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Thrust Bearing --Alignment-- help 454 Mark IV *pics*

1.3K views 15 replies 8 participants last post by  scott foxwell  
#1 ·
Hello. End play is .005", this is not a question about end play.

There is no dowels for these engines.

Removed Cap for Rear Main Seal. Going back together now.
Setting Thrust --Alignment-- using the pry bar on crank or tap crank method(hokey to say the least)

My measurements using a feel gauge there is a .008-9" difference im Bearing halves.

Bearing in Block measures .005-6"
Bearing in Cap measure .013-14"
Using a feeler gauge.

So Ive already RTV'd the new RMS and put Annerobic sealant on a small edge section of the Cap. Should I take everything back apart start over?

Next time can I not just tap the Cap to where it should be? Smacking the Crank to move a Main Cap that fits very snug in tue register is not a great idea, Imo.

Maybe use a feeler to set it where I think it should be then pry or tap the Crank in usual method, tighten it down?

Oh, added question: You pry or tap moving the Crank to flywheel first. Then you pry/tap to move towards Balancer last? Correct?
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#4 · (Edited)
You see what Im talkin about tho. All the engine guys I know are clueless wanna talk about end play etc, start going in left field for diversion.

It mite be fine, idk. Seems like you'd want both bearing surfaces riding exactly same kissing that crank. One bearing is doing all the work.

Since the cap is able to move, i figured I should move this cap. Again, idk. Seems like a sh**ty method imo.

Do it over or no? The only mark i was using to align it was lining up the rear main seal. Making sure it lined up with its other half. Then i tapped annd pryed on Crank. Torqued it down.
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#6 · (Edited)
Its strange there is no way to verify this cap is in right spot.

Crank only moves .005" with cap on or off. Maybe .006 with it off.

If I was .018 for instance to start with. Distance away from crank. I would have to tap that cap -.018 to touch crank. Then smack Crank or use a pry bar to move it .005"(end play)

That leaves me 0 clearance now. Which is what you want allegedly.

But what if I hit crank too hard, the cap scoots .009", now Im .004" open again. Or vice versa I dont hit it hard enuf and it only moves .002"


Not to mention the sister Bearing in the Block has a diff clearance as well. This means only one half bearing is doing all the thrust work.

Is there no way to make sure it aligned correctly? Like an actual measurement of something?
 
#10 ·
Tighten all main bolts to 20#. Then loosen to finger tight. Tap crank back. Pry crank forward. While holding forward, tighten thrust cap. Measure endplay with dial indicator. If not in spec, thrust surface of the bearing can be reduced slightly with a sheet of fine wet/dry sand paper on a piece of glass with WD40. BBC will live at least .005". 006"-.008" desired depending on automatic or manual transmission. JMO.
 
#11 ·
I have a very old MK4 Bowtie Block that I have had to do the very same thing on for 32 years. Pain in ass, sure, more work, but what's the alternative? Get the cap machined? May be worse after that. I have to sand the thrust surfaces on piece of glass also, along with tapping the crank to "seat" bearing.
I have over 2,000 runs on this thing, and crank is still Std. mains and rod surfaces. Go figure....just the way it is....