Oil leak source

Sunday afternoon question. Is there an easy way to clean cylinder heads? I'd like to get these so that I see my ugly mug in them, but it is taking a lot of time and scraping with a plastic card.....

 

That’s^ a piston, you could try oven cleaner but don’t leave it on too long and wash it off well.

 

I'm tired.... Pistons, cylinders, cases, cranks, cams.....



Thanks

 

I used Brillo pads mate. I just took the coal off the face rather than looking for polished finish. I figured it didn't need to be that clean. Ive read about people carefully chiseling carbon off so I think they're reasonably robust and will take a bit of abrasion...

 

That was a particularly even coating until you chipped it.

 

Oops, hopefully no damage done. I'll keep going now so that it's all gone at least on this piston. Should I clean the rest? They are all similar.

Separately, I was not planning to clean the valves as the leak and compression tests before this work was very good for all cylinders. Any thoughts on this plan?

Thanks everybody for there support.

 

I was just messing.
Yes if it ain't broke...

 

Hi all

Since the last update, lots of cleaning has been going on, but more importantly, some measurement. Bit of a curate's egg, with some bits better than hoped but some bits are worst than thought.

I think the crankshaft journals are good with my measurements as follows. I took 3 readings on each one going from front to back:-
No1 - 59.98/59.98/59.98
No 2 - 59.98/59.99/59.99
No 3 - still enclosed so not measured
No 4 - 40.00/39.99/39.99

I think the camshaft is new care of PO, and with no obvious wear points I'm hopeful this is good to go.

However the crankcase may need attention. I onlymeasured the bearing housing No 1 as the measurements are not great so the others may not matter. 3 readings to get an average
Vertical - 70.075/70.11/70.07
Horizontal - 69.85/69.95/69.97
I think a linebore might be needed. Any thoughts?

I've also tested the crackshaft 'wobble' and it looks like the shaft is dead straight... phew!

However, I did find some wobble in all of the con rod pins. If the con rod it vertical, then the movement of the pin is up and down not side to side. These I fear will need new bushes. The pins fit nice and snuggly in the pistons so this at least is OK.

I haven't opened up the big ends to check the bearings there but they feel OK. My socket set won't fit round the nut properly, so I've left that alone for the moment.

So may I ask if people agree that the crankcase needs to be linebored? I assume new bearings, but does this mean that the crankshaft journals need to be changed?

With the con rod needing new bushes, should I check the big ends?

Finally, can anybody recommend a good place for these to be sent? I'm understand that Stateside Tuning have a good reputation, but any other options would be helpful. If it makes a difference, I'm located just SW of the M25.

Thanks

 

Reference a couple of points earlier -

I straightened some pushrod tubes by bashing a tight fitting socket down them - this did a good job of taking the dents out; however check carefully for small pinhole cracks as they will leave you with an annoying leak..
To clean carbon build up I used a brass brush thingy in a dremel - this took the build up off without damaging anything. You do get through a few of them as the bristles tend to fall out after some heavy use (clean the part well afterwards and don't do it in the vicinity of an engine where there's a chance of them vanishing into the case....)
Regarding rebushing etc - any half decent machine shop should be able to sort these out - same with honing the bores if you are planning on reusing the barrells.

hope this helps a little!

 

Crank bearings go oversize on the outside to accomodate taking material off the case and undersize on the inside to accomodate taking it off the crank, so you can use your crank if it's good and machine the case only if required

Make sure you get the right bearing to match up and check what's available.. not all sizes are around all the time. Might be easier to machine to what's out there than find

 

Good points all. Thanks

 

The crankshaft dimensions are okay, but the crankcase needs align bore, 70.03 is the upper limit and it should be round, it’s not really a surprise when you know the thrust bearing was loose. And you’ll need to replace all the main bearing so #3 will have to come off.

The pin should be a sliding fit in the rod with no perceptible movement and not every machine shop with have the equipment to fit small end bushes or check the rod for twist and bend. HT Howard might not be too far away https://www.hthoward.co.uk/con-rod-services/

Big end bearings are cheap and as you’ve stripped the engine this far it would be sensible to replace them. I’d deglaze (hone) the cylinders and replace the pistons rings too but then I’d also remove the valves and lap them into the seats – I’m a ‘fix it before it breaks’ rather than ‘don’t fix it if it isn’t broke’. It would give you something to do while waiting for the crankcase and rod machining.

 

I was just looking at HT Howard's webpage. They are relatively close. I'll give them a call to chat as well as Stateside who have been mentioned offline to me.

 

Stateside can be hard work at times but Jims work is first class. I got some reconditioned exchange rods from them and they were spot on. If you’re going down the align bore route make sure the new Main bearings are available as some sizes seem to be in short supply.
Also worth costing up how much.
It was more cost effective when i rebuilt a type 4 recently to purchase another case which didn’t need a bore & I could use standard size main bearings.
It’s a bit of a lottery with second hand cases but there are still good ones out there.
Wasn’t the mating sealing faces of your case also iffy?

 

Cheers @Gooders. I don't know where the leak was coming from - all over p##sing out from all orifices!

The sealant was just horrible.

Looking at the mating faces, no obvious issues there but the push rod tubes, rocker cover 'gaskets' and the cam cap that wasn't are all likely culprits.

 

Out of curiosity, could my horizontal measurements difference to my vertical be explained by the lack of a chemical gasket when it was tested? What is an assumed thickness of chemical gasket?

As @77 Westy says a few posts ago, the max is 70.03, so my vertical measurement exceeds this, which is not affected by a gasket thickness, means a line bore is needed anyway.

Strange what thoughts come to you in the middle of the night!

Here is an interesting link I found about types of sealant.
https://www.klassikats.com/index.php/2019/11/08/porsche-crankcase-sealant/

 

The thickness of the sealant should be virtually imperceptible, it’s a metal face to face joint and the sealant simply fills the machining imperfections.

Interesting article, bottom line is don’t use RTV type sealants.

 

Just spoke to HT Howard who were very nice but don't do 2ltr type 4 VW air-cooled

Stateside can do it but I'll need to take off all of the long bolts first!

Any other recommendations would help as I'll have to post the case etc to them so distance is not an issue. Not that I have any problem using Stateside, I've had good service in the past, I'm just looking at my options.