Vintage FF Engine Life Expectancy

[Churchill]

heh, this is a good question, I think...

how long do most of your engines last... measured in weekends, and how far do you wrap them... does shorting yourself a few RPM help extend their useful lives???

[D.T. Benner]

If you talk to a good engine builder they can build you an engine that will live longer. If you are not after that killer National winning last bit of horsepower. And yes limiting RPM does help. With a refresh of the head and NOT overreving the darn thing you can get a longer life from an engine built with that in mind. Just don't expect dino busting performance. Getting that last 5 HP makes a big difference.

[Brian]

The thing with engine life is how long you make the HP that you want to have. The main reason that big HP engines don't last long isn't that they are worn out, it's that the fine edge has come off the HP output.

These things don't benefit from over-revving, so you won't really give up much by not over-revving it. In vintage you can't use the new lighter flywheel or the aluminium head, so you don't gain the advantages in longevity that they give. The main things that wear out in the engine are piston skirts, ring lands, rings themselves, valve springs, valve seats, cylinder bores, timing chains, camshafts and lifters. Plus the crankshaft cracking, of course. Running Mobile One oil and keeping the oil pressure set at about 60 PSI hot (robs power but we're not concerned with that are we?) helps a lot.

If you're not concerned with keeping the edge on the powerand you shift at 6500 rpm or less, then you could probably do a refresh every two years/30 - 50 hours. Or when it starts burning oil noticably or when you can't keep up with that pesky Formula Vee in your run group. Or when the crank breaks.

I know one guy who had 15 years on his motor. Rebuilt it when he couldn't keep the FVee's in sight anymore...

Brian

[Churchill]

thanks for the info guys, that's what I was looking for. me driving the crap out of a hot motor is not going to help at all for at least a few years, so short-shifting is looking more and more like a good idea, and I'll have to look at re-build costs for a "longevity motor" and then just expect whatever I buy will need one in a year or so.

thanks for the great info...

[Churchill]

btw, you said "30-50 hours"

the way I figure a weekend is 6-8 hours, am I close on that one???

[racer27]

I'd say figure about 4 hours for a two day weekend. The clubs I run with offer 1.5 to 2 HRs per day. Most I've ever put on may car was 3 hrs during and SCCA School. I think thier race events are considerably shorter.

[Jonathan Hirst]

I agree with racer27, a Monoposto race weekend may be closer to 2.5 to 3 hours.

Very broadly speaking:
Saturday - 30 min practice, 30 minute qualifying, 30 minute race
repeat on Sunday.

If it is a 3 day race weekend then the times are spread out over the three days.


It is is a 2 day race weekend, you might include a Friday practice so add another 2 - 3 hours, again, very generously estimating 6 x 30 minute sessions.


jon

[Churchill]

BRIC= 2x practice thursday, 2x practice friday, 1x practice saturday, qualify, sunday warm-up, race.

but I think that is the ONLY 4-day on the calendar. the rest are 2s and 3s.

[Michael Bowen]

The biggest issue with running these engines too long is the old cast crankshaft. If it breaks, things get real expensive real fast. Most everything else is performance related, and being a new driver, that won't be the difference for quite a while. I ran my engine for 3 full seasons, and that was a little too long. The engine builder just found a cracked crank in the usual place and a crack in the block between a main bearing and a oil gallery. I probably had 3 or 4 sessions left before it would have come apart. The new crank eliminates this problem and you can run it without worrying about it breaking, assuming you're not having flywheel to ground strikes!! Even if you don't rebuild the engine, the old cranks really need to be checked for the inevitable cracks every season. By the way, the new forged pistons have been approved, and Mr. Ivey says this may double the time between rebuilds.

[Churchill]

would Ivey be able to supply any sort of price list for a rebuild with a new crank and forged pistons?

[Michael Bowen]

Yep...give him a call..

503-255-1123

[Churchill]

putting that in the file......