Measuring deck on built type-4

Thank you all for your help and guidance

As it happens my wife was talking to the guy who does our decorating (indoor and out door very good). He asked how my engine was progressing, her reply was "oh he wants some part, some spacer thingy and he cant find one anywhere. I recieved alink to CSP Germany and promptly made a purchase, I wonder if he has any underbarrel tinware.

the moral of the story is if your stuck talk to a decorator........................................................

I chose 7.6CR as this is the standard for stock type 4 engines. The other engine will need careful consideration for the correct CR, webers cam etc


PS, the decorator runs sub 10s quartermile in his beetle.

 

I though they were, they measure 0.7mm thickness so fitted with some 0.3mm spacers i was ready to go, or so I thought.

I was at the point where I'd applied the sealant to the bottom of the barrel and was attenpting to fit the above, only to find they were too small. Gutted. then the penny dropped they were cylinder head gaskets.

It ruined my day. That "this is what you could have won" feeling came over me.

 

Just out of interest what is the deck height? And what did the decorator think about the CR?

 

I'd be aiming for a little under 8:1 if it was physically possible.

 

And me, there is nothing to gain with a very low CR.

 

Getting me worried now.... my CR is up at 8.8!.. static.. dynamic brings it down to 8.2 might actually get to drive it soon

Sent from my SM-T580 using Tapatalk

 

But you don't have a stock cam do you so your dynamic is the thing. Calculating dynamic... impossible IMO for us hobbyists, you need to know the volumetric (??) efficiency which you can only make a stab at.

The static CR numbers that have been arrived at for different cam profiles are the result of experience and even now with the entire history of ICE behind us there is not accurate widespread agreement. A great example is what suits a car is not the same as what suits a heavy bus.

 

Today's job is removing some evil sealant called "Wellseal". As you can see, it certainly sealed welded the green o-rings to the head. I didn't mention it at the time but to get the tubes out was... difficult.

Normally an open ended spanner on the thin part, thumbs on the rocker cover seal surface and squeeze - out they pop.

These ones need a block of wood against the case, an extended spanner and a lot thumping on the leveraged "removal tool".

I'll try 2-pack paint thinners. At least I can practice on the head without lying in a puddle. I haven't looked to see if the o rings are similarly stuck to the now rather dented tubes.

I'm going to say it because I've been here before with hours and hours cleaning up these bores. DON'T USE SEALANT. Let them leak if they must, they normally don't fitted with just oil for lubrication. Removing this baked on crud is a job that should not be required.

 

Yep, for example, I would never put the cam from my Bug in a Bus engine, it doesn't wake up until 4000 rpm.

 

The other head? With the o-ring sealant situation for now I'm going to just expose the nuts and crank the torque up to 27-28ft/lb.

 

Isopropyl alcohol worked quite well on the permatex brown stuff off my case joint.. that sets quite hard, but still needed a plastic spatula to scrape.

The push rod holes needed a light sand to smooth out the screwdriver marks previous builder left.... that was probably the reason for half a tube of silicone. Seem ok after the break in run..

Sent from my SM-T580 using Tapatalk

 

The only odd bus engine I built myself worked from 3,000 rpm upwards. Great fun out of the roundabouts around Milton Keynes but barely on cam at cruising speeds. At 50-60mph mph for instance it really wanted to be in 3rd which is pretty stupid!
But it's the CR with the same cam is interesting. VW pushed it higher for cars with type-4 engines and lower for buses. When they made the engine bigger they pushed it even higher...for cars only.

 

So very true^. Spotlessly clean, no sealant is the way.

 

^Head gaskets - should be thrown away.

^Cylinder base shims.

 

I suppose the gearing helps too, yes. The old 4.135 R&P in the Bug was absolutely mental, but long distances, like going to a show, I mean anything longer than an hour, were exceedingly wearing on the senses. I still use earplugs and thats after spending 4 years taming it down enough to still be fun but be more usable. I followed a couple out of Bug Jam once in their Cal Looker, they looked like Cybermen from behind, as I passed them doing 65 with their engine on cam, I realised they both had industrial ear defenders on

 

Amen...

Sent from my SM-T580 using Tapatalk

 

Must be good money in decorating , running a sub 10 Bug ain't cheap and sure as eggs is eggs, stuff breaks when you go racing.