|
Lifter Problem?? |
Post Reply 
|
| Author | |
CFoss 
Senior Member 
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
 Post Options
 Quote Reply
 Topic: Lifter Problem??Posted: 03 May 2010 at 8:46pm |
|
Hey all.
With the intake off I decided to check valve lash. I got a surprise... I checked out how to do it in the manual. It recommends swiveling the push rod and tightening until friction is felt then adding .75 turns. this is kinda tough. I checked pennocks and they recommend going to 0 lash by taking the slop out of the rocker, then go 1.5 turns. I tried both procedures and for the most part they worked ok. I found the second was the most repeatable and easiest. The lifters seem to have a sprung center where the pushrod connects. I remember these when I put them in. When I push down on the lifters I can feel them spring back. Except for two. They seem solid. I guess they are toast? Anyway, if I follow either procedure the valve starts actuating when I do the .75 or 1.5 turns, which is not right of course. So I left those two looser, so I just got the slop out of the rockers but then didn't add the extra turn and a half. Has anyone experienced this before?? Chay |
|
|
86 SE 3.4
|
|
 |
|
|
Dr.Fiero
Senior Post God 
Joined: 12 February 2007 Location: Canada Status: Offline Points: 1726 |
Post Options
Quote Reply
Posted: 04 May 2010 at 7:16am |
|
You've either got two seized plungers (in the lifter), or two are pumped up - or you're just looking at the two that are open in the sequence! Somewhere amongst the 6, one will be on an inlet stroke, and probably one will be on an exhaust.
If you don't like those valves being open - rotate the engine. A new couple will open up in there place.  |
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 04 May 2010 at 8:24am |
|
As far as being in the right spot to adjust them....
I didn't follow the book, but this is what I did:
I rotated the engine clockwise looking at the pulley(passenger) end, and watched as one first valve opened, then the other immediately after it, then adjusted 1/2 turn beyond that.
My way of thinking is that with this sequence, the first valve has to be the exhaust valve opening/closing, then the second the intake opening closing.
Then 1/2 turn beyond and you're definately into the compression/power stroke, both of which are on the base circle of the cam (Non lobe). So I think where the cycle was is fine. I did this for each pair.
How does a guy tell whether they are pumped up or collapsed? They are only 6k old! The engine has been sitting for 2 months now, so they should be drained one would think?
Chay
|
|
|
86 SE 3.4
|
|
|
|
|
Capt Fiero
Admin Group
Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039 |
Post Options
Quote Reply
Posted: 04 May 2010 at 8:25am |
|
Just to clarify, you are setting 1/2 the lifters then turning the engine over 1 full revolution? As to the pumped up lifters, that is normal. I have always had at least a few that did not bleed down. Just take that into consideration when setting the lash. For the record, I always spin the push rod in my finger or wiggle it until I just feel the slightest resistance, then I go 1.5 turns down. Zero lash is when the lifter piston is still at the top, and there is no more slop in the push rod or rocker. If you start to push the piston into the lifter you have gone past zero lash. Its my honest belief that due to the fine thread on the Fiero rocker studs, 1.5 turns is the correct setting and not the 3/4 turn that is used on regular Chevy V8's. |
|
|
Capt Fiero
88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
|
|
|
|
Dr.Fiero
Senior Post God
Joined: 12 February 2007 Location: Canada Status: Offline Points: 1726 |
Post Options
Quote Reply
Posted: 04 May 2010 at 8:41am |
|
The whole 'turns past' thing is really just how far down in the bore you're preloading the plunger. As Dave pointed out, SBC's and 2.8's aren't the same due to thread pitch on the rocker studs. It also matters if you've got new or used parts. New, I go about 1.5 turns, used I do 3/4 turn.
I've got an article here that shows the TINY shift in power when they dyno tested an engine all the way from the plunger being bottomed out in the bottom of the lifter, all the way to zero lash (great way to blow out a lifter BTW), and then having it loose. As long as there was SOME preload (.001") the power shift was very minimal. As for WHEN to set them... What works on ANY 4 stroke engine: Intake valve JUST STARTS CLOSING, set exhaust. Exhaust valve JUST STARTS OPENING, set intake. Other method that works on some engines is to simply look down the valley, and see if the lobe is point 180* away from the lifter you're setting! That's the optimal point. Right on the heel. This doesn't work on all though, since some (like my rollerized 350) have a virtually solid valley, and you can't see anything!  |
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 04 May 2010 at 10:35am |
|
Ok, I realize the goal is to get some preload on the lifters. It's more of a maintenence thing than a power thing because if the lifter is working, then it finds it's own level to harden up at. So, the .75 vs 1.5 turn is sort of acedemic, as long as it has some preload, and isn't bottomed. I agree 100% about the 0 lash as the capt has described it. I found I could feel when the push rod became captive between the lower end on the lifter and the upper end on the rocker. Good so far.
The difficulty is, if the 2 lifters in question are pumped up, the 0 lash point is also the point at which the valve will start to actuate, beacuse there is no 'give' in the lifter. How do you account for that in setting them up? If they are collapsed, then I should change them because they will either tap all the time, or be too tight.
I guess I have to pull the lower manifold to check em out. Crap.
Chay |
|
|
86 SE 3.4
|
|
|
|
|
Capt Fiero
Admin Group
Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039 |
Post Options
Quote Reply
Posted: 04 May 2010 at 9:10pm |
|
The ones that seem to be stuck up, will bleed down the first time the engine fires up, you have to realize the tremendous force's applied to them, its normal to have a few that don't bleed down. Even my rather expensive "Fast Bleed" lifters don't always drop down when I am pulling things apart. |
|
|
Capt Fiero
88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 05 May 2010 at 8:22am |
|
Right.
So, does one assume it is stuck in the down position or the up position when setting lash?
If it is up, then 0 lash, then turn down 1.5
If it is down, then 0 lash, and turn up 1.5
If they are halfway, then 0 lash and that's it. Have you been able to tell whether they have been stuck down, up, or halfway?
Thanks,
Chay |
|
|
86 SE 3.4
|
|
|
|
|
Dawg
Senior Member
Joined: 15 August 2009 Location: Canada Status: Offline Points: 988 |
Post Options
Quote Reply
Posted: 05 May 2010 at 10:16am |
|
Are you aware that lifters have springs in them to push them up when there's no pressure? So none of them should be down. DG |
|
|
You dream it up....I'll make it
|
|
|
|
|
Dr.Fiero
Senior Post God
Joined: 12 February 2007 Location: Canada Status: Offline Points: 1726 |
Post Options
Quote Reply
Posted: 05 May 2010 at 10:37am |
|
Unless a spring has broken (unlikely), or the plunger has jammed in a downward spot (still unlikely, but I've seen it).
I'd still be inclined to pull the lower intake for what a couple gaskets are worth. Pull all the lifters, take them apart and clean them up (one at a time!!!!). Polish the pistons with oiled 1200 grit. If they're empty (devoid of oil), you should be able to freely push the piston/plunger assy up and down with no more than about 30lbs of force. Needless to say, lifters are mated for life with a cam lobe. Don't swap them around (another reason I say do them one at a time). |
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 05 May 2010 at 11:40am |
|
Righto.
I alrady bought the gaskets cause I needed a middle intake one anyway, and they come in a package.
Now, if the weather would smarten up (constant unpredicatble showers) I could actually do it! I'm looking forward to seeing what's going on.
The ones that are 'free' are easy to push. In fact it's kind of a good test. If the lash is adjusted right, the rocker should be able to be pushed down and bounce back and still have a bit of tension on it. All but 2 are like this. Chay |
|
|
86 SE 3.4
|
|
|
|
|
Dawg
Senior Member
Joined: 15 August 2009 Location: Canada Status: Offline Points: 988 |
Post Options
Quote Reply
Posted: 05 May 2010 at 12:11pm |
|
Another idea.
I have found that an hour in a bucket of lacquer thinner will dissolve any gummy residue and free things up. Then blow all the parts clean and soak in oil before installing. They can be a bitch to reassemble with the spring tension. DG
|
|
|
You dream it up....I'll make it
|
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 05 May 2010 at 6:34pm |
|
Ok, I got the manifold off.
The two which didn't compress are stuck at the top. I'll try removing them and soaking them and using air to free them up, then reassemble. Everything looks nice and clean though. Chay |
|
|
86 SE 3.4
|
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 05 May 2010 at 7:27pm |
|
So, I soaked the one that wouldn't move at all. No dice.
So, I found a 1/4 drive socket which fit just inside the wire retainer on the 'plunger'. Then, I protected the lifter face with some thick cardboard and gently viced the whole thing. With very little pressure the 'plunger' moved, and now it is completely free like the others. I guess I'll use it again? Chay |
|
|
86 SE 3.4
|
|
|
|
|
Dr.Fiero
Senior Post God
Joined: 12 February 2007 Location: Canada Status: Offline Points: 1726 |
Post Options
Quote Reply
Posted: 05 May 2010 at 9:15pm |
|
They're really not hard to take apart and reassemble. I've done hundreds!
If you just use a pushrod to squeeze it down like .001" you've got enough room to get the clip out (I use a little pokey-stabby tool). When you put it back together it's even easier, since there's now no oil in it. Just put the clip on the top of the pile of parts, stick that pushrod back in there then push down. When it's all in place, then you just slip the clip into the groove and you're done. |
|
|
|
|
CFoss
Senior Member
Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
Post Options
Quote Reply
Posted: 05 May 2010 at 10:20pm |
|
Yeah, it seemed ok, so I put it back in and put the manifold back on.
Thanks to everybody for their advice. Chay |
|
|
86 SE 3.4
|
|
|
|
|
Post Reply
|
|
Tweet
|
| Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |
Topic Options
Dr.Fiero wrote: