Testarossa rod bearings? | FerrariChat

Testarossa rod bearings?

Discussion in 'Technical Q&A' started by JohnMH, Feb 8, 2024.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,818
    Bologna
    My 91 TR has had reasonably gentle highway use during my 15 years of ownership, frequent oil changes (annual changes, so about every 2000 km) and has 66,000 km on the clock. It runs smoothly and has never even had the valves go out of spec. It unfortunately needs head gaskets now. I will check the valve seats and guides and replace the original valve guide seals while the heads are off (if I can get them off - wish me luck).

    While it is apart, is it worth replacing the rod big end bearings? I don’t want to split the cases.

    I suspect the right answer is to leave them alone, but…
     
  2. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,217
    Georgia
    Full Name:
    Wade Williams
    I think you are correct. If it ain't broke, don't fix it. It sounds like your car is well maintained and has no oil issues. I would not even try and look at them. You are just asking for trouble. If there were any indication that the oil pressure was less than optimal, then yes, take it apart and expect to replace all the bearings.
    Good luck with the heads coming off. I have built some crazy rigs for lifting heads. I had a half inch plate that attached to the spark plug holes and had threaded holes at the studs. I was able to tighten the screws at the studs and slowly pull the head off the studs. It wasn't cheap but it worked and left no damage at all. The client actually took the tool. He wanted it as a shop story prop. He paid for it and I wasn't likely to need it for that particular engine again. It was a rather rare engine.
     
  3. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,090
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    Well considering that they have a very well established reputation for longevity and bearings of the quality it has are no longer made I think its a poor idea.
     
    RayJohns likes this.
  4. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,818
    Bologna
    I am surprised the new Mahle stuff is not as good as Ferrari original bearings in the 80s. No sense in fixing what's not broken.
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,090
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    Except for some filters Ferrari is not even in their catalog.

    They do make pistons for Ferrari. They are proprietary and Ferrari has exclusive access to them. Those are for modern production only and even the replacements are no longer Mahle.

    Except for the OE contracts Mahle is concentrating on high volume fast moving parts only.
     
  6. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,090
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    I should also say if you are aware of Mahle bearings available for older Ferraris it would be good to know. They were never a supplier back then so they would need to be aftermarket modern production.
     
  7. RayJohns

    RayJohns F1 Veteran
    Silver Subscribed

    May 21, 2006
    7,925
    West Coast
    Full Name:
    Ray
    They don't make bearings like they used to. I vote let sleeping dogs lie - especially if the engine has always had good oil pressure and clean oil.

    Ray
     
  8. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,818
    Bologna
    Mahle will make custom bearings in the UK, but you are correct that no off the shelf TR stuff exists. I will just leave it alone for now.
     
  9. Veedub00

    Veedub00 F1 Veteran
    Owner Silver Subscribed

    Jun 30, 2006
    5,069
    Troy, Michigan
    Full Name:
    James
    What issues led to a head gasket replacement ? Just curious.
     
  10. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,818
    Bologna
    Not entirely sure. I have had the car since 2008. It was neglected, and off the road for 18 months while I brought it back. I have always run Evans NPG in it, so the system works without pressure, you can drive around without the radiator cap on. It never goes above 90c, even in traffic on the hottest day of the winter here in Dubai (which is still over 30c). I service it religiously and perform a major every 5 years, which is about 7-8,000 km. It does not get abused and has 66,000 km on the clock.

    We entered it in the Dubai version of the Mille Miglia in December. On the first night getting to the hotel we were stuck at the Oman - UAE border, and then in an endless row of speed bumps, taken very slowly. The rad fans worked constantly, until the fuse burned out for the right side fan ( I suspect the connector in the fuse box was generating resistance as it was burned). Water temperature went to 100c, but given our location there was no choice than to drive the last 30 km to the hotel (and getting some speed up to get air through the radiators). It was that next morning I noticed the coolant level had dropped. We finished the last 600 miles of the event without issue.

    Afterwards, I detected a slight leak at the thermostat housing which I fixed, hoping it was the cause of the loss. I flushed and refilled the cooling system, but 2-3 drives later, it still dropped. As I was noticing residue in the oil vapor recirculation system, my best guess remains a head gasket. When I removed the sump plate I found some oil/coolant residue at the bottom of the sump. I will conduct a leakdown test before the heads come off.

    Engine is out of the car, valvetrain removed, while I await the tool that allows me to remove the nuts securing the head. I understand that coolant seeping into the area where the studs travel through the head are one of the reasons the studs and head corrode (and stick to each other). My hope is that as there is no water in the NPG to cause corrosion, the heads might be less stubborn to remove.

    Oil pressure seems fine (middle of the gauge) at normal highway speed. At idle, when warm it drops below the first tick on the gauge (it has always done that). Thus, I expect the original rod bearings should be ok.

    The question is what else I should do while it is apart. I will inspect and measure the valves and guides and replace valve guide seals, but hope that I don't need to perform any major head work.
     

Share This Page