Rebuilding my stroker.

[DeathBySnuSnu]

Gotta say..... aint seen that one.

So whats that supposed to do?
Link to the design theory?

[Martin S.]

Adds turbulence to the chamber. That 1776 has tight deck height at .030" and doesn't ping on reg gas at 9.4:1. The engine is a joy to drive and sounds like a diesel. You can short shift it all you want without a problem and it revs well too. This is probably the original guy who started doing the groove but I don't know for sure.. http://www.somender-singh.com

[DeathBySnuSnu]

Thanks for the info.
I have been researching since you posted the info.
Might just be something I try. I dont see how it could hurt.
Lots of controversy in the vw world about it working or not.

[Martin S.]

A few people around here have tried it. It can't hurt anything, so why not? Singh made that comment about short-shifting and I did notice that. Last summer we took a family trip in my all-original 71 Bus. When my wife drove the Bus I complained when she tried short shifting it as she was used to the 1776 with the high CR and flame port. She said, 'it was something Steve did to my engine, right?' I said yeah.

[DeathBySnuSnu]

And so it is done.

[ Attachment: You are not allowed to view attachments ]

[Martin S.]

Looks good! Both sides on yours is interesting. He only did one side on mine, not sure why. Here's a different shot.

[Martin S.]

What deck?

[DeathBySnuSnu]

Zero piston to cyl top deck.
.050 inch copper ring gasket.
Flat top pistons flat squish pads.

[Martin S.]

That's too much clearance. We went with .030" on that 1776 in the pics and the thing pulls like a locomotive. I'm not sure what my 2332 is but not over .040". The 1776 runs perfectly on 87 RON gas. Setting the timing is critical of course, and the distributor was re curved by lightening the advance weights. But the heads don't need much advance and won't lose power as you retard the timing to eliminate the ping. Everything going in gets burned so the heads run cool. My 1776 sounds like the pistons are just kissing the heads when started up cold for the first 20 seconds or so until the pistons warm and expand so they run straight in their bore, so I would use .035" deck next time. Good luck!

[DeathBySnuSnu]

From what i can find .040 to .080 is the reasonable deck range.
I would consider tigher IF I had better thermal controll of the engine.
I do not run a fan or any tins. All my cooling is mph dependant.
I run a wide range of temperature .
From so cool at 60mph that you can rub your hands all over the heads and cylinders. To screaming full hot after a couple stop lights and city traffic.
If i could warm up and maintain temps i could tighter.

[Martin S.]

I don't think operating temp affects deck height much. When an engine is dead cold, the piston is smaller and rocks in the bore. As it warms up to operating temp it then fits properly and goes up and down squarely without rocking and seals properly. If the piston is too big in diameter it can seize as well if overheated (like 2 stroke bikes do sometimes). My engines get  hours of continuous use in hot and cold weather on the street and I haven't had a problem. The larger deck height will make your engine ping but since your ride is a light one hopefully it won't be an issue.

[DeathBySnuSnu]

I once built at .035.
Ran fine at first, but around 20k miles it started hitting when hot.
Stuck .020 more in it and ran it about 10 to 15k more before bearing time.
After much research it appears that .100 is the max before pinging and lack of squish becomes an issue.
I am comfortable at .050

I have sized the chambers.
58cc now. 9.9 cr static, somewhere around 7.2 dynamic.

[DeathBySnuSnu]

[Martin S.]

I doubt your close deck height caused your bearings to go. Sounds like your motor had other issues. It has to be decked square to the crank centerline with even clearance all the way around to work.

[DeathBySnuSnu]

Never said or meant to imply that a tight deck made my bearing go bad.

I did mean to say that .035 deck that just the slightest amount of wear made it hit.

 I corrected the problem before any damage could be done.

All I have ever gotten is around 30k miles out of this engine before a rebuild/freshen up.

I run it hard. I dont let it warm up. I treat it bad. I lug it hard.
When the oil pressure starts being low at idle or I start getting blow by, I give it a quick freshen up rebuild. Slap some rings and bearings in it before other wear happens.

I have been running this engine since 1981. It has been through this cycle many times.
This is the first time I have had to do a major rebuild.
Case and heads are still good. Most everything else is getting changed this time.

[DeathBySnuSnu]

A few pics.
Some assembly required.

[Martin S.]

That's gonna be one wild ride! 

[Neil Davies]

I've just re-read the whole thread and spotted the bolt on extra fins - never seen that before! The two gearbox cases is interesting too, and a clever way of raising the axle height relative to the crank centre line. Some totally out of the box ideas!

[Martin S.]

Yes I agree. I'm not the only one crazy enough to try some unconventional ideas, especially for cooling. We also both have the flame ports
Here's an idea that seemed to work out wonderfully. Who knew something as simple as drilling the fins would cool the heads so well 

[DeathBySnuSnu]

I have seriously considered this.
Does it seem to work?
I have done this on a dirt bike way back when I was young.
As I understood it back then was that a certain diameter hole would increase the surface area. Then there would be more air flow also through the holes.
I was young and did not know anything. DrillEd the hole size someone said. No data to back anything up.

[Martin S.]

Yes it worked great! The heads on my engine run cool as anything. Small deck height, high CR for a turbo (8.5) and a 2332 with the closed under the decklid turbo should mean a hot engine but I have ran it for a few years now and no movement in valve adjustment or blow by in the head/cylinder joint mean no warpage. I've been stuck in traffic idling for an hour and a half on hot summer days as well as done extended summer drives with no sign of overheating. Steve said he wouldn't deburr the drilled holes because the burr will help add turbulence and further cool the head. There are also cross-drilled holes near the exhaust port. I have more pics of that somewhere if you're interested. I got the idea from the old 2 stroke dirt bikes.

Ps. It also has a @&$@);/$@"86&(; huge cam as well.

[DeathBySnuSnu]

Hmmmm.
Considering again.
If I could just find some empirical data.

Yes i was there with the dirt bikes. But the fad never took off like it really didn't do much or anything.
Back to the research

[modnrod]

Empirical data? In the VW game?
 

I'm curious too. If the diameter drilled adds total surface area, added to the slight extra cooling of all the edges, then it should work OK.
Dunno whether it would work as well as your additional fin area that you've already done, or lowering 1/2 point comp.

Doesn't matter I rekn. Speed holes are always cool!

[DeathBySnuSnu]

Yep.
Do need the mass for the heat to go into.
Also need the area to dissipating.
I might do this but on a limited scale on the outer area.

[Martin S.]

You can always fill in the holes if it doesn't work 

[DeathBySnuSnu]

On the ground.




Looks like a place to put a 2387.

[DeathBySnuSnu]

Slowly going together.

[DeathBySnuSnu]

Is this enough top fuel dragster/ mad max look?

[modnrod]

nearly, not quite.....

https://www.summitracing.com/int/parts/sum-g3021/overview/

 
Coming together nicely.

[DeathBySnuSnu]

It has been a while.
Finished the top end.