leaking exhaust valves, questions about new head

[b00st_catalyst]

So i put my head back on my block with a new head gasket to do a leak down test.

Cylinder 1-3 leak on the exhaust side - 100%

Cylinder 4 - No loss, perfect.

I have access to a 6 bolt head, which i have read is better. I need to enlarge the head bolt holes on the head right?

Also will my 2nd gen cams work. TIA.

 

[ZmanIV]

Be careful about saying a blanket statement like the 6 bolt head is better In certain situations it may be.
Just get your head rebuilt and go from there.

 

[ZmanIV]

I just checked your mods and since you don't have any just do like I said and have your's redone.
You will be into the car for a lot more money instantly if you go the 1G head route.

 

[b00st_catalyst]

I received the motor not-running and in pieces, to help clear up a little. I haven't set my mods yet because i am still reading a lot on options. I want 350whp or so. I was unsure about running a stock/rebuilt bottom to this safely.

Sorry i thought i had read the 1st gen was a better head. Looks like i will send this head for a rework...save the trouble for hunting down other parts.

 

[AndrewD5418]

A ported 1g head will outflow a non-ported 2g head. A ported 2g head will outflow a ported 1g head due to the angle. Or so I've heard this.

 

[ZmanIV]

Morpherex be careful with statements like this.
I myself have a 2G ported head and I will continue to have a 2G head. My car is not an all out drag car.

 

[AndrewD5418]

Morpherex be careful with statements like this.
I myself have a 2G ported head and I will continue to have a 2G head. My car is not an all out drag car.

Just saying what I've heard on my local forum. I would not be surprised if it turned out to be true.

 

[kidrabbit84]

How are you doing your leak test? Is this a head you just rebuild or a junkyard? What is the history (some other post)?

When I do my cylinder leak tests I pull the cams...that way I don’t have to mess around with finding exact TDC, nor have I had much luck finding it either. If you just lapped in the valves you might have some grit in the seats, that can be blown out by popping open the valves during your leak test. I have personally gone from 80 to 16% leak by popping the valves a few times.

Adam

 

[gsxeclipse97]

Morpherex be careful with statements like this.
I myself have a 2G ported head and I will continue to have a 2G head. My car is not an all out drag car.

Just because you have a 1g head doesn't dictate what you car will be able to do. I would be more inclined to say that its more about turbo size and displacement what makes your car a drag car or not. I have a 1g head and i intend to use my car for auto cross. But know i that the 2g head provides more tq i used a cyclone to make up for that loss. I also gained more tq than what i would of had with the 2g head. Besides porting the runners really isn't what increases the power. If you port the area behind the valves that is where you are going to see the most benifit.

 

[ZmanIV]

Do you have #'s to prove that the cyclone manifold makes more torque, I would love to see them.

 

[b00st_catalyst]

How are you doing your leak test? Is this a head you just rebuild or a junkyard? What is the history (some other post)?

When I do my cylinder leak tests I pull the cams...that way I don’t have to mess around with finding exact TDC, nor have I had much luck finding it either. If you just lapped in the valves you might have some grit in the seats, that can be blown out by popping open the valves during your leak test. I have personally gone from 80 to 16% leak by popping the valves a few times.

Adam

Its on an engine stand. I got a talon TSi, that ran supposedly. It had no compression, so i went ahead and pulled the motor. Upon tearing it down, i found a broken BS belt, hmmm.. I removed the cams and began testing...

I have never seen one go from 100% loss to anything worthwhile, popping the valves. 80%, maybe.