L46 camshaft recommendations - NCRS Discussion Boards

L46 camshaft recommendations

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  • Peter S.
    Very Frequent User
    • March 28, 2012
    • 327

    #16
    Re: L46 camshaft recommendations

    Thanks for the replies all. I ordered the 962 replacement this afternoon after Duke's strong position. I think that this is a good decision.

    Duke, the only markings I find on the head gasket shim are a "V" stamped over a "G" and "C4". I cannot find anything googling, do these markings mean anything to you?

    Peter

    Comment

    • Joe L.
      Beyond Control Poster
      • February 1, 1988
      • 43220

      #17
      Re: L46 camshaft recommendations

      Originally posted by Peter Stout (54749)
      Thanks for the replies all. I ordered the 962 replacement this afternoon after Duke's strong position. I think that this is a good decision.

      Duke, the only markings I find on the head gasket shim are a "V" stamped over a "G" and "C4". I cannot find anything googling, do these markings mean anything to you?

      Peter

      Peter-----


      The "V over G" embossment denotes Victor Gasket. Victor was a major supplier to GM so it's possible the gasket was as originally installed. However, it's also possible it's aftermarket since Victor has always and still does sell gaskets in the aftermarket. Now they're known as Victor-Reinz, though. I don't know what the C4 signifies. Some sort of manufacturing code, I expect.
      In Appreciation of John Hinckley

      Comment

      • Duke W.
        Beyond Control Poster
        • January 1, 1993
        • 15670

        #18
        Re: L46 camshaft recommendations

        Originally posted by Peter Stout (54749)

        Duke, the only markings I find on the head gasket shim are a "V" stamped over a "G" and "C4". I cannot find anything googling, do these markings mean anything to you?

        Peter
        Okay, maybe you can take a look sometime again with a magnifying glass. My bet is that there is a small stamped GM part number, but they can be difficult to see on an old gasket. In the meantime, don't throw them away. I may want you to mail them to me.

        I don't think Victor Reinz makes a similar gasket for the aftermarket, today, but I haven't checked for a few years. The thinnest I know of is the Fel Pro polymer coated 1094, which is .015" compressed. It's okay to use if the block deck and head surface check out level. and it doesn't cause the CR to be too high for the configuration.

        Duke

        Comment

        • Peter S.
          Very Frequent User
          • March 28, 2012
          • 327

          #19
          Re: L46 camshaft recommendations

          Duke,

          I spent another 20 minutes looking over the shim. I did give it a good wipe down with some brake cleaner. This did expose a "GM" stamp, but still no part number. Do you have an expectation where on the shim you would find the part number?

          Comment

          • Joe L.
            Beyond Control Poster
            • February 1, 1988
            • 43220

            #20
            Re: L46 camshaft recommendations

            Originally posted by Peter Stout (54749)
            Duke,

            I spent another 20 minutes looking over the shim. I did give it a good wipe down with some brake cleaner. This did expose a "GM" stamp, but still no part number. Do you have an expectation where on the shim you would find the part number?


            Peter------


            If it's there, at all, it should be on one of the end extensions (i.e. the location where you found the "GM" and "VG" symbols.

            The closest you can come today to this gasket is a Victor-Reinz #1178BS. This is a steel shim gasket of 0.016" thickness. However, I would not use this gasket unless I knew that both the head and block surfaces were perfectly true.
            In Appreciation of John Hinckley

            Comment

            • Duke W.
              Beyond Control Poster
              • January 1, 1993
              • 15670

              #21
              Re: L46 camshaft recommendations

              ...location would most likely be where Joe said. I have gaskets that came off a L-46. They are stamped GM 3830711 in the location where you found the stamped data. This is the service replacement gasket, so the heads had been off that engine. It actually measures .022", but I've seen it speced at .026".

              This gasket is also stamped Mc 6631 on the other extension, so it's a McCord 6631 that they sold in the aftermarket without the GM stamped data.

              I'm surprised you didn't find a GM part number or some other identifying data. That .018" gasket was used by Flint for about 20 years. I don't think there were no other small block gaskets in use in that time period, so I guess they knew that any head gasket at Flint would be the one you have, and it didn't need specific ID data.

              Thanks for spending the time to check it out.

              Duke

              Comment

              • Peter S.
                Very Frequent User
                • March 28, 2012
                • 327

                #22
                Re: L46 camshaft recommendations

                Thanks for the info Duke and Joe. I won't be reusing these gaskets. Duke, they are yours if you still want them - let me know and I'll drop them in the mail next week.

                As far as the deck height, the machinist measured 9.023", so it looks like it is still standard.

                To clarify on the engine bore, The machinist said that maximum wear at bottom of any bore is 0.002", maximum wear at middle of any bore is 0.002" and the maximum at the top of any bore is 0.005". His opinion is that the wear is very acceptable at the bottom and middle with the minimal wear on the piston skirts. The wear at the top is acceptable because only the rings ride at this point, so no concern of piston slap.

                Comment

                • Peter S.
                  Very Frequent User
                  • March 28, 2012
                  • 327

                  #23
                  Re: L46 camshaft recommendations

                  I wanted to update this thread: The camshaft ended up in a 3-month back order and by the time I received it, we had sold our house and everything put in storage. Well I am out of storage now and this has given me plenty of time to think about the block. I am going to proceed having the bores opened up 0.020".

                  I plan to move forward with the Keith Black Hypereutectic 4.020" pistons w/ a -1 cc dome. (http://www.summitracing.com/parts/uem-skb358-020)

                  I plan to use the Fel-Pro 1044 head gasket w/ a 4.200" bore and a 0.051" compressed thickness. This should put me at a very manageable 10.1 CR.

                  Comment

                  • Duke W.
                    Beyond Control Poster
                    • January 1, 1993
                    • 15670

                    #24
                    Re: L46 camshaft recommendations

                    I don't see a SKB358 listing on the manufacturer's Web site, and the data on the Summit site doesn't make sense. - a .100" dome with no valve reliefs and a net dome volume of (actually) 1 cc. This data doesn't add up! This page lists available pistons for 350s with 5.7" rods:



                    Always use the manufacturer's Web site, not some retailer's site when you are looking for part numbers and specs.

                    It looks to me like the SKB 119 is a good place to start. The effective dome volume is 0.5 cc, which is about 2 cc less than OE. It is VERY IMPORTANT to understand that KB uses an opposite sign convention when stating "dome volume". Most use a positive number, but since an effective "dome" subtracts from total chamber volume KB lists a net "dome as negative and a net "dish" as postive, but this value must be entered as a postive number for net domes and negative for net dish in most CR calculators. You can't be too careful!!!

                    I use and recommend the following CR calculator:

                    This calculator is designed to show the different Compression Ratios for different sized engines.


                    The SKB119 has .001" more compression height that the OE 1.560". So using 9.023" nominal deck height that was measured, nominal deck clearance should be .022" - 4.02 x 3.48", 65 cc head chamber, 0.5 cc "dome"(entered as a positive number), 4.08 x .038" gasket I get 10.37, which is good; 10.0 is very conservative with the L-46 cam.

                    Always measure deck clearance after the short block is assembled and use this data to make final head gasket selection to get the CR into the proper target range.

                    If I have not already sent you the article on managing compression ratio, send me an email through the TDB and I will get it to you.

                    Also, I don't think Summit has the lowest prices, so once you verify the piston part number you should shop around

                    Duke

                    Comment

                    • Peter S.
                      Very Frequent User
                      • March 28, 2012
                      • 327

                      #25
                      Re: L46 camshaft recommendations

                      Duke,

                      Thanks for the link directly to KB Pistons - I agree, SKB119 looks to be a good start. And also thanks for pointing out the compression height, I did not take that into consideration.

                      I am not sure if I have your paper on managing compression ratio, I do have the "Special 300HP" and "Tale of Two Camshafts" papers. I do like technical papers, you'll receive an email from me shortly.

                      Peter

                      Comment

                      • Jimmy G.
                        Very Frequent User
                        • November 1, 1979
                        • 976

                        #26
                        Re: L46 camshaft recommendations

                        Peter contact me at tio2jim@aol.com for head gaskets
                        Founder - Carolinas Chapter NCRS

                        Comment

                        • Mike F.
                          Expired
                          • April 25, 2011
                          • 668

                          #27
                          Re: L46 camshaft recommendations

                          Here are my 70 L-46 dyno results, before (detuned) and after rebuild.

                          1.https://www.forums.ncrs.org/showthre...highlight=dyno

                          2.https://www.forums.ncrs.org/showthre...highlight=dyno

                          Comment

                          • Mike F.
                            Expired
                            • April 25, 2011
                            • 668

                            #28
                            Re: L46 camshaft recommendations

                            3. https://www.forums.ncrs.org/showthre...highlight=dyno

                            4. https://www.forums.ncrs.org/showthre...highlight=dyno

                            Comment

                            • Peter S.
                              Very Frequent User
                              • March 28, 2012
                              • 327

                              #29

                              Comment

                              • Mike F.
                                Expired
                                • April 25, 2011
                                • 668

                                #30
                                Re: L46 camshaft recommendations

                                Cam is not advanced.

                                Comment

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