Rebuilding my motor

[SGKent]

Can I make a suggestion at this point? Take the ones you have and lay them on a new piece of 2000 grit sandpaper on a piece of glass and run them around a few times. Wipe them carefully and look at them closely. One or more may be wavy or uneven. You can't get an accurate read on a cupped, wavy, damaged, or bent shim.

It is also very hard to get an accurate endplay read on a new motor when the distributor drive gear is in. If you pull it don't lose the shim under it or you will have to split the case again. You can try turning the flywheel a little as you push and pull to see if that changes things because it will let the drive gear turn on the brass gear. However you will also be reading any differences in the flywheel. Your readings should be accurate whether you have no or 2 shims however the accepted manner of choosing the last shim is as TCash and others have said, read with 2 shims then choose the last shim based on that. Prices on new shims are getting pretty outrageous. BusDepot still has them on their site for $7.50 each but you'll have to call to see what they are able to ship at that price.

If you plan to rebuild T4 motors occasionally or plan to check the end play again after 2000 - 30000 miles, (which I do any time the motor is out), bite the bullet and pick up 2 or 3 of each if you can. It will set you back $100 but you will always have what you need and the time it will save is well worth the money. T1 and T4 shims are different.

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[DeltaBravo]

[DeltaBravo]

SGKent,

I appreciate and welcome your suggestions...thank you.

As far as the shims go, I stopped using them because they are cupped, wavy and damaged from the excessive endplay from before. So after several measurements in four different spots on the shim I realized the variant (errors) in the shim. Two of them are severely damaged.

I didn't know that about the distributor drive gear, I will look into that tomorrow and see if my endplay/thrust is any different.

I don't "plan" on rebuilding T4 motors occasionally, but...I don't know if I will need to tear this thing down again after I turn the key and it sounds like a bucket of bolts getting thrown around

[Tcash]

[SGKent]

[DeltaBravo]

[SGKent]

[DeltaBravo]

I've been busy with "other" life events...so haven't been able to focus on the build.

Need to order new shims and "hopefully" get a measurement that will allow just one more shim to get within specs.

But something that was bothering me earlier that was kinda shadowed by the endplay issue. After setting the valves (hydraulic) I notice it seems the screws are pretty much on the last thread. I have rechecked my procedures (verifying TDC, rotating counter-clockwise, adjusting 1,2,3 and lastly 4) adjusting to zero valve lash then tightening 1 1/2 turns to 2 full turns. The only thing that has changed within my valve/cam assembly are new lifters...

Here are some pics.
1

2

3

4

[Bleyseng]

I would say it's because the lifters aren't pumped up as you haven't run the motor to break in the cam yet
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[DeltaBravo]

[busdaddy]

They can't/won't pump up any more than the adjuster allows them, but I suspect your interpretation of zero lash is different than others'. For the moment set them 1 turn in from where you feel zero is and readjust after break in, soaking them isn't really the way to bleed them, it's likely they are all still dry inside.
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[DeltaBravo]

[busdaddy]

[SGKent]

on a hydraulic lifter there is a small spring inside. That is the moment the lifter starts compressing. As you tighten the screws that spring compresses as the pushrod pushes on the plunger which in turn pushes on that small spring. You don't want to compress it but you want no freeplay between it and the pushrod. If you go to far then it bottoms and you begin to feel the main valve spring. Let's say the spec is two turns in - that is from the moment you start to compress the hydraulic lifter spring, not the main valve spring. Borrowing photos from Richard Atwell's page explaining it, http://www.ratwell.com/technical/HydraulicLifters.html

You are two turns in from the freeplay gone when this lite spring holding up the plunger has just lost freeplay - it is subtle but you can feel it.

Not these springs below although the screw sits against them. You will feel the pushrod just stop wiggling when the slack is taken up between the pushrod and the plunger which is sitting on that spring inside the lifter.

You are looking to just feel the pushrod push the internal plunger down against the plunger spring then 2 turns more. BusDaddy says 1 so you don't go too far and so the lifter fills with oil. You can't fill one by soaking it. You have to depress the check valve in it and apply oil under pressure to bleed it.

Here is a well known "Boston Bob" (RIP) article on all that they don't tell you about pre-bleeding those lifters http://www.ratwell.com/mirror/www.bostonengine.com/articles/hydraulicll.htm
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[old DKP driver]

Not meaning any disrespect but, Whats up with the length of those
valve adjusting screws.

Stock screws are 25 mm in length & these look do be about 20 mm or less

6 threads should be showing against the valve with the nut in that
position.Which is close to 7 m.m.


Yepp, i had to go to the garage to check this out.
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[busdaddy]

Good eye, they do look a little on the stubby side. I'm also curious about the copper looking washers under the rocker shaft retainer nuts.

And yes, I suggested 1 turn just for break in to bleed the lifters, 1.5-2 is the usual preferred preload, whatever you end up with do all of them the same so you can count turns at the next valve adjustment, if 1 takes more or less to unload that valve or lifter is becoming a problem, keep a log.
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[SGKent]

[DeltaBravo]

Great info guys!

SGKent,
Thanks for the in-depth explanation on the lifters. I didn't "pump" the valves with the push rods while they were soaked in the oil...maybe that would help? I have installed the pushrod retaining wires, thanks for double checking.

busdaddy and old DKP driver,
I will measure the length to verify 25mm long. They are the same length as the old ones I removed...but that doesn't mean they were correct either.

busdaddy,
The copper washers are use specifically in aviation and I picked them because
1) they were available.
2) the old ones were not correct, miss-matched or missing.
3) if they are good enough for aviation...then they are good enough for me.

old DKP driver,
I was expecting about the same, "6 threads should be showing against the valve with the nut in that position". This is why I am concerned.

I was wondering something, a hypothetical question, if you will...

After setting all the valve preload to (1 turn in) and after installing everything else. I was thinking of turning the engine over (using the starter, but not "starting" the engine) to verify good oil pressure with a gauge. After verifying good oil pressure would it be a good idea to revisit the valve preload and adjust if needed prior to the engine break in.

I am thinking this will "pump" the lifters and change the preload...dunno? What do you think? Good idea or waste of time? Or do I need to completely back track because there is something else completely wrong and preceding forward is futile.

[busdaddy]

OK, the washers may work as long as they don't compress and lose torque, that's a particularly high stress stud that's doing a big job, keep an eye on it.

As for a reset after cranking?, no... it takes 20 minutes of running in most cases to bleed out the lifters, a little cranking isn't going to do squat for them. But do remove the plugs and build oil pressure before firing it up regardless, the rest of the bearings will thank you.
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Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[ToolBox]