[Fot] Race Engine Refreshing Frequency - compression results

[Anthony Parker]

Hmmmm.

Which engine?
How high do you rev it?
How much HP over stock?
CR?
Cam lift and duration?
Oil system?

All of these are more important to me than compression or leak-down tests.

Are you worried about the last few HP, or catching issues before expensive parts get damaged?

I cut oil filters, carefully remove the filter media, and visually inspect each pleat after every race. If I see something, it may be too late, or it may help avoid messing up something that I don't want to replace. Need to be able to differentiate what you find in the filter.

Oil analysis is fine, but you need to establish a trend for the specific engine and then understand what the changing analysis is pointing to.

You have all winter (unless you're going to Florida for winter racing). Take the cam and tappets out to inspect contact faces. (Keep track of the location and orientation of all parts.) Take the oil pan off and at least look at a couple of main bearings and rod bearings. This can be done with the crank, pistons, and rods still in the engine.

Looking for leaks at the valve seats, inspecting rocker clearance, touching up or lapping the valves, and doing a rough check on guide wear is the easy part.

If you've been doing this once or twice a year for a few years and nothing ever changes, then you're in heaven.



________________________________
From: Fot <fot-bounces at autox.team.net> on behalf of James Trudeau via Fot <fot at autox.team.net>
Sent: Sunday, October 29, 2023 9:45 AM
To: Ken Knight <kknight at klaenv.com>
Cc: fot at autox.team.net <fot at autox.team.net>
Subject: Re: [Fot] Race Engine Refreshing Frequency - compression results

Thanks Ken and Tony,

Glad to hear the bottom end has more life. Will do a leak down test and be asking about Triumph top end rebuilders in New England.

Jim

Sent from my iPhone

On Oct 28, 2023, at 7:06 PM, Ken Knight <kknight at klaenv.com> wrote:



If you can barrow a leak down tester that is still the best tool to assess engine health.  I also change oil filters after each race and cut it open to see what is trapped inside.   A well built TR race motor can easily do double those hours on the bottom end.  In my opinion the key to long tern motor health, assuming a good build, is a high quality race oil.  My choice is Joe Gibbs Driven XP-3 10-30, I have bearings that look almost new at 50 hrs. using this oil.  No such thing as “cheap” racing oil.  “Never be beaten by parts” K. Kastner.



Ken







Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows



From: James Trudeau via Fot<mailto:fot at autox.team.net>
Sent: Saturday, October 28, 2023 2:06 PM
To: fot at autox.team.net<mailto:fot at autox.team.net>
Subject: [Fot] Race Engine Refreshing Frequency - compression results



I finished a 9 weekend race/school/track day season that started in April and finished at Thompson in October with no obvious performance problems. Total of 38 engine hours including warmup, grid, race, cool down.



Did a dry compression test today:

  1.  210
  2.  225
  3.  195
  4.  200



I get some oil blow by at the valve cover cap and maybe some drips from lower end seals (not sure if oil starts at valve cover).



I’m sure I’ll hear a suggestion to do a leak down test and / or wet compression.



Oil filter forensics?



In the absence of obvious issues, how much of a tear down is warranted?



Jim

Sent from my iPhone


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