CU engine stripped down, what now?! Gearbox?

[Zomerzet]

Right, I've bought a non runner T25 which I'm told has a dead engine which needs replacing. Now I'm tight and aren't going to replace an engine if only certain components are FUBAR'd. Was told the Oil cooler had blocked previously, overheating the engine leading to a broken piston ring on cyl 3. New pistons and barrels were bought, but only changed on cyinders 3 and 4. A new single Weber had been installed recently (Yes, I know they're supposed to be rubbish!). I've got the other two pistons and barrels along with a half used gasket set.

I got the beast home and decided to see what the craic was and see what I was dealing with. Got a battery and she turned over fine with compression on all cylinders good. I set up the dizzy (Which wasn't installed) on TDC and turned her over confirming I was getting sparks to all plugs. She's running an electric fuel pump into the Weber (Which wasn't working, but after a strip and rebuild was fine). I got some fuel and tried to start her and eventually got a backfire! So all the components were there for running but the timing was incorrect. I need to confirm the fan timing/dizzy orientation is correct before the rebuild. I gave up an decided to pull the engine anyway due to it's suspicious history.



I've now got the engine stripped down and am going to fit the remaining new pistons and barrels. During the rebuild I found the thermostat had almost completely expanded. I also need to identify the gaskets that I've got left in the kit and fit them. I'm going to lap in the valves and examine/clean up the heads too.

Is there ANYTHING ELSE I need to remember to do for the rebuild?
I havn't got the pushrod retaining wire. Do I need this or can I get away without it as I'm having trouble sourcing some?



Whilst I'm this far I'm going to drop the gearbox. What wears on these? I'm going to fit a new input shaft seal and replace the fluid. Is it worth having a look inside for any wear?

Sorry for all the questions, but this is my first CU engine and I don't want to be dropping her out again for as long as possible!

[sarran1955]

Hello,

Just been looking at this and your other thread.

Do what Dugcati says.

These videos may help:

http://www.youtube.com/user/sarran1955/videos" onclick="window.open(this.href);return false;

I know they are of the CT engine, but they all come apart and go together the same.

By the way ALWAYS fit pistons as a set of 4, because they are machined for matching weight.

Cordialement,

[Zomerzet]

Yeah, I'll be happier once all the piston set is fitted. Had a look inside the case today with the pistons removed and it looks like the cam is pretty worn so will split the case. I tried today and it looks like the 135k motor has never been split and it's not coming apart. I don't want to force it and have levered on the fan mounting/fan seal, being careful not to score the case.

[CovKid]

When you try to split the case with all the nuts/bolts removed, chances are there will still be one you've missed - take your time and check right round.Trying to force it open with screwdrivers etc marks the mating surfaces. A block of wood and a lump hammer should split the two halves no problem so do check for bolts you may have missed.

On the positive side, theres no reason why you can't make a great job of this. Few garages will do this work for others (I won't either) because of the stress and hassle of any subsequent problems and potential for litigation but on your own vehicle, taking your time and being careful about reassembly, you should get many trouble free miles. If you're splitting further (and cams always look worn in my experience) you may want to fit new crank bearings - do some measurements comparing with a manual.

[sarran1955]

Hello,

Have you split an Aircooled before

If not, then there are 2 ways to go.

Follow the haynes to strip the engine.

Then take the clean, crack free Crankcase 1/2s, the crank, the con rods the cam , a OE quality oil pump and engine gasket set to your local friendly machinist.

Get him to regrind the crank and fit oversize case and crank bearings. Ask him to re-bush the con rod small ends. Ask him to inspect the cam,

Then ask him to re fit the case together with correct bearings throughout.

This will cost money, but avoid you making expensive mistakes, and having to do the job over again.

You would also have plenty of opportunity to fix, fettle and paint all your tinware and exchangers.

The other route is not to strip the crankcase. With all the pistons off , buy an aerosol of WD 40 or other de-watering oil, and get the block really thoroughly pressure washed inside and out till its squeaky clean,
then dried out with compressed air, followed by WD 40 EVERYWHERE.

If you had no oil pressure issues before, there is no reason why a full top end and exhaust/heat exchanger overhaul should not give you a good reliable engine.

It would help you, if you have the room, to get a spare engine for your van, This you could strip and recondition at your leisure. (Thats what I do)

Get the thing nicely back together and running, for my money, ditch the electro-mechanical ignition, fit a new clutch and starter oilite bearing, oil change your gearbox, do the cv joints, and enjoy it this Summer.

Cordialement,

[Zomerzet]

Hi Sarran, thanks for the info.

I've not stripped an Aircooled engine before to this level, but know my way around a toolkit. Going to attempt to split the case again tomorrow, but it seems like the Cam's pretty well worn as shown (Badly) in these pics.




New cam and hydraulic lifters is definately on the shopping list, along with new cam and crank bearings. Haven't inspected the oil pump yet but imagine if the cam's in this state prbably best to change on spec. I want to do as much of the work as I can myself as money is a big issue. Just fitting fresh bearings onto the crank without work isn't ideal, but it will be an improvement on the existing bearing's wear. Will have to see what state everything's in first I suppose. The case is definately going to get a really good scrub and brush up before reassembly The igition is eletronic, so that's a bonus. I'm planning on dropping the gearbox for an oil and input shaft seal change.

If I do get any engineering work done, is it worthwhile to get everything balanced while I'm at it

There are a number of sheared tinware screws in the heads (Only one of which was my fault). Is it possible to drill these and 'easy out' them

On the subject of splitting, I can get the top of the case open about 1mm but the bottom half is solid. I will double check for any bolts I've missed tomorrow, but has anyone had experience of stubborn cases (Esp. ones that havn't ever been split in 135k like mine!)

[Zomerzet]

Huzzah!

I have finally got my case split I was at my wits end so popped to my nearby garage for assistance. We set at it with a hydraulic press, big hammer and at one point a welding torch for heating it up. Eventually the guy at the garage eventually spotted a bolt I'd missed under the followers/above the sump It wasn't all embarrasment though. Whilst there I found they're planning to shut up shop at the end of the year and gave me a load of bits and bobs for my Metro including a gearbox with a busted casing with all internals



Definately worth rebuilding as once I got inside I could see exaclty how worn the crank is... Cam is on the shopping list. But the biggest eek moment was when I removed the cam and saw what state it's bearings were in. A large amount of the surface had simply broken away meaning the cam was turning on only minimal bearing in some spots

[faggie]

i have a brand new set of hydraulic lifters, tubes and seals for one side of the engine if you decide to replace them

[Zomerzet]

Hi Faggie. By that do you mean you have got a half set of everything or just the gaskets?

I've spent today cleaning the engine halves (And think I've been busted by the missus for putting them in the diswasher ). I've also been trying to locate a place where I can get a replacement cam. VW Heritage have them for £200 with seperate can drive gear and that seems to be about it for new parts suppliers. I'm not keen on getting a seconhand part as it's likely most secondhand hydraulic cams are going the same way. I spoke to Coolair who said they had a cam made by CB performance that was the same as the factory one for £210, but this didn't include the gear

I looked up CB performance online and they're an American company specialising in performance Aircooled tuning.
http://cbperformance.com/category.asp?CategoryID=7
They have a number of cam options available including what seems to be an 'increased torque' version which is stated for type 2 hydraulic engines (I thought type 2 meant bay/split camper, but didn't think they had hydraulic followers). I have emailed them hoping they may be able to provide me a cam at American prices with the added benefit of a slightly uprated cam profile

[sarran1955]

Hello,

Well you've gone and done it now... no going back.

When you take all the bearings and shells out make sure you label them with tippex

Front to rear left to right etc.

This is to avoid you putting the wrong bit back in, or wrong way round, VERY EASILY DONE.

You will use them against the new for the rebuild.

Cam. All that happens with a reprofiled cam is that the 'overlap' is longer. This means that the valves are both partially open for more of the camshaft revolution (1/2 engine speed).

Unless you do other things like fitting oversize valves and better valve seats all you will do is increase fuel consumption and stress the heads.

Get a standard cam, if poss to reuse your camdrive, because they are machined to the crank drive. If you fit an aftermarket cam with drive, say Engel, then it risks being a 'screamer'.

As I said before, get EVERYTHING pressure washed. and WD40 'd.

Secret of a good engine rebuild is WORK CLEAN. no dust no grit.

I use Wynns or STP to assemble the engine, (sticks stuff in place, but is a great lubricant)

Once the block halves are really clean and before fitting crank and cam, do a dry run assemble to check all ok. Use new 8.8 nuts and bolts throughout. Once dry assembled, use a bright lamp inside the crankcase to check the mating surfaces. (stops oil leaks later on.)

Fit a new oil pump. (OE)

Use a 'german quality' gasket set, (theyre often american, but worth the higher price.)

Use hylomar, not orange silicone goop.

Fit new (OE) pushrod seals, green and black)

Repaint all the tinware before assembly.

Watch my videos on rebuilds.

Have fun, work safely, take your time, and if you're not sure ASK

Cordialement,

[faggie]

have you tried csp or any of the german type 4 tuning specialists

[Zomerzet]

Hi Faggie. I havn't tried them yet. I'm new to the camper scene so haven't built up a good knowledge of parts suppliers yet. Although I have discovered at least 2 local VW firms I never knew about before in the area hidden away in little corners of villages around Lincolnshire

I've had a look at CSP and they seem pretty good. I've also happened upon VWparts (Another American Site) who do a selection of a wide selection of Cams. I've found a slightly uprated Hydraulic cam, the Web-Cam 107i. I'm not after anything lairy, just something to give a little more lift than the standard set up as I'm planning on fitting twin carbs in the future too. I know tuning a type 4 too far may lead to cooling issues, but they must be able to take some mild tuning. The heads are a fairly big limitation on these engines, so allowing the valves a little more duration will just give that little more push along the motorways & hills. I've not actually driven a T25 yet so am worried about it's lack of progress. I know it's not a sports car, but just want to ensure once the engine's rebuilt, it'll be a good un!

http://www.vwparts.net/mm5/merchant.mvc ... webcamt4ch

Sarran, The Mains are actually in pretty good shape so I'll be leaving them be. There is a little sideways play on the rod big ends so am umming and erring whether to swap them out, but probably will in the end. When you say Wynns or STP, are you referring to cam, or some other type of lubicant? My tinware's in a pretty sorry state So I'll refurb what I can but I think I may have to try to trace some replacement bits from somewhere

[sarran1955]

Hello,

Now you've opened Pandora's Box, change the mains.

You don't want to do it twice.

If you don't you'll risk having little or no oil pressure.

You're determined about the rinky- dink cam are'nt you.

Look VW Aircooled heads have cast iron valve seats. The contact between the seat and the valve is the ONLY heat transfer available, so now you want to reduce that time with a Jules Fandango cam, ok., all this with unworked heads, iffy valve guides...

And now you want to shtonk on a set of twin dellortos.....

It will end in tears....

STP is thick clear goop, perfect for building engines cos it hold all the bits in place, and is a great lubricant on startup.

Some people say Special treatment Petroleum,.......

for me it was always Sishkebabes Titillate Persians



You'll end up finding s/hand tinware, or better making your own,

'cos some of it is viewable only in the Swiss 'Unobtanium Museum', eg under tins.


Cordialement,

[Zomerzet]

Sarran,

Thanks for all the advice. It is appreciated. So for the rebuild you would recommend stock everything as the heads are so fragile? The only tuning options for this engine seems to be a balance and a set of good carbs, otherwise I risk melting the chocolate heads

I've seen plenty of tuned Beetles, so why are there such limitations to the type 4 engine? Sodium filled valves help dissipate heat better, compared to earlier aircooleds so surely they should be more robust? This coupled with other features such as the hydraulic lifters and a REAL oil filter.

You appear to have a good level of experience in this field so I am taking everything on board, so I'm wondering whether it is worth uprating anything at all? Surely the VW CU motor must have areas where aftermarket options improve it in some way? I believe this engine should have around 70bhp, which doesn't sound like much, considering the weight it has to push around in a camper. I will be changing the oil regularly and looking after it and can understand how failures can happen when cooling/oil issues occur with an Aircooled engine.

As stated previously, I'm not looking to build a race engine, just aiming to get the best out of it. This isn't meant as a dig at you. I'm simply used to the trusty A-series with cast iron everything and tuning options aplenty.

Basically, what I want to know is if you were building a CU engine which you wanted just a little more than standard out of it what would you recommend...

Cordialement!

[sarran1955]

Hello,

Quick reply before I go play brakes on son's T25.

You can get 84 bhp with a good standard engine setup.

Save your money for later stuff.

My first vw was a ti karmann ghia.... back in '74.

Cordialement,



Cordialement