all about

Cheers

Jerry
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[TynoPrime]

Yeah, thats everyone for your help! And thanks Jerry!

I don't understand how it's wrong when every other function works like it should. And it shows a constant-ish number - just seems really out x_X almost like it's x 4 or something. Ah I don't know. x_X