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PostPosted: Wed Oct 20, 2021 6:06 pm 
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Joined: Wed Oct 23, 2002 7:57 pm
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Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
When you have a race car what is the best way to determine when to freshen things up? I'm not considering it yet but just wondering out loud when that should be? Do I go by my compression readings , since I know what the car had when new. Do I go by number of runs on a engine down the strip? I have about 150 give or take a few. Or is there some other good measure? Like, It hasn't slowed down any since its best runs. Thanks for any input.

PS. I do have some things I want to do when freshen up time comes due! More horsepower!! :D :D

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PostPosted: Wed Oct 20, 2021 6:28 pm 
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Joined: Wed Sep 17, 2008 6:48 pm
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for things like bearings, you could either pull the engine, remove the pan and pull a main cap or rod cap or two, or
get an engine oil analysis done. The analysis will tell you if there are higher than expected amounts of bearing material or piston ring material in the oil, either would indicate the potential for a problem.

I don't know if this is a good one or not, just a representative example of what is available

https://www.summitracing.com/parts/wix- ... f0QAvD_BwE

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PostPosted: Wed Oct 20, 2021 8:30 pm 
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Supercharged

Joined: Thu May 12, 2005 11:50 pm
Posts: 6292
Location: So California
Car Model: 64 Plymouth Valiant
Do you have a leak-down tester?

If you don't get much leak down, oil pressure is good, and an oil analysis looks good; I'd wait.......

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64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

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PostPosted: Wed Oct 20, 2021 8:52 pm 
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Supercharged
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Joined: Thu Jan 27, 2005 8:32 pm
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Location: SW Washington
Car Model: Fiat 500e
What the engine tests mentioned won't tell you has to do with fatigue. You can have great leakdown, good oil analysis and run on par with the car's best times, then break a rod, spin a fatigued bearing or break a valve spring and drop a valve. For me the question moves to what is likely to happen at your power and RPM levels? Did you buy stress relieved conical valve springs? Are you using stock or aftermarket rods?

Engines die for many reasons.

A lot of engines fail from corrosion. Rust forms on cylinder walls far more than most people realize. Short intake and exhaust tracts and high humidity make this far worse. The rust gets taken off when the engine is run next, but it does damage. The rust will show up in used oil analysis. BTW, Napa sells the same test kit as Summit. One of the oil labs is here in Portland.

Engines are put away with plain water in the block and crack in Winter. I put petcocks in place of coolant drain plugs on race engines.

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PostPosted: Thu Oct 21, 2021 5:56 pm 
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When you start slowing down.


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PostPosted: Thu Oct 21, 2021 6:07 pm 
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Joined: Sat Oct 19, 2002 12:06 pm
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or start going too fast.

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65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
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PostPosted: Fri Oct 22, 2021 7:05 am 
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I just listen for noises, watch oil pressure profile and stable values, watch coolant temperature, and run it til.... I did re-ring/bearing my 64 motor after 50k on the street, a few hundred drag passes, and several track weekends.

Lou

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PostPosted: Fri Oct 22, 2021 8:19 am 
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Joined: Wed Jan 29, 2003 4:42 am
Posts: 8441
Location: Fort Bragg, NC
Car Model: More cars than sense...
Posers like me have folks like Howard Davis go through their engine to fix a bunch of stuff, git it back all ready to go, make about 10-12 dumb dumb passes with the methanol settings all jacked up, then pull the engine back out and send it back to Howard fer him & some other smart fellers to go through it again... :roll: YMMV... :lol:

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PostPosted: Fri Oct 22, 2021 3:01 pm 
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Joined: Thu Oct 17, 2002 7:27 pm
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Location: Park Forest, Illinoisy
Car Model: 68 Valiant
Mike freshened my old motor up right after I knocked the top land off some pistons with the sauce. He checked the bottom end and put it back together with the same bearings.

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PostPosted: Sat Oct 23, 2021 1:01 pm 
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Board Sponsor & SL6 Racer

Joined: Wed Oct 23, 2002 7:57 pm
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Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
Quote:
Do you have a leak-down tester?
Yes I do.

My engine is a Molnar rod, Wiesco piston engine, .085 over. Head has Ferrea valves and conical springs, Bearings are all King bearings, with Peterson external oil pump. 10W30 Joe Gibbs Racing oil is what I was told to use by the engine builder. All in all good parts were used.

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PostPosted: Sat Oct 23, 2021 3:57 pm 
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You will hear things like Lou suggests. If something sounds different, it probably is. I like to examine oil and filter. Magnetic drain plugs are nice, but what's in the filter can be more telling, as your bearing material isn't magnetic, right? When the ET changes for no explicable reason, that's a good time to cut the filter open. If it isn't making some weird noise, leave it alone. It's either in your nogin, or some part of the setup went sideways. If something is borked, it'll make a different sound. Your ears are way better than your butt at sensing actual trouble.

You have good bones in that build, Kudos. It should be good for a lot of passes,

CJ

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PostPosted: Sat Oct 23, 2021 6:03 pm 
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Board Sponsor & SL6 Racer

Joined: Wed Oct 23, 2002 7:57 pm
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Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
Quote:
It should be good for a lot of passes,


That's what I figured! :D :D

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!
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PostPosted: Sun Oct 24, 2021 6:27 am 
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Joined: Sat Oct 12, 2002 11:22 am
Posts: 3739
Location: Sonoma, Calif.
Car Model: Many Darts and a Dacuda
The "long rod" 225, with the longer connecting rod and lighter piston, is a durable SL6 engine combination.
Add forged pistons, premium bearings, careful machining / assembly and it is more "bullet-proof" then the factor built 225s.

http://blog.wiseco.com/stoker-crank-sci ... xplained-0

In my opinion, the thin rings are the "weak spot" with this combination.
When gapped and installed correctly, these thin rings work fine and do not break but over time they do wear and loose oil control a bit faster, compared to thicker rings. Truth is that any piston, piston pin and ring, living with 4000+ fpm piston speeds, is living a hard life.
Bottom line: Monitor oil consumption and spark plug color... and use a leak down test to see if the rings are OK if engine slows down or starts using more oil.

We all know where the major failure will occur in a well built performance SL6...
At the oil pump drive gear.
DD


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PostPosted: Sun Oct 24, 2021 2:10 pm 
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Board Sponsor & SL6 Racer

Joined: Wed Oct 23, 2002 7:57 pm
Posts: 7405
Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
Quote:
At the oil pump drive gear.


Thanks Doug, and that has been eliminated in my combo with the Peterson external pump.

PS. I still have the test pump/13T gear you sent me to test. If you want it sent to you PM me your address and I'll send it to you.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!
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