compression test results. Fine or dead?

[scoop2004]

Comp tested the 520 this morning,here are the results

Cyl 1 1.1 bar average and holds
Cyl 2 1.1 bar average and holds
Cyl 3 1.1 bar average and holds
Cyl 4 0.7 bar average and holds
Cyl 5 1.1 bar average and holds
Cyl 6 1.1 bar average and holds

Whats up with cylinder 4?? its not leaking but its down on pressure.

What would make this happen,will it be an expensive fix?? reason i tested it is down to water pump failure to check i havent warped/cracked the head

[scoop2004]

Comp tested the 520 this morning,here are the results

Cyl 1 1.1 bar average and holds
Cyl 2 1.1 bar average and holds
Cyl 3 1.1 bar average and holds
Cyl 4 0.7 bar average and holds
Cyl 5 1.1 bar average and holds
Cyl 6 1.1 bar average and holds

Whats up with cylinder 4?? its not leaking but its down on pressure.

What would make this happen,will it be an expensive fix?? reason i tested it is down to water pump failure to check i havent warped/cracked the head

just to correct that,its 11 bar and 7 bar, not 1.1 and 0.7

[632 Regal]

thats a big drop there, to check if it is rings add a couple tablespoons transmission fluid and re-check. If it goes back up than rings, if not generally its valves. If the valve lash is way off that could cause it too.

Good luck!

[scoop2004]

a)what is valve lash
b)ill try what you have suggested re the rings
c)can i add that when i stop cranking it it HOLDS 7 bar,it doesnt lose the pressure.
d)would using 98 octane fuel,red-ex and intake cleaner help rasie it a bit (if its down to dirty/stuck valves
e)if its head gasket how much will it cost to buy all the parts needed to change it (DIY)

[DaveVoorhis]

a)what is valve lash
It's the amount of free clearance between the cam lobe and the valve stem (via the rocker arm) when the lobe is at its lowest point. In the M50 engine, this is not adjustable.


e)if its head gasket how much will it cost to buy all the parts needed to change it (DIY)
You'll need at least a head gasket, head bolts, intake manifold seals, exhaust manifold gaskets, valve cover gaskets, and possibly shaving the head if the surface is poor or slightly warped. You can price the parts at http://www.eurocarparts.com, and you can usually get a head gasket set that will include all the necessary seals and gaskets. You'll need a torque wrench if you don't have one.

[scoop2004]

If its rings how hard is it to change the rings,whats involved briefly?
Can u just remove sump,disconnect rod,drop piston,change ring,re-fit piston,reconnect and refit sump???

If its valves then how hard/cost to change,whats involved briefly

This sounds like its gonna cost more than its worth to get it running.

Would the car be roadworthy with this low compression??

[e39dream]

it's probably been driven several thousand miles with the compression as is. put it back together, keep an eye on the coolant level and temps and pretend you never noticed that cylinder, don't beat the car up too hard. thats what I'd do.

[scoop2004]

................then when it goes bang break it for spares and buy an E36 325!

i like ur thinking mate

Or maybe ill get an E39 530. Wasnt gonna keep the 34 long anyway as its pretty rough

[632 Regal]

you can only replace the rings by taking the piston/rod out the top of the engine..ie: remove head too.


................then when it goes bang break it for spares and buy an E36 325!

i like ur thinking mate

Or maybe ill get an E39 530. Wasnt gonna keep the 34 long anyway as its pretty rough

[stu1]

If I'm calculating that acurately, 11 bar is about 160psi (bar x 14.5), which is quite low. Mine read about 220 to 230 psi (or roughly 15 bar).

Your 11 bar is right at the minimum.

Is it low on power? Burning oil? (blue smoke out of the exhaust).

Stu.

[scoop2004]

exhaust gas looks fine. It currently doesnt get driven due to the fact the water pump is dead,i was merely comp testing to diagnose weather its overheated and killed the head/head gasket.cant comment on power. As for the 11bar reading
a)it is at the minimum
b)that was the average,the needle was flickering on the guage from 10-12/13 and when on 7 it was flickering up to 9 so i just took the middle figure of the deflection

[SnakeyesTx]

Are you sure its the waterpump? You keep going back to potentially a headgasket issue which makes me wonder. If you can run the motor, take it to a shop and have them run a test for exhaust gasses entering the cooling system. This can happen instead of water in the oil and vice versa. If you find the headgasket went, you'll need the HG kit with all the seals. Also you'll need to get the head resurfaced before reinstalling it. They'll basically take it apart and rebuild it and check for cracks. If they find the typical cracking at cylinder 4's exhaust port to coolant jacket, (several people including myself had that and even pelican-parts test car for headgasket replacement had it - if this is the case, you'll need another head :( ) you'll want to resurface the deck of the block as well so both surfaces are flat and true. Based on the milage, you might wanna consider a bottom end rebuild since the machine shop would have to disassemble the shortblock anyway.

[scoop2004]

so basically,what we're asying here is.......its gonna cost a lot to get it running reliably again.Probably more than it'd cost to change the engine. Which if were going to say is cheaper,how easy would it be to fit a 2.5 M50 from a manual 525 into my auto (what needs changing?)

[SnakeyesTx]

They should be the same aside from the flywheel. Have your local shop do that exhaust in the coolant test though. Also yes, its probably cheaper to replace the engine (in my case, the shortblock rebuild was 1200, the head was 1800-2100 new, and the labor of R&R was about 1000). I managed to pick up a honey M50 with 79k miles for 1600 and paid another 1500 for R&R with a new radiator and shroud.

If you do repace it, make sure you get the same engine you have... as in, don't put a Vanos engine in a non-vanos car since the wiring is different.

[DaveVoorhis]

If it were me, I'd just pop in a new waterpump and see what happens. If it runs well and doesn't exhibit symptoms of head gasket failure, you're done. If the engine is sacked, put the new waterpump on the replacement engine.

[scoop2004]

may as well give it a try eh. Cos if the engine is sacked then i'll prob just break the car for spares and buy a running roadworthy 520/525 from autotrader or Ebay and fit the new waterpump to that car as preventative maintenance..my ford escort cooling fan stopped working today,so now i have both cars with cooling problems