[Nickhey71]

Hi


I'm new on here so apologies if this has already been discussed previously.

I recently had an engine rebuild, to standard specification by a local marque specialist.

This was while the engine was out of the car following a shunt at the race track (Donnington Park ), so I thought it would be a good idea to get it refreshed while the car was being rebuilt.


After the engine was stripped, I took several photos of the components, including the block and bores, which were in good serviceable condition.


The engine was rebuilt with new bearings, rings, seals / gaskets, water pump, belts / tensioners, timing chain and a good pair of camshafts to replace the worn originals.


There were no changes to the fuel, exhaust, ECU or other related components following the installation in the car. I used a 15/50 semi synthetic oil, which was changed at 500 miles along with the filter.


Unfortunately the engine smoked on startup and used excessive oil from the first time it ran. I discussed this with the engine builder and they told me it was just the rings bedding in and to put some more miles on it.


So 3000 miles later I now have badly scored bores in all 4 cylinders.


Engine builder is reluctant to help using the excuse that it is more than 12 months since I fitted the engine. I am obviously disputing this as I told them of the problem and took the car back to them inside 12 months ( actually less than 6 months ).


I need to have a good understanding of what could have caused the problem, so I know what to say when I talk to them again.


Please could you give me some suggestions of likely causes?


Thanks in advance


Nick

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[banditsc]

If the engine was fresh with new rings a straight 30 break in oil should have been used with a specific procedure to allow the rings to seat properly. I would guess your rings never seated properly with the oil you were using. 

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[unknown4u]

Are the cilinders polished? You have to be careful because this is a special proces!!! it can not be done like a normal engine.
Maybe they have ruined with the wrong tools the surface of the cilinder.
It is equal to the 928. Was it a porsche specialist who rebuild the engine?

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[flash]

both of the above, plus, did he use the right rings?

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[Nickhey71]

Hmm,

Thanks guys.

I wasn't given any instructions regarding a special break-in oil.....

Just to warm the car properly and not labour the engine or use max revs for the first 1000 miles.

No idea what rings they used, just assumed standard.

The bores were not reworked, they were the factory finish.

Somebody else has mentioned fuel wash, maybe a faulty injector, but that would just be the one cylinder.....?

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[flash]

if you're using up oil, it's most likely the rings.  they either did not seat, or are the wrong ones, or your cylinder walls were not treated properly

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[Nickhey71]

Thanks, yes I guess the rings seated themselves in the bores instead of the pistons

:-(

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[banditsc]

This is a break in oil, gives you some info on why it's needed. I'm sure you can find similar in the UK. https://www.amsoil.com/shop/by-product/m...-(sae-30)/

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[Nickhey71]

Thanks for the link, good information.


I understand the importance of breaking in a freshly honed cylinder bore.


In my case, the pistons had new rings, but the bores were not touched, so I assume they were already broken in / worn by the original rings.


How would new rings bed in against a surface that is already worn, do you think this could be part of the problem?

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[unknown4u]

Wrong rings will damage the surface. If the cilinderwall was worn,a good rebuilder would not have rebuild the engine.

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[MCL968]

In my experience, an un-honed wall will not seat new rings. There has to be a slight degree of roughness to bed the rings. Compound that with the incorrect break in oil and you get rings that didn't seat and possible scoring on the walls.

 

There used to be a fix that builders would use to get rings to bed. I never attempted this because I thought the idea was insane, but I have heard others use it with some success.

 

They would sprinkle a finely powdered scrubbing kitchen cleanser into the carb of a running engine. Something like Bon-Ami or Comet was preferred because it was a finer powder. This would break the glaze on the cylinder walls and bed the rings to the walls.

 

Nuts? Perhaps, but I heard it worked. Would I try it? Probably not, but I can see that you might have to use it to get the car on the track so the reduced oil consumption would allow you to finish the race and the Tech people would not black-flag you during the race for excessive smoke.

 

http://www.accessnorton.com/bon-ami-ain-...19798.html

 

As they say on TV, don't try this at home.

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[flash]

i remember the bon-ami trick from 40 years ago.  i also never tried it.  not sure if it would work with alusil.  worth a try at this point i suppose.  not much to lose.

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[Nickhey71]

Thanks guys,


I've decided that the best course of action is to get a replacement engine, as the cost of fitting liners to the original block is higher than a complete replacement!


Regarding reworking the existing alusil bores, I wasn't aware this was possible? All the engine builders I've talked to in the uk have said liners are the only option.


I've also read up on the fuel wash issue, and am starting to think this could be the main contributor to the problem.


Not sure if I'm supposed to post links, but have a look at this article:


https://www.hastingsmfg.com/ServiceTips/fuel_wash.htm


It talks mainly about carb engines rather than EFI, but I think it's relevant!


Thanks

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[flash]

you can definitely rework the bores.  i had mine punched out to the OEM upsize of 104.5.

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[Nickhey71]

Thanks guys,


I've been advised that Sunnen are the company to talk to regarding machining of the bores.

I've sent an email to the UK rep, and will let you know what they say regarding whether the damage is too severe to repair.

In the interim the 2nd hand motor will have a refresh with belts, tensioners, water pump and seals / gaskets etc, and then I'll swap it with the damaged unit.


I'll post some photos if I can work out how to do it from iPhone / iPad. I don't use a computer these days.....

Any tips on how to do that, ( if possible? )would be appreciated.


Cheers

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[Bulti]

Click on "more reply options" next to the "post"-button. There you will find the buttons to choose the files, attach them and finally add them to your post. In that order :-)

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[MLB]

To see the "more reply options" button you havd to switch from mobile version to the "full version" of the site, which is definitely more awkward to view and navigate on a mobile device, such as my iphone. But i suppose it can be done. This has been a frustration for me too.

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[Nickhey71]

Thanks, but it doesn't seem to work. The choose file button is greyed out.

Is there a way from the mobile version?

I'll try to access a computer at some point if not......

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[Bulti]

On an IPad the normal version works just fine...

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[MLB]

Ok i just tried this from my iPhone, since i hadnt done it before

I was able to select "choose file" browsed photo library to pick one

Select "attach this file" and if its not over 500k, then

Add To Post button becomes available

If u can see a motor pic it worked

If it doesnt work for u something else must be wrong...

   

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