[v869tr6]

Looking to run sealing rings dry deck.
No head gaskets.
6.535 rod, yes a short rod
1.53 rod/stroke ratio
1.4 compression height
10.240" deck height
0.180" down the hole, no valve pockets, would be 8.67compression with a 4.25 x 4.25 engine.
Turbocharged 20+ psi boost, approx. 5500 rpm
Solid roller 250 duration at 0.050", 0.585 total lift, 115 c/l

Street/Strip Dragweek combo

[LiL Jack]

NitrousTTF???

[v869tr6]

Originally Posted by LiL Jack

NitrousTTF???

Thanks Jack, I will keep that in mind, LOL

[Tom Vaught]

v869tr6,

Bob and Frank now have Marty's Sealing Rings. That might be an alternative.
They are a solid square cut ring.

Then there are also pressurized gas rings available.

http://www.agemak.com/tr_/pdf/Helico...tal_O-Ring.pdf

We used (at work) a lot of the Helicoflex pressurized gas rings in a lot of our single cylinder engine test engines. Very good durability overall.
They will make most bore diameters in a variety of sealing ring tube diameters.
We used the .090"+ tube diameter parts as they have a lot of cylinder head lift sealing capability.

Tom V.

[v869tr6]

Originally Posted by Tom Vaught

v869tr6,

Bob and Frank now have Marty's Sealing Rings. That might be an alternative.
They are a solid square cut ring.

Then there are also pressurized gas rings available.

http://www.agemak.com/tr_/pdf/Helico...tal_O-Ring.pdf

We used (at work) a lot of the Helicoflex pressurized gas rings in a lot of our single cylinder engine test engines. Very good durability overall.
They will make most bore diameters in a variety of sealing ring tube diameters.
We used the .090"+ tube diameter parts as they have a lot of cylinder head lift sealing capability.

Tom V.

Tom, I ordered the sealing rings from AllPontiac already, Just wondering if the combo above would work?
BBC run way worse rod/stroke ratios
Trying to build a tuff engine.

[Tiger Paw]

I'd try to find another way to dish volume than running the piston .180 down. Seems to me incomplete combustion would result.

[taff2]

No reason why the short rod combo won't work, they will put more side load into the bore walls for sure,but shouldn't be a problem with an aftermarket block.

[mgarblik]

We run the piston .120 to .170 down with a 6.700 rod. This is to achieve a nominal 6.0 CR for nitro. Flat piston. We do run O-rings with a copper gasket which gives us an additional way to raise/lower compression through gasket thickness. No reason the rings wouldn't work. If you haven't done it already, you might want to consider up-sizing the deck fasteners to 9/16". If the heads you are using will allow, that will give you 30-40% more clamping load at the deck.

[73 TRANSAM]

When I got my sealing rings from Marty. He told me to torque it down to 100 ft lbs with moly. He said the Eheads would collapse on anything over 100. I am running a similar combo like yours if I ever finish my project.

[Tom Vaught]

Scott Tiemann actually had a E-head head issue very early on (with removing a lot of boss material on the head bolt support bosses) of the second gen E-heads. This may have been where Marty first saw the Torque issue. Believe several fixes were tried with limited success. Eventually I think the fix was less porting for a few CFM and more boost and actually higher durability of the heads.

Tom V.

[Hooter]

Curious, with a short rod like that, is there any concern with how far the piston is out of the bore on BDC? I ask this question not so much for a race engine, but more a street engine since Ed plans on doing DW with a lot of street miles.

[Tom Vaught]

Would be nice to have the piston length and then we could do the match vs the compression height/stroke, etc. It has been posted before what the actual Pontiac Bore length is on a stock block but I do not have a dimension on a IA-2 block.

Tom V.

[v869tr6]

Originally Posted by Hooter

Curious, with a short rod like that, is there any concern with how far the piston is out of the bore on BDC? I ask this question not so much for a race engine, but more a street engine since Ed plans on doing DW with a lot of street miles.

Good point, my present engine is a 4.5" stroke with a 6.7" rod.
If I add the 1/8" less stroke ( 4.5 - 4.25 divided by 2 ) to the 6.535 rod I get 6.66" so the pin would be 0.040" farther down the bore.
Wonder what the 4.5"+ cranks use for a rod length?

[v869tr6]

Originally Posted by Tom Vaught

Would be nice to have the piston length and then we could do the match vs the compression height/stroke, etc. It has been posted before what the actual Pontiac Bore length is on a stock block but I do not have a dimension on a IA-2 block.

Tom V.

I measured the liner in my alum Ia2 block and with a tape measure it looks like 6.25"
So with 1/2 of the stroke 2.125 added to 3.99" (10.24-6.25 ) I get 6.115" at BDC to the bottom of the liner.
6.535 rod minus 6.115 = 0.420" using a 0.990" pin 0.075" of the pin would be out of the bore at bottom dead center.
Is the math right?

[v869tr6]

Originally Posted by mgarblik

We run the piston .120 to .170 down with a 6.700 rod. This is to achieve a nominal 6.0 CR for nitro. Flat piston. We do run O-rings with a copper gasket which gives us an additional way to raise/lower compression through gasket thickness. No reason the rings wouldn't work. If you haven't done it already, you might want to consider up-sizing the deck fasteners to 9/16". If the heads you are using will allow, that will give you 30-40% more clamping load at the deck.

Thank you for the input, helps knowing running the piston way down the hole is workable!

[v869tr6]

Originally Posted by 73 TRANSAM

When I got my sealing rings from Marty. He told me to torque it down to 100 ft lbs with moly. He said the Eheads would collapse on anything over 100. I am running a similar combo like yours if I ever finish my project.

My E-heads are crushing on the 3 exhaust studs mainly the center one, top hat washers didn't fix the problem, now to press in some chrome moly tubes so I can get down to just the deck part of the head.

[Tom Vaught]

Originally Posted by v869tr6

I measured the liner in my alum Ia2 block and with a tape measure it looks like 6.25"
So with 1/2 of the stroke 2.125 added to 3.99" (10.24-6.25 ) I get 6.115" at BDC to the bottom of the liner.
6.535 rod minus 6.115 = 0.420" using a 0.990" pin 0.075" of the pin would be out of the bore at bottom dead center.
Is the math right?

I did the calculation slightly different but come up with close to the same distance the pin is out of the bore.

6.250" - 1.400" - 4.250" - (0.990"/2) = 0.105" out of the bore.

Tom V.

[73 TRANSAM]

I did that to my Eheads. I spoke to Charlie and I had my machinist press the .120 moly tubes on the 3 exhaust locations. I have the step washers on all the rest. Need this project to get done

[v869tr6]

Originally Posted by 73 TRANSAM

I did that to my Eheads. I spoke to Charlie and I had my machinist press the .120 moly tubes on the 3 exhaust locations. I have the step washers on all the rest. Need this project to get done

Did the tubes break into the exhaust ports? Are the ports ported?

[73 TRANSAM]

Yup, I have the Butler wideports. The machinists knurled the tubes before pressing it in. He said no way it will leak and he milled the tubes a little higher than the surface. This way it can sink a little and not crush the head. I cant wait to get done, waiting for my headers. I finally got a TIG and will fabricate the rest when I get my turbo headers.