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Author Topic:   Off season refreshing??
UFnARacing
Member
posted October 25, 2002 02:14 PM
I've got a sbc 350 that has about 16 races on it. As far as I know that's it after a complete rebuild. What should I replace and/or check this off season. I was planning on replaced valve springs/guides/keepers and the rod/main bearings. I usually turn up to 6200RPM max. What else should I keep an eye out for?

Thanks,
Randy


DMA Racing
Member
posted October 25, 2002 05:15 PM
mine has about 40 shows in 2 years have not changed anything on it.change oil and go. i need to know the answer to. mine has cast crank and cast hyperteck pistons pulling a 6.50 gear still runs great


UFnARacing
Member
posted October 25, 2002 06:33 PM
Yeah, I guess I should've gone a little more in depth. It's all stock with flat top pistons,460" lift cam, stock everywhere else. What about the TH350? Didn't even think about that!

Randy

rico 08
Member
posted October 25, 2002 08:44 PM
DMA is right i don't think you need to do anything that's only 1/4 of a season's worth of racing but 40 shows now that's stretching it!


racer17j
Member
posted October 26, 2002 12:34 AM
i agree there is still plenty of life left in her if you kept up with the maintence as far as your tranny goes a new filter is all i ever do to her not a problem yet


DMA Racing
Member
posted October 26, 2002 10:19 AM
rico o8
yeah, i think i'm on thin ice. lol


awkwardjeff
Member
posted October 26, 2002 04:45 PM
Here is the problem ......you got a motor you THINK only has 14 nights after a complete rebuild........did you buy the motor used?

Here is what everyone needs to do....call speedway motors and order a leak down tester. I think they cost around $50 dollars, and will be the BEST money you can spend on your motor program.

After the racing season you are backing off all the valve springs anyway, so leak the motor down.....it threads into the spark plug hole and has 2 gauges....the first gauge shows the amount of air pressure at the gauge......the 2nd gauge shows the amount of air pressure the cylinder is holding. I set the regulator on my compresser at 100 psi, then plug in the gauge.....if the 2nd gauge shows 95 psi that tells me it is leaking 5 percent.....

You should leak a NEW motor (SO YOU HAVE A BASE LINE TO KNOW WHAT IT NORMALLY LEAKS) then you can see when it has problems. If you don't know what it normally leaks you might think 8 percent is too much but if you got cheap rings and file fit them poor it will leak 8 percent....if you got good rings and properly fit them 1 or 2 percent would be NORMAL. Then check it every 3 nights of racing.......this will tell you when the rings start to give up and not seal any longer....... But remove the radiator cap and the carb and headers..... now when you leak the motor you can hear and see if you have a intake valve leaking, exaust valve, or head gasket out or craked head..........if the rings are leaking you will hear the air in the breather tubes in the valve covers.

Bearings last almost forever.......if the line-bore is straight and true. And you are buying the good bearings.........

The leak down gauge you tell you when to freshen a motor.

I got a motor i'm freshening this winter...at 61 shows it started slowing down. I leaked the motor to find the number 8 cylinder was leaking 5 percent out the exaust valve. We ran the motor 3 more nights without fear. If I didn't leak the motor to find the problem we would have just CHANGED motors. I didn't want to put a fresh motor in the car and run it for the last weekend just to let it sit all winter after.... so the $50 I spent for the leak down gauge paid for itself AGAIN......by saving me TIME and MONEY.......

rico 08
Member
posted October 26, 2002 06:40 PM
if it's a claimer just run 'er till she smokes(if it doesn't yet!)


DMA Racing
Member
posted October 26, 2002 07:44 PM
the leak down tester is a good thing to do ,but what i worry about is the cast pistons, and cast crank could handgrenade at any time


YAZ
Member
posted November 02, 2002 11:31 PM
I DID THE SAMETHING LAST YEAR.
I FINALLY GOT TALKED INTO TEARING
IT DOWN. I'M GLAD I DID, THE ROD BEARINGS
WERE WORN ALOT AND I FOUND MY MACHINIST
PUT THE CAM BEARINGS IN WRONG AND THEY WERE
WORN ALOT. I BOUGHT A TOOL AND DO MY OWN
CAM BEARINGS NOW.
IF I WAS YOU I WOULD PUT NEW ROD BEARINGS IN.


Eljojo
Member
posted November 03, 2002 07:19 AM
UFnARacing, (nice screenname-it took me a minute LOL)There are about a half dozen or so guys on this forum that should be paid CLOSE attention to, and AWKWARD JEFF is one of them. That leakdown tester will save you pulling good rings off when you've got a poorly seated valve robbing you of your compression. As far as your crankshaft and piston worries, it sounds to me like you just going to have to worrie until you invest the money to rebuild with quality parts. I think I'd do a leakdown test, pull the pan and check the rod and main bearings, and finish up with a peek at the timing set.
I think that would re-assure me enough, as long as I didn't find excessive wear.


dirtbuster
Member
posted November 20, 2002 12:53 PM
One thing we will do between seasons, especially with cast cranks is to have them crack checked and checked for straightness. This could save you a broken crank later on.
While bearings do last a long time i feel they are one of those parts that while you have it apart you might as well change them for no more than they cost. Granted a motor with 5 nights is different than one with 30 nights.. you have to be the judge.

Over the winter I would back off your rockers to take spring pressure off. Also if you have the heads off its a good idea to check spring pressures.

We will generally tear motors down around 25 nights or 1000 laps. Check over everything, look for anything obvious, put bearings and rings in, and check crank, springs, heads etc. Its not really that they start to get weak on the track and it might be overkill but with the money involved i would rather not stretch it and lose a motor to poor maintenance.

You may have a motor that is strong on the track, but when you tear it down and find something about to go wrong...you will thank yourself.
[This message has been edited by dirtbuster (edited November 20, 2002).]

[This message has been edited by dirtbuster (edited November 20, 2002).]

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