New service available at Supertec

[Henry Schmidt]

New service available at Supertec. We are now offering to bore your 47mm cam towers out to 49mm.
We can do this on 3 or 4 journal cam housings. 47 mm, 4 journal housings require an oiling modification.
For a street car with low lift cams, 3 journal housing will work perfectly well with a 4 bearing cams.
We did deflection test to verify the conclusion.

We offer a complete cam tower restoration including cosmetic restoration, stud removal & plating or replacement, resurfacing of sealing surfaces and oil tube cleaning or removal and replacement.

We can also convert 964 or 993 cam housings to use external cam feed lines to retrofit on early cases.

[Old H2S]

Nice..Can you make the cam flange bigger so I can run cylinders without base shims?

[Henry Schmidt]

Originally Posted by Old H2S

Nice..Can you make the cam flange bigger so I can run cylinders without base shims?

Honestly, I don't understand your question.

[Old H2S]

When you remove the cylinder base shims the cam towers do not line up with the chain boxes so the 3" O ring is not compressed evenly and they will leak, oil runs down the bottom edge of the cam tower. The back of the engine is higher than the transmission side and the oil drip runs to the front and falls on the front of the heater boxes looking like a leak at the front of the engine when the leak is really at the chain box to cam tower joint.
So yes, I'm a hack and did not build the engine to Rolex spec's but I have 200 PSI static compression with a small cam and it runs great.
A bottle of AT-205 has stopped the leaks but it is a hack so when I buy some correct cams from you for a 3.2 short stroke Weber engine I can have the cam towers done right. Thank you for this service
it is needed and I have been worried about age and wear on them.

[callard]

I usually just skim some off the bottom of the chain boxes to match.

[Henry Schmidt]

Originally Posted by Old H2S

When you remove the cylinder base shims the cam towers do not line up with the chain boxes so the 3" O ring is not compressed evenly and they will leak, oil runs down the bottom edge of the cam tower. The back of the engine is higher than the transmission side and the oil drip runs to the front and falls on the front of the heater boxes looking like a leak at the front of the engine when the leak is really at the chain box to cam tower joint.
So yes, I'm a hack and did not build the engine to Rolex spec's but I have 200 PSI static compression with a small cam and it runs great.
A bottle of AT-205 has stopped the leaks but it is a hack so when I buy some correct cams from you for a 3.2 short stroke Weber engine I can have the cam towers done right. Thank you for this service
it is needed and I have been worried about age and wear on them.

Is this what you had in mind?
We made these spacers when we made the peanut heads. We milled the heads to create the smallest combustion chamber as possible.
These were an .080" thick. They were cut with a laser but I guess water jet would work as well.
Milling the chain boxes could work but changing the engine dimension has it's issues. Extra chain slack is first, things like fan shroud is next.

[Old H2S]

My son ran off with my milling machine..

[PeteKz]

Tom: Last time I built my 3.2 engine, I left out the base copper gaskets to get the piston closer to the head. I recall that there was enough slop between the O-ring carrier and chain boxes to allow it to center on the cam. No leaks there on my engine.

[Old H2S]

The chain slack is solved with Stomski solid tensioners and work fine for street use with no noise and are smooth IF you set the the gap to 3mm. Steve says 1/16" and that is too tight and makes noise. I beat the crap out of this engine every day as my beater car. That might have caused the leak which is my fault. I have done the 3.2ss with Nickies and a 2.4 with Mahle and they are both leaking at the same spot?
The 3.2ss I did 3 tear downs on because of the RMS fiasco with the Elring RMS being undersized, I was able to push in with light thumb pressure. That engine was spit shined by the time it was done with no nicks, burrs or old parts out of spec. I am keeping the old parts now off of the engines now for repair and improvement because the new parts are having more problems.
Having this service available now is a key part rebuilt for the future of these old engines. Some of the engines from MotorMeister I have rebuilt were an abomination of different parts, cam towers being the most beat up inside and made me say "how could that thing run"
Pete I sent you an email a while back, dig around in your spam folder..

[Henry Schmidt]

Back on topic please. The scarcity of 49mm cam towers facilitated the need for this service. With new cam towers exceeding $2K each and the plethora of early cam towers on the market, this new service allows us to dodge another parts issue.

[Henry Schmidt]

Originally Posted by Old H2S

The chain slack is solved with Stomski solid tensioners and work fine for street use with no noise and are smooth IF you set the the gap to 3mm. Steve says 1/16" and that is too tight and makes noise. I beat the crap out of this engine every day as my beater car. That might have caused the leak which is my fault. I have done the 3.2ss with Nickies and a 2.4 with Mahle and they are both leaking at the same spot?
The 3.2ss I did 3 tear downs on because of the RMS fiasco with the Elring RMS being undersized, I was able to push in with light thumb pressure. That engine was spit shined by the time it was done with no nicks, burrs or old parts out of spec. I am keeping the old parts now off of the engines now for repair and improvement because the new parts are having more problems.
Having this service available now is a key part rebuilt for the future of these old engines. Some of the engines from MotorMeister I have rebuilt were an abomination of different parts, cam towers being the most beat up inside and made me say "how could that thing run"
Pete I sent you an email a while back, dig around in your spam folder..

The better way to deal with the chain slack is to replace the idler gear with a larger Mercedes sprocket. Solid tensioners put way too much load on the chains and sprockets and can even damage early mag cases by overloading the intermediate bearings.

[Old H2S]

I used new Iwis heavy duty chains, they were a tight fit from the beginning, plus new shafts, and sprockets and had all parts DLC coated in the engine. After 20k miles the chains have not grown at all, and to Pete's chagrin I check them every oil change. I am retired living in the best fishing spot in the world and I got this parasite on my brain from Germany..After I left PNA in 1982 I swore I would never touch another 911, but they inserted the bug and I mess with these cars every day with my wife kicking me in the ass to go fish.. Life in Buxton
Last night.

[Neil Harvey]

Henry,

Question, why the need to modify the early housings? Why not cut the 49.00mm cam journals down to 47.00mm and modify the grinding sheets for the 49.00mm designs to fit the smaller journal cams. This is my approach so we can offer more modern A symmetrical cam designs for the earlier engines.

Many ways to approach the same problem. Interested to know why you decided to go your way?

[Henry Schmidt]

Originally Posted by Neil Harvey

Henry,

Question, why the need to modify the early housings? Why not cut the 49.00mm cam journals down to 47.00mm and modify the grinding sheets for the 49.00mm designs to fit the smaller journal cams. This is my approach so we can offer more modern A symmetrical cam designs for the earlier engines.

Many ways to approach the same problem. Interested to know why you decided to go your way?

The need to modify early housings comes from the fact that late housings are getting rare and expensive.
49mm cams offer a larger base circle for any given grind. This larger base circle creates better rocker geometry. The 3.0 and larger heads even have shorter valve stems. If you run 47mm cams on a 3.0+head the rocker geometry turns to shyt.
Of course you could make special, long stem valves to compensate for the smaller base circle.
47mm journals limit the amount of lift you can generate and still have a base circle of at least 1.120". Even at 1.120" the rocker adjuster is sticking out way too far.

EDIT: as a side note, there are 47mm 4 journals cam towers that were parts of the transition period 75-77. The 3.0 Carreras and 3.0 turbos (49mm) used the same castings as the 2.7 (47mm) so boring them is a no-brainer.

[Neil Harvey]

Henry,

Understood, to a point but, not quite sure I understand completely. You do this so you can use existing 49.00mm cam lobe designs, I assume?

As an engineer I question everything. But when I put on my marketing hat, I look at what others do and say, that's a good idea, why didn't I think of that?

There are many ways to do this work. The more that get involved in giving new and better solutions the better for all.

We approach this stuff from another direction. We modify the grinding spec's of our 49.00mm cams for 47.00mm journals which does change the base circles but not the lift nor the geometry. When you design the lobes it opens up another way of supplying some of the latest 49.00mm designs for the earlier engines without modifying the cam decks or using older lobe designs

These early heads do not flow a lot so large lifts and durations are pointless.

I'm not well versed in these early engine as some others are so when we get involved in such ventures we do all of the engineering required to make the result successful.

[Henry Schmidt]

Originally Posted by Neil Harvey

Henry,

Understood, to a point but, not quite sure I understand completely. You do this so you can use existing 49.00mm cam lobe designs, I assume?

As an engineer I question everything. But when I put on my marketing hat, I look at what others do and say, that's a good idea, why didn't I think of that?

There are many ways to do this work. The more that get involved in giving new and better solutions the better for all.

We approach this stuff from another direction. We modify the grinding spec's of our 49.00mm cams for 47.00mm journals which does change the base circles but not the lift nor the geometry. When you design the lobes it opens up another way of supplying some of the latest 49.00mm designs for the earlier engines without modifying the cam decks or using older lobe designs

These early heads do not flow a lot so large lifts and durations are pointless.

I'm not well versed in these early engine as some others are so when we get involved in such ventures we do all of the engineering required to make the result successful.

"large lifts and durations are pointless" ? hummm
I do it because early 47 mm cams don't work well (if at all) on 3.0+ heads.
Also, of course, cam tower bores are a limiting factor on cam lift if base circle consistency is import. Ask any cam grinder if small base circles are a detriment to 911 cam design.
I find it hard to believe that you don't understand the negative results created by small base circles no matter how "magical" your new cam profiles might be.

[PeteKz]

Originally Posted by Old H2S

Pete I sent you an email a while back, dig around in your spam folder..

Tom, I just checked my junk mail and did not see a message from you. Did you send that to my personal @iCloud.com address? I will send you a PM now

[Henry Schmidt]

Originally Posted by Neil Harvey

Henry,

Understood, to a point but, not quite sure I understand completely. You do this so you can use existing 49.00mm cam lobe designs, I assume?

As an engineer I question everything. But when I put on my marketing hat, I look at what others do and say, that's a good idea, why didn't I think of that?

There are many ways to do this work. The more that get involved in giving new and better solutions the better for all.

We approach this stuff from another direction. We modify the grinding spec's of our 49.00mm cams for 47.00mm journals which does change the base circles but not the lift nor the geometry. When you design the lobes it opens up another way of supplying some of the latest 49.00mm designs for the earlier engines without modifying the cam decks or using older lobe designs

These early heads do not flow a lot so large lifts and durations are pointless.

I'm not well versed in these early engine as some others are so when we get involved in such ventures we do all of the engineering required to make the result successful.

Well Neil, I think your confusion is based in concentrating on camshafts rather than cam towers.
There are plenty of camshafts of every description available. This is not about putting 49 mm cams on early engines. It's simply about supplying 49 mm cam towers during a time of scarcity. Like many other engine builders, we are finding more and more cam towers usable for various reasons and finding "good" 49mm cam towers at a reasonable price is hard. There is an over-abundance of 47mm cam towers available making this repurpose financially attractive. The 47mm cam towers are not suitable for 3.0+ engines without this modification.
That's it.

[Henry Schmidt]

Originally Posted by PeteKz

Tom, I just checked my junk mail and did not see a message from you. Did you send that to my personal @iCloud.com address? I will send you a PM now

Pete and Old H2S, let's try to stick to the topic of the thread.

[Neil Harvey]

Henry,

First off, I would not call our Camshafts magical. Modern would be a better choice of wording.

Typically PD supplies camshafts on new billets. These are getting harder to find. They are available in both 47mm and 49mm but when the demand is for 49mm we stock these and when required cut down the journals to 49.00. This also gives us more scope with the lobes.

I suggested that the early air cooled heads do not flow a lot so cam designs that have large lifts and durations make little sense. Not that lifts or durations do not. Read the email in its full context.

The late Cam housing can be repaired. The common fault I have seen are the rocker shaft bores damaged. We have repaired these in the past.

I have commended you on your work in the past and supported you. In my last email I suggested that the work on the 47mm cam housings was a good idea and something I wish I had thought of.

This forum is not mine or yours to own opinions or facts. It for anyone who wants to participate. The more the better. I am too busy with other projects that I cannot think of everything that can be done to make these engines better. Many have contributed with ideas and products. Hopefully more will do the same.

I come here to ask questions when I do not know. That's the engineer brain in me. I am happy to offer my way of doing things but never suggest mine is the only way. If I can be of help, or open and widen the thought process of the DIY and shop, I'm happy to do so. I have been privileged to learn from some of the best and work in the engine business at the very top.

Giving back is an opportunity to offer support to those that have the same passion but not had same opportunity. Its my pleasure to do this.

I thankyou for your input here as many do and offer my sincere hope that you continue to do so.
You are hard work and as others have suggested show an underlying sense of hostility, so I'm going to pull back from adding to your posts and focus on my own "air cooled developments".

Good luck in the future.