1641 Clacking on startup then silence...

[jamesbissland]

Hi All

I have a 1500 case with 1641 barrels and twin port heads that when I first start the engine after it sitting for a few hours or overnight it make a TERRIBLE clacking noise for the first 5 or so seconds until the oil pressure builds up (on the gauge) then silences and the engine purrs away.

The noise is a real metallic clack as if it has thrown a bottom end bearing.. but then goes away as fast as it starts.

The car has an old full flow external cooler and filter set up, which I am wondering if its just the oil draining back out of that at rest (even though the filter supposedly has an anti drain back valve) and its taking that 5 or so seconds to re fill/pressurise before pressurising the bearings... either way, its an un-nerving sound, but then goes and as the engine purrs

Oil level is satisfactory, and oil pressure is the standard when warm

has anyone come across this before??

Cheers
James

[Piledriver]

My guess-- Worn lifter bores, usually, or hydraulic lifters that have sucked air sound horrible for awhile.
Doesn't hurt anything but it certainly sounds like it is.

1: Make sure the external filter hoses are plumbed right, anti drainback valves don't work backwards.
2: Mobil1, Purolator One or K&N oil filters... Made on the same line.
3: My engines sound like that for a few seconds if they sit for a week or so.

I change my oil like the manual says, every 12K, when I check my valves.
Sometimes 15K. ish.

[jamesbissland]

Fantastic info !! - Thanks so much!

jb

[Bruce2]

I change my oil like the manual says, every 12K, when I check my valves.

What manual says you can go 12k miles between oil changes on an air cooled engine with no filter?

[Bruce2]

The car has an old full flow external cooler and filter set up, which I am wondering if its just the oil draining back out of that at rest (even though the filter supposedly has an anti drain back valve) and its taking that 5 or so seconds to re fill/pressurise before pressurising the bearings...

A 1641 does not need an external cooler. This is part of your problem. The other part is that your filter's anti-drain back valve isn't working. All your oil is draining back and it takes a long time to refill your filter and cooler. Take your cooler right off, then buy a different brand of filter.
What filter do you have?
What oil are you using?

[jamesbissland]

A 1641 does not need an external cooler. This is part of your problem. The other part is that your filter's anti-drain back valve isn't working. All your oil is draining back and it takes a long time to refill your filter and cooler. Take your cooler right off, then buy a different brand of filter.
What filter do you have?
What oil are you using?

Yeah I did think that, and am in the middle of collecting everything needed for a doghouse cooler set up to get rid of it.

Plus the filter is sitting up quite high on the fire wall which I can’t imagine helps anything.

I’m using a 20w50 Penrite High Zinc Mineral which is produced down this end of the world, and is the grade 99% of people run down here in aircooled engines...

[Piledriver]

Aren't you in Oz?
A proper thermostatically controlled, full flow filter/cooler setup may be very helpful depending on exactly where he lives//drives. The recommendation for say Melbourne would be far different than for Coober Pedy.
(US equivalent: South Carolina coast vs Phoenix or Death Valley, only hotter)

if the setup is properly full flowed, he just needs to add an oil thermostat and mount the filter somewhere sane.
If the filter and cooler are running off the oil cooler ports, then rip it all out and go stock, it's worse than useless.

[Piledriver]

I change my oil like the manual says, every 12K, when I check my valves.

What manual says you can go 12k miles between oil changes on an air cooled engine with no filter?

The one for my T4-engined vehicles, those motors came with a filter from the factory.
If I had a t1 with a sand seal and full flow filter/cooler and a 5 quart oil sump I'd probably consider the same change interval...with some oils.

[jamesbissland]

Aren't you in Oz?

haha thats like asking if you're Canadian,.. eh?

Im in Christchurch, New Zealand; so pretty close.

Most people just think it is on the other side of the Sydney Harbour Bridge


We're down at 43deg south, so pretty similar latitude to Chile and Argentina; our winter only really gets down to 28F at night in the coldest part of winter and summer up to 80F during the day

[jamesbissland]

My guess-- Worn lifter bores, usually, or hydraulic lifters that have sucked air sound horrible for awhile.
Doesn't hurt anything but it certainly sounds like it is.

This is the best case scenario .. certainly better than a bearing (at this stage)

1: Make sure the external filter hoses are plumbed right, anti drainback valves don't work backwards.

Have checked and running the correct direction, however the oil cooler is before the filter. I would have thought it would go pump > filter > cooler > bearing to avoid potentially blocking the cooler up.

Out of interest, if the clearance on the oil pump was too high, would you think the oil would drain back through it at rest? However, if that was the case I would expect to see low hot idle oil pressure wouldn't I ?

2: Mobil1, Purolator One or K&N oil filters... Made on the same line.

Very good to know thanks... what is your thought on FRAM or RYCO?

3: My engines sound like that for a few seconds if they sit for a week or so.

Thanks for your input !! I always appreciate a second opinion !

[Bruce2]

I’m using a 20w50 Penrite High Zinc Mineral which is produced down this end of the world, and is the grade 99% of people run down here in aircooled engines...

Then 99% of the VW people there are wrong. Nobody needs to use 20W-50 tar in a VW engine where the max ambient temps are only 80ºF. Your engine was designed to use 30wt oil. By using your tar, the oil pressure will be a lot higher than VW intended.
This is bad for several reasons. First, that thick oil can't properly flow into the tight bearing clearances. The proof of this is the reading on your oil pressure gauge. When the oil can't get out of a cct (into the bearings), the pressure goes up. In other words, with your tar, a lot less oil will be getting to the bearings than if you used the proper viscosity oil. Because the pressure is so high, most of the oil goes out the relief valve, giving you no benefit. Here's a little known fact about the relief valve. The temp of the oil goes way up the instant it passes through the relief valve. This is good when your engine is cold, but not when your engine is hot
Next is the oil cooler cct. Look at the diagram in your manual. Instead of using temperature to decide when to send the oil through the cooler, VW used pressure. Cold oil = high pressure = bypass the cooler. Hot oil = low pressure = through the cooler. But you're using 20W-50 tar and that artificially raises your oil pressure so high that even when it's hot, the pressure is high enough that it bypasses your stock cooler. Then the really _____ engine builders tell you to put an external cooler on it!
Your engine was designed to use 30 wt oil. Modern oils give you a wider viscosity range for no extra $, so you can use a 5W-30.

[Bruce2]

Very good to know thanks... what is your thought on FRAM or RYCO?

Fram is your problem. Worst piece of junk on the market today. Cut one apart to see for yourself. The anti-drainback valve of a Fram is so poorly made, you're seeing the effect. Once you get a good filter in there, your startup noise will be gone.

[jamesbissland]

Great info !! - thanks for the insight.

Ok, might look into dropping that tar out and putting some Xw30 in over the coming weekend if you think that is best.

We can't actually get Fram down here, but I see them in all the photos on the net and in magazines and was wondering what all the fuss was about

[Piledriver]

Fram makes cheap filters in every sense of the word.
Avoid.
I assume there are good quality filters on the market in NZ, but you will have to do some research.

FWIW I run 5w30 in winter and usually 5w40 in summer here in Dallas.(although I have run 5w30 in summer)
My current engine was running clearances on the upper limit of new when assembled >100K miles ago.
My oil pressure is ~same today as when first assembled from all used parts.(except the cam bearings)

Admittedly a t4 is not a t1 but the oil pressure/temperature issues and factory oil cooler layout are essentially the same.

This is important:
Are your oil cooler and filter plumbed off an adapter from the case oil cooler boss?
(This is easy to do, so its sadly a common setup)

If so, you aren't getting enough oil flow through the filter and cooler to worry about once warm.
OIl will take the path of least resistance once the oil bypass piston is seeing pressure to open and will go the 1 inch to the main oil gallery, avoiding the filter/cooler altogether.

[jamesbissland]

This is important:
Are your oil cooler and filter plumbed off an adapter from the case oil cooler boss?
(This is easy to do, so its sadly a common setup)

It comes off the oil pump cover and returns into the main gallery by the crank pulley... at least something was done right!

In the aftermarket range on the shelf at the auto parts store we can get k&n, mann, valvoline, marhle & ryco, but the others you mentioned above are only really 4 days away from the States. May invest in a few to be sent down

If I go back to a dog house set up would you think it beneficial to move the filter lower, possibly engine level / rear guard area?

The system I have I found out was installed in 1996, so potentially the lines are old and swell up(?) robbing some of that initial start up pressure also