tacker

There was a project done by the Capricorn group/ perfect bore where they screwed the cylinders into the heads to create a much improved seal. I never found any test results of the arrangement.
I currently have a mold expert working with me and I'm kicking around the idea of casting a couple sets of heads. My thoughts are to make the heads .3 taller but have the liners screw in and have a 2 piece cylinder cooling fins.

I will most likely use the 996 liner and turn the flange into a threaded section.

In order to get things started I need the model all the factory parts.

Does anyone have a cylinder and head that I can model up. They can be scrap parts I just need to be able measure surfaces. I would need them for a couple months.

Any help I can get would be much appreciated

Basal Skull

Have cylinders but no heads... you're welcome to them if you can use them.
Seem to recall reading about the screwed in heads too.

Basal Skull

Are you experiencing a leak?

tacker

No leak or problems. Just building a better part.
thanks for the offer on the cylinder I'll keep you posted
mike

Bradford

Verden has a set of 993TT heads. You can check with them to see if they would loan you one. Same as Basal here, I have a set of cylinders if you need to borrow them. They are 3.8 Wossner cylinders.

MarinS4

A welded and flame ringed 993tt head is pretty stout. Once that's done the weak link is the air cooled limitations IMHO. Even with E85 CHT's will ultimately limit power capability. Not head sealing.

tacker

Bradford, I will check with Verden. Thanks for offering the cylinders.
I'm waiting on a multi channel Amplifier to show up so I can monitor all the CHTs.After some WOT testing I should be able to determine the heat capacity the engine has for my power level.

In the meantime I would like to model the parts to see the feasibility of doing a screwed in steel liner.

MarinS4
I have the heads welded and flame ringed and no problems so far. If not the Head Seal, what do you think the failure point would be when temps are approx 450 CHT for 1 minute. Random numbers,
dropped valve seat? oval cylinders

The RR350 material is very good but maybe 2618 in wrought form would be a good choice.
Just kicking around ideas

MarinS4

When CHT temps sky rocket detonation to be my primary concern. Even race fuel has it's limits. With that you knock out rod bearings, lift heads and peel back the upper ring lands of the pistons.

The barrels are made with a slight taper so when at operating temp they will be square. Taken to the further extreme I imagine the piston would get sloppy in the bore. Maybe it would pull more oil and increase detonation changes?

The RR350 material is good for this application. Is 2618 better? That's a tough question. There is a LOT to consider than just strength. I for one would not want to take on that engineering task.

Not sure what you're up to but given your location maybe it's Texas mile stuff. IMHO run E85 and tune around max CHT's. Whatever that yields is what you get. Going beyond it will be very expensive per HP gained. If that's your goal I would focus on water cooling the heads before trying to find a better sealing method. Just watercooling the exhaust port would help a ton.

tacker

Definitely a big project that will take quite some time to engineer. My thoughts are,first model the parts then start looking at concepts to improve the head seal. I will definitely look into water cooling jackets around the exhaust port.
Even Onthe 996 platform big power engines have had issues with head seal. They go to Evoms 12 mm studs and some studs require a re-torque after the engine has broke in.

Wouldn't this concern be eliminated if the cylinder screwed into the head?

Many steps in a project like this. I'm thinking after modeling and playing around with concepts I will find some configuration that inspires me to start cutting.

I need to find a head to barrow for modeling

Basal Skull

I know you are a master welder Mike, and although it would be a problem if you need a rebuild, and more difficult to assemble, but can you just weld the heads to the cylinder?

MarinS4

I was going to suggest the same but did not want to get stoned off the island. All joking aside a small weld bead on the two weak sides would be all that's needed.

tacker

I know you could just weld the two together but the parts would need to stressed relieved after the weld and would be hard to reuse the parts if needed. The best thing to do is to make a batch of heads and maybe weld them to the cylinders. Maybe a disposable component design. After the design and programming is done the real cost is in the valve seats,valves, springs.
I still think using a screw in liner is a better solution than welding.
When I model a decent concept I'll share for a healthy discussion.
I plan on modeling as soon as I can get a cylinder head in hand. Working on some local leads

buildandtune

Hi My name is Scott. My website is buildandtune.com
If you are still looking for someone to weld your heads- please send a few jpegs and your ph# I will be happy to comment. scott