engine rebuild or replace 1.9dg

[adrian1975]

Hi all,

its been a while since i was last on asking asking for advice, which means all the advice i received last time was spot on and i have had a few years trouble free motoring,

my 1.9 dg full devon camper maybe showing signs of a tired engine, let me outline, she uses 1 ltr of oil every 300 miles no oil leaks what so ever uses no water and no oily deposits on the tailgate, or in the water tank, i havent done a compression test yet or and oil pressure test i should be doing those this week and will post the results, i purchased the camper 3 years ago with the engine running, i did a top end rebuild jackets, gaskets, valve guides, decoke, reseated valves etc and shes run fine i did not replace the piston rings, there are no bangs, rattles or noises.

when i stripped the engine down last time there were some oddities listed below,

solid tappets
oversize oil pump (new replacement wont fit)
was told it had a beetle camshaft
squashed water pipe

i was told it may have been botched together by volks spares many years ago

the problem is this engine pulls like a train, is very quick away from the lights and sits at 60ish+ , she is pretty rubbish uphills changing down ect some times to 2 gear i know she is very heavy but i think the engine is at fault together with the high oil consumption, i have purchased another top end rebuild kit and im going to change the piston rings aswell, now i could just buy an engine from vw heritage or the likes but i dont want anything slower than i have already, i have not driven another t25 for comparison but she is fairly lively, she ticks over like a dream and starts fist time every time, we were in cornwall 2 months ago for a week and covered 1200 miles in 5 days no overheating ect, so questions are

do i change all the bearings in the case
is this engine worth saving
what are the possible cause of high oil consumption
why is she very slow uphills, loses a lot of power

thanks for taking the time to read this post and thank you in advance for any replies, Adrian

[itchyfeet]

Do the compression check first, if it's low you will expect more power, if it's not you won't.

Check HOT oil pressure too (going to have to drive it down the motorway for 1/2 hour at least in these temperatures to get oil temp up) , if it's low when hot then rebuild the with new bearings is a wise choice, if not then leave it, I'd say.

Another thing to look at when you have barrels and pistons off is the state of the cam, you can see it quite well, if it's very worn consider crankcase rebuild, but this will cost you quite alot if you want to revert to hydraulic cam, Cam ( £200), bearings (£100) tappets (£100)

High oil consumption is rings or valve guides worn

https://club8090.co.uk/forum/viewtopic.php?f=37&t=156269" onclick="window.open(this.href);return false;

[mbcamper]

Do you have a smokey exhaust? This can be another sign of worn piston rings.

Might be worth getting someone to follow you on a drive to observe...

[adrian1975]

hi, and thanks for the replys so far,

i have carried out a compression test today the results are as follows

COLD TEST-
1=95psi/6.5 bar
2=135psi/9.3 bar
3=145psi/9.99 bar
4=150psi/10.3 bar

HOT TEST-
1=120psi/8.2 bar
2=140psi/9.6 bar
3=147psi/10 bar
4=140psi/9.6 bar

oil pressure hot

idle=0
aprox 2000 rpm=20psi/1.3 bar (not sure if it was 2000 but sounded like it as no rev counter)

the plugs on 1 and 2 had heavy deposits as per haynes manual picture on back page
plugs 3 and 4 were normal

thanks for looking, and let me know your thoughts
cheers Adrian

[itchyfeet]

compressions are a bit low, oil desposits could be rings or valve guides,both can be done without a full rebuild.
The oil pressure is more of a concern

what did you measure it with and where?

What oil are you using?

if you genuinely had zero your oil light would be on, your oil light does work doesn't it?( on when ignition on but not started)

Assuming the measuring device is accurate it's probably worth new cam and crank bearings, should be 2 bar min at 2000 rpm, you may get a few more years lke that depends on milage.

[adrian1975]

Thanks itchyfeet, 20/50 oil, oil pressure kit, neilson I think, I didn't realise until I had done the test the oil level was just below min would that effect results, I'm going to redo it tomorrow as its still connected, connected to nearside of engine between pushrod tubes, I think the oil light flashes once then stops I will Check tomorrow cheers ade

[itchyfeet]

I'd try to check with another gauge before ripping it apart, these cheapo gauges can be wrong, happened to somebody on here, it sounds pretty low if correct.

Another thing you can do is try to connect the gauge to a car tyre of a known pressure to check it, I used my easy bleed kit and a few bits of pipe

[mbcamper]

It was me who had low oil pressure readings from a cheap meter. I've just gone to look back at the thing and can confirm it's a Neilson gauge. I ended up getting a refund for it and the eBay supplier didn't want it back!

So as itchy says check it's accurate before going any further.

https://club8090.co.uk/forum/viewtopic.p ... 8&start=30" onclick="window.open(this.href);return false;

I connect my oil pressure gauge to my track pump and had alarming differences which fortunately pointed to normal oil pressure in my engine.

[adrian1975]

hi guys,

im sorry but i realised this morning on my way home from work at 3.30 that my compression readings were done with a closed throttle i have redone the tests today with wide open throttle please see results=

cold test
1=125 psi
2=155 psi
3=145 psi
4=140psi

hot test water temp 1/2 way fan cut in

1=130 psi
2=135 psi
3=135 psi
4=140 psi

oil pressure with a new gauge/ idle 800 rpm

cold @ idle 4 bar
hot @ idle 1.5 bar i think
hot @ 2000 rpm 2 bar
increases with engine revs

let me know what you guys think sorry for earlier results


just a quick one, my new gauge has now filled with oil and so now is no good how do i stop that in future

cheers adrian

[mbcamper]

The cheap Neilson gauges strike again!

hot @ idle 1.5 bar i think
hot @ 2000 rpm 2 bar
increases with engine revs

These oil pressure readings are fine.

I'll let other comment on the compression test, but they are fairly equal which helps.

Keep up the 6 months oil and filter changes and you should see life in this engine yet.

[what2do]

Could someone please explain why some compression figures are higher when cold and vice-versa on certain cylinders? I expected them to be uniformly higher when the engine is hot. Thanks.

[CovKid]

Compression, or at least lack of, is as much down to valves as rings.

[itchyfeet]

Ok so sounds line oil pressurs is OK and compressions OK but it is using 1l every 300 miles ( whicb is alot) and plugs oily.
So as said rings or valve guides.

[adrian1975]

Thanks itchyfeet, I'm taking engine out tomorrow now I know, once done what will i expect as in, less loss of power etc cheers Ade

[adrian1975]

One other thing, how ok is ok cheers