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#1
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Head work
Lets say non hypothetically that I'm rebuilding a motor for boost. I got my bottom end straighten out pretty well, on the heads I am still very uncertain. I haven't decided for sure about going with a custom cam grind yet or not but thats easy, I want to know what should be done when rebuilding these guys up for boost. I do not plan on reving any higher than stock, maybe 500 ish more so I do not want nor can I afford to swap out everything in it to a Toms/ Rally Bob non hydraulic conversion. I mean as in, would you pit in all new valves and springs or not. Seems like a no brainer but if it isn't necessary then I'd like to skip it and get on the road that much quicker.
If it should be done, does AWD change everything over because their site isn't real clear to me. I see that they mill and vacuum test them and put new seals on but do they do anything else? |
#2
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Re: Head work
Valves have to be changed..... turbo engines run quite hotter through the heads and will burn valves of incorrect composition. Im sure YT can specify more because im not certain where you can get them, or if compatible with the newer turbo 4's.
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#3
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Re: Head work
Phastsvx could answer this. His is boosted and his motor is fairly stock I think.
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Seth 94' Barcelona Red w/ Tricoat black 2-tone AWD Ls -Sold Mods:AWD conversion/4.44 swap by Budfreak, Custom red interior lights, Custom Satin black dash, Power mode switch, Cold air intake, Permecool tranny filter,Sony xplode 10" sub, Sony xplode 1000w amp, Blitz in-line driver, DDM Tuning 6000k HID's, New paint job/body work by me, 97' Grill, QC shift kit, 17'' MB Motoring rims, 15&20 min mod, front & rear urethane swaybar bushings, Custom fiberglass sub box, Custom red led a/c control unit, perrin lightweight crank pulley, Black wrinkle finish powdercoated intake manifold w/ clear hoses , 02' outback heated/power black leather seats Soon to come:Fiberglass hood, upholster ALL suede to black leather Past subies: 92' Pearl White/black top LS-L-SOLD 96' Legacy Outback-TOTALED 99' Legacy Outback Limited 30th anniversary edition-TOTALED 98' Forester L -Totaled Other toys: 99' Forester S -WRX brake upgrade, soon an 04 wrx motor swap 06' B9 Tribeca-Stock 1982' Yamaha xj650 Maxim Mods: work in progress |
#4
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Re: Head work
his engine and mine are totally stock. They will hold up but still restrict airflow esp in higher RPMS. Even big cams with stock length valves cannot stack up to the ability to get the bigger lift numbers.
Tom |
#5
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Re: Head work
What I guess I'm saying is that I am aware there is nothing I can buy to upgade these peices other than brand new stock ones, is that nessessary or if the ones currently in mine are fine can I just roll with them. The few people I'm aware of that have boosted so far were not built and did not run the crazy boost I want to shoot for so I'm kind of pioneering here... Which sucks cause I'm a 'follow a guide' kind of guy
It may just be something I'll have to convert to later on down the road if it doesn't perform well. |
#6
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Re: Head work
oddly enough, I'm struggling with this as well. :/
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Marisa '93 LSL Anniversary Edition - 02/93 - 150,998 Daily Driver - Forged EG33 (long block), 6MT swap, and re-upholstered interior '92 Pearl - 100k Side restoration project Locker | Old Locker | Shutterfly | ReadingIX | Facebook | Instagram |
#7
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Re: Head work
Exactly, cause were both building motors to be turbocharged and theres not a lot of info on this to go around. We know the parts aren't there, we don't know what the stock ones will handle, especially with 100,000 miles on them. We don't know if dumping 300 dollars in new valves plus whatever the rest costs will even be sufficient if we were to take the dive and do it.
I guess if you both keep it stock and whoever is done first blows up, the other will know to upgrade |
#8
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Re: Head work
The parts will work. Just not as well as I think you would want them to. If you invest enough in the bottom end, you would be wasteful not to spend some extra to get the top end of the engine to match...
Basically, the stock valves are restrictive because they cannot support the ideal lift and the srpings are too soft to support high RPMS ie, where your boost will likely be TOm |
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