Rocker install |
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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Posted: February-05-2012 at 10:10pm |
I just bolted on my new gt40p heads and am reusing my old rockers, lifters and rods. Do I need to check the rocker to valve clearance? Is it possible I may need different length pushrods? Do I need a lifter compressor tool to check the clearance between the rockers and valves?
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Justin you need to check your lifter preload,this is just one way to do it.
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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ok, the ford power manual described a technique using a lifter compressor tool. In that crane desription they just torqued them waited, made a mark and took the torque off and measured the change. Correct, seems much simpler.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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So long as youre not shimming out the wazoo, you should be fine with your rocker to valvestem geometry. Thats one of the advantages of a non-adjustable valvetrain. If you want to check it, then color the top of the valvestem with a sharpie (prior to installing rockers) and roll the motor over a few times- the rocker tip should wear the marker off roughly in the center of the valve stem. Too far off to the top or bottom would indicate less than optimal geometry.
I didnt read Gary's link to the Crane instructions, but here is the Comp version on how to adjust lifter preload. Make sure you read the non-adjustable valvetrain section. Get some rocker shims- a kit is about $10. Measure each lifter individually- I had variations of up to .060" between rockers. If you have to shim any more than .090" to reuse the original pushrods, then you may want to consider new (shorter) ones. |
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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yes, I was wondering about the shims. I have no shims now, I just took the stock rockers, rods and lifters off the old heads and put in the new. In the same order and piston position of course.
I am also correct in thinking that the only way to reduce the preload if it is too high is to get shorter rods. Right? Those comp directions are the same seems to be the way to do it. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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To reduce preload, you either need to shim the rocker or get shorter pushrods.
If everything is installed now, then go around and mark your pushrods (make sure the cam is on the base circle when you do this) and then pull everything off and remark and measure the difference. |
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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ok I will go mark everything, by base circle you mean on top of compression stroker? Valves closed?
To increase preload I will need to get longer rods, right? just ordered a shim kit. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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Yes, cam on base circle = valve closed.
Yes, to increase preload you would need longer pushrods... but this scenario is unlikely unless youre installing a new factory head, and even then, the stock pushrods *should* be ok. When you install used or remanufactured heads, theyve usually been resurfaced- so all else being equal (reusing all the same parts), lifter preload would increase by roughly the same amount as the material removed (~.020-.030"). |
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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gotcha, thanks tim!
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lakedog55
Gold Member Joined: November-11-2010 Location: Lake Weir Fl Status: Offline Points: 835 |
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Justin,
If you do not mind let us know how the install went, Hopefully how much better it runs, I am getting ready to bolt on a pair myself soon as I can hide 350 from the wife for a freshen up on the pair I have. I was wanting to know if you can feel the difference. Mike |
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Lakedog55
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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ok so I need some more advice here. I followed the instructions and giving and I noticed that according to the scribe marks they were pretty consitently measuring around .090. So too much preload so I was put .060 shims in and started noticing after the shims were in when the valves were closed the rockers were real loose.
I can spin the pushrod and actually then I noticed I could rock the rocker back and the pushrod back down by hand. Is this normal? am I doing something wrong. When I took them off the old heads they were not this loose. Thoughts? advice? |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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Sounds like you did something wrong. 0.090 - 0.060 should have left you with a preload of 0.030 (just about perfect). If you could spin the pushrods and the rockers were loose, then you had none at all.
Im also surprised that you had consistent preload across all the valves. Like I said before, mine varied up to 0.060 between valves. (I shimmed from 0.030 to 0.090.) Sounds like you need to start from scratch and re-measure the preload on each lifter without any shims. |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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are these new lifters? They may need to be pumped up and try again. tightening the rocker down with out oil pressure can force the oil out of the lifter. Do you still have the intake off, if so pull lifters out one at a time, submerge in a can of oil and pump them up using a pushrod. Reinstall and see what happens.
There's a point where you have to trust your measurements, if you have confidence in them then button it up and fire it. You'll know right away if they're loose but my guess is they will pump up and be fine. Easy enough to check again after you get some oil pressure in the engine. You could also spin the oil pump with a priming rod and check again but if you trust your measurements just fire it up. |
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You can’t change the wind but you can adjust your sails
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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no these are not new lifters. There was a little inconsistency, they were mostly .060 a few .030. No double shimming yet anyway I only got one side done. The intake is on so no oiling them now.
So if they are too loose they will clatter/ make noise? How will I know. I know my measurements are consistent I was using a straight edge etc and I made sure both valves were closed all the way. I had one rod with no preload, it was the same before and after I torqued down the rocker. I guess I will need a longer pushtube. |
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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The one with no pre-load, maybe a collapsed lifter?
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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well it goes up and down fine.
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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all I'm suggesting is that if you had to shim that much than when you tightened then down the first time and took your measurements without any oil pressure in the engine you may have pumped the oil out of the lifter. Again if you trust your readings fire it up, worst case is you have some lifter noise and you need to repeat the procedure. Once you pump the lifter out the plunger will still return to the top but it's hard to get a good read on them because they are soft until oil pressure returns.
This is fairly simple so don't overthink it, I would fire it up and you'll know right away. If you've shimmed all worse case is you'll have a little noise, too tight and you'll have a bad idle but I don't think that will be the case. If you're not sure just check them again after you run the engine a few minutes. I also don't like the scratch and measure deal so I use a dial indicator with a magnetic base and get real numbers. |
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You can’t change the wind but you can adjust your sails
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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good advice alan,
Ill push on then, just wanted to make sure I wasnt making a big mistake. I will say that is probably what happened as they were stiff at first but after some turning over and what not things got real loosey goosey. |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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This is why I love stud mount adjustable rockers!
By the way a quick tip for finding tdc on all cylinder and the way I do mine is to get the motor on TDC of #1 on the compression stroke. Then mark the balancer with chalk or white toe nail polish if that's your bag at 90 degree intervals. Measure your pushrod length at #1, then rotate the motor in it's correct direction 90 degress or a 1/4 turn to the mark on the balancer. Go to your next cylnder in the firing order and that cylinder will be at TDC, do this 6 more times through the firing order and your done. |
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You can’t change the wind but you can adjust your sails
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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ahh very clever good advice. Thanks!, I just kept cranking and watching the valves open and close to figure out where they were, probably the hard/long way.
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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i always like to keep the cordless drill in the distributor hole to keep pumping up the lifters, its a 5/16's hex to prime the pump, pretty much a sure hit so the lifters dont bleed down, even though they really shouldnt
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"the things you own will start to own you"
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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good thinking eric, since my engine was apart there is no oil at all in these lifters so thats probably why they bled down. Also I turned it over several times. probably should get some oil back in there.
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slmskrs
Gold Member Joined: January-03-2012 Location: SF bay area, CA Status: Offline Points: 522 |
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Okay, so I'm a number of steps behind and I'll need to read through the procedure several times as I don't yet know where the shims go, where you are measuring, etc. So I'm sure I'll be asking lots of questions.
But, can someone please explain to me about the drill in the distributor hole and how to pump oil that way? First, I want to make sure the lifters are all full when I do my measurements and adjustments (shims as needed), and secondly, if this is somehow running the oil pump and I can pump oil through the engine while off, that would be great (I could do that just before reinstalling the distributor and firing it up). |
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Gordon '97 Ski Nautique, GT40
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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slmskrs,
This is what you want oil primer You attach it to a drill and place it into the distributor shaft hole, spin with a drill and it pumps oil through the engine. Go slow at first because you can send oil flying with a fast drill, you don't need much rpm to get the oil moving. Yes it is used for the exact reason you suggested, pumping oil through the engine before a cold startup. Doesn't matter if the engine is new or just hasn't been run in a while the purpose is the same. |
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You can’t change the wind but you can adjust your sails
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slmskrs
Gold Member Joined: January-03-2012 Location: SF bay area, CA Status: Offline Points: 522 |
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Thanks. Ordered. How does it work? Is it turning the oil pump (don't know how that is possible)?
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Gordon '97 Ski Nautique, GT40
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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if you dont want to purchase one, you can use a long 1/4' extension with a deep well 5/16th's socket electrical taped to the extension. the extension will chuck up in the drill
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"the things you own will start to own you"
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Normally the camshaft turns the distributor shaft, which in turn, turns the oil pump. Now, with this distributor out, you are putting in this tool, and attaching it to the oil pump, where the distributor shaft normally goes. And, instead of the camshaft spinning the distributor shaft, your drill is spinning the tool, which will turn the pump. It's kind of like when someone has a cardiac arrest, and the surgeon reaches into the chest cavity and squeezes the heart by hand to make it pump |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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When you get it compare it to the base of the dist shaft below the gear and you'll see it's same. It simply drops into the top of the oil pump in place of the dist. (you'll feel it drop in and engage)and you turn it with the drill so YES you are spinning the pump without turning the motor over. |
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You can’t change the wind but you can adjust your sails
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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hahah what an analogy!!!
the shims go under the rockers to lift them up, this relieves some of the tension from the lifters when the valves are shut. Just google rocker arm adjustments or preload and read up on the idea. You dont want too much or too little. |
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slmskrs
Gold Member Joined: January-03-2012 Location: SF bay area, CA Status: Offline Points: 522 |
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Aha! Now I get it (I didn't realize the pump was rotated by the distributor). What direction does it rotate (does the drill go clockwise or counter clockwise?). With right hand rotation engine (looking at the front of the engine and facing the stern), which way is the drill supposed to turn?
And on using shims, what part of using shims makes this non-adjustable? I would think that non-adjustable would mean they are auto setting, etc. and you shouldn't have to do anything. Instead, it just seems to be a painful way to adjust.... |
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Gordon '97 Ski Nautique, GT40
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