Announcement

Collapse

Seven Wiki Available

Please check out our wiki available at:

http://www.californiacaterhamclub.com/wiki7
See more
See less

My car's engine is sick

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • My car's engine is sick

    At least I believe so.

    I got the cam sprockets finally installed and the timing dialed in.

    To my big surprise the engine started with minor nudging. It is running a bit lean in idle (leaner than before the cam sprocket work) but I would say it may be incidental or could be the cam timing was a bit off before leading to different mix requirements. That is easy to fix.

    However....

    - after starting the exhaust spew quite a bit of white smoke for a minute. It did not really smell like coolant but it had been sitting for 2 months and I would not know what else that could be. It was pretty warm outside and I doubt it was just water vapor.

    - I measured compression warm at 155 / 145 / 160 / 180 and compared it to the values after the rebuild 5 years ago (was 208/210/205/212). Not sure what to think about that. The car has done only 15-20k road miles since then, very little track time.

    I am beginning to wonder if I may have a leaky head gasket or a cracked cylinder head. I guess I will do a leakdown test and see if I can learn more from that and probably take the head off. Sigh...

  • #2
    I just happen to have a spare SVT engine, essentially new, just waiting for the right buyer....

    Comment


    • #3
      Originally posted by slomove View Post
      At least I believe so.

      - I measured compression warm at 155 / 145 / 160 / 180 and compared it to the values after the rebuild 5 years ago (was 208/210/205/212). Not sure what to think about that. The car has done only 15-20k road miles since then, very little track time.

      I am beginning to wonder if I may have a leaky head gasket or a cracked cylinder head. I guess I will do a leakdown test and see if I can learn more from that and probably take the head off. Sigh...
      Ouch. Compression way down across the board. Yikes.

      Originally posted by Doug Liedblad View Post
      I just happen to have a spare SVT engine, essentially new, just waiting for the right buyer....
      Doug - you know what to do next after it sells...
      Chris
      ------------
      A day you don't go a hundred is a day wasted

      Comment


      • #4
        Gert

        Did you measure the compression with the throttles wide open?

        It can make a difference.

        Comment


        • #5
          Yes, wide open. I am also wondering if I dinged the valves due to the loose timing belt. Or when the wrench slipped while trying to loosen the sprocket bolts. Or it may have been going on for a while already, who knows.
          I am not excited about taking the cyl head off but I guess that is what needs to be done.

          If there is something really wrong, I still have a complete engine broken down to nuts, bolts, pistons, block, rods etc. All waxed up and in plastic bags out in the shed. Just not with a ported head and sharp cams.

          That means, sorry but I hope I won't need your SVT engine for now. But I really hope that I don't need that spare pile as well.

          Comment


          • #6
            Have you double checked the cam timing with the new pulleys. A mistimed cam might explain the compression loss in all cylinders. Just a thought.

            Randall

            Comment


            • #7
              Originally posted by rzempel View Post
              have you double checked the cam timing with the new pulleys. A mistimed cam might explain the compression loss in all cylinders. Just a thought.

              Randall
              good idea!

              Comment


              • #8
                The SVT has forged rods, hotter cams than stock, already ported head (bigger intakes, ports and valves). Lighter pistons, higher redline plus some other bits I don't remember right now. I also don't remember how our power curves compared on the dyno day but I did post mine so it's here someplace.

                It will bolt in and may not be much more expensive than fixing yours.

                Comment


                • #9
                  I'll keep it in mind, thanks for the offer. For now I repeated the compression test, same result. Have not re-checked the cam timing yet.
                  But I did a leakdown test and that does not look too good.
                  I tested in cyl 1 and, while the leak rate was still in the green segment of the gage, I could hear the air coming out of cyl #2.
                  Then I tested #3 and while there was no audible leakage to the neighboring cylinders, the leak rate indication was pretty bad and I could hear some hissing from the oil filler neck.

                  So I guess it is the head gasket as a minimum which is easy enough to fix but a pain to do. Or it is something more insidious in which case I might take up Doug on his offer.

                  I will slowly and methodically take it apart over the next week and see.

                  Looking around the engine, I found that also my alternator bracket has a crack (still works, though). That is probably my 4th rendition on that stupid thing but it has held up for maybe 6 years now. Oh, well. let's weld it up again.
                  Last edited by slomove; March 22, 2014, 02:53 PM.

                  Comment


                  • #10
                    So I took the cylinder head off and expecting a mess I find everything looking just fine. Gasket is perfect, no apparent cracks, the cylinder bore looks good, can even still see the honing traces. Just a bit of carbon crud. I would be surprised if the piston rings are bad.

                    But there must be something. Should I take the valves out and have a look at the seats? Or just put it all back together, blame it on my clumsiness and try again?







                    Somewhat unrelated, I used the opportunity to grind the sealing surfaces of the Raceline water rail thermostat housing. That must be funny aluminum...after a couple of years there is some pitting corrosion and the cap does not seal anymore. I did that the second time now since I have the car.

                    Comment


                    • #11
                      With the head off, I'd pull the valves and look at/touch up the seats and check the valve guides and seals.

                      Randall

                      Comment


                      • #12
                        Is that silicone sealer I see on your exhaust ports?

                        It won't be a cause of your issues but you should not need anything but a gasket.

                        As Randall suggests, lapping the valves is a good thing to do. You can do it yourself.

                        Did you check the valve timing?

                        Comment


                        • #13
                          Originally posted by Doug Liedblad View Post
                          Is that silicone sealer I see on your exhaust ports?
                          Yes it is. This was Woody's recommendation. When he installed the semi-close gear box, he had the header flanges ground flat and used no gasket at all, only the copper silicone.
                          It works very well and I have reinstalled the exhaust with that method 5 or 6 times. It goes off easily with a wire brush.


                          Originally posted by Doug Liedblad View Post
                          As Randall suggests, lapping the valves is a good thing to do. You can do it yourself.

                          Did you check the valve timing?
                          O.K. will lap the valves while I am at it. Yes, timing was O.K.

                          2 more observations...when I start running the engine I see a faint whiff of smoke from the front left of the engine (around the thermostat). Obviously only visible when running in idle. So far I thought it was just some spilled coolant on the headers because I usually check the coolant when the car has sat for a while. But now I am not sure anymore. Also, that area has a lot of oil smear. Nothing that would be dripping and it collected over long time but I never found out where the oil comes from (may be the valve cover, though).

                          FWIW, the coolant (maybe 2 years old with occasional top-off) is very clear, no oil film and the oil does not show any coolant intrusion, either.

                          Comment


                          • #14
                            Oh No! It's the dreaded 'faint whiff of smoke from the front left of the engine'. A well documented sign of impending catastrophic failure.

                            Just in case, I have reserved for you:
                            Attached Files
                            Last edited by Doug Liedblad; March 24, 2014, 11:53 AM.

                            Comment


                            • #15
                              Thanks Doug, appreciate it. Give me another week or two to fiddle with my engine.

                              Is that a crate engine or a crash victim?

                              Comment

                              Working...
                              X