446ci motor

Mossy68 · Post by **Mossy68** » Fri Aug 30, 13 9:35 pm

Cannonball wrote:
Mossy68 wrote:Sorry. Off topic I know but curious about the o rings.
When I built my 1260 motor for my bike I used a fine gauge wire set in a rebated groove with a cometic copper gasket. ( recommended by a drag bike builder )
Worked a treat.
My question is why such a large gauge o ring ? And as Dunc pointed out would require a receiver groove.
Would the system I used not cope with the pressures ?

Sorry for hijack
well in theory you need the groove so as you clamp the head down the gasket is forced in to the groove by the metal o ring i had a mtr with no groove it would not stop leaking water as the head could not clamp down correctly had someone make me a tool that fitted the bore used a cutting tool and made my own groove it worked perfectly after that no water leaks

Cheers Dunc.
Sorry. Should have made myself clearer.

I understood the need for receiver groove with such a large o ring. Just wasn't sure why the ring had to be so large which I think Ade has the answer

Birdman · Post by **Birdman** » Fri Aug 30, 13 10:33 pm

Yes Dunc, I knew you and Pete would pick up on that. Have to see what Rob at ICE suggests.
Compression should be 12.2 with heads at 65cc, but, will have to check as porting will have increased the volume I'm sure.
Great to see comments coming in, plenty of wise heads out there in Mopar land.
Cheers Chris

Cannonball · Post by **Cannonball** » Fri Aug 30, 13 10:50 pm

Birdman wrote:Yes Dunc, I knew you and Pete would pick up on that. Have to see what Rob at ICE suggests.
Compression should be 12.2 with heads at 65cc, but, will have to check as porting will have increased the volume I'm sure.
Great to see comments coming in, plenty of wise heads out there in Mopar land.
Cheers Chris

good luck with it what ever you decide see you at the hrds

terryr · Post by **terryr** » Sat Aug 31, 13 12:28 am

at least with ali heads you will have inserts which will stop the pinking ,,hopefully,,the demon was 12to 1 and with iron heads used to pink like mad when you booted it ,always drove with race fuel mixed ,was spot on then ,but you have ali heads which they say with expansion would bring you down to 11to 1 ,,,,so very streetable,,that's my way of thinking anyway,,

ps don't make your car so lairy its no fun no more,,,,,it happens

mopar_mark · Post by **mopar_mark** » Sat Aug 31, 13 9:13 am

I have ran 'O' ringed heads without receiver grooves without issues, that was with Ali heads, cast block & copper head gaskets.

I made sure the depth of the 'O' ring was machined to leave the stainless material proud of the head, but not greater than the head gasket thickness, but enough to provide force when heads were bolted down.

I forget the wire size & depth, but was pretty close to what the supplier recommended

pete walton · Post by **pete walton** » Sat Aug 31, 13 9:37 am

I had my heads o ringed ,,,,I use felpro gaskets 13.5 compression ,,,no grooves in block with NO issues at all.....

Pete · Post by **Pete** » Sat Aug 31, 13 9:48 am

You have to be VERY careful about machining the "O" rings down, it is VERY easy to pull them out of the head and then you ARE in trouble.......

I personally can't see the point of "O" ringed heads with non-"O" ringed block...you have just made a cookie cutter for the head gasket.

Each to his own..............

pete walton · Post by **pete walton** » Sat Aug 31, 13 9:58 am

I was advised to o ring my heads because of the compression I wanted,,the key here is the thickness of the wire and depth of groove .... On grumpys car the heads are o ringed and the block grooved ,,,,the head gasket is copper ,,,if I can remember correctly the heads are bolted down to 140lbs ...so this is a totally different animal ,,, They say nitrous moters should be o ringed ,that's serious NOS cars ....

Blue · Post by **Blue** » Sat Aug 31, 13 10:30 am

Detonation has nothing to do with static compression, it's dynamic compression which is the key, and that involves the cam duration. If Rob chose the cam it will be fine, he has built many a street eliminator engine with that sort of compression and more, they have to run hard on pump gas.

pete walton · Post by **pete walton** » Sat Aug 31, 13 12:36 pm

Stuff

Mick · Post by **Mick** » Sat Aug 31, 13 2:28 pm

Those heads have a very small chamber, be interesting to see how much timing it likes. The small blocks are around 65cc and they only like around 32 degrees.
If i'm not mistaken, they are a slightly raised head, is it the intake side ?
Alan Knight was trying to sell a set for ages, he kept offering them me but they were a little too costly for my liking.
Mick

Birdman · Post by **Birdman** » Sat Aug 31, 13 9:11 pm

The stainless o-ring is just proud of the head,so, should be ok. Thanks for the further input on this.
Mick the heads have a raised exhaust port needing headers , such, as the ones that fit Indy heads. TTI do them but leaning towards Hedman Husler depending on which car it's going in. Need longer pushrods too, but, have Harland Sharp rocker arms.
Terry, making the Satty difficult on the road is my main concern, as, you rightly point out.
See some of you at the HRD's