Quote:
Originally Posted by RET_COP
Maybe a forged aluminum piston with more piston to wall, different from hyperutectic. I'm not getting it either Brent. We did run our drag engines a little on the loose side in the 80s. a little.
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Bingo!
When stating your engine uses more
oil than a modern day factory car and saying you have looser tolerances, your not talking about bearing clearances. Bearings have nothing to do with
oil consumption. Of course they are talking about piston clearances.
Everybody fits forged pistons with more clearance than a hyperutectic piston, because if they don't the piston will swell up (thermal expansion), stick to the cylinder wall, and jerk the top off of the piston.
Someone mentioned their cylinder walls were badly worn. It's possible that there wasn't enough clearance.
To put this warranty into perspective, my 1966 Comet Cyclone GT with 390 Hi Po (a whopping 335 Hp) said in the manual that 1 quart in 500 miles was not to be considered excessive for the 390 Hi Po engine. It used 1 quart in 1000 miles.
My 1992 Crown Vic 4.6 ltr used 2 quarts in 3000 miles early on. Ford dealer showed me in writing that it had to use 1 quart in 1000 mile or more before they would consider it defective and do anything about it. At 155K mile it was burning a quart in 500 miles.
I do not see the warranty that Roush is putting out as way out of line. However all the problems I see people on here reporting scars me away.