Engine Heads in or out of car

[Dontknowchit]

I just wanted to hear folks experiences with replacing heads with the motor pulled vs. doing it motor in car. I know pulling the motor is not too bad of an job but I would likely need to borrow a picker and a stand to do it. Just seeking wisdom from others with first hand experience.

 

[Noobz347]

If you're only going as deep as the heads, I would [Pull the hood] and leave the engine in the car.

 

[89ripper]

Yeah ive replaced heads with engine in car. Just have to get some stuff out the way. No biggie

 

[General karthief]

Lets get a little deeper into this, original oil pan gasket? Timing cover/water pump gaskets original? A lot of miles? Any seepage?
If you feel nothing else needs attention then swap the heads in-car.

 

[Dontknowchit]

Lets get a little deeper into this, original oil pan gasket? Timing cover/water pump gaskets original? A lot of miles? Any seepage?
If you feel nothing else needs attention then swap the heads in-car.

It's a recent rebuild. Not a lot of miles on the rebuild but a few years. Just thinking on "the next thing"

 

[Noobz347]

It's a recent rebuild. Not a lot of miles on the rebuild but a few years. Just thinking on "the next thing"

Translation:

Contemplating boosting the out of this thing and wonder how much ass-pain the head gaskets will be.

 

[nickyb]

Use real good head gaskets and head studs and you won't need preparation H.

 

[Dontknowchit]

Translation:

Contemplating boosting the out of this thing and wonder how much ass-pain the head gaskets will be.

I'm staying at 10lbs, real happy with the griptec pulley even on the 6 rib I'm not slipping but I don't think these e7 heads are gonna let me hit my 400hp at the crank goal

 

[Noobz347]

You will lose a couple lbs of boost with better flowing heads with the same pulley.

 

[Dontknowchit]

You will lose a couple lbs of boost with better flowing heads with the same pulley.

True, but the power is the goal. Lower restriction but better power with more flow. Any smaller pulley and I have to dive back into the rabbit hole with different crank pulley and more ribs. I might be able to get there with longtubes and 1.72 rockers but by then I'm already into some cheap aluminum heads.

 

[Noobz347]

Yep.... You will make more power.


Down the road, we'll talk about the advantages of an oversized crank pulley.

(the only real reason to use UD pulleys on the street IMO)

 

[General karthief]

Engine Masters is a great source of info on what works and how it does it.
You can make the same power with good heads on less boost, kinda have'n cake all day long.
Same power, less boost, parts last longer.......well unless you get greedy.
Just the ramblings of an old man.

 

[Bullitt347]

Engine Masters is a great source of info on what works and how it does it.
You can make the same power with good heads on less boost, kinda have'n cake all day long.
Same power, less boost, parts last longer.......well unless you get greedy.
Just the ramblings of an old man.

True.
But...
You can make the same power as the good heads with boost as the "bad" heads just by turning up the boost a lb or two.
They made 25 or so more hp with the good heads N/A over the baseline heads, but it only translated to 18 or so more hp when boosted.
Yes the boost was lower due to efficiency, but turn up to boost to the previous level, and the hp advantage went away.
It proved that "bad" heads are not that bad when using boost.

 

[General karthief]

True.
But...
You can make the same power as the good heads with boost as the "bad" heads just by turning up the boost a lb or two.
They made 25 or so more hp with the good heads N/A over the baseline heads, but it only translated to 18 or so more hp when boosted.
Yes the boost was lower due to efficiency, but turn up to boost to the previous level, and the hp advantage went away.
It proved that "bad" heads are not that bad when using boost.

absolutely true!!
but my point is 'same power on lower boost plus the engine is less stressed, it should last longer,
boosting stock heads is great....but the quest for 'more' is undeniable.

 

[Bullitt347]

absolutely true!!
but my point is 'same power on lower boost plus the engine is less stressed, it should last longer,
boosting stock heads is great....but the quest for 'more' is undeniable.

Explain how the engine is "less stressed'
It is making more hp.

 

[Dontknowchit]

Well, it's not just boost, it's also heat. It's obvious when the ecu starts pulling timing due to IAT being too high. The charger gets that air hotter and hotter and without an elaborate cooling process (which I don't have) you lose power. More pulley, more heat, less dense charge, less timing. Better heads, less pressure, lower temps, power gain is 2 fold.

 

[General karthief]

Explain how the engine is "less stressed'
It is making more hp.

Easy, think about it.
Nevermind, it's one of those infinite discussions.
Everybody is right to a degree.

 

[limp]

Easy, think about it.
Nevermind, it's one of those infinite discussions.
Everybody is right to a degree.

What is the best oil to use? LOL

 

[General karthief]

What is the best oil to use? LOL

 

[nicholase]

Well, it's not just boost, it's also heat. It's obvious when the ecu starts pulling timing due to IAT being too high. The charger gets that air hotter and hotter and without an elaborate cooling process (which I don't have) you lose power. More pulley, more heat, less dense charge, less timing. Better heads, less pressure, lower temps, power gain is 2 fold.

Right. Heat is the answer. The more air you cram in there and compress the hotter it gets. The heat and addition cylinder pressure is what is tough on an forced induction engine.

Aluminum transfers heat much better than cast iron. So an aluminum head (forget about flow for now) will transfer heat quicker to the coolant passages. Resulting in lower cylinder temperatures. That gives the ability to run more timing at equal boost levels. Also the ability to run more boost in general without detonation. So I'd say aluminum heads will get more performance in boosted applications even if they flowed exactly the same as a cast iron head.

In a N/A application it would be more about flow and less about dealing with boost related heat. So an aluminum head (material alone) isn't going to be as important.


That's just my 2 cents worth....