engine life
09-02-2015, 07:30 AM
#21
Team Owner
Dude, do what you've been doing and done listen to all that speculation from the doomsday crowd. Really, a builder told your builder thus and such...and now you're fretting over it ? Is this a reality show or something ?
You have empirical evidence that they are full of horse poo every time you run the car down the road. If the tolerances were bad do you think you would have the compression ratio you cite, or, you wouldn't be blowing oil, or, your engine would still be all together and running like a raped ape ?
You have empirical evidence that they are full of horse poo every time you run the car down the road. If the tolerances were bad do you think you would have the compression ratio you cite, or, you wouldn't be blowing oil, or, your engine would still be all together and running like a raped ape ?
09-02-2015, 08:33 AM
#22
Drifting
Con rods are "consumables. They have a certain number of hours at a certain speed, then must be replaced. I ran thru MANY "pink" rods, and they ran thru my cylinder blocks. there is a huge difference between a RACE engine and a street engine which occasionally sees a few high RPM runs thru the gears, or even a DRAG race engine, which sees "race" events of 12 seconds, My 13:1, 412hp 327cid engine runs Carillo rods on a billet crank with Mahle pistons. They (may) last for one season. My engine is built for reliability, not power. The high horsepower engines start at 500hp and $25,000, and last for....whatever, depending on your rev limit. REAL "fast guys", run 15:1 NASCAR based engines of LOTS of HP, cost $50,000, and are "refreshed" every race event! Still, even those use a rev limit of around 6500+ rpm. The 302cid engines and Boss 302 Fords run 9000 rpm!
To answer the OP question I have the original 327 in my 64 and it was rebuilt in 1993 at 10.5:1 compression still going fine. In general if the lower end was built well the top end will wear out much sooner from my experience. But that is just for normal driving. Over revs cause issues to both ends of the motor. So like said, keep over reving it and you will be a hero!
Steve
09-02-2015, 02:50 PM
#23
Burning Brakes
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C2 of Year Finalist (performance mods) 2019
I agree. High Performance engines will not last long. You will never get 200K miles out of it like you can from a modern passenger car engine.
Of course it is all a matter of perspective as I pointed out above. What does "last long" mean to you, or to them? To me, 75K to 100K miles would be a long and fruitful life for a high performance engine. My Chevelle "basic" performance engine has about that and while it could use some TLC, and maybe a cam (it "feels" weaker), it could keep going for a lot longer.
I'd be pissed if a builder would not expect their engine to last 7500 miles.
Of course it is all a matter of perspective as I pointed out above. What does "last long" mean to you, or to them? To me, 75K to 100K miles would be a long and fruitful life for a high performance engine. My Chevelle "basic" performance engine has about that and while it could use some TLC, and maybe a cam (it "feels" weaker), it could keep going for a lot longer.
I'd be pissed if a builder would not expect their engine to last 7500 miles.
09-02-2015, 03:43 PM
#24
Race Director
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I think that the op stated that he thinks that the builder re-used the original HC pistons that had too much cylinder clearance.....either due to piston wear or cylinder wear. Like and old time 'ring and bearing' overhaul. Replace the bearings, don't measure the crank, re-ring the pistons with iron rings, run a ball hone thru the bores, and presto....rebuilt engine. In my years of automotive adventures, I have seen more than one of these 'down and dirty' overhauls make good power and last a long, long time. Which tells me that the 'builder' got lucky and, unknowingly re-assembled an engine that still measured withing specs.
09-02-2015, 03:45 PM
#25
Team Owner
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My 11:1 '69 Z/28 blew up in June, 1970, and got a fresh "CE" short block; hasn't been apart since, runs strong like any properly-tuned 302, gets 1500 miles to a quart of oil, and apparently doesn't care that it's 45 years old. Compression ratio has nothing to do with engine longevity. 
09-02-2015, 06:52 PM
#26
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I think that the op stated that he thinks that the builder re-used the original HC pistons that had too much cylinder clearance.....either due to piston wear or cylinder wear. Like and old time 'ring and bearing' overhaul. Replace the bearings, don't measure the crank, re-ring the pistons with iron rings, run a ball hone thru the bores, and presto....rebuilt engine. In my years of automotive adventures, I have seen more than one of these 'down and dirty' overhauls make good power and last a long, long time. Which tells me that the 'builder' got lucky and, unknowingly re-assembled an engine that still measured withing specs.
Out of spec means it's no longer serviceable to run to design duration doesn't it? So what if it only runs half as long? I'll still never wear it out.
PS. Advertised 11.25-1 compression. I don't know what it is now and don't care.
09-02-2015, 06:59 PM
#27
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Mike, there are plenty of engines running just fine that are a little out of service specs....as you well know. I may end up doing a 'ring and bearing' overhaul on the 383 in my '61 which is a powerhouse, but shows some blowby at WOT.....but still has 195-200 psi compression in every hole. If it ain't broke don't fix it..........
09-02-2015, 08:03 PM
#28
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Mike, there are plenty of engines running just fine that are a little out of service specs....as you well know. I may end up doing a 'ring and bearing' overhaul on the 383 in my '61 which is a powerhouse, but shows some blowby at WOT.....but still has 195-200 psi compression in every hole. If it ain't broke don't fix it..........
09-02-2015, 08:13 PM
#29
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It blows me away the money some of these guys spend on an engine and will never, ever recoup their expenses.
09-02-2015, 09:36 PM
#30
Loose is good, a lot of the circle track guys build them loose. I don't really understand the statement your builder is making? Unless he just needs work? If it does not have blow by or using oil your good, now that I think about it, the best running and hardest running engine I have is a 327 with blow by. It sees 7000 rpm every time i get it out. Been that way for 10-12 years.
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