Any thoughts on these heads for 2.4?

**pcrussell50** · 07-29-2022, 01:42 AM

These heads: Pro's and cons versus the older two piece heads?

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Any idea what these carbs are?

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-Peter

**RNM018** · 07-29-2022, 11:52 AM

These where the early lost foam process . I have had a couple of the leak through the combustion chamber into the water jacket causing over heating issues . I'f I have the option , I personally prefer the 2 peice heads an a 2.4 and the ones marked with the casting # 3 1/8 indicating there off a 2.0 liter 135 / 150 hp motor which will give you 150 ps1 compression on a 2.4 200 .

Rich Martin 018

**pcrussell50** · 07-29-2022, 12:26 PM

Originally Posted by RNM018

These where the early lost foam process . I have had a couple of the leak through the combustion chamber into the water jacket causing over heating issues . I'f I have the option , I personally prefer the 2 peice heads an a 2.4 and the ones marked with the casting # 3 1/8 indicating there off a 2.0 liter 135 / 150 hp motor which will give you 150 ps1 compression on a 2.4 200 .

Rich Martin 018

Thanks for the heads up. Why do you think that is? Warpage? Or Casting flaws?

I have a couple of sets of two piece 2.0 heads, but I would worry about 150psi since this would be a simple recreational/family boat motor using pump gas.

How hard is it to find two piece 2.4 heads?

-Peter

**rgsauger** · 07-30-2022, 12:36 AM

Those are what I run. One piece. Never had a problem. Mine are cut so I’m around 145-150 psi

**pcrussell50** · 07-30-2022, 12:54 AM

Originally Posted by rgsauger

Those are what I run. One piece. Never had a problem. Mine are cut so I’m around 145-150 psi

slight diversion… how big/heavy is your boat? And do you run pump gas? And how much rpm do you run? Any more than 5800?

-Peter

**pcrussell50** · 07-30-2022, 03:46 PM

Deleted

**tlwjkw** · 07-30-2022, 04:02 PM

ran tha two piece at several different comp numbers as high as 220 + o-ringed on 2.4 blocks for years.. no problems.. one piece showed up in '87 i think.. did same with no problems..

**rgsauger** · 07-30-2022, 11:13 PM

My Shadow is pretty light. Not sure on weight. I turn 6500 or so. Run 93 octane every single tank. 40:1 on penz XLF.

**pcrussell50** · 07-31-2022, 04:26 PM

Originally Posted by rgsauger

My Shadow is pretty light. Not sure on weight. I turn 6500 or so. Run 93 octane every single tank. 40:1 on penz XLF.

Damn! 6500? On a stock rotating assembly? What prop pitch? And I guess the chrome bores are up to it too?

-Peter

**rgsauger** · 08-01-2022, 12:33 AM

A 2.4 will turn 6500 all day. That’s a 26 pitch. The 2.4 200s came with metal cage bearings. A bunch of these same motors get turned 8k+ in drag racing

**pcrussell50** · 08-01-2022, 09:40 AM

Originally Posted by rgsauger

A 2.4 will turn 6500 all day. That’s a 26 pitch. The 2.4 200s came with metal cage bearings. A bunch of these same motors get turned 8k+ in drag raising.

damn! These motors get more and more badass by the minute. Loving this learning journey.

-Peter

**RNM018** · 08-20-2022, 05:01 PM

Casting Flaws . The lost foam process they used looked t
like a styrofoam and was very porous . The combustion gas would leak straight into the water passage .

Rich Martin 018

**rgsauger** · 08-20-2022, 11:24 PM

Originally Posted by RNM018

Casting Flaws . The lost foam process they used looked t
like a styrofoam and was very porous . The combustion gas would leak straight into the water passage .

Rich Martin 018

wow, first time I ever heard that. Interesting

**tlwjkw** · 08-21-2022, 02:57 AM

Originally Posted by RNM018

Casting Flaws . The lost foam process they used looked t
like a styrofoam and was very porous . The combustion gas would leak straight into the water passage .

Rich Martin 018

????????.............. what did you use instead?