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Chas,
It depends on the journal size. Most of the bearing manufacturers tell you to be at about .001"/inch of journal, and you add a half thou for the "hipo" stuff. My SBC rod journals are usually at around .0020-.0025". BBC journals are the same. Cleveland, SVO, and FE main journals are around .0027-.003". My BBF and Windsor stuff is around .003" on the mains. If it's a few tenths each direction, I don't sweat it. Cup engines run really tight clearances (they are pretty small journal though) and you know what kind of rpms they pull. There has always been a tendency to start opening up the clearances when "race" is written in front of "engine", but I've never really seen the need. |
Brent,
Thanks for clarifying for the members . The Windsors, SBC and BBC's were right on your numbers at World. Agreed about the 'race' myth. Hope Clayton chimes in too. Now who's torn down a new Roush and mic'd rods and mains?? |
My 402 goes through a quart of oil in about 2k.
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I have a feeling they use really low tension rings....9-10 lbs.
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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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high oil consumption, out of spec valve guides, cracked pistons, rebuild costs, ya sure! I like spending money on parts that fail. I must call Rousch on the next busines day to order me one of those aaaaaa, what was it now?
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Don't even get me started on the laundry list of failures with those of us that got the first 511's. at least 5of us in Arizona got the first batch of those motors. And I think everyone has had catastrophic failures if not total rebuilds in the first 1-5k miles
Ron |
Yeah but you can get polished intakes, chromed coils, efi and black and chrome valve covers and big-ass air cleaners that say 'ROUSH' in big letters on 'em.
Takes a lot of design engineering to make that stuff. So's everybody in the parking lot can get wowed by that. That's what counts-they can see you wrote the big check. Clearances? Ring tensions? Valve guides? Spare qt of Royal Purple in the trunk?; not to worry. You'll make it home. :MECOOL: |
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I hate to spoil your impression but I could of cared less whose name was on the valve cover, I didn't know about Keith craft or kirkham at the time and I simply wanted the most horsepower I could fit under the good.
If I had to do it over I would do a kirkham but why is it everyone craps on the CSX owners about writing a check for their car but not the guys writing bigger checks for their alloy kirkhams or the $175k I am sure the super snake kirkham with twin superchargers cost? |
Ok, I guess I'm one of the lucky ones only used one qt in and maybe 1/2 at the track in 17000+ miles and that was when the intake gasket went south! Not happy with the scorpion roller rockers, and by the way no cracks in them. Car has been tracked a little and not afraid of the loud pedal! Will probably blow up now! LOL
B i l l |
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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. |
Manufacturers always Ok high oil consumption as normal because they don't want to face recall.
I would bet that most of you with high oil consumtion do not run PCV, s ....I am really confused as to how a " new " motor can have worn out valve stems , cylinder walls etc, etc. Are these manufacturers using used parts to start with...?... Someone send me your motor to rebuild...... |
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same here...13k...uses very little oil...maybe 1/2 quart in between oil changes. |
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[b]Got the Bug[b]- My 402R is reliable, does not overheat, sounds great, crazy fast, gets 15+ mpg and burns no oil.
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Tony,
Let's try this again, I don't know anyone who is pleased with the Roush injected engines, and very few who are pleased with any aftermarket fuel injection systems used on the street. J |
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Loose clearances are a thing of the past. In the 60's/70's everyone kept opening the clearances up. It's not necessary and many SAE studies have shown that excessive clearance can cause oil to cavitate. |
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