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Engine Damage

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  • Engine Damage

    Some may know that I was on a longer trip with the Seven to Montana and Idaho. It was going well until I lost power while passing (maybe 5000-6000 rpm) and the engine (old silvertop/ZX1 Zetec) emitted some really ugly noise. I coasted to a stop, found no external problem but a valve stem was visible inside cyl #2 plug hole. So, we made the trip back to our trailer in Idaho Falls with the help of AAA and Uhaul.

    Today I took the cylinder head off and took a few pics of the damage (see below and next post). Apparently the valve retainer disintegrated. I believe the following has happened: Last year I had new valves installed. The old valves had additional keeper grooves ground in to accommodate the high lift cams and avoid binding of the stronger springs. However, the engine builder who did the change swore up and down that this was not necessary according to his calculations and measurements. Being an experienced guy with all kinds of exotic and expensive engines in his shop I believed him. The engine did probably over 5000 miles since but I guess the aluminum retainer fatigued and fell apart.

    I do have a complete spare stock engine disassembled to parts. Now my options are (assuming the head is beyond salvage):

    1. Check if the piston damage is not too bad and install my spare stock head, live with the minor power loss. I don't go the track anymore and for the road it is still ample power.

    2. If the piston is toast, I could put my spare parts engine back together and use that as-is. Cheapest solution but then I would still have a used engine with 60k miles and hard-to-get internal spare parts.

    3. I could buy Doug's new SVT engine and install that with some modifications. I will have a look on Saturday. It would require some changes to the alternator mount and belt configuration and I would have to use my old main bearing bolts for the crank on the SVT machine because they have stud extensions for the windage tray (not in my Raceline sump like for the ZX3 model). Otherwise I believe it should be a drop-in and I guess the ECU maps should pretty much work since the engine power is similar.

    4. I could buy a used Duratec. While the engine is quite inexpensive and spares are easy to find, I would need new exhaust headers and probably a bunch of other adaptations. Cut holes and plug others in the skin. Probably cut/move a chassis tube, re-route most of the engine wiring harness and modify the exhaust can or get a new one. That sounds like a serious and more expensive project.

    So, I will make up my mind over the next few days. Any input is welcome.








  • #2
    More pics...






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    • #3
      I will included my ECU map. I don't know if you can cut and paste it into the Emerald.

      The odds of there being rod damage or rod bearing damage are high. IMHO Valves don't compress too well.

      Any marks on the cylinder wall?
      Last edited by Doug Liedblad; July 2, 2015, 04:48 PM.

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      • #4
        It is time, Gert: https://en.wikipedia.org/wiki/Caterh..._RST-V8_Engine

        /Magnus F.

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        • #5
          Originally posted by magnusfeuer View Post
          Well, I am not working in the oil industry like Mike Biddell so I have to scrounge some money from my retirement savings to afford Doug's engine...

          Comment


          • #6
            Originally posted by Doug Liedblad View Post
            I will included my ECU map. I don't know if you can cut and paste it into the Emerald.

            The odds of there being rod damage or rod bearing damage are high. IMHO Valves don't compress too well.

            Any marks on the cylinder wall?
            I know, the valves should really be made from foam rubber. After some navel gazing I have pretty much written off that engine. Miraculously, there are actually no marks on the cylinder wall.
            I suspect, the piston may even have a crack.

            I googled "retainer failure" and found that aluminum retainers are generally not recommended except for short rebuild race use. But that kit (stage 2 cams, stronger springs, lightweight retainers and lifters) made by Kent Cams was recommended by Burton Power/UK and no mention of short life (I have about 50,000 miles on that engine). After all, it may not have been the engine builders' fault.

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            • #7
              Ouch! Sorry to read about this, Gert. Sorry to say that I can't really help in any meaningful way, but still... Ouch.
              | | Sean

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              • #8
                With the help of Doug's spare SVT engine I got it up and running again. At least in idle and need to check how it drives tomorrow.
                It did require some adaptation of the windage tray, removal of the cam phaser and fabrication of a new alternator bracket and belt tensioner.
                I also took the opportunity to replace a bunch of wear parts like clutch and throwout bearing, coolant hoses, exhaust wrap. Also checked the Laminova but no visible gunk and I left it alone.
                So, the maps are close enough to give it a try.

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                • #9
                  I think I can claim to be on the road again. At least the first 20 miles went quite well. The old engine map was really almost on the money but not surprising, given same intake, exhaust, displacement and similar cam specs. Compression on my old engine was a tad higher and the cam overlap more aggressive. Maybe that is the reason that I had to adjust the fueling ridge in the injection map at 2500/3000 rpm a little. On the positive side, the new engine idles smoother. I did not go above 5500 rpm yet, it is a new engine after all....

                  All adjustment with accelerator/brake road dyno and wideband lambda logging. At some point I should probably do a real dyno session again.

                  Old ZX1 engine map with Kent FZ2002 cams:


                  New SVT map:
                  Last edited by slomove; August 13, 2015, 09:32 PM.

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                  • #10
                    Break it in HARD is the current thinking. That's how Larry at MSI did mine. I had to leave while he took my new engine to 7000 rpm on his dyno.

                    By the way, your warranty has now expired.

                    Doug

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                    • #11
                      Nice!

                      Congratulations to Doug for a successful sale that just took half a decade to complete.

                      /Magnus F.

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                      • #12
                        Originally posted by Doug Liedblad View Post
                        .......By the way, your warranty has now expired.....
                        What? How about the 100,000 mile power train warranty that was promised? Not to mention the Caribbean cruise and a condo in Hawaii as part of the deal...

                        Oh well. At least I sold the VCT parts for 80 bucks....and I am thoroughly grateful that Doug saved this engine for 12 years or so.

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                        • #13
                          Next time we go to Hawaii I will invite you and Rosie.

                          The condo will be on me but you have to get there on your own.

                          Doug

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                          • #14
                            How is the power vs. the old engine?

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                            • #15
                              I made it only twice around the hills on 210/2/134 freeways (just too hot for fun) with maybe 60 miles and I was mainly occupied to exercise the engine through all possible map regions for logging. But so far it feels good. Given that the map has not changed much I would assume same fueling at same AFR might indicate similar power. Few years back on Bisi's dyno your engine showed similar results as my old engine did.

                              But you should really check your cam timing. At 5 degrees vs. the timing tool base settings you have practically no overlap whatsoever. I needed about 12 degrees advance to get only 1mm lift at TDC for intake and 4 degrees retard for exhaust.

                              I bought a 7mm borescope USB camera to check the collision margin with the pistons. A little hard to see but even at the settings mentioned above, there seems to be ample reserve.

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