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3.4 History


synistershadows

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A couple of things...the LQ1 was designed a full decade before those "late 90's" cars...and Ford didn't even build the engine they put in the SHO--Yamaha designed and built it for Ford... :)
Right. The Yamaha engine was also meant for a Fiero style car, but seeing how public interest of that style of car was dwindling, the project was scrapped, and instead it was put into the Taurus.
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On a somewhat related note, what's the safest you can have LQ1 heads resurfaced to without making it an interference motor?

 

Seeing as how they are interference motors from the factory and can potentially bend valves, any resurfacing is going to increase the potential for damage should the belt break.

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Seeing as how they are interference motors from the factory and can potentially bend valves, any resurfacing is going to increase the potential for damage should the belt break.

incorrect. 1991-1995 models are non-interference. 1996-1997 are interference.

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Not exactly a scientific answer, but since you're looking at putting '92 heads on the '95, the clearances are going to be (going by memory) around .012 piston to valve. My short answer would be to mill them no more than absolutely necessary to get a flat surface. I don't really think there's enough to gain by going further than that, balancing the potential performance gains versus the greater risk of valve damage...if you're looking for significant performance over stock, your best bet is still supercharging/turbocharging, in which case, if anything, you'll want to lower compression, at least a bit, to keep the engine from killing itself from detonation.

 

so. no official specs for how much I can have machined off before it decides to commit suicide again?
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Not exactly a scientific answer, but since you're looking at putting '92 heads on the '95, the clearances are going to be (going by memory) around .012 piston to valve. My short answer would be to mill them no more than absolutely necessary to get a flat surface. I don't really think there's enough to gain by going further than that, balancing the potential performance gains versus the greater risk of valve damage...if you're looking for significant performance over stock, your best bet is still supercharging/turbocharging, in which case, if anything, you'll want to lower compression, at least a bit, to keep the engine from killing itself from detonation.

lol. I'm not doing this for performance. The compression ratio bump is just a nice bonus. I'm doing this only to get the damned thing running again. But thanks. I'll keep that in mind when I bring them in to be machined.

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For what it's worth...the machine shop that planed my '93 3.4 cylinder head took .015 off of it. Interference or not, it's going back on.

 

Single question at this point is whether I'll be too lazy to remove the other head and have .015 cut off of it to match the other one.

 

Do you have the head off? What do the exhaust valves look like? I have one head off my engine, and I bought another pair via Craigslist; all three have wonderful-looking intake valves, wonderful-looking intake and exhaust seats, and exhaust valves that look like DEATH. (Thus my incentive to yank the other head and grind the exhaust valves.)

Edited by Schurkey
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If the valves look that bad, I'd pull the other head, easier to pull now, than pull later. But, that's easy for me to say, I'm not having to do the work, or pay for it. :)

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