Compression issue on G 617
My very very old G has a five cylinder diesel engine, I believe the 617 with turbo. I believe I have some power problems as it has quite struggle to go uphill. I measured the compression and all cylinders indicate 12 bar. The manual says 16 bar. Is this difference responsible for my power issue? I wonder if there isn't more to it. The engine starts fairly well even cold. I would welcome any views. Thank you, Dan
Ah ha !
Have you checked your throttle linkage ? (I do not know if them wiesels are the same as the good gear but i can only assume they would still require a throttle linkage ? have a look at the part which is attached to the bulkhead at the back of the engine bay. it has rubber gasket in the centre which holds the rod and is probably perished ? in addition check the plastic ball joint in the centre of the rods. (it should a clear whiteish color) your is probably an orangey red and brittle ? might be broken there ?)
Full throttle is definately needed to get up them there hills !
Good luck
neil.
In percentage terms that's a big loss but you say they are all the same. This indicates no huge issues with your engine.
is it a 617 with an aftermarket turbo ? if so pistons and rings take a good hammering, check back pressure bay taking oil cap off
Heres my Slug! on the way back from Graz on Monday night. Its covered 520000 miles!
Thank you. I don't mind it being a slug if it is a healthy slug. I just don't want to have a fault in theengine. I cheked your suggestions what is left now is to check the turbo.
Sorry - 617 and struggle to go uphill? Surely that's always been part of the deal! Oh for problems with my turbo (as in what bleedin' turbo)!?!
Considering getting mine modified by removing floorplan so can emulate Flintstones! But as Kev pointed out, off to France in a couple of weeks and might just check my oil as otherwise engine just keeps on running running running... Well, pootling really.
Sorry, not helped with compression issue, but contributing as member of slow club.
My very very old G has a five cylinder diesel engine, I believe the 617 with turbo. I believe I have some power problems as it has quite struggle to go uphill. I measured the compression and all cylinders indicate 12 bar. The manual says 16 bar. Is this difference responsible for my power issue? I wonder if there isn't more to it. The engine starts fairly well even cold. I would welcome any views. Thank you, Dan
Have you owned the G for long? is this a deterioration or do you just wish for more? one thing you need to be aware of these engines need to rev to produce power, they have nothing to give below 2200 revs, as you can see Kevin sees 80 mph out of his, and I've seen him driving it in the flesh and he doesn't spare it. If you change down on hills at about 2400 revs and on steep hills even higher it'll keep going better, if you change down at 1800 revs or less you'll miss the power-band in the next gear an so on. This is a VERY under-stressed engine at 35.3 HP/L if yours is a turbo it may be better but I doubt it. most of the aftermarket turbo kits are just using the std injection pump with no increase in fueling.... so the turbo is a useless ornament. OR it may just be time for an engine rebuild.
As someone else said check the tappet clearances these are critical on these engines to get the last few horses working.
Gordon
I am not sure where you have found the compression pressure of 16 bar, I used to have an old 300td 5 cyl engine which is the 617 engine. The compression ratio was 21:1. In which case , the 12 bar you are measuring is well below the limits.
Is this low compression measurement on all cylinders or just a few??
This may explain some, but not all, of the reasons for lack of power. Loss of compression is not only due to worn out piston rings. it could be also due to blown head gasket , leaky valves, damaged valve seats, . Malfunctioning turbocharger, injection pump start of delivery, injectors . blocked pre- pump fine filter , etc etc You are saying that you have no starting problems, which means that the piston rings are still providing sufficient compression. but you do not mention any effects on fuel, consumption .
It may be worthwhile to start by checking the fuel pump at a specialist shop before dismantling the engine
Your compression test results don't sound right.
Stew, have you thought about fitting a Flux Capacitor?
it's unlikely that at starter-motor cranking-speed, that you'll actually measure 21 bar on a gauge, but 12 bar appears low.
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Neil thnaks! Still, do you think that 12 bar is enough to giver satisfactory performance? Should I eventually overahaul the engine?