It's my fault, Todd was trying to keep up with me ..... JK !

Since I'm more than happy to change the topic, to follow up on Jemal's comment:

Here's the sound of rods with 1/8" if not 1/4" of big end play, so much we could tilt the pistons back and forth with our fingers.  And almost no cam lobes left as Jemal says.  How it ran, let alone well, is totally beyond me...  Here's one of the last runs, where Dr. Dave and I were trying to figure out the noise...

Sorry if you feel set upon. I have been watching your threads and wondering what happened

 when you went silent. Was there anything in what I posted that did not happen? I'm quite aware 

of the problems when using the 5 port alloy head. That's the reason I do a dry build using what

I call flash light springs. I hope they know the valve guides are stepped and must be pressed out from

valve seat/ port side. We machine new guides and move the guide lower into the head. I guess you could 

just mill guides down from top but you would loose the seal retaining groove. As for push rod rub you

can drill the block but be sure to get the angle right as the holes do not go straight down. I'm concerned about 

the quality of lifters and the radius on the face. The harder we work the harder the suppliers make it to do a

good job. I mean you no harm and while interesting I don't know that grooves would help what I do. I know 

what it costs to build a first class unit. I would not want to do any other kind of work. Believe me in 46 years

of engine building I have learned my share of hard lessons. When you get it right you will be glad. Don't take

things so personal. It's all good. Steve (CTR)

I don't think there is a thread yet.... We suspected damage to the crank thrust washers, as Todd was always chasing his clutch adjustment with the adjustable pushrod.  So I had him bring me the engine for some exploratory surgery.  Turned out the crank thrust was fine, but the cam had 7 of the 8 lobes destroyed, 7 lifters severely mushroomed and pitted, and signs of metal bits through the rod bearings, as well as small chunks of piston missing above the top ring.  These were .060 over 21253s... the good pistons.

Is this a zzdp thing? We don't know for sure... We did have some issues with the original set-up on the alloy head... the seats were cut very shallow, so the 1.5 rockers had the spring retainers bouncing of the tops of the guides, ejecting the little springs out of the valve seals.  Could a bit of coil-bind occurred?...  we did have a bent pushrod on that initial assembly, but that's not terribly uncommon when setting up the aluminum head... The valves are CAST further apart so you can't obsess over getting your rockers centered over the valves. Production tolerances have the push-rod holes in the head not quite lining up with ones in the block, so very careful set-up is required, and even then it's quite possible to bend a pushrod with slight contact. 

Mascherk you are so right.   

I'm hoping this is leftover steam from the Robster days, but I'm pretty sad to be raked over the coals here for showing something I thought would be merely interesting for everybody.

And Steve, do I really deserve this?

Sorry to share my mistakes.  I've never said anything but compliments about you, sent potential customers to you, and learned a lot from your posts.

And no, detonation was not "the" problem and it is out of respect for others that I'm not sharing what the problem was.

Air2air, you asked for a discussion and that's what you got.

Kelley

Can someone link me to the thread with pictures and text about what happened to your current engine. 

Seems I recall  you killed the first engine with a lean or over advanced condition. Do I recall a story about

over loading the car and running up hill at full throttle? Let's see then you had it rebuilt and it got dumped

in the floor on it's face. Now it's back for a second rebuild and detonation is once again the problem? I guess

you don't know what the death rattle sounds like. I can undersatnd not hearing  high speed detonation on a

race car with open exhaust turning 8000 plus. That's why we are so careful to know where our timing and

fueling are. Building the engine in my car I backed the C/R down to 9.5 to 1. It has been in service for 3 years

now with any luck it will be the last engine this car ever needs. Not knowing what fuel would do I took .7 off my

normal build. I also had Advanced Distributors rebuild and curve my dizzy to match everything I did to this one.

Nick Swift is sending me a new cam that should improve my 650 idle and pull to 5000 smoothly. I will provide

Advanced the new cam info and see if we need to change anything there. I don't think I will be removing the head

to grind slots in the chambers. Steve (CTR) 

That will never happen based on your past experience with him.

We're just a hard-core group hell bent against new-fangled technology!

This would be a great topic for The Lobster!  Come on... we can admit it.... We miss him!   You know he did email me and offered to call and talk to me, but hasn't yet!

I'm rebuilding Todd's engine myself.  Then I will test-run it, and make sure I properly train Todd on it's care and feeding!  Got to get him to loose the big stereo.... there was detonation damage... and it's very hard to sense detonation on these things... what with all the normal noise they make!

There were other issues as well that may have contributed to detonation.  We've gone bigger another .040" to 1362. Maybe a touch lower compression.  Some other refinements too... Hope to test in the next few days!

Tough crowd huh.

Look, I'm not pitching the idea, merely thought it was worth showing... geez guys....

I think the question should be - Todd was your latest engine having an excessive problem with preignition/detonation and ping?

And if so can't that be resolved with a professional tune?

As I recall your first engine had a catastrophic ping problem but didn't that go away after the rebuild?

Looking through the links it appears people started talking about it 9 years ago and stopped about 4 years ago and noone managed to do a dyno test in that time. There also seem to be two cases of great results that later turned into massive detonation. I love the internet...

Kelley

I'm not sure who or how they made this thread 5 ft. wide. Other wise I would try and read it.

It has been always said that a dish piston will make more power than a flat top with same compression. 

I'd be far more interested in the condition of your engine. Little said about for some time. Steve (CTR)

The Mini has fantastic swirl to start with, why confuse things with squish ?

Plus, those itty bitty little grooves will get coked up in minutes...

Darn you nonbelievers!  Check the forum threads above...  Even this Bini guy , this drag racer and this farmer seem to like the results.

Ony after reading the responses of the guys doing it and how many there are, it seemed worth posting at least.

"What it does:  Highly mitigates detonation, pinging and preignition by getting rid of unburned fuel." 

Really?  Who says unburned fuel causes detonation?  On the compression stroke, the cylinder is full of unburned fuel... so I suppose since it's there, it will take part in detonation, but I don't see it "causing" the phenomenon!  Detonation occurs when the fuel quality can't take the combination of the heat (including that caused by compression), and the load (including that caused by a tall final drive under an engine that must spin to make power).  The mixture ignites explosively before the spark we so carefully time for it!  The solution is to reduce heat or reduce load.... unless of course you can increase the quality of fuel... so many variables!  Big brother doesn't want those tasty lead molecules floating around, and most of us won't do $11 per gallon Sunoco.... so back to the two "solutions".  They can be summed up as "reduce power"!

One way this mod works is by reducing compression.... remember, an average head gasket for a Mini has about 3cc volume! For a 20cc(ish) chamber and flat-tops (to make the math easy!) The head gasket contributes 15% of the combustion chamber volume.  Some of those grooves pictured would contribute quite a bit too! 

But let's try it on your head first!  remember there is a water jacket around the combustion chamber.  How deep do you want to cut the grooves?

Kindly keep in mind we're talking about Minis in this context. Obviously, technology allows for some much more refined engine controls now. Modern cars have brought compression back up, and with it, power and efficiency.  And modern superbikes.... My R1 has 12.8:1 compression, and runs just fine on pump gas!

Looks like someone slipped up with the grinder while modifying a head. And, instead of fessing up, duplicated it on the rest of the chambers and called it a "performance improvement". [rolleyes]

I think I'll wait till I see some ACTUAL comparisons on a Dyno. Until then I'll just keep the wirlygig thingy in my intake pipe...........................................

Agree completely BD, on the forum threads people raise exactly the same concern.  The best technical thread is here on hotrodders.