I got into a little bench racing the other day and the subject came up. I know that the power level and setup will dictate how often that tear downs occur. I was just curious as to how many passes some of you put on an engine before tear down.


Jeff

On my first ss 440 I pulled it out at 400 passes, on my 500 I pull it 250 + or -. I put new gears in the 8 3/4 before 250 runs.
My stuff gets about 1000 per year in street miles also.
I used to run both motors to 7000 rpm but only 6500 now, smaller cams.

I just measured the leak down and compression
to say when.. unless something broke

We usually tear ours town and put new rings and bearings in every other year (300-400 passes depending on how good we do). Our stuff is just basic, stock cranks, aftermarket rods and pistons, spin em to 6000 and mid .500 solid cams.

When it slows down is the best indicator.

When I ran a stock block, I checked leak down a few times per season, and I have a system one oil filter, so trash in the screen and percentage of leak determined when it was time to rebuild. That usually worked out to around 300 passes. Since I switched to an aftermarket block, I tore it down after 4 seasons and it looked like brand new, so I am back to filter inspection and cylinder leakage. I also have a valve spring tester that fits the rocker arms, so I check springs when I adjust the valves. The aftermarket block was the best investment I ever made. Its a world products aluminum block. I do the transmission every third season. 3200lb car, runs 9.70's

That is the best advice
That every other year teardown is usually not needed on normal bracket engine

Usually every other winter I pull it apart for a check. I make about 200-250 runs a year so somewhere in the 400-500 run range if nothing is wrong.

I don't think waiting until it slows is ANY indicator. By that time it's probably too late. I have seen them run real good before they come apart as well. Experience will give us a maintenance plan that will work. My rotating assembly is more than 15 years old and has more than 1000 passes. Even though it probably checks out, I will replace it before I race it very much more. I have replaced roller lifters, intermediate shaft gears and valve springs. Normal stuff for longevity in a very happy combo. It has only been totally freshened once in 2012. Honed the cyls. and installed a slightly larger ring pack. Bearings are coated and were re-used.

Once the rings seal, they're all slowing down. Hopefully it's a slow, predictable rate of decline. Spikes in the decline are my indicators.

I've always used leak down results or oil pressures changing.

We raced a top alcohol dragster for 9 years. When I started we were running a wipple screw blower that made 50 pounds of boost. We would cool and adjust the clutch every run. We would change the 18 qts of oil and replace 16 spark plugs every run.
Then every 2-3 runs we would replace 3 clutch disc and 2 floaters and pull the pan and replace the upper rod bearings.

After 12-14 runs it got new rods and pistons. Then after 20-24 runs the block came out of the car for new main bearings and we put in our 2nd motor and serviced it the same way.

Then we went to a PSI screw blower, one 44 amp mag instead of 2 12 amp mags, brad billet block. The PSI blower made 60 pounds of boost which required us to replace the upper rod bearings every run and replace the clutch every run. The good thing was we were only using 8 plugs per pass now. BFD
I tuned the car off the upper rod bearings and spark plugs each pass.
There was other stuff that got replaced every run like the CO2 tank and more. I had 6 guys helping me.


We replaced 2-4 inner valve springs too every run and a complete new set put in at 12 runs.

I had 3 complete motors, still have 2 of them. 449",451",454" low deck hemis.

Got to go...

That's bad a$$, and another extreme example of slowing as an indicator lol. When it eats springs, and bearings every run, like it should it's slowing, just faster than can be measured.

Torque it and whack it!

We never put a ton of runs on the car. 100-150/year. System 1 filter got looked at and the car got cleaned and looked at every week, regardless the run count. Plugs, valves, carb, etc., were taken care of regularly. Any abnormal issues that popped up were put on the list of things to keep a closer eye on every week.

It came completely apart every winter. Engine, trans, fuel system, suspension, brakes, everything, and was checked/freshened as needed. Engine got rings, bearings, heads looked at, everything cleaned and inspected. Trans got resealed and anything funky replaced. Ignition parts were changed out, I started the year with everything fresh and didn't run it until it was about to fall apart. If the trans had to come apart mid year to look at to get it to the end of the year in good shape, we did it. We had very few problems with anything failing at the track and were able to work on making the car better from race to race as a result.

For me, I am about 650hp with a stock block so when I get to around 450 passes the block gets replaced along with bearings, rings, springs.