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  • #1

    0.o

    So... I pulled my heads off the other day. Well, I pulled my valves and springs and keepers and oil seals today. Holy cow.

    The valve guides had slipped anywhere from halfway to 3/4ths of the way down into the intake/exhaust ports. They were completely covered in carbon on the exhaust ports, and were no doubt restricting flow and valve movement. I wonder how this affected perforamce... Anyways, I got them pressed up into the proper place after cleaning them off pretty good. I also need some advice on what to use to clean out the combustion chambers, and if it's safe to mediablast the heads, or how I should clean them out.
    1994 Pontiac Grand Prix GTP Special Edition, Black 5-Speed
    1995 BMW 540i, Alpineweiss-III, 6-Speed
    1995 BMW 540i, Schwarz-II, Automatic
    2004 Honda 919, Light Silver Metallic, 6-Speed
    Tags: None
  • #2
    hot dipped

    Hey Husky,

    You have always lots of fun it seems. LOL Stripe the heads down and get a engine shop to clean them. The place we use has a Hot tank or a machine that is like a hot tank but also uses Ultrasound to vibrate the peice in the tank. The pieces come out like brand new. At least the pieces we have ever had done. The charge us next to nothing to do it and sometimes nothing at all. Then again they have know us for like 25 years. LOL

    By the sounds of it. I would look into geting new Valve guides put in. If I was me, the is no question if there loose are worn at all. It save a LOT of pain and suffering later.

    Make sure they use either BRASS OR BRONZE VALVE GUIDES!!!! They'll last a long time and wear far better. I know MANY race engine I have seen and had built with them!

    Any more questions Husky just ask!

    Regards,
    David Hayes
    1991 Grand Prix STE
    3.4 DOHC
    1 of 792 Produced
    Extensive Mods Done

    1991 Lumina Z34
    3.4 DOHC
    Getrag 284 5spd
    1 of 30
    Canadian Z34 Models Made with the Getrag 5spd Wahoooo!

    1980 GMC Sierra Classic C25 With 18,000 ORIGINAL MILES!!!!

    sigpic

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    • #3
      Re: 0.o

      Originally posted by Husky
      So... I pulled my heads off the other day. Well, I pulled my valves and springs and keepers and oil seals today. Holy cow.

      The valve guides had slipped anywhere from halfway to 3/4ths of the way down into the intake/exhaust ports. They were completely covered in carbon on the exhaust ports, and were no doubt restricting flow and valve movement. I wonder how this affected perforamce... Anyways, I got them pressed up into the proper place after cleaning them off pretty good. I also need some advice on what to use to clean out the combustion chambers, and if it's safe to mediablast the heads, or how I should clean them out.
      It's odd that yours slipped. And I thought it may be just a 1 time thing, however, after Ben and I tore this head down...Note the guide on the left, It actually slipped up into the spring about .100" Maybe not so odd after all. Certainly not good though.
      If you are driving a Chevy, everything else, is just a blur. 3.4 Carbon Footprint.
      sigpic

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      • #4
        When I was putting some heads on the shelf I noticed that the 96 head that I have apart has 2 guides down in the port area. 1 is almost flush on the top of the head! This is disturbing. So I guess I will add the DOHC guides to my search for part upgrades.
        Ben
        60DegreeV6.com
        WOT-Tech.com

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        • #5
          My valve guides had also slipped into the ports. Some slipped in far enough to the point where the stem seal had nothing to grip onto. Funny it didn't smoke. So the valve guides were all in good condition, but they aren't locked in too well. I'm thinking about getting out the dremel, and putting a few notches around the base of the exposed stem on top of the head, put a snap ring around it and put the valve spring shim on, it will keep the snap ring from riding up with the stem, and the snap ring will keep the stem from slipping down into the port... sounds like a solution, just so long as the stem with the snap ring doesn't force the valve spring shim and the spring up. Shouldn't be a problem. I'll have to look into this more. There is a bit of space under the valve spring shim where a snap ring will fit without it pushing the shim off the head.

          I think it is caused by different thermal expansion rates... it's difficult to press the valve stem back in on a cold head. I tried it once.

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          • #6
            Originally posted by Fierobsessed
            My valve guides had also slipped into the ports. Some slipped in far enough to the point where the stem seal had nothing to grip onto. Funny it didn't smoke. So the valve guides were all in good condition, but they aren't locked in too well. I'm thinking about getting out the dremel, and putting a few notches around the base of the exposed stem on top of the head, put a snap ring around it and put the valve spring shim on, it will keep the snap ring from riding up with the stem, and the snap ring will keep the stem from slipping down into the port... sounds like a solution, just so long as the stem with the snap ring doesn't force the valve spring shim and the spring up. Shouldn't be a problem. I'll have to look into this more. There is a bit of space under the valve spring shim where a snap ring will fit without it pushing the shim off the head.

            I think it is caused by different thermal expansion rates... it's difficult to press the valve stem back in on a cold head. I tried it once.
            I had two like that, and the motor barely smoked at all, usually not at all.
            1994 Pontiac Grand Prix GTP Special Edition, Black 5-Speed
            1995 BMW 540i, Alpineweiss-III, 6-Speed
            1995 BMW 540i, Schwarz-II, Automatic
            2004 Honda 919, Light Silver Metallic, 6-Speed

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            • #7
              It sux. Who is the retard at GM that thought of this? Floating Valve Guides.

              On the other hand, anyone have an issue with it? Drop a valve? I am more disturbed that it goes both ways.

              Can't wait to pull my stock heads.
              If you are driving a Chevy, everything else, is just a blur. 3.4 Carbon Footprint.
              sigpic

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              • #8
                Well, i found out that my heads had over 200,000 on them with no work(including HGs I guess... dammned ghetto mechanics and cars) and it wasn't too serious.
                1994 Pontiac Grand Prix GTP Special Edition, Black 5-Speed
                1995 BMW 540i, Alpineweiss-III, 6-Speed
                1995 BMW 540i, Schwarz-II, Automatic
                2004 Honda 919, Light Silver Metallic, 6-Speed

                Comment

                • #9
                  I had one or two shifted valve guides as well, but my motor had been overheated by the previous owner. I'm sure overheating is related.

                  You can safely beadblast the heads, valves, etc before you machine them. The block can be hot tanked and shot peened. You can't hot tank aluminum; it will just dissolve.
                  If you have a nasty varnish on your valvesprings as I did, the best way I found to remove it was to put them in a tumbler with a good solvent.

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                  • #10
                    Originally posted by series8217
                    I had one or two shifted valve guides as well, but my motor had been overheated by the previous owner. I'm sure overheating is related.

                    You can safely beadblast the heads, valves, etc before you machine them. The block can be hot tanked and shot peened. You can't hot tank aluminum; it will just dissolve.
                    If you have a nasty varnish on your valvesprings as I did, the best way I found to remove it was to put them in a tumbler with a good solvent.
                    Wish I had seen that before I installed them.
                    1994 Pontiac Grand Prix GTP Special Edition, Black 5-Speed
                    1995 BMW 540i, Alpineweiss-III, 6-Speed
                    1995 BMW 540i, Schwarz-II, Automatic
                    2004 Honda 919, Light Silver Metallic, 6-Speed

                    Comment

                    • #11
                      Sorry, I don't check this forum much.

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                      • #12
                        it's okay.
                        1994 Pontiac Grand Prix GTP Special Edition, Black 5-Speed
                        1995 BMW 540i, Alpineweiss-III, 6-Speed
                        1995 BMW 540i, Schwarz-II, Automatic
                        2004 Honda 919, Light Silver Metallic, 6-Speed

                        Comment

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