Monday, February 11, 2013

3.1L engine (GM): replacing intake manifold gaskets

      The original lower intake manifold gaskets will leak and then the gaskets must be replaced. Here's how.
      This is a difficult job, so I took detailed notes and digital pictures to help.
      I successfully completed the job on 2001 Buick Century. I recently completed a more detailed post on the similar 3.4L engine.
This is the before picture of the 3.1L engine


Preliminary Removal

1) Disconnect the negative cable at battery.
2) Unplug and mark 8 or 9 electrical connectors from their devices at the top firewall side of the engine.

Here is a close up view before the air intake assembly is removed

3) Now you can remove the air cleaner duct.
4) Remove the accelerator and cruise control cables from the mounting bracket. Set off to the side.
5) Remove the bracket. Three fasteners (10mm) hold it.
6) Unbolt the evaporative canister purge solenoid valve. It bolts with a 10mm to the end of the upper manifold cover. There is a hose going to the PCV valve on the front valve cover and another to the manifold itself. Move it off to the side.
7) Remove the EGR valve. This mounts on the right rear end of the upper intake manifold by two bolts. There is a gasket. The valve will just hang there by the rigid pipe that goes to the exhaust.

The air intake hose is now off, providing a better view of the remaining components

8) Remove the MAP sensor (one 13mm bolt) .
9) Unplug the spark plug wires from the ignition coil and mark both  the wires and the coil terminals where they plug in. Remove the coil assembly. Three 10mm bolts.


10) Remove the two little heater bypass hoses from the throttle body.
11)  Remove the alternator. There are two bolts in the back that hold it along with the pinion one in the front. The bracket for the alternator will have to come off after the alternator is removed. There are four bolts holding the alternator bracket and an engine eyelet for pulling  the engine out. These are of three different lengths so keep track of them.
11) Unbolt the remaining six bolts from the upper intake assembly. It pulled right off. The bolts are different so keep track of where they belong.

View with upper intake plenum removed




                                       
Removal of  lower intake manifold

1) Relieve fuel pressure. There is a cap on the left rear end of the back fuel rail. Take off the cap and push in the spring-loaded nipple with a small allen wrench. The pressure will relieve. I put a hose over it and activated the release with a small Allen wrench. There was just a drop of fuel and that’s all.
2) Uncouple the gas lines. The gas lines are uncoupled upstream from the fuel rail. A little plastic tool is inserted into the coupling and the lines will pull apart. There is some loss of gas. I put a zipper bag on them with a twist tie to hold it on. It isn’t necessary to unplug the injectors.


3) Unplug two connectors, one large one behind the engine and one small one right in front, atop the front valve cover. Now just pull up on the whole rail assembly and wiggle till it comes off as an entire assembly.
3) Remove hose clamps from the two ends of the bypass hose and separate them from the metal tubing. These pieces of tubing are pressed into the intake manifold. An 8mm bolt threads  into a housing by the water pump.
4) Remove the coolant overflow bottle. Two nuts.
5) Remove the serpentine belt. It takes a large allen wrench on the tensioner.
6) Unbolt the power steering pump and move it out of the way.
7) Remove both valve covers. These are 8mm retentive bolts, 4 on each cover.
8) Remove a 13mm bolt holding a bracket for a heater hose that is press fit into the thermostat housing.
This requires a ¼” deep well socket. A wiring harness mounts in a hole on this bracket and must be removed to fit the socket in there.
9) Remove the pipe from the thermostat to the upper radiator hose. Two 13mm bolts hold it on. The lower one is tough to get a wrench on and impossible to get a socket on for clearance.
10) Remove the lower intake manifold. Remove the four middle bolts first and then the four outer. Put them in a cardboard box, punching holes and marking their locations. I had to use a crowbar on an exposed corner (very carefully) to get it out.
11) Remove the pushrods and similarly put them in a box. A 10 mm socket will loosen the lifter assemblies to get clearance to remove them.
12) Now the gaskets are re-moveable. Take the crappy things out and clean all mating surfaces thoroughly.

View of the 3.1 with the lower intake removed



                                                                            Re-assembly
Lower manifold
1) Put new gaskets in place. I used a Fel-Pro kit (see below post for a link to the kit) that includes metal gaskets that are much more stout than the original plastic ones. See the link below these instructions to this excellent gasket kit.
2) Install pushrods in original positions. Tighten arms to 14 ft/lbs plus a 30 degree turn. This is as far as they will go.
3) Install lower manifold. Lay a 3/8” bead of black RTV to the section in the end of the valley between the two banks. Tighten the four inner bolts first to 5 and then to 10ft lbs. It is impossible to get a torque wrench at the inside end bolts (one on each end). I had to guesstimate the torque.
4) Install the valve covers. Should be about 7 ft lbs,  I purchased a 3/8”-1/4” socket adapter to allow use of the torque wrench with a 8mm ¼” socket.
5) Install the heater hose in the thermostat housing. Replace the o-ring in the end of the pipe first. Use a 13mm deep well here to attach the bracket welded to the pipe. Re-attach the wiring harness in the hole on the bracket.
6) Install the thermostat. Install the thermostat radiator side housing. It’s easier if you start the troublesome lower bolt first and then work the hose housing over the thermostat. Use a short 13mm wrench to fit around the exhaust pipe cover.
7) Install the heater bypass pipe. It goes under the upper radiator hose. Reattach two clamps and an 8mm bolt to the housing that attaches the assembly to the water pump.
8) Mount the fuel rail assembly at the same time as the power steering pump. Work them down into position together. If the pump is put in first the rail assembly will not fit and vice versa. I found that thin coat of motor oil on the injector gaskets was very beneficial. Mount the two 10mm fuel rail bolts.
9) Reattach the fuel line to the fuel rail. They just snap into place. Put the retainer clips on. Put the fuel lines 10mm mounting bolt back in.
10) Mount the power steering pump with the three 13mm bolts.

Upper Manifold

1) Place the new gaskets for the upper manifold in place. They have nice plastic guides for proper placement.
2) Set upper manifold in place and loosely tighten the six mounting bolts. The middle rear bolt holds the MAP sensor, so it goes with it when mounting. The two front left bolts hold a wiring bracket and the front right holds a spark plug wire holder. Torque to 18 ft lbs. There is guesswork on the MAP sensor bolt, since no torque wrench would fit there.
3) Plug in the Map sensor and the wiring in front of the upper manifold. Attach vacuum hose to fuel regulator upper right of manifold.
4) Mount the alternator bracket with the three 15mm bolts on the front and one in the back. Make sure the power steering lines are properly routed  between the bracket and the pump. There is holder down below.
5) Mount the alternator with the long through bolt on the front, a 13mm nut to a small bracket on the left rear stud of the upper manifold and two 15mm bolts to the bracket in the rear. Attach wiring connector to lower alternator.
6) Plug in oxygen sensor and small vacuum line to left rear of upper manifold. Plug in large injector wiring harness.
7) Mount the ignition coil assembly. Note the spark plug holders that go on the right side. Plug in the two electrical connectors on either side of the coil assy. Plug in the spark plugs. Snap them into the routing channels.
8) Mount the EGR valve. I reused the old gasket. Two 10mm bolts.
9) Attach the coolant lines to the little hoses that run though the throttle body.
10) Install the evap canister solenoid valve with a 10mm bolt to the upper manifold, right rear
11) Install the throttle assembly bracket.  A tie-wrap is helpful here.
12) Install the air intake duct.
13) Plug in all remaining electrical connectors. Nice work! Pop the top off your favorite
beverage and celebrate…after you start it up.

Conclusion

     The Buick has been leak free for several years now. This is a challenging repair for sure. I hope these instruction helped you "get it done." They, too, can be a lot of work and a challenge to create. If you found them useful I hope you would consider making a donation to this blog (see the "Pay Pal" link on the left side bar).  Have a good one and come back again.


                

 About the "Original Mechanic"

62 comments:

  1. I did head gaskets on my 3.1. When i put my intake manifold back on, there was about a 3/16 inch gap between the manifold and the block between the heads. Any ideas?

    ReplyDelete
    Replies
    1. INSTALLATION TIP: The locating pin often breaks off the plastic carrier type
      gasket being replaced. Be sure to clean out the locating pin holes in the heads to
      remove the old broken pins and any debris. Failure to clean these holes will
      prevent the new locating pin from seating properly in the hole (allowing the
      gasket to set flat against the head) and will result in failure of your new gasket.

      Delete
    2. That's a very good tip. Thanks Anonymous.

      Delete
  2. I seem to recall something like that when I did this job last year. I don't remember what I did, if anything. I put it all back together and it ran fine.

    ReplyDelete
  3. I just went through this nightmare job, installed reman Jasper 3.1 in a Malibu. Intake manifold was rotten and leaking antifreeze, I had to replace it after I just got it running then I had a fuel leak, fixed that! Then another bypass tube leaking antifreeze, still dealing with that! I can't get this job out the door!

    JIMMY.

    ReplyDelete
  4. Sometimes all you can do is keep at it. Good luck, sounds like you could use some.

    ReplyDelete
  5. David,
    Thanks for your very good instructions & photos.
    I can't take credit for the tips. They're from the good folks at Fel-Pro.





    From Abraham Torres-Arredondo:



    Thanks to everyone.

    ReplyDelete
  6. Hi,
    Awesome DIY instructions, thank you very much.
    I found a couple points for improvement:
    1) Didn't need to remove the fuel rail from the upper intake manifold. It could have come off as a whole assembly and saved time & risk.
    2) Didn't need to attach the power steering pump and fuel rail at the same time. (My Century is a 'limited' maybe the 'custom' is different. )
    3) cleaning the gasket surfaces: use either a dremel tool with a very soft bit, or a green kitchen sponge & some carb cleaner (or alternative).

    Thanks again for putting this together,
    Phillip

    ReplyDelete
  7. As with most jobs, there's always room for improvement. Thanks for the useful comments.

    ReplyDelete
  8. How do I replace the lifters?

    ReplyDelete
    Replies
    1. I never removed and replaced them on this car. If I was, I would have a look at a Haynes or Chilton manual. Good luck with it.

      Delete
  9. Hi, and thanks. I am starting my tear down tomorrow,and Googled it one last time,and picked yours first. Thanks for making it so much easier. I have Haynes,but like your version better!

    ReplyDelete
    Replies
    1. Thanks for the good words. Just take your time and label the parts and fasteners and I'm sure it will come out fine.

      Delete
  10. Re: 2000 Buick Century Custom, 3.1L SFI OHV 6cyl
    THANK YOU for taking the time to write and publish all these detailed notes on such a complicated job!
    My Buick Century has, what I believe are, two AIR Check Valves --one is near the Oil Dipstick, the second is between the Coil Assembly and the Firewall. The second one seems to be attached to the Coil Assembly and is very difficult to access. I can't remove the Assembly until I remove the Check Valve. Any tips on how to remove the AIR Check Valves?
    By the way, I'm not sure if the webpage is loading correctly; the article mentions plenty of digital pictures, but I'm only seeing three of them (‘before’, ‘upper intake’ and ‘lower intake’ pics).

    ReplyDelete
    Replies
    1. I could find no information on these valves in my Haynes manual. Yeah, there only are three pictures. This is my earliest work and I didn't take as many as I do now, back then. Thanks for the comment and I wish I coud help with your problem. Good luck with it.

      Delete
  11. I wish I had seen these instructions before tackling this job. I disconnected the fuel Lines at the rail and when I was finished the job I started the car and gas poured out of the air intake down onto the air filter housing and onto the floor. Was there supposed to be an O ring seal on the connection between the fuel line and the fuel rail? In the 2nd picture its the top fuel rail I'm referring to. When I disconnected it I don't remember one and when I put it together there wasn't one. I'm thinking that there should be an O ring in that connection.
    Any thoughts?

    ReplyDelete
  12. I don't specifically remember an o-ring, but I bet there was one and yours fell out. You might want to ask them at an auto parts house. They should have an exploded view showing all parts and they could get the right one for you. I enlarged the three pictures and I wish I had more pictures of this job because it's my most popular post. I hope you are able to get it squared away.

    ReplyDelete
  13. Yes, there is supposed to be an O ring seal on both connections to the fuel rails and one of mine was missing. I had to order the kit which contains both O rings because it wasn't stocked in town. Very pricey, $40 for 2 little O rings.

    ReplyDelete
  14. David, Thanks for taking the time to write out the steps so I could just print them out and take them out to my car!! I did this replacement just over a year ago and forgot to torque down the center lower manifold bolts first!! I didn't realize the importance of this step until I already had the upper manifold torqued down. Needless to say, I am just finishing up the second replacement. DUH!
    Anyhow, I really want to suggest to others that they purchase a metal fuel line disconnect tool rather than the plastic "tools". I purchase a Autocraft tool at Advance. Part No. AC522/W83114. I am sure that any auto parts store would have something similar. I had both lines apart in less than one minute. Since I did not need to replace my thermostat, I left my housing on the manifold. No problem, just disconnected the hose. I did try to replace the injector O rings with the Fel-Pro replacements. They are thicker than the originals so while they are the same size od, they have less id. I had cleaned the ports where they install, and lubed them (the O rings) with oil as you suggested but could not get the injectors to seat. I put the old ones back on. So readers, If you are replacing your injector O's, please don't throw away or damage your old rings until you see if the new ones fit. I'm 70 years old and it took me 16 hours to complete. I had a lot of parts cleaning to do. Thanks again!

    ReplyDelete
    Replies
    1. You're welcome and thanks for sharing these details from your job that may help others. Unexpected problems and do-overs are just a normal part of many jobs for the home mechanic. I've had my share of "Duh" moments. Sometimes the best quality we have is patience and stick-to-it-iveness. Thanks again for using this post and sharing!

      Delete
  15. This comment has been removed by a blog administrator.

    ReplyDelete
  16. how about anti freeze in the upper intake? there are traces of anti freeze in the upper. cylinder 6 and across the upper. just did lower gaskets 3 days ago

    ReplyDelete
  17. Sorry, I don't have an idea about how that got there or what the cause might be.

    ReplyDelete
  18. Sorry, I don't have an idea about how that got there or what the cause might be.

    ReplyDelete
  19. What are the torque specifications for the upper intake to mate with lower intake on a Buick century 3100?

    ReplyDelete
    Replies
    1. 18 ft lbs is the spec for that. You can find it the re-assembly instructions.

      Delete
    2. 18 ft lbs is the spec for that. You can find it the re-assembly instructions.

      Delete
  20. thank you so much man. im in the middle of re-assembly and reviewing the steps. seriously great job and a huge help. thank you

    ReplyDelete
    Replies
    1. You're welcome. I should mention that I now have a more detailed post on the nearly identical 3.4L engine

      Delete
  21. Thank you so much, on my 1999 Malibu 3.1, I got the removal portion done in about 5 hours following these instructions. I found the coolant leak in the upper intake manifold, but decided to go all the way down to the head gasket seeing as the 90k mileage suggests it was due.

    First thing, I sent the heads off to the machine shop prior to ordering any parts. They just had to be cleaned and resurfaced, no warping. My question is, other than just cleaning up the block real good, should I be worried about block flatness? When removing the head gaskets, you could see a little bit of migration of the dex-cool but there was not leakage. I can go out and buy a flat edge and feeler gauge if it is an absolutely necessity. Thanks a gain.

    ReplyDelete
    Replies
    1. It doesn't hurt to be thorough. I commend you for doing the head gaskets and having the head gone over by a shop. I didn't have the determination to go that far with this pain of a repair. Smart!

      Delete
    2. Thanks David, I have to say I was definetly helped by your instructions and that just motiviated me to go on.

      Delete
  22. Did u have to adjust the valves?

    ReplyDelete
    Replies
    1. No, machine shop said that they just cleaned it up and resurfaced. Everything else looked good.

      Delete
  23. I have a question, hoping someone can answer, i have a 98 buick century with a bad im gasket. I stripped it down to the gasket and ive had it sitting a couple weeks in the garage. I didnt cover the bottom part that goes into engine, ive read some different threads that say to do that but its a little to late. What harm could i have done, the entire engine is covered but i didnt stuff rags or anything into the bottom. This may be a really dumb question but like i said i read something that made me concerned.

    ReplyDelete
  24. I have a question, hoping someone can answer, i have a 98 buick century with a bad im gasket. I stripped it down to the gasket and ive had it sitting a couple weeks in the garage. I didnt cover the bottom part that goes into engine, ive read some different threads that say to do that but its a little to late. What harm could i have done, the entire engine is covered but i didnt stuff rags or anything into the bottom. This may be a really dumb question but like i said i read something that made me concerned.

    ReplyDelete
    Replies
    1. You should be alright if you covered the engine. What you might try as a precaution now is use a shop vac to suck out anything that may be in there. Wrap a rag around the nozzle and give each port a few seconds of suction. The peace of mind may be worth a little extra trouble.

      Delete
  25. I have another question, should i use cam lube before putting manifold back on? I was told this is good for dry start, i dont fully understand. I followed instructions on this thread thus far and it went well. Now i have to reassemble and i dont wanna make any mistakes. I drained all fluids in engine.

    ReplyDelete
    Replies
    1. I haven't heard of cam lube. It probably won't hurt. Being careful and thorough on this job is just smart. I never had a problem without it, but I've only done two of these jobs.

      Delete
  26. I have another question, should i use cam lube before putting manifold back on? I was told this is good for dry start, i dont fully understand. I followed instructions on this thread thus far and it went well. Now i have to reassemble and i dont wanna make any mistakes. I drained all fluids in engine.

    ReplyDelete
  27. In the first two pictures there is a plastic line with a right angle boot that comes off the air intake hose. Can anyone tell me what this is? Mine goes around to behind the intake manifold and is loose into whatever it goes in, not sealing correctly.

    ReplyDelete
  28. This is a fresh air breather that is supposed to seat in the rear valve cover.

    ReplyDelete
  29. This comment has been removed by the author.

    ReplyDelete
  30. Well, update, i overtightened the lim bolts. Never used a torque wrench and the help i had misread inch pounds for foot pounds, i felt and heard a snap but the bolt did not break. It stripped the threads. Taking the lim back off i cannot see any damage so i got a helicoil kit, ordered new bolts, studied a little more on the specs ( feeling pretty dumb) im gonna go back at it this weekend. When i started this job i drained all fluids, thats whyi asked about the cam lube or even oil, should it be oured directly in engine before i secure lim? I had a few issues along the way, like breaking a couple clips on the fuel rail harness, they still plug in but the part that locks em in place is no longer, any suggestions? Distributor oring comes in kit, should i replace that? Last i keep reading in these threads about fuel orings, i havent come across them that i know of but the kit comes with some so i suppose ill figure it out when i get to that point. Any help, suggestions are appreciated.

    ReplyDelete
    Replies
    1. Too bad about the bolt. It happens. I would try to use zip ties on a broken harness. I just put the oil in at the end. I don't worry about that. Any o-rings that you have in a kit...always use them. Sounds like your doing fine on a tough repair!

      Delete
  31. Little by little, installing the fuel rail and electrical harness, i searched for a few hours now for a diagram. I dont want to hook injectors up wrong but i cannot find anything. I took it completly apart and apparantly deleted my pictures. Any help? Ideas?

    ReplyDelete
  32. Little by little, installing the fuel rail and electrical harness, i searched for a few hours now for a diagram. I dont want to hook injectors up wrong but i cannot find anything. I took it completly apart and apparantly deleted my pictures. Any help? Ideas?

    ReplyDelete
  33. I have a few more picures on my very similar 3.4L post. http://www.originalmechanic.com/2016/06/how-to-replace-lower-intake-manifold.html
    They aren't very good but it's all I have. You should be able to get them back in the right injectors by length of wires alone. Good luck

    ReplyDelete
  34. Hi i did this job and head gaskets but when putting manafoldback on there was a gap. Im gonna check for the pinholes to see if the old gasket broke off in there

    ReplyDelete
  35. I thought it was going to be some boring old post, but it really compensated for my time. I will post a link to this page on my blog. I am sure my visitors will locate that extremely useful..
    engine overhaul gasket set

    ReplyDelete
  36. I appreciate the link. I'm glad you found this information worth your while!

    ReplyDelete
  37. So I broke what you called the fresh air breather hose on a 1995 Pontiac Grand Prix with the 3.1 L engine. Do you have any idea where I could find a replacement? I have been searching for quite a while to no avail. Is there some technical term for this plastic piece? Or is it just unobtainable.

    ReplyDelete
  38. Hello. You guys are kinda my only hope because most forums dedicated to this topic are completely quiet and there is no online guide. To cut a long story short, I broke the PCV hose as I was trying to replace the PCV valve, which was supposed to be a simple job. It's probably still simple to replace the hose, except it's covered by some components I need to remove to lift out a connection point on the tube in the middle. Part of this article includes instructions on how to remove the obstructions, just not in the detail an amateur like me would need, so I hope this comment isn't too off topic and if it is I apologize. My hope is for an expert on here to let me know what I need to do to replace the hose. I have ordered the replacement hose already, but it appears a metal bracket that also holds the throttle cables is covering the hose and the fresh air breather hose above it might be in the way. I think those are the only two components I really need to get out of the way, but I'm not too sure. Will I be able to unbolt the metal bracket enough to lift the hose out and slip the new one in without messing with the throttle cables, and if I need to move the fresh air breather hose out of the way, can I just yank it out from the air cleaner duct/intake duct like the PCV valve? I would really appreciate it if somebody could confirm that those are the only components I need to move out of the way to remove and replace the PCV hose and let me know how exactly I should remove them (so I don't break anything else :P). If I can accomplish this successfully I will document it along the way and then post the guide online crediting you, so nobody else has to bother you about this. Thank you.

    ReplyDelete
    Replies
    1. Well, maybe I could leave the fewsh air breather hose alone which I highlighted in yellow (at least I'm pretty sure that's the correct name), but the red bracket definitely needs to be lifted up at least a little. https://buickforums.com/forums/attachment.php?attachmentid=11376&d=1517693058

      And here's the high quality unedited photo: https://m.imgur.com/a/76h6G

      Once again I appreciate you guys volunteering on here.

      Delete
  39. Hey all. I stumbled upon this forum looking for torque specs for the intake bolts. My sister in law has a 3.1 liter that pulled a rocker arm assembly bolt out of the boss in the head. So heli coil it is hahaha. This procedure is very thorough in letting a person know what has to be done in order to replace the Gasket. One very important step that has been missed right at the end is that the oil needs to be changed. Any coolant that is left in the lower intake manifold will drain past the cam shaft and into the oil pan contaminating the oil. An oil change is absolutely necessary in my opinion. It also does not hurt to replace the spark plugs while you have such easy access to the back ones while the intake is off. Great write up.

    ReplyDelete
  40. Just used your guide to do this job on my daughter's 2001 Malibu. It started right up and no leaks! Thanks so much!

    ReplyDelete
  41. Great post but after a day and half trying to figure out why car would not start I found the crank position sensor wires cracked and shorted. two wires that attach at coils tan and purple i think. well check them first! car runs perfect now!

    ReplyDelete
  42. I have never done work on my car other than a coolant flush and oil change. Do you think I could do this job? If so, how long would you expect it to take and how difficult would you expect it to be from 1-10? Thank you in advance!

    ReplyDelete
  43. I have severe pitting around water jacket ports on lower intake manifold. It appears a previous repair had used epoxy to fill. It lasted 6 years. What kind of epoxy should I use?

    ReplyDelete
  44. how to reconnet fuel inlet to fuel rail

    ReplyDelete
  45. WARNING: It's not just your intake gaskets!

    I'm the owner of a 94 Camaro with the 3.4 V6 that I just restored. Both the 3.1 and 3.4 have the same type of heads which use the intake manifold to complete the valve cover, gasket surface.

    When you remove the valve covers, you'll notice that the aforementioned surfaces are not equal in height. The intake surface will be lower than that of the head. The reason for this is because the intake bolts go "straight down" into the head, resulting in a "wedge effect" which will drive both heads downward and away from the intake's mating surface over time with expansion and contraction. The intake bolts are not directed at a right angle towards the head's intake surface(as they should be and had been for decades for this very reason).

    When you remove your heads (which you will), remove and take a close look at the four, metal dowels that hold them in place. You'll not only see thread marks within them from the head bolt, you'll see that they are distorted from being sheared between the block and heads. I recommend that you not only replace them, but find some that are beefier to help prevent the problem. The factory dowels are quite thin and must be replaced; along with the head bolts that stretch upon torque and are useless thereafter. Clean your block threads with a tap, too.

    Be sure to check all lifters to make sure none are flat. "KEEP THEM IN THE BLOCK, AS TO PREVENT MIXING THEM UP." I disassembled each of mine, using a bent coat hanger, plyers, and a copper gun cleaner brush to remove the residue within that causes collapse, and a dab of assembly lube on the lobe surface upon reinstalling each one. Upon finishing this task, which assures no collapsed lifters and proper starting height for valve adjustment, tighten the rocker nut while moving the pushrod "up and down" until it just barely can't be moved up and down anymore without depressing the lifter plunger. Don't do the twisting method; that's mindless and stupid. Just find the correct valve to crank position procedure and follow my advice. Also make sure to tighten the rocker nut "one full turn" after removing the aforementioned lash. You'll find that most books say 3/4 to 1 1/2 turns, as if valve clearance bears no relevance, lol. Idiots. I've been working on Chevy's since the 70's, and one full turn has always been the standard... worked for me.

    ReplyDelete