[bug71]

Hi all I have a 1971 1600 beetle and although the engine pulls fine and has never given me any problems at all I’ve started to get the low oil pressure warning light on at idle when hot. The idle is set to 850rpm, now I do have 10psi at 1000rpm, 20 at 2000rpm 30 at 3,000 and it tops out at 40psi at 4,000 rpm and above it’s only when at idle the oil light comes on. The engine doesn’t over heat at all as well. Is this ok?

Now the second question which I’m guessing the answer will be the engine is toast is that I have some end play of 0.3mm / 0.012” now this as I understand is twice over the max allowed. Does this mean the engine of the engine ?
I’m taking the reading from the crank pulley.
Thanks for your help

 

[Bada Ben]

The excess End-float does not necessarily mean the immediate end of the engine, it could still be rescued, but the work should be done sooner rather than wait until it goes past the point where repair is possible.
The combination of oil pressure reduction and end-float does show the extent of the wear, which is now accelerating. End float is usually the result of the main bearing at the flywheel end having worked itself loose in the crankcase seating, (it takes the bulk of the forces there), the seating in the case will have been battered so it is no longer gripping the bearing tightly, and it will only get worse now.
I would look for a reputable VW engine specialist to quote for getting the crankcase align bored for oversize main bearings, and probably for a crank regrind too.

 

[Manxdavid]

How many miles a year does the car cover? Is it a daily driver or just a weekend cruiser? If the latter then to be honest I wouldn't worry about it, don't go too thin with the oil; something like a 20/50 with 1/2 a bottle of STP in it and it'll be good for at least another 10,000 miles.

 

[bug71]

Thanks for the replies 👍
I’m currently running 15/30 oil and on a cold start up I hight around 80psi oil pressure wouldn’t the 20/50 oil cause to high of a oil pressure?
Last year the car done under 500 miles but on average I would say I will be between 1,500 to 2,000 miles a year in it.
I’ve contacted limebug and they said they would do a line bore for £110 is this a good price ?

 

[skip*rat]

How many miles a year does the car cover? Is it a daily driver or just a weekend cruiser? If the latter then to be honest I wouldn't worry about it, don't go too thin with the oil; something like a 20/50 with 1/2 a bottle of STP in it and it'll be good for at least another 10,000 miles.

^WHS^

 

[M.I.B]

I've contacted limebug and they said they would do a line bore for £110 is this a good price ?

For £110 you will probably have to strip the whole engine down including the removal of the long barrel studs - I would check what you get for your money.

Add to that the cost of getting it to and from them.

 

[bug71]

Ok I’m about to order some oil. I take it this is the oil your taking about?

 

[bug71]

For £110 you will probably have to strip the whole engine down including the removal of the long barrel studs - I would check what you get for your money.

Add to that the cost of getting it to and from them.

Yes I will have to fully strip the engine and remove all the cylinder studs. It's still going to be cheaper than paying a new case ?

 

[Manxdavid]

Ok I'm about to order some oil. I take it this is the oil your taking about?

Get 20/50 from Wilkos for about £16.

 

[bug71]

Get 20/50 from Wilkos for about £16.

Nice one cheers mate

 

[Manxdavid]

VW changed their oil recommendation from sae30 to 20/50 back in the 70s.

 

[bug71]

Cheers for that information mate 👍

 

[Bada Ben]

This gent has done 2 Beetle crankcases for me : https://www.facebook.com/vwgearbox
Although he specialises in gearboxes, has all the gear for Align bore & thrust cut.
Really nice guy, good price too.

 

[bug71]

I will look him up now mate. Cheers 👍

 

[gojira]

Yes I will have to fully strip the engine and remove all the cylinder studs. It's still going to be cheaper than paying a new case ?

about 15/20 years ago i paid £140, dropped off the case, crank and rods and was given back a bored and cut case with a set of bearings to match and a clean bill of health for the crank and rods. (iirc one of the bearings was machined to an interference fit in the case.)

i suspect your £110 is for just a line bore, which is not the whole story when building a short block.

if i were you i'd contact somewhere with a really good reputation like stateside tuning or GAC and see what they recommend.

 

[Beetlebank]

For £110 you will probably have to strip the whole engine down including the removal of the long barrel studs - I would check what you get for your money.

Add to that the cost of getting it to and from them.

Also add in the gamble that it is likely to end up nowhere near VW tolerances, and it could seize in short order (see the recent post about this) or give you low oil pressure in a few thousand miles. Oh, and don't forget that 40 year-old cases are well past their sell-by and ready to develop cracks.

Think for a moment that we are looking for 0.0008"/0.020mm tolerance on the bore diameter - half that for the radius, ie. 10 microns. Now consider the following:

1. There has to be clearance of the boring bar 'bungs' so they fit in the case.
2. There has to be clearance of the boring bar in the bearings so it can turn.
3. There is a tolerance when setting the cutter.
4. The cutter cannot cut precisely to size.
5. The boring bar is not infinitely rigid so will flex away from the cutting forces.

Think of these compounding clearances and resultant errors when you picture the 'engineer' pushing the tool through your case at a variable rate on the end of his cordless drill... Line boring requires machinery and precision which very few machinists can achieve even though they '...set the cutter with a one micron gauge...' as if this means the holes will come out the right size.

If you still want to get a line bore, ask the company if they can or will supply an inspection certificate detailing the bore sizes, degree of uncertainty, and copies of their NAMAS-accredited calibration certificates for the measuring instruments used. And don't hold your breath.

Now of course there are many engines out there using line bored cases, but if they enjoy a long life it will be through luck, not precision engineering. I have lost count of the number of engines I have seen fail due to this inability to machine to limits - try not to be another victim.

 

[Bada Ben]

How many miles a year does the car cover? Is it a daily driver or just a weekend cruiser? If the latter then to be honest I wouldn't worry about it, don't go too thin with the oil; something like a 20/50

/\ /\ WHS /\ /\

 

[bug71]

Also add in the gamble that it is likely to end up nowhere near VW tolerances, and it could seize in short order (see the recent post about this) or give you low oil pressure in a few thousand miles. Oh, and don't forget that 40 year-old cases are well past their sell-by and ready to develop cracks.

Think for a moment that we are looking for 0.0008"/0.020mm tolerance on the bore diameter - half that for the radius, ie. 10 microns. Now consider the following:

1. There has to be clearance of the boring bar 'bungs' so they fit in the case.
2. There has to be clearance of the boring bar in the bearings so it can turn.
3. There is a tolerance when setting the cutter.
4. The cutter cannot cut precisely to size.
5. The boring bar is not infinitely rigid so will flex away from the cutting forces.

Think of these compounding clearances and resultant errors when you picture the 'engineer' pushing the tool through your case at a variable rate on the end of his cordless drill... Line boring requires machinery and precision which very few machinists can achieve even though they '...set the cutter with a one micron gauge...' as if this means the holes will come out the right size.

If you still want to get a line bore, ask the company if they can or will supply an inspection certificate detailing the bore sizes, degree of uncertainty, and copies of their NAMAS-accredited calibration certificates for the measuring instruments used. And don't hold your breath.

Now of course there are many engines out there using line bored cases, but if they enjoy a long life it will be through luck, not precision engineering. I have lost count of the number of engines I have seen fail due to this inability to machine to limits - try not to be another victim.

In that case I'm just going to run the engine till she stops and build a new one myself

 

[Beetlebank]

In that case I'm just going to run the engine till she stops and build a new one myself

True story. I bought a 1300TP Beetle from Bristol Volksfest way back and drove it home to North Devon with the advice that it would require a rebuild in pretty short order. I tuned it, made sure the tinware and seals were sound, and tried to kill that engine, I really did, because I wanted to know how it would fail. 2mm endfloat, oil light always flickering at idle, sounded like a bucket of hardcore, burnt oil at about the same rate as petrol, but would it die? Not a chance. A customer even used it as a courtesy car driving 75 miles each way to his home while I worked on his Bay.

I eventually dismantled the engine when I got bored of trying to break it and it turned out to be a totally original high mileage engine which had never been machined. All the main bearings were loose in the case but I think there was just enough oil getting round and the clearances were just so huge it simply couldn't seize; the rings had all but lost tension and a couple were in several pieces. It takes a lot to kill a properly engineered and built flat four, however well-meaning but poorly performed machining work can see it seize solid in 30 seconds, as I have witnessed.

 

[GARRICK.CLARK]

As beetle bank says.
The machining is key to the success of an engine build. You can prep the build all ya want, but if the align bore job is done wrong, your freshly built motor is still..... 💩