does every one still oring there blocks.

we are putting together a new motor and all of our blown alcohol blocks have been oringinged in the past. i have guy at a machine shop who is telling me that it is old school and they dont do that any more. He is saying they use these special kenetics head gasket. This is a BBC , 14-71 blower with 30 lbs of boost. Am i to believe this?

 

Cometic head gaskets vs O-rings and copper gaskets

The "search" feature here works good, here are some good posts already discussing the topic. Looks like plenty of guys have unsuccessfully tried using Cometics. I'd be careful about listening to your machine shop guy, maybe find a machine shop more experienced in blown alcohol motors.

http://www.insidetopalcohol.com/showthread.php?t=25231&highlight=cometic

http://www.insidetopalcohol.com/showthread.php?t=23203&highlight=cometic

http://www.insidetopalcohol.com/showthread.php?t=21447&highlight=cometic

Good luck
Chris

 

Certainly people are trying and doing many things. But my opinion is that an o-ring is still the most common.

I'm kind of stuck now because of block and head interchangeability but, if I was starting from scratch, I'd put the wire in the alum head and the receiving groove in the sleeve or in my case the cast iron block.

 

thank you guys

 

Certainly the movement is away from O-rings in most applications. And because it has in big engines, nitrous and mild blown applications, people immediately think it is better in every application. But when you are dealing with that much boost on that much of a blower, certain deals just don't beat the old standard. Although, if you have a nice solid iron block, you can run the ICE Titan deal from SCE and they work pretty nice against that much boost wihtout O-rings.

 

I am not an expert but the reputable people I have spoken to favor the o ring on the block and head.Mine are both done Rodeck block and solid head,and have had no problems at all in that area.Our spare motor is solid heads and a Dart iron block and were going to try the route your thinking of,the gasket people say it will work fine the old school people are a little shy.
Rick

 

Perhaps your local machine shop is building turbo LS1 motors using MLS type head gaskets, these are working well on 400 inch LS turbo street motors with 1000 hp. See LS1tech.com for info on the MLS gaskets, but again, they are on 1000 hp wet block wet head street cars, not 2000 hp drag engines.

I understand why the street race engines are moving away from o-ring & copper gaskets. I went the old school version on my 496, coolant leaks don't appear to be stopping, so I just keep on adding more Bars Stop Leak...

 

Put O ring in head

O ring the aluminum head, put the receiver groove in the block. you will have a sharp edge in the block for the gasket to seal against. if you do it the other way around the receiver groove in a aluminum head will gradually flaten out and will not have the sharp edges to seal against.

 

I agree 100% with the ring in the aluminum and receiver in the cast iron not only will it round off often the "points" where the cylinders meet will fracture.

Lots of people running coolant and copper gaskets have suffered coolant leaks so they have switched to MLS. In my experience the cause of most of these leaks is that these people are running an iron block and aluminum heads these materials have dissimilar expansion rates and the head slides back and forth on the block, because of this you need to run either a nonhardening sealant or a preapplied bead sealant ( Like on the titans although I much prefer nonhardening sealant) the sealant of choice in my experience is Hylomar° sealant. The other problem of course is poor machining of both the o-ring grooves as well as the receiver grooves, I can not tell you the number of times I have seen posts where a guy says his o-ring protrusion is .006 and his reciever groove depth is .012 or something of that nature, then of course you have problems with misalignment.

My feeling is the vast majority of these people would be fine with just the o-ring in the block and leaving the heads flat a couple of coats of spray hylomar° and they would be good to go.

If anyone is using or going to use the MLS gaskets its pretty much of a pain in the ass. You need ensure that the head and block are both flat and very smooth, then clean them thoroughly with brakleen and a paper shop towel. Now take the gaskets and drill the rivets out that hold the layers together and apply sealer to all of the surfaces and reassemble the pieces and install and torque to spec.


Although the MLS will seal pretty well when prepped in this fashion it still is not close to a ring and groove deal done correctly particularly on a dry block and head deal. One of the benefits of the copper gasket is how well it transfers heat between the surfaces. The other big difference is if the head ever does lift slightly due to detonation the copper will soak heat a lot better than the thin steel shims and also will melt at a lower temp between these two properties you will be a lot less likely to torch the head and block or if you do the size of the canyon will be less.


Lastly more and more people are switching to FelPro MLS and staying away from Cometic MLS.


Richard G

 

FelPro is my choice. I like them better than the actual Cometics.

 

thank you

thank you guys....im going to stick to the o ring and find a new shop to do my blocks or buy the tool from isky and do it myself

 

Looks like Isky's cutter only goes upto 4.375 bore, are there bigger ones?

 

adapter

you have to buy the adapter for bigger bores....50 bucks i think