Ignition hassle..

[Kobold]

If this is posted in the wrong realm please feel free to replace it to the correct one..

Thing is, the head of my '85 2.25l p 90 has been overhauled, new cam, rockers, valves, hardened valve seats (for LPG is it's main fuel), distribution chain & sprockets, waterpump internals, the whole shish-kabam..

Also a new electronic distributor instead of the dreaded ignition points and a fresh high powered coil.. (and new leads & plugs of course)

But it keeps under performing and lacking power, like it's running on 3 cilinders when the engine becomes loaded, it has been back to the workshop for 3 times to have it re-timed and the valves adjusted, but after a week or 4 (that's about 800 km / 500M) it runs stable but poorly.

There is another issue, that the engine is leak free, doesn't smoke while driving or depressing the throttle but I've to add almost half a liter oil every week or 2, should I consider this acceptable?

The cilinders do around 8 bar compression as I was told, and that is well within the limit.

I can keep  on going back to the garage were it has it's regular maintenance and I do understand the valves have to be re-adjusted every 20K,

The valves had been run in and re-adjusted on intervals (has been @ 1, 5, and 10K)

Can any of you enlighten me what the source of this hassle can be?

 

kind regards,

 

Peter

Edited April 5, 2021 by Kobold

[steve b]

It sounds like fuelling issues so if it's on LPG the delivery ring to the carb. , connections to vapouriser and the vapouriser itself should be inspected . What is it like on petrol ? 

cheers

Steve b

[Kobold]

It actually runs better on LPG as on petrol in fact, due to the 10% methanol that's mixed in on the E95 we only use E98 petrol.

But either LPG or E98 it won't get the engine run properly.

[steve b]

Oh , ok , so not fuelling then . Does your electronic distributor have advance weights and vac. advance too ?  

[Kobold]

That might be something I've overlooked, it is a Lucas type with the electronic insert.

It has a vacuum advance, the tube could well be leaking or porous.

I'm not sure if it has advance weights.

[Snagger]

I had a 2.25 petrol that had sweet running and really easy starting on choke, but would go bad with terrible performance and occasional backfiring once warm.   I replaced everything I could think of, including carb, entire ignition, fuel pumps, manifolds, exhaust and so on.  It was only after it was sold that it occurred to me that the brake servo vacuum is drawn from below the carb on these older petrol engines (I’m more used to 12J and Tdi engines).  Try removing the servo vacuum hose from the connection to the induction system and solidly blanking that port to see how the engine behaves - if the hose or servo are leaking, the engine will run very lean.

The oil consumption is not likely to be directly related.  I have a similar problem with one of my Tdis, which I had rebored and I rebuilt before fitting, but I haven’t been able to find a cause after two head rebuilds, a turbo rebuild and a turbo replacement.  I very much doubt it’s the top end, so have to suspect either a problem with the rebore or maybe the rings didn’t bed in and the bores got glazed.  You may have something similar, or it could just be worn rings or bores if you haven’t done anything to them while the head was rebuilt.

[Kobold]

24 minutes ago, Snagger said:

 it occurred to me that the brake servo vacuum is drawn from below the carb on these older petrol engines (I’m more used to 12J and Tdi engines).  Try removing the servo vacuum hose from the connection to the induction system and solidly blanking that port to see how the engine behaves - if the hose or servo are leaking, the engine will run very lean.

 

That's worth a try! Thank you for the tip!

As far for the oil mystery, the cylinders have not been re-bored, neither the pistons nor the pistonrings have been replaced, I've suggested it to the mechanic but he dis-encouraged me as het told me they were just fine, and I shouldn't replace stuff if it wasn't worn or broken

 

[Snagger]

Losing that much oil should produce some smoke that’d be visible at low speed or standing.  The conditions under which the smoke is thickest will give a lot of information.  If it’s on start up and initial idle, then it tends to be the valve stemn seals or guides, but if it’s worse after starting at idle or on overrun, then it’s more likely bores or rings.

[FridgeFreezer]

What make are all the shiny new ignition parts?

[Wytze]

If you would like, i could come round and have a listen..     

[Kobold]

27 minutes ago, Wytze said:

If you would like, i could come round and have a listen..     

That would be very kind of you! I have no idea how far away you're from me but I guess you figured that out already!

 

[Kobold]

On 4/6/2021 at 12:57 PM, FridgeFreezer said:

What make are all the shiny new ignition parts?

The standard Lucas components from Paddock for a 2.25P

[Kobold]

On 4/6/2021 at 11:20 AM, Snagger said:

Losing that much oil should produce some smoke that’d be visible at low speed or standing.  The conditions under which the smoke is thickest will give a lot of information.  If it’s on start up and initial idle, then it tends to be the valve stemn seals or guides, but if it’s worse after starting at idle or on overrun, then it’s more likely bores or rings.

Well.. that's the thing really, I do drive frequently drive behind her 90 but no visible smoke or smell.. no oil on the driveway, no visible leaks, I'm stooped..

[Wytze]

21 minutes ago, Kobold said:

That would be very kind of you! I have no idea how far away you're from me but I guess you figured that out already!

 

You live on the edge of Drenthe/Groningen?    I live on the edge Flevoland/Overijssel.   So, i think it would be one hour between us..   I had a lpg 109 beside my project.