How often to rebuild ITC engine?

[John Payne]

I am new to IT racing after many years in small bore prod and GT. I have had 1 person tell me that these engines are good for 40 to 50 hours with general head maintenance. I have a Datsun 1.4L with 28 hours on it (it is reasonably stock per the regs). I would like to get some "expert" advice on where the rebuild threshold really is.

Thank you so much for your help. Really enjoying what appears to be a minimum maintenance - high enjoyment car>

[spawpoet]

I'm sure every engine is different, but on our L-6's we've been told about 50 hours between full rebuilds. We will replace the valve springs at the beginning of every season, but don't otherwise do anything else outside of plugs regularly. And outside of the engine that came with our car which was an unknown, we haven't had a major engine issue in 5 years of running our car.

[John Payne]

Seems to confirm what I heard from another source. Interesting that you are replacing the valve springs when you do the head maintenance. Makes sense!

[joeg]

For me, it is run them until they leak too much oil (blow-by manifestation).

When I ran more races, I could expect a season and a half before changing out.

[spawpoet]

Seems to confirm what I heard from another source. Interesting that you are replacing the valve springs when you do the head maintenance. Makes sense!


We are doing that based on the recommendations of other Z racers and also the engine builders we've talked to. It's just to avoid valve float if the springs are getting fatigued from constant high RPM use. It definitely can be an issue with the L motors, and we've popped rocker arms off 3-4 times, luckily without any other resulting problems.

[Jim Royal]

My engine is on it's 82nd start over 6 seasons and I've never had the head off. Still has good leak down and no oil blow-by. We don't crank the RPM like a GT car so the engine is not stressed much beyound flogging it on the street. This is the main reason I love IT. Minimal work for maximim fun.
enjoy,
Jim Royal
ITC Renault

[Flyinglizard]

You can measure the seat pressure with the head on , if you look around for the lever and load cell. You may have to make the lever/press, for your head.

I run the car and see how fast it is. , check the compression,. If you get passed on the straights rebuild it.
If you run pretty well down the straights, check everything that you can for a baseline. Write stuff down***
Mon post race, check those . Like leak down, cranking compression and maybe valve spring pressure..

IN my case, The ministock needed the valves lapped in every 8 races. It ran to 7400RPM -70 times per night.
The Prod car needs them lapped about every year,as it is shifted @ 6800, and pulls to 7200-7300, one time each lapp @ Sebring.

[itccrx36]

My ITC Honda engine has about 75 races and an estimated 5000 race miles over the last 9 years. This is mostly sprint races but I have run several enduros including a few 3 hour races. It is not showing any signs of wearing out. Oil consumption is stable at about 1 quart every 200 race miles and still making good power. This is the engine that won the 2007, 2011 and 2012 ARRC and has the Road Atlanta lap record.
I think there are several things that help you have an engine last.
1: A good build in the beginning and then proper break in.
2: never let it run hot.
3: never run low on oil.
4: A good air filter. Just a little dirt can really kill an engine.
You can check compression and leak down to judge when to rebuild but the main thing we are after is power. I don't worry about it until power is starting to go down or other problems like using too much oil.
Will Perry