Fruitcake Type 4 engine rebuild - Finally started

I know you've checked but that video was exactly the the noise i had from the base of manifold not sealing on the head.

Sent from my SM-T580 using Tapatalk

 

I guess they caused more problems than they solved.

Anyhow, guessing over the internet from a recording you say doesn't sound like reality is probably more hindrance than help... though what deefer says now rings a bell - mine sounded like that once when I forgot to reconnect the brake servo pipe. i.e. big inlet leak somewhere.

 

That was my first thought as well @Deefer66 but if it was surely the revs would have shot up when I squirted them all over with Easystart, that's my goto method for finding leaks.

 

One cylinder needed idle mix adjusting to stop that thudding.

 

What thudding ?

 

Unfortunately, if you used the aluminium head gasket and it leaks it will probably get worse. VW deleted them to improve heat transfer and increase durability.

Technical Bulletin 10-90 T01
Eliminate aluminium seal 021 101 341A between cylinder and cylinder head.
Eliminate paper gasket 021 101 341A between foot of cylinder and crankcase.
Install 1.6mm aluminium shim 071 101 341 at foot of cylinder to compensate for removed paper gasket and aluminium seal.

 

You won't hear it on a phone. Too deep man. On my monitors it's loud.

Always looking for noises.

 

Nope mine went with more revs exacly like yours, couldn't figurebout why it looks and sounds like it blows out there! The bowing out marks might have been the carb backfire opening the hole in the first place then sucking causing the squeek

Found the pic

 

Leaking gaskets rarely fix themselves, not what I need to hear but it's probably engine out again.

 

If you fitted both head gasket and cylinder spacer the CR will be very low and don’t forget the Scat C25 cam needs a higher than standard static CR to work well.

 

A bit confused now. Originally installed was a 0.2mm shim underneath the barrel and a 0.7m shim in the head, totalling 0.9mm, surely removing both of these and installing a 1.6mm shim underneath the barrel will reduce the CR? The shims supplied in the gasket kit are the same thickness as the originals, there is one pack of 0.2mm and two packs of 0.7mm ones. Am I supposed to fit 3 underneath each barrel, 0.7+0.7+0.2=1.6mm?

I'm off out shortly but when I return I'll take the engine out and whip off no 3&4 head to see if it has been blowing.

 

The 1.6mm was just tech bulletin to swap like for like. You would measure deck height with nothing and order base shims to get compression ratio you need.

Sent from my SM-G960F using Tapatalk

 

The service bulletin is assuming all standard parts are used, cam, cylinders, pistons and heads and originally the combined thickness of the aluminium head gasket and the paper cylinder gasket was supposed to be 1.6mm.

As soon as one part is non-standard, and really even if they are, the combustion chamber volume and deck height should be measured and the CR calculated to determine the required cylinder spacer thickness. There should be one spacer under the cylinder and no head gasket. Deck height ideally between 1mm and 1.6mm.

 

In a desperate attempt to avoid the inevitable I removed, resealed and refitted the N/S heat exchanger but to no avail the canary was as loud as ever. So in a grumpy mood I dropped the engine and ripped off the head.

I know there's a lot of people that love these old engines but I have to say they really are awful pieces of marmite in the way that they're designed. The head doesn't come off until the piece of tin behind the fan housing comes out, that doesn't come out until the fan housing is off, that needs the fan removing, the 4 bolts coming off, the alternator, the oil filler (then the bellows come off that you can't reach until the other heat exchanger comes off). etc, etc,etc, ........ 5 seconds with the tin snips, 10mm of tin removed and it can now be removed and refitted with ease . Whoever designed the damn thing had one hell of a warped sense of humour.

Anyway, it's obvious that the head was blowing from No3 as the photo of the sealing ring shows. The deck height as measured with the barrels bolted down using spacers with no shim underneaht is 0.8mm so using 0.7mm spacers it's now 1.4mm. Just the other side to do now and see if the canary has been laid to rest!

 

Can we assume they are original heads i.e. flat without a step once the gasket is removed?
The head chamber size will probably be 53-55cc
CR 8.6:1 to 8.9:1, I'd say perfect for C25
If it was 50cc 9.3:1 which might be a tad high but might be ok.
I sense you won't be measuring it...

Or do they have a step?

 

The heads do not have step and are probably original, I've seen the calculation spreadsheet and agree with your maths, I took the view that I could spend hours (that I don't have) measuring them and come up with 53-55 cc as you say! Hoping to put it back together and put it back in on Saturday when my Son in Law can come over to help.

I've always been happy with the performance of the bus it was just the noise from the lifters that used to drive me insane. To be brutally honest I potter to Eddies twice a year, potter to Download Festival, Skegvegas and the odd short trip to the beach. If it lasts 10K miles it'll see me into my eighties when I'll probably be sitting in a corner dribbling anyway.

 

You can turn the hearing aid down then...

Sent from my SM-G960F using Tapatalk

 

A productive day today , I put the engine back together and decided to have a go at getting it in by myself.................and it's in, it runs and the canary seems to have flown the nest. It's great to have a bus that sounds like everybody elses bus and not like a skeleton doing something unmentionable in a biscuit tin.

In terms of running it's definitely a bit rich as the plugs are sooting up, I need to research how to set up the Empi progressive carb. It also needs to be over advanced to idle and to pickup from low revs. For some strange reason the timing notch in the pulley is 180 degrees out so I'm timing it from No3 and it needs to be off the scale, I can tell it's too far advanced as it struggles turning over on the starter until it starts.

It revs freely and feels lively once the revs have picked up, however it doesn't like idling and I've had to set the idle fairly high to avoid it stalling when I select drive. Unfortunately It's very low on gearbox fluid and the nearest shop is a 30 mile round trip so I haven't driven apart from 100 yards across a field, I'll get some fluid tomorrow and give it a go. Meantime I'll try and sort out the mixture settings on the carb.

 

Sounds like great progress. What dizzy do you have, Paul?

 

That might be a characteristic of the C25 cam, it has a lot more duration than a standard cam but it should idle at 800 revs although it’s not developing much torque.