Ghibli de Hongrie [ENG]

C'est ici qu'on présente nos voitures
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Blu Sera
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Re: Ghibli de Hongrie [ENG]

Message par Blu Sera »

Hi Peter ! Be warmly welcome on Maseratitude ;)
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Froggie
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Re: Ghibli de Hongrie [ENG]

Message par Froggie »

+1
Good to see the attractiveness of Maseratitude to foreigners.
Now, to complete the loop, you have to work out your French so that one day you can surprise us!
You seem quite knowledgeable on your Maser, btw...
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Re: Ghibli de Hongrie [ENG]

Message par gemini »

Hi Peter, nice to hear from you again.
I followed the work you did on sportmaserati (for all, take a look here for the suspension overhaul, you'll find a lot of very useful pictures: http://www.sportsmaserati.co.uk/showthr ... n-overhaul), congrats.

I can't understand how you could have good compressions AND worn rings. A leaking injector was probably the culprit for the oil increase, and, hopefully, it didn't had the time to "wash" the cylinder/destroy the ring.

250HP is not that bad for an italian lada-shaped pile of rust ( :mrgreen: ;) ), check for boost leak, check your valve clearance (it will not take to much time, and despite of the opinion of alpa, I can say that I saw a big improvement in the performance of my ghibli after the valve adjustement -full disclosure, the valves were replaced 1000km before) , check the timing (don't rely solely on the old marks), check your sem valve, check the wastegate and you should find the cause of your loss of power.

As you've already removed your engine and you've bought the chains, replace, but it won't change the power your engine produce.
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Dom3200
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Re: Ghibli de Hongrie [ENG]

Message par Dom3200 »

Hi Peter and welcome and congrats for the very nice job on the rear.
I heard that replacing the camshaft timing chains is useless if we don t replace the "wheels" (I know it s not the correct word :? ) as well as the dents should be worn too. Is that correct ?
3200 GT Juil 2001 / RACING Nov 1991
spacecadet
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

Thanks for the welcoming words, even Hungarian, I'm flattered :)

Yes, I'm from Budapest. Unfortunately I haven't seen the Primatist, only heard about it and also talked to the owner after he sold it.

I've sent the injectors for cleaning and measurement when I verified the sensors because I was also suspecting an engine management issue. Some of them were dirty indeed, leaking or producing a bad spray pattern. At that time I checked all of the sensors except the MAP sensors. Also checked the SEM that it was switching and not leaking in unwanted directions.

Turbos are working as described, boost goes slightly into red and comes back a bit. If that's the case they shoudn't be in a too bad state?

About compression: the first workshop measured 6.5, which I've found too low. Dyno test was done later after I checked engine management, and I don't think with 6.5 it could produce the power measured. I also checked it myself, right now my notes are not with me but as I remember they were around 7.5, hot and cold, and also tried a few drops of oil to see if the problem lies with the rings. The numbers didn't change. I took it then to a different workshop working only on engines, and they also got similar numbers.

I don't think (hope) bearings got destoryed because I only drove a few hundred kms after the last oil change, and also sent the oil for analysis and they couldn't measure significant amount of fuel in it.

If there would be such a significant wear on the rings that would be visible on a leak down test no? So I'll start with that.

I like the Lada reference, we had a lot of them here, so the first words in my family was: What is this Lada?! :D But I have a measurement from 2006 with 283bhp (at 95'000 km) , so I would like to reach that number at least.
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alpa
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Re: Ghibli de Hongrie [ENG]

Message par alpa »

I'd rather say Delta HF, not Lada.

Ok so compressions seem OK.
Then check timing, may be it was altered.
But I'd still check management and fueling. For example are you sure richness is correct at full power ? Fuel pump or hoses inside the tank may be leaking, fuel pressure regulator may be out of spec (it's adjustable, just remove the cap on the top of the regulator).
Injector cleaning ... I don't have good experience on these old injectors, once they don't work they don't work. Just one not well working injector is enough to make big difference, it's all about richness and thus combustion pressure disbalance,

Measuring power is tricky and to have reliable numbers you need a good bench that extracts transmission losses. What does not lie is time measuring, say how long does it take to get from 2000 to 7000 rpm in third gear. And compare with another car.

Dom3200, chain wear out by elongation (on segment axles), gears don't move.
gemini: having to re-adjust clearance after engine overhaul is not surprising, it depends on the quality of the seat work. But once it's good it's good for a long time. If it moves it moves by say 0.05mm, you won't feel difference on a street turbo engine. This is my experience, I've never had to adjust underbucket shims on my old (up to 250mkm) Alfa engine.
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ghibli30
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Re: Ghibli de Hongrie [ENG]

Message par ghibli30 »

Clearances were still OK two years ago on my '97 Ghibli GT, 38 000 km, not a single valve to adjust.
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spacecadet
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

That's good to hear that valve clearances don't go easily out of spec.

I'll then check timing, leak down, and recheck management and fueling too. I've only checked pressure at idle, that was ok (3 or 3.5 bar whichever should be at idle).

This will take some time because I only have time to work on this on some weekends.
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

Sorry for the long silence, but finally I had a whole weekend to work on the engine.

First measured the valve clearnes. The intake valves are mostly ok on the tighter end 0.35, a few 0.30 (factory spec is 0.35-0.40), but the exhaust valves are nearly all too tight, most is 0.40 a few 0.35 or 0.45 (factory spec is 0.45-0.50). Still no huge deviations.

Then also checked the valve aperatures at TDC.

Right block

Exhaust valve: 0.65
Intake valve: 0.60

Left block

Exhaust valve: 0.60
Intake valve: 1.05

Factory spec is: exhaust 0.65-0.75, intake 0.90-1.00

Image

The big delay of the intake side on the right block is probably because of the slack in the chain. Strangely the chain on the left block is very thight, no slack, that's why the values are much more close to the factory values. Is it common that the right chain wears much more than the left?

So I can either adjust the difference between the exhaust and intake cams by changing the pin in the sprocket in the back, or just change the chain since I already have it. By the way found the manufacturer mark on the chain: https://www.reginachain.net/ They mainly do chains for motorcycles, another Ducati connection like Nigusil?

Either way I have to remove the cams if I want to adjust the valve clearance. Is there anything I should prepare for? First remove the timing belt and then simply remove the cam caps?

I also found some exhaust leak around the exhaust manifolds so removed those as well to replace the gaskets. Unfortunately one of the manifold has a small crack which has to be addressed before it gets bigger.

Image

Finally I have a questions regarding the front axle. I would like to remove the stub axle from the carrier, but no luck. Tried with a shop press, but nothing happend with 3t, and I was afraid that the carrier will break. The workshop manual also didn't mention anything special. Is there some trick?

Image

Thanks
Dernière modification par spacecadet le mer. 25 avr. 2018 00:08, modifié 1 fois.
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Froggie
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Re: Ghibli de Hongrie [ENG]

Message par Froggie »

Can't help for the chain or valves and the axle.
Hope others will chime in.

I'm curious though wrt your exhaust manifold crack.
Did you smell the exhaust leak or had a check engine light before removing it?
And how do you intend to address it: drilling/welding?
spacecadet
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

No check engine, no smell. I guess because it's just a small crack there was no visible leak. The visible leak was at the exhaust port of the head.

I thought about welding, but the places I've contacted with couldn't guarantee the outcome, I've just found a place who claims 100% success with thermal sparying of metal.
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plm
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Re: Ghibli de Hongrie [ENG]

Message par plm »

spacecadet a écrit : I've just found a place who claims 100% success, with thermal sparying of metal.
Can you ask them for an example of work? Or a sample?
Dernière modification par plm le mar. 10 avr. 2018 20:23, modifié 1 fois.
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Froggie
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Re: Ghibli de Hongrie [ENG]

Message par Froggie »

spacecadet a écrit :No check engine, no smell. I guess because it's just a small crack there was no visible leak. The visible leak was at the exhaust port of the head.

I thought about welding, but the places I've contacted with couldn't guarantee the outcome, I've just found a place who claims 100% success with thermal sparying of metal.
Interesting.
I thought drilling was necessary to block the crack tips, and welding to have a perfect re-bonding of the crack (plasma may only "coat" the substrate with fused powders).
But this video shows that it may work well if properly done:
https://www.youtube.com/watch?v=hoaPSaNYl34
Look in particular at how they pre-heat the substrate to high temps before starting thermal spraying and thereafter melt in a controlled way both the powders and the substrate to close the gap.
Also noteworthy is the fact that they have apparently drilled the cracked zone before starting the heating/spraying process as it is essential to avoid propagation of the crack at the tips.
Not sure however if stresses (promoting further cracks) may not develop during cooling... Probably needs some annealing afterwards.
Hope your shop does a good job!
spacecadet
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

The process is pretty much as you describe. Preparation is the same as when welding, drilling and grinding. They heat up the whole part so not only the small areas get high heat. Then comes the spraying and melting. Afterwards annealing, cool down time is around 2 days.

I also hope they do a good job :) but they do similar works regularly and I have seen reference work.
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

So here is the result after resurfacing. The repair was pretty expensive (because of the powder used in the process), but also included a crack test, which revealed a smaller crack on the other side. All in all 145 EUR + 35 EUR the resurfacing. Still cheaper than a used part. And I will probably do some grinding work to remove the protruding parts.

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Froggie
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Re: Ghibli de Hongrie [ENG]

Message par Froggie »

Thx for the feedback and well done.
Btw, if you have some spare time, you should reload your previous pics in the thread (not visible anymore).
Just click on the image, then change the extension from postimage.org to postimage.cc in the web address
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bay
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Re: Ghibli de Hongrie [ENG]

Message par bay »

Froggie a écrit :Thx for the feedback and well done.
Btw, if you have some spare time, you should reload your previous pics in the thread (not visible anymore).
Just click on the image, then change the extension from postimage.org to postimage.cc in the web address
C'est corrigé ;)
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Re: Ghibli de Hongrie [ENG]

Message par spacecadet »

Yes, I've fixed the pictures :)

Finally did the leak down test, should have done much earlier. The results are really not good, nearly all the cylinders show 25% leakage, regardless the number there a lot of air is escaping at the exhaust valves.

https://www.youtube.com/watch?v=XyRx4Bmjmq0

I don't think this is acceptable, I fear this means the heads should be removed. Could be burnt valves (they are pretty white)? Any suggestion?
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Re: Ghibli de Hongrie [ENG]

Message par Froggie »

Goddam...that's annoying!
I'm no expert but wrt leaks, maybe only the valve seats may be reworked?
But then it may be worth rebuilding the whole heads.
Experts will chime in
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alpa
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Re: Ghibli de Hongrie [ENG]

Message par alpa »

Yea this does not look right.
I'm sorry I did not read the entire thread. I guess you've checked first that there is a lash between cams and buckets ?
Your valves may have been burned if timing/richness was wrong and combustion was continuing with open valves.
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