Dauntless 225 Engine Parts Suggestions

So what is the difference CC wise between the two heads?

 

MEEP 3B,
Well I certainly see nothing wrong with a little experimentation.
Excepting trial and error methods how else can we learn ?

By far most relatively modern engines that fit well into Jeeps tend to run about 8.7 or 8.9 CR.
That's just a tad low in my mind thinking it may be wasting away a slight amount of the 87 octane.
The GM 181 I-4 engine has about the highest standard CR I've seen in a Jeep replacement engine.
They are generally around 9.5 to 1 CR.
I don't wanna run any smog equipment and definately want to stay below 9.5/1 CR due to greenhouse gas emissions.
But mine is definitely intended as a daily driver and not just for recreational use-age.
9.0 just happens to be the perfect CR for my daily driver needs.
That's why my next 2 Jeeps will have standard Dauntless engines.

But please carry on with your experimental Dauntless engine and let us know how it turns out.

 

It looks like the stock 225 heads are 45CCs
The 231 heads are 41CCs with the stainless dished valves from TA Performance.
With the stock flat valves it was around 39CCs, I think.

Most of the replacement pistons for the 225 have a 8.5 CR target. EGGY is one of the few 9.0CR available.

EGGY has a high compression piston that ran the CR up to 10.93 with the 231 heads and flat valves. Too much. That is when I went back to the 9.0CR pistons.

 

Thanks, I only have the KB No.1 manifold installed. The heads are from the 231.

I have been driving the engine, but I have a funny (disturbing) noise that I haven't been able to pinpoint yet.

The adventure continues...

 

How did you get to those Compression ratio numbers in your motor?

The only true way to accomplish that is by taking any piston to TDC.......seal the ring area at the top of the piston to the cylinder wall with wax......do the same around the valves ..........clamp the head on with the correct gasket , torqued to spec and do a total volume CC pour using green alcohol and a CC Burette like pictured below through the spark plug hole.....but only to the base of the threads , of course the motor has to be on an engine stand and rotated to get the spark plug hole vertical....................no other way to get true compression ratio other than doing a total volume pour on the engine as assembled...........with that info and the bore and stoke you can do a swept volume calculation that will get you within a tenth with no more guessing............

On your squeaky noise have you pulled the covers off while running to see if the rockers are getting adequate oil? Remember your early block oils through the block which I assume you plugged off , whereby the later heads are getting oil to the overhead through the oil galleys to the push rods...........which requires some mods to those early galleys to oil like the later block.

 

Well... I relied on my pro engine builder to apply his expertise. He calculated;
Sweep 622.06
head 41.0
piston 16.0
deck 6.2
gasket 8.2
= 9.71CR

On the precise method he came to these numbers, I'm not sure.

It sounds like your method is the most accurate if you can avoid introducing an air bubble in the dish of the valves.
But, I'm not the expert. And I think this was an effort to get as close as we can to find an acceptable range. I do have around 200 psi compression.

As far as the valve oiling, we plugged the block oil orifice. The oil travels through the front cam bearing galleys, the lifter oil galleys, through the lifters, pushrods and out on the rockers. I have removed the valve covers, and in my opinion, witnessed adequate oil flow, but not excessive flow. I have also squirted additional oil to check for any change, nothing. I have also confirmed push rod lengths, lifter bleed down rates, and rocker play with no discrepancies noted. But, there has been no other modifications to the oiling system. My oil pressure at idle is high, around 40 psi, hot.

There has been some discussion about the "down ramp" angle being very steep on this particular cam grind making it noisy. I don't think this mild lift cam would have this problem myself.

I have been concerned that the noise is coming from my new timing chain or tensioners. There doesn't appear to be any looseness in the chain rotation as noted through the distributer rotor , but I did notice a slight flop in the spring tensioner when the engine is rotated counter clockwise when viewed with an inspection camera through the fuel pump opening. Thinking that the tensioner may not be seated on the tensioner bolt shoulder correctly.

Thanks for your thoughts on this.

The quest continues...

 

Looking at your math..........with the numbers supplied assuming it's still a 225 ci motor I agree its somewhere around 9.6:1...........

200 lbs of cranking compression also seems high........but then again I have no Idea what that cam grind is nor whether it's installed straight up or advanced a degree or two?...................Higher cylinder / cranking pressure also means that you will need more octane to slow the burn rate down in the cylinder. Which in turn can also cause detonation or a rattle which might be the noise your hearing.

On your Idle oil pressure that also seems high at 40 psi Hot.........the last one I did I spent a ton of time in the oil galleys , pickup and getting the pump gears and end play correct ....it Idled at 22-25 warm.......which for an average 225 is on the higher side , but just the same in a range that I feel is appropriate for this type of motor.

Which again may possibly relate somewhat to your complaint of noise in the motor as in some instances..........................High oil pressure is just about as bad as low pressure.......as pressure increases , the oil is forced by the part.or bearing much quicker............which can degrade the oils ability to fully lubricate and draw heat away from the surface............

Have you pulled your filter and cut it open to see if you have any metal in there or had the oil analyzed?...........that might tell you if the ticking is something more serious.

Enough said.............Return to your Regular Programming

 

The cam is a pretty straight forward mild grind and no advance.

You mentioned that there might be some other mods for the new oiling path. Do you know of anything special? I have done nothing special other than the pushrods, lifters and the stock rocker assembly.

I have noted the high oil pressure and have been concerned that it might stress the oil pump and cause some noise. The engine builder doesn't think there is a problem.

I have checked the filter and haven't found any metal.

I have also thought that my noise might be a result of the high compression. I have added some octane booster to premium gas with now changes.

To briefly describe the noise, There is no noise on a cold start up, the noise increases as the engine warms up and is driven. The noise changes from a little to louder during acceleration and is loudest after the engine is driven for a few miles. The noise is loudest at a stable cruise rpm of around 1800 RPM and on deceleration.

Thanks in advance for you thoughts.