Whats wrong with my VG?

I think he's trying to make me feel better.

its not great, definitely not perfect. but its not exactly throw out material just yet.

 

It's not dead, that's for sure. Means your engine is alive! Good stuff, just puzzling as to what the problems could be. God I hate cars.

 

yeah 112 ok okay , it will got to about 130 hot .( cold test is VERY inaccurate but it shows us that there is psi in that cylinder ) ( its not the best test , but thats not what the problem is )

sure .

the stock tt bottom end runs .5 piston to bore , not much room for expansion there .

when the engine is hot there is oil under the rings this creates a seal , similar thing happens on the intake side , when fuel gets injected in, it hits the valves as well , this also creates a seal , yes evey thing in the engine will expand due to heat , but piston ring need more then 80 degree , they do expand but not enough to make or brake

 

a radiator pressure test?

this is new to me. what would that show and how is it done (tech section , I know, I know...)

it was clean water, not coolant. the radiator has coolant in it, but it is missing some, no surprise though since it probably hasnt been topped up since the first time it's run after the install.

definately wasnt coolant though, so i'm betting just water in the socket.


but i'm doing everything else, midaswell do that rad test too.

 

would there be any benifit is some of those oil cylinder treatments I've just heard of? or would it be better to put some oil in the cylinder before doing a comp test?

the oil treatment I've heard some people do is take the plugs out and drop some particular oil into the cylinders of engines that havent run in a while. leave it overnight or for 8 - 10 hours then crank the engine and catch some of the oil with a rag.

supposed to help with sticky valves and piston rings i think.

 

it will show you if there is water leaking from anywhere ,

you will need the tools to do this , you need to put 4 or 5 psi in the cooling system , if the presure drop , you have a leak if it hold your good to go ,,

the problem is when you doing a test on the cooling system some times rust and shit( or what ever is flating around in the system ) will brake of and block up the hole , ( this is a big some times , but it does happen )

 

I still don't understand if it's not expansion, why test results go up when warm? Eric just said it wasn't due to oil, so what is it?

 

its definately on the sad side.

but considering I need this car asap as a daily, its better to have a sad tt than a completely non usable TT. at least it can get me around until i can build something proper to put in.

air temperature bro.

the cylinder is filled with air and fuel mixture, mostly air, so think of air when it is in a cold state like in a balloon, the balloon will deflate (less pressure)
then when you put the balloon with the same amount of air in a hot environment the air expands and takes up more space.

so the air in the cylinder is the same amount of air that is in it when in a cold state, but the air molecules have expanded because of the heat which is causing higher compression.

 

and this to .

in not a fan of the cold test but my opinion

 

sshhh trying to be nice ,

the main concern is it will run with those numbers , so atm its not a dead cylinder ,

 

funny thing is, the cylinder which we thought was the problem is the one with the best compression.

it was drivers front that wasnt firing.

I got excited after that, but the passenger bank let me down

 

no point really , this will tell you if the rings are no good , atm you have something there , ok its not excellent but something is something , atm ,

( dont know how long it will last )

 

Alright.

well thats the Comp test done.

really appreciate all the info and the convo and the help.

now I just have to wait to get the injectors back. i've put in an order with carcraze for a plenum gasket, so theres not much to do now accept sit back, grab a coffee and wait....

 

well if anything your in a better spot now , so you can sleep at night

 

Lesson learnt.

''If you want something done right, You have to do it yourself.''

last few days have been quite fun getting the injectors out and doing all this testing, its not that hard.

 

100

 

yeah well 7 k is not a walk in the park man .

i may be sugar coating a little because of that reason , but i do think you will be ok , lets go step by step and get this going and not over think things atm

 

Good stuff Wayne.

As mentioned those numbers will get you running and probably will for a while, providing you don't go doing anything silly with it.

Regarding no.6 cylinder, pass rear. Just run with it. Our engines been down in compression on the cylinder for years and years. Old girl hasn't died yet. We even threw it in a dyno one day and walked it well past factory redline. Still no probs. We'll just keep driving it and maintaining it up until it throws a leg out the side, or something.

The vg is a tough old donk. With a little care and love it'll hold its own.

Getting excited for you mate for the day you turn the key and have it popping on all 6. And you've done it mostly yourself and saved a stash of extra cash along the way.

Keep us up to date

 

WOW !!!! , just WOW !!!! I rebuilt my whole driveline and bought the car that went into it for less than that . Well only just

BTW , if you ever move to Sydney and still having issues with your TT I'll donate my time and labour for free to get you going ... the right way

 

Hey!! Long time no reply...

cheers kakaboy, I'll keep that in mind