Extrude-honing 99+ intake & other bright ideas

[PurpleCherokee]

Accurate Power's heads were reworked stockers with SBC 2.02/1.60 valves. While they flowed more air at higher valve lift numbers, the bigger valves caused shrouding and the low lift numbers weren't so good, and it's at lower lifts where most of the torque is made and where the engine spends the most time. Stock sized valves work best. The intake/exhaust ports simply aren't big enough to take advantage of oversize valves.

You're absolutely right about the low lift. However, lower rpm torque isn't where max power is created. I guess it makes for a more effective daily driver (oxymoron?) but as I've said before, a completely stock XJ makes plenty of torque at lower rpms to suite my daily driving needs

But when it comes to going fast, pure torque isn't nearly as effective as horsepower, unless you have a really low geared 6 speed which obviously isn't nearly as viable as just building a motor for max power rather than rock-crawling torque.

But the bottom line is to quote from your very own website: "This produced a dyno-proven 16hp gain on a stock 4.0L engine and a 22hp gain on a 4.6L stroker engine". I think it's just a torque vs horsepower issue, which I've already addressed.

Lets compare apples to apples. The accurate power head was not a Jeep head. It was a completely redesigned piece with different ports that were engineered for more flow.

Uhhhh... wrong. But I'm not gunna call you stupid (though I easily could) and lower myself, and the forum to the level of the kind of people like Talyn.

The only thing you have experience is with your pos convoluted exhaust system and valve seals that leak compression. Just do everyone a favor go waste your money on this mod because its your money and a fool and his money are soon parted. And don't bother reporting back with your failed results because no one cares. Yeah,. that's also a lot of weight to add to the valve train for no gain... but you know what more weight does to the valve train too...

Then go spend the money and tell us how it works out. We are expecting dyno sheets, which I have. Put your money where your mouth is stupid.

"NO PERSONAL ATTACKS! There is going to be ribbing and teasing among friends, but when posts turn into personal attacks THEY'RE DELETED AT THE ADMINISTRATORS DISCRETION!!"

There's no need to start name calling. Keep your ignorant opinions on my exhaust on another thread. Hell, start a damn thread for all I care. And about the weight difference... what's about 12% of not much? Cause that's how much difference there is between stock intake valves and bigger intake valves. Take a chill pill and go read a book

 

[seanyb505]

Thats my mistake for not knowing better on the Accurate power head. Apparently it was a reworked head, and Im guessing the valves werent the only thing reworked. Im going to go ahead and say larger valves alone wont give my stroker an extra 22hp.

 

[alex22]

This thread almost makes me want to hit up the flowbench just to stop this bickering, but its mildly entertaining.
Just re cutting the seats to a 2.02 valve will just leave a nasty edge in the port and assuming accurate power doesn't leave that edge in there it would require some blending work in the bowl (increasing volume, helps at high rpm) and blending it into the short side radius (steeper short side helps low lift). But since the port has a high velocity increasing the bowl too much will cause short side separation. short side separation at any lift will hurt HP, even if the separation occourrs at a lift that is above the cam lift.

~Alex

 

[PurpleCherokee]

Do it! :yelclap:

 

[BlueCuda]

Slap that shit on the bench! LOL

I am fixing to have another 4.0 head done since mine sucks(needs guides). When I had my stroker I took the block to one shop and the head to another(time crunch). With 190K on the motor the head shop said it only needed one guide replaced. Thats BS because it smokes on startup.

Anyways enough rant lol. I am going to have another head redone and I am going to go with a better valve but not sure if I am going to with larger valves. I won't put the effort into any porting beyond whats needed to blend a larger valve.

So the new head right now sits at. Stainless stock sized valves from SI, 3 angle valve job, some kind of aftermarket spring.

 

[alex22]

Slap that shit on the bench! LOL

I am fixing to have another 4.0 head done since mine sucks(needs guides). When I had my stroker I took the block to one shop and the head to another(time crunch). With 190K on the motor the head shop said it only needed one guide replaced. Thats BS because it smokes on startup.

The guides and valve stem seals are the only way a cylinder head can cause smoking upon start up. They did put seals on it, right? I've seen people forget them too (I did it once but noticed it as I was bagging the head). With a good Viton seal you should be able to have .005 clearance and no smoke. Its also possible the shop honed the new guide out too far and used a cheap seal.
The AERA spec sheet and the FSM do allow for more clearance than I would run in my engine, which is most likely why they didn't want to replace all of the giudes.

~Alex

 

[BlueCuda]

The guides and valve stem seals are the only way a cylinder head can cause smoking upon start up. They did put seals on it, right? I've seen people forget them too (I did it once but noticed it as I was bagging the head). With a good Viton seal you should be able to have .005 clearance and no smoke. Its also possible the shop honed the new guide out too far and used a cheap seal.
The AERA spec sheet and the FSM do allow for more clearance than I would run in my engine, which is most likely why they didn't want to replace all of the giudes.

~Alex

They put the shitty umbrlella seals on it at first. It was using 1 quart of oil each tank of gas! My dad and I went back in and put the fel-pro seals that came in my gasket kit in there. It greatly reduced the consumption but it still burns some and smokes on startup sometimes(we replaced all but the last one which was exhaust anyways). Its been 30K since it was done I just don't like the smoke on startup. With the excpetion of the head I built the motor and I don't like it looking like a hoopty :dunce:

There is better seals out there but it did have 190K on it when it was torn down. I really thought it would have needed more parts than just one guide. But the motor was in VERY good shape other than bieng hydrolocked.