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Discussion Starter · #1 ·
I've recently bought myself an old beetle engine to strip down and re-build as a 1641, mainly as a learning exercise for myself, and possibly to fit it into my beetle when I'm done.

Before i took it apart i measured the end float with a DTI gauge and got a result of about 1mm, which is considered excessive and needs to be put right. As i took off the flywheel the end float increased some more to about 2mm or more, but this is what normally happens (am i right?). The engine is now fully stripped and down to bare case halves and boxes of labelled parts.

I understand the end float is caused by the main crank bearing at the rear (flywheel end) moving back and forth in the case with the crank, and it appears to have about 1mm play back and forth when put back in the case, so that seems all normal and what was obviously causing the play. My only confusion is that the crank moved back and forth loads whilst resting in the case half moving independently to the main bearing and only being stopped by the large mis-shapen washer at the pulley side of the case (is this referred to as the 'oil thrower'), is this normal for an engine to do this once split, and is it only really held in place by the case components, pulley and flywheel?

I've read that the only way to 'Properly' remove crank end float is to get the case line/align (which ones right?) bored. Am i right in thinking this is where the thrust faces of the main bearing holder in the case are machined down by a set amount, and then a oversize bearing with a bigger 'collar' is fitted when building back up, removing and back/forth movement of the main bearing in the case and subsequently removing end float (once the right size 3 shims have been fitted and flywheel + crank pulley re-fitted)?

There's a machine shop near me who have been around since the dawn of time so I'm told, and I'm going to get the crank reground with them as it's one of the things they specialize in. There site also mentions that they do Align boring/Honing there too.
I've done a quick search for "Line bore" on Google and it came up with a good few results, and a few videos which i watched.
The videos i watched showed an engine case being drilled through the center with a big tool, cutting through the circular shaped crank journal holders (what ever they're called) and making the diameter of them bigger.

I'm now really confused as to what the proper meaning of line bore is, as I'm sure if i go to the machine shop they will be confused as to what i want doing to the case, as I'm pretty sure the pic on the site of line boring is not what i had in mind.
Here's the link to the line boring bit of the site:
http://www.foxwooddiesel.com/line-boring-honing

Can someone help me as to the proper meaning of line boring actually is, as I'm under the impression that it is different to vw people as it is to normal engine people:lol:.

Any help would be ace:).
Max
 

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A line bore is to cut a perfectly straight hole through the case thus removing any wear usually on the centre bearing area.
Oversized bearings are to allow for a larger bore created by the line bore and or machined crank journals.
The bearing shells should be sung in the case with no play, if they are not your case is likely scrap.
It's usually the flywheel end bearing that get's punished as it gets load from the clutch engaging.
Over time the end float increases eventually leading to a spun bearing or worse.
End float is set with 3 shims and takes up the slack where the crank journals move horizontally in the shells.
 

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Discussion Starter · #3 ·
Ok thanks for the info, it seems i had the wrong idea in my head about line boring.
I think what my engine needs is a 'Thrust cut'. Does this seem about right? And do many companies do this?
Or should i just buy a new bloody case:lol:
I would have bought one by now if they weren't £500+:(
 

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Discussion Starter · #4 ·
actually, i've just been thinking this through in my head, if align bored by say .25mm, the oversize bearing collar (the piece that sticks out of the bearing either side) will clear the wear the old one pounded into the case (originally causing the end float) and rest in it's rightful place against unworn case material.
is this right?
My head hurts:lol:
 

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if it did 0.25mm is not enough ......bearing in mind that it will only be 0.125 at any one place

you need to have the case line bored AND thrust cut ......then get oversized bearings with a larger thrust shoulder .....

i'm not sure on thrust cuts ....but line bores go in 0.5mm incraments
 

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Discussion Starter · #8 ·
Ok thanks for the help.
Does anyone know where i can send my case off to be line bored and thrust cut? I'm in Staffordshire and also in Derbyshire most days, so somewhere near there would be good. Although i would courier if i had to.
 

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Ok thanks for the help.
Does anyone know where i can send my case off to be line bored and thrust cut? I'm in Staffordshire and also in Derbyshire most days, so somewhere near there would be good. Although i would courier if i had to.
Hi there,

Whoever you take it to, insist on an inspection report listing the actual bore diameters after machining. If they won't, can't or try to baffle you with BS, walk away. It's quite simple; they are providing a service to you and if confident in their work should be able to prove it. Sadly many companies with line boring bars have little or no concept of how difficult it is to do it properly. I have seen too many engines fail or lose oil pressure in a few thousand miles due to incorrect line boring not to be extremely wary of this process as commonly carried out.

The total tolerance on the bores is 0.020mm, that's 10 microns from centreline to allow for bar runout, toolbit setting and bearing clearance. I have personally never measured a line bored case that has all four bores within OE tolerance... A friend's engine that failed three time in quick succession had one bore that turned out to be 0.050mm under bottom limit, the case having been line bored by one of the best-known and longest established VW tuning shops at the time.

No inspection report, no sale.

Cheers, Carl.
 

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Discussion Starter · #12 ·
Hi there,

Whoever you take it to, insist on an inspection report listing the actual bore diameters after machining. If they won't, can't or try to baffle you with BS, walk away. It's quite simple; they are providing a service to you and if confident in their work should be able to prove it. Sadly many companies with line boring bars have little or no concept of how difficult it is to do it properly. I have seen too many engines fail or lose oil pressure in a few thousand miles due to incorrect line boring not to be extremely wary of this process as commonly carried out.

The total tolerance on the bores is 0.020mm, that's 10 microns from centreline to allow for bar runout, toolbit setting and bearing clearance. I have personally never measured a line bored case that has all four bores within OE tolerance... A friend's engine that failed three time in quick succession had one bore that turned out to be 0.050mm under bottom limit, the case having been line bored by one of the best-known and longest established VW tuning shops at the time.

No inspection report, no sale.

Cheers, Carl.
Hi,
Thanks for the advice, i will definitely get a report of the work done and measured. I don't want to have an engine seize on me.
I asked last night in the tech mech garage recommendations forum for line boring, thrust cutting and crank grinding and was recommended 63ragtop on here, who i have read time and time again is a top bloke, and does work to a very high standard. I have not heard a bad word about the guy.
I'll still ask for a report though.
Thanks, Max
 

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Discussion Starter · #13 ·
I also need some more advice from the wealth of knowledge that is VZi.
The engine i've bought was described as running when it was removed from the car, but badly, the seller said he suspected a bad seal on one of the O/S cylinders, and could mean cracked head.*
Oh well i thought, i am replacing pretty much all of the top end for 1600 while re-building this, so stuff like this doesn't matter, it just means i get the engine cheaper.
Turns out upon stripping down the engine, about 70% of the head nuts weren't even on properly (showing thread) and one of the case suds was wound out quite far, actually fouling on the rocker shaft:confused:.
It turns out, upon fully stripping the engine and splitting the case, No.1 pistons con rod was missing the bearing altogether!!! This has caused some heavy scratching on the crank and rendered the con rod scrap. Here's some pics:


Not good:mad:.
I'm pretty sure the crank is salvageable, as i'm having it re-ground anyway and the scratches aren't that deep. But the con rod is scrap and needs replacing.
So, can i just replace one con rod, all do i need to replace all 4? I was hoping i could just replace 1. I would replace it with an original that has had a normal life, as all the others are fine.
I've contacted the seller on ebay, but he's having none of it and refuses to even part re-fund me. Although i have opened a PayPal case, so something might get sorted out.
I can't believe what it must have sounded like, it must have been ear splitting.

Max
 

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Crikey, no big end bearing! Bet that was a nice knock. It might actually be that the bearing got so pounded it just disappeared, and wafer thin bits of metal in the sump?

You can just replace one con-rod, but it must weigh the same as the others. Use accurate scales and get it no more than 2g different to other three, and really, you want it spot on same weight.

Given the amount of abuse that engine has evidently been through I'd seriously consider finding another case to rebuild. Feel for play of lifters in bore. Oiled up, they should slide up and down with the merest trace of drag. Any side to side play, bin the case. The cost of getting the bores sleeved will be more than a second hand case.
 

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Ok, the crank can be reground but I would be concerned about it's overall condition if it was run with a big end missing.
I stripped a subaru engine that had been run with a shot big end bearing and the crank was bent.
HI there,

The VW crank is a good strong forging and very understressed. Checking it on Vee blocks will tell you if it within tolerance, however if it is not too far out then the regrind will bring it all up true again. Get it crack detected too for peace of mind and ensure all the oilways are scrupulously cleaned.

Cheers, Carl.
 

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also beware ....when my crank was re-ground .....I took it to a place to get it balanced ,and there was a 2 thou throw out on the end,where the flywheel bolts to .....this then had to have the dowels removed ,and turned true again .....even tho the journals that were reground were spot on .....if I hadn't noticed this the flywheel would of had a wobble like a badly balanced wheel,


so what i'm saying ,is check the journals after re-grind ...but ALSO check the trueness of where the flywheel bolts on
 

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Discussion Starter · #18 ·
The case is in overall good condition, i've drained the oil and found no horrors in there, and none in the case when i cleaned it out with the parrafin parts washer.
The follwer bores all seemed ok, and they moved back and forth with the slightest drag. I don't recall any play on them, but wont be able to check until tuesday as the engines at my college.
I'm sure the case and crank will be ok once line bored, thrust cut and re-ground.
I hope:(
 
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