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105 new engine - ceramic pistons


New Member
Dec 9, 2023
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G'day members - I'm on my second 1999 105 series GXL manual. I love the vehicles. At 190cm and110K find it so comfortable and non of that beeping crap etc etc! I had to sell the first when I was out of money - big mistake as it was mint.

The one I have now the engine blew after I'd had it a few months. I've been buying and selling cars for 30 years and had done due diligence, but that's the way it goes.

I had it rebuilt by a well known reputable company. After diagnosis they told me and showed me a part melted piston and said the injectors were partly to fault. It had previously had LPG added to give more power I believe, removed before I bought it and is turboed - still has a DTS turbo which they said is fine.

It was rebuilt with ceramic pistons and brand new head, injectors and injector pump. I picked it up and did the first 1000 or 2000ks with turbo disconnected, then went back and they reconnected turbo at 10 pounds. I drove it for a month or so then asked if turbo could be increased safely. They increases to 17 pounds and said that is fine - any higher would need an intercooler.

After that, I got even unluckier than just the engine blowing! It needed new alternator, new air conditioning unit, new starter motor and it already had a new radiator. So a lot of what is under the bonnet is new. I have since changed the gear and trans oil, and diff oils.....gearbox seems ok.

BUT - as the ceramic pistons etc are not standard spec and I can't find others who have done this yet - I can't get much confidence in it. Given what I have spent on it I want to keep it and use it. It spends relatively few ks on road as I ride bikes as my daily.

So any general thoughts on:

1. With the current spec is it likely to last and can I trust it to go to remote locations? We all know how reliable the 1HZ is - but now I just need to rebuilt confidence!
2. Obv related to 1 - is running the turbo at 17 pounds too high with no intercooler if I keep an eye on the EGT and keep below what temp? OR are there other factors that mean that could be too high?

Great if you could let me know what your level of experience is - respectfully there is a lot of people who don't have a clue offering advice, but I appreciate the time of those who do.

Thanks in advance people. Ed
My understanding is that if EGTs are within ‘safe’ limits the 1hz is probably okay at 17psi but it is a big if. I don’t believe it is possible for EGTs at 17psi of boost to be anywhere near safe without a good intercooler. Is your EGT probe in the manifold?

If you are managing your EGTs within safe limits then I suspect you are not benefiting from the 17psi and could probably lower boost (and associated fueling) substantially which may go some way to improving reliability….