ALL RAT Engines are based on our brand new head castings with either or CS, RS or LE port and chamber profiles. We do not offer any engines with old, junk, 40-year-old heads like our competitors. We also offer some of these head profiles to non-engine purchasers; read below.
Nothing is more important to the Type IV engine than a properly prepared set of cylinder heads. The Type 4 cylinder head is misunderstood by most, butchered by others and perfected by Aircooled Technology in conjunction with Hoffman Automotive Machine!
Len Hoffman of Hoffman Automotive Machine is our head technician. Len has years of experience with the Type IV cylinder heads and with our working relationship we have configured the best cylinder head packages ever arranged for the Type IV engine. In years past the Type IV engine gained a bad reputation for having head related problems, and with developments and refinements Len and I have solved all those problems- No more dropped seats and no more valve failures- period!
It is never ending… The calls and complaints and failed engines that we see from misconfigured heads that have been worked with by less than knowledgeable persons! Most issues concerning the type 4 cylinder head are the direct result of a human being that didn’t care enough or wasn’t lucky enough to have the experience that is demanded by the Type 4 cylinder head!
Many people make the mistake of confusing the Type 4 head with any other aluminum head, those that are “lost” the most compare the Type 4 head to the Type 1- yet the two share literally zero in physical dimension or the thoughts and ideas and even procedures that are a necessity to properly manipulate them into solid, reliable performers. Hell, these days most shops can’t even be trusted to make simple repairs or even do a valve job on a Type 4 head!
A few days ago I was visiting an online forum that I frequent and saw a post from an individual that had just received his spit-shined cylinder heads back from a local professional. I was absolutely amazed when in his posted photos there was a very significant void in the combustion chamber of one of the heads! The worst part of it was the fact that this was visible to the naked eye, yet the “pro” told him that “It would be okay, just don’t remove the exhaust stud that’s under that hole”!!!!! Blasphemy!!!
Issues like these are why we no longer complete procedures on used cylinder heads and also the reason why we have persevered with the development of our “Leading Edge” cylinder heads that you will read about within these next few pages of information.
These cylinder heads are the answer to the shoddy rebuilds and head cores that HAVE BEEN CYCLED FOR THE PAST 30 YEARS OF ABUSE, NEGLECT AND OVERHEATING! Nothing makes a Type 4 engine like a brand new head casting, especially one that has been fully rebuilt right out of the box to the tolerances created by the leading Type 4 developers in the world!
So…. what makes our cylinder heads so much different than the rest????
Below I will break down many facets of our cylinder head program that puts our head program in a totally different classification than any other.
1. Direct benefits of in house testing to offer back to back comparatives concerning the effects of material and procedural alterations.
2. Direct Benefits of using our components in our Racing Applications
The exact same components that are used in ALL of our cylinder head offerings are also used in the Aircooled Innovations Racing Porsche 914-4 race engine. This includes valves, valve springs, valve seats and all other major components! We have been known to run 23 consecutive races (two seasons of SCCA competition) with these same components without a single failure. Keep in mind that this engine spins as much as 8,500 RPM for 30 solid minutes. What does this mean to you??
Well, even if you want a low compression, low-speed engine for your Bus or a high CR Performer engine you can know that the components that are used to comprise your cylinder heads are completely overkill engineered.
3. Material and hardware selection
Replacing the 30-year-old heads with new components is just plain smart and that’s why we do it as a standard. Trying to build an engine that’s based on a 30-year-old head would be equal to painting up an old house that’s full of Termites and rotting down- it’ll work, but not very well and not for very long!!
4. Valve Seats
5. Valve Springs
6. “Better” Springs
Retainers-It’s the job of the “retainer” to do just that, Retain! These very simple but very important parts play a big role in valve control and engine failures.
Retainer failures generally allow the engine to “swallow a valve” as the valve keepers are generally pushed through the center of the valve retainer allowing the valve to simply slide right through the retainer and into its meeting place with the piston, in the combustion chamber. This immediately creates a catastrophic failure and wastes the engine.
When RPM demands lighter and stronger components we offer Titanium retainers as well.
Even our lowest performance offerings right up to some full race, 8,500 RPM beasts feature stainless steel valves and the stock valves that come new in the heads when we receive them new, are removed and trashed as they are substandard.
Our most extreme cylinder head offerings, the LE 220, LE 230 and our Billet “Ultra” heads come with proprietary valve options that open up new doors for RPM levels.
The fact is that valve guides are THE BIGGEST wear item associated with the cylinder head! This is mainly because they are made of softer material than the valves they are supporting and sometimes with improper valve train geometry their wear is accelerated. With worn valve guides, valve jobs are short lived and oil consumption and crankcase pressure is also elevated, both of which impede performance and tuning.