Forced Induction and lifting heads.
Thread Starter
Launching!
Joined: Apr 2006
Posts: 216
Likes: 0
From: Maple Grove, MN
Forced Induction and lifting heads. I've been checking out the forced induction forums for a while and noticed that 4-bolt setups start running into head-lifting/water-pushing around the 900 to 1000rwhp mark (sometimes earlier). What im wondering is if there's ways to prevent this with current technolgies..such as an 'ideal setup'? (L19 head studs with a high quality head gasket)
Ive seen cool methods like this one
https://ls1tech.com/forums/forced-in...lbs-today.html
Its a 6.0 with 'pyramid rings' that cut into the heads to save the head gaskets. I like the fact its a stock crank and heads motor.
Of course there's always o-ringing the block, im not convinced yet that its a end all solution. A little more info on that process would be nice.
Many on this forum can't afford the LSX block, let alone cylinder heads...so im wondering what other ways are there to keep heads down (torquing down the heads an extra 2-3 ftlbs)?
Ive seen cool methods like this one
https://ls1tech.com/forums/forced-in...lbs-today.html
Its a 6.0 with 'pyramid rings' that cut into the heads to save the head gaskets. I like the fact its a stock crank and heads motor.
Of course there's always o-ringing the block, im not convinced yet that its a end all solution. A little more info on that process would be nice.
Many on this forum can't afford the LSX block, let alone cylinder heads...so im wondering what other ways are there to keep heads down (torquing down the heads an extra 2-3 ftlbs)?
If your building a 1khp + application the words "cannot afford" probably shouldnt come into your vocab. The cylinder pressures are huuuge at that level. Your making over 150hp in each cylinder. I think ringing the blocks the way to go.
EDIT : I reread that and decided I sounded like a smartass, which may be true, but I apologize.
EDIT : I reread that and decided I sounded like a smartass, which may be true, but I apologize.
On The Tree
Joined: Aug 2008
Posts: 143
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From: honolulu
o-ringing the block- in the words of Rehr Morrison :"racing engines often have problems maintaining the integrity of the head gasket seal. high cylinder pressures tend to lift the heads off the block. differences in rates of thermal expansion between aluminum heads and ferrous blocks cause a sliding action against the head gaskets. in high horsepower/extreme cylinder pressure applications, we sometimes add steel o-rings to the head around each cylinder. the o-rings compress the copper head gaskets into a reciever groove in the block to create a very effective barrier to gas pressure losses. this procedure effectively eliminates head gasket sealing problems in these engines." And this is pertaining to pro-stock engines making close to 2000 hp...so i would go that route along with good studs (arp?)
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Thread Starter
Launching!
Joined: Apr 2006
Posts: 216
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From: Maple Grove, MN
LSX block , $2,000.00 still needs machining. 6 Bolt heads , $2,000-3,500 BARE. Kinda puts a downer on going that route. Maybe theres other ways to solve the issue than throwing money at it.
BTW , not building anything here
BTW , not building anything here
8 Second Club
Joined: May 2004
Posts: 371
Likes: 0
From: Savannah, TN
As he said with out buying 6 bolt stuff what is options . How many guys over the 1000hp range answerd. I run cometics on everything I build. Some ford guys use solid copper and a o ringed head. I am not a fan of that leaking set up. I will tell you If you go cometic making it work is all in the finish. Do some research on how smooth the head and block has to be and you had better stay with it. i think 1000 hp can be done . temps and tuning play alot of the edge living thing in forced induction. You go out and make a hit and the engine is already 200F and you really ask yourself whydid i blow a head gasket. All i can say is i have put over 1500 to the wheels with a car you can daily drive and i love cometics .
lower compression for starters try running 9:1 or lower maybe high 8':1cr. cometic imo are **** they either work or dont and i dont feel like decking anything to perfection just to run a head gasket. try running the new zr1 gaskets there 7 layer i have a pair my self. they did cost double what a normal pair of head gaskets cost.
like other people have said o-ring it
like other people have said o-ring it
8 Second Club
Joined: May 2004
Posts: 371
Likes: 0
From: Savannah, TN
lower compression for starters try running 9:1 or lower maybe high 8':1cr. cometic imo are **** they either work or dont and i dont feel like decking anything to perfection just to run a head gasket. try running the new zr1 gaskets there 7 layer i have a pair my self. they did cost double what a normal pair of head gaskets cost.
like other people have said o-ring it
like other people have said o-ring it
From all the reading/phone calls I've done, the only reasonable budget minded things you can do to help prevent lifting heads are:
Good head studs
Good heads with a thick deck
Good head gaskets (The gaskets Disturbed Bird mentioned seem to be better than most)
I've researched this quite a bit as well since a guy that I consider a reputable source informed me that stock manifolds flipped to face the front, won't clear the extra bolt per cylinder on the LSX block. I'm not 100% sure the ERL setup will not clear, but I would doubt it.
I would also be surprised if lowering the compression decreases the tendency to lift heads. Its cylinder pressures that cause them to lift, which directly relate to the power produced.
My .02 fwiw.
8 Second Club
Joined: May 2004
Posts: 371
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From: Savannah, TN
What are the semilarites of the ls and a ford small block ? I used ford as a comparison because they being ford is very close to the same bolt pattern of the ls and also have the same issues as ford heads. Ford will out flow the early chevy stuff because they used less bolts for more flow chevy used more bolts to keep integrity and most good flowing 23 degree stuff and even the 18 degree stuff is still limited to bolt configuration. Chevy steps up with the ls and the good stuff flow like the ford but if you cant keep the head to the block where are you back to the drawing board or 6 bolt stuff. I think we can all learn from the ford guys on sealing just my thoughts . I am not limited to just on kind of engine.
Last edited by pmbmax; Mar 2, 2009 at 03:11 PM.
I don't mean to sound like a jerk, and I think I probably do, but I am an engineer in the CNC field, and I have to setup machines to cut ridiculous surface finishes for aerospace and defense applications all the time...the surface finishes required for MLS gaskets are nothing compared to those, and the CNC machines in use on modern engine work are the same ones in use on the aerospace and defense parts...any modern shop telling you they're using a CNC to port your heads that then says "we can't cut the deck that smooth and flat" is someone to walk away from.
Last edited by Mike454SS; Mar 2, 2009 at 12:22 PM.
8 Second Club
Joined: May 2004
Posts: 371
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From: Savannah, TN
Thats like saying you don't feel like grinding and micropolishing the crankshaft to spec just to run bearings. Specifying an Ra number and flatness tolerance for the deck on the block and the mating surface on the heads is not a big deal, and a good machine shop with good CNC machines will have absolutely no problem getting you to the Ra necessary. A lot of shops cut things with an old school mentality still, and thats what works with old school head gaskets, but with newer MLS gaskets, surface finish is king, and it's very easy to obtain, flatness requires a bit of skill, but it's not rocket science. Squareness of the deck to the bores is very important (and something a good shop can take care of) too.
I don't mean to sound like a jerk, and I think I probably do, but I am an engineer in the CNC field, and I have to setup machines to cut ridiculous surface finishes for aerospace and defense applications all the time...the surface finishes required for MLS gaskets are nothing compared to those, and the CNC machines in use on modern engine work are the same ones in use on the aerospace and defense parts...any modern shop telling you they're using a CNC to port your heads that then says "we can't cut the deck that smooth and flat" is someone to walk away from.
I don't mean to sound like a jerk, and I think I probably do, but I am an engineer in the CNC field, and I have to setup machines to cut ridiculous surface finishes for aerospace and defense applications all the time...the surface finishes required for MLS gaskets are nothing compared to those, and the CNC machines in use on modern engine work are the same ones in use on the aerospace and defense parts...any modern shop telling you they're using a CNC to port your heads that then says "we can't cut the deck that smooth and flat" is someone to walk away from.