It Just Does Not Sound Right

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Dan Kalinski
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It Just Does Not Sound Right

#1 Post by Dan Kalinski »

Believe our '63 Cab has developed a compression leak on # 3 and maybe a bit on #4.

Compression test shows 180lbs on all cylinders.

Leak down on #3 can hear the air go by the rings and when it is up on the lift, can definitely hear the hiss from under the car.

Same on #4.

Leak down tester show about 20% on the gauge.

Have read in the past that the guys building engines usually don't need to retorque the heads, however, could it be the head /cylinder bolts have backed off enough to cause a compression leak and retorqueing would fix the issue or is it more of an issue with the bolts pulling out of the case?

This engine rebuilt by a pro and has just over 7K miles on it. Dang....

Anyway, know I'll need to pull the engine.

Thanks for any insight on this issue.
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Vic Skirmants
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Re: It Just Does Not Sound Right

#2 Post by Vic Skirmants »

"Have read in the past that the guys building engines usually don't need to retorque the heads, however, could it be the head /cylinder bolts have backed off enough to cause a compression leak and retorqueing would fix the issue or is it more of an issue with the bolts pulling out of the case?"

Heads don't need to be re-torqued. The studs do not pull out of the case.

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Re: It Just Does Not Sound Right

#3 Post by David Aronson »

You did not report on the performance and oil use. With 7k and good performance, I would have fun and drive it. JMHO.
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Mike Wilson
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Re: It Just Does Not Sound Right

#4 Post by Mike Wilson »

When was the last time the valves were adjusted along with a full tune up, checking the timing, etc.?

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Dan Kalinski
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Re: It Just Does Not Sound Right

#5 Post by Dan Kalinski »

Vic Skirmants wrote: Mon Sep 26, 2022 6:33 pm "Have read in the past that the guys building engines usually don't need to retorque the heads, however, could it be the head /cylinder bolts have backed off enough to cause a compression leak and retorqueing would fix the issue or is it more of an issue with the bolts pulling out of the case?"

Heads don't need to be re-torqued. The studs do not pull out of the case.
Thanks Vic.

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Dan Kalinski
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Re: It Just Does Not Sound Right

#6 Post by Dan Kalinski »

David Aronson wrote: Mon Sep 26, 2022 7:27 pm You did not report on the performance and oil use. With 7k and good performance, I would have fun and drive it. JMHO.
Performance is pretty good. Zero or very little oil use.

It is just that clicking sound that is driving my concern.

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Re: It Just Does Not Sound Right

#7 Post by C J Murray »

180lbs compression test is very high, too high, race engine high. 140 would be plenty. Did the engine ping? Are you saying that 3 and 4 have 20% leak down but all 4 pump compression at 180? Strange.
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Dan Kalinski
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Re: It Just Does Not Sound Right

#8 Post by Dan Kalinski »

Mike Wilson wrote: Mon Sep 26, 2022 7:29 pm When was the last time the valves were adjusted along with a full tune up, checking the timing, etc.?

Mike
Hi Mike.

I'm a consistent and careful valve adjuster. Every 2K miles which means the valves have been looked after 6 times and just yesterday prior to compression test and leak down to make sure the valves were not a part of the issue.

Timing is spot on as are the points which I set with a dwell meter. Again, the noise the engine is making has me thinking there are other issues.

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Re: It Just Does Not Sound Right

#9 Post by Mike Wilson »

I'd follow up with Cliff on the compression numbers.

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Re: It Just Does Not Sound Right

#10 Post by Dan Kalinski »

C J Murray wrote: Mon Sep 26, 2022 7:56 pm 180lbs compression test is very high, too high, race engine high. 140 would be plenty. Did the engine ping? Are you saying that 3 and 4 have 20% leak down but all 4 pump compression at 180? Strange.
Yeah, I too thought 180 was high but that may be just the nature of my gauge........ However, the readings were consistent at all 4 corners. And yes, on the leak down gauges, when the compressed air was delivered to the cylinder after calibrating the tester, the % side went to 20%.

Thank you, Cliff.

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Harlan Halsey
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Re: It Just Does Not Sound Right

#11 Post by Harlan Halsey »

Why not take it back to the "pro" who built it?

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Dan Kalinski
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Re: It Just Does Not Sound Right

#12 Post by Dan Kalinski »

Harlan Halsey wrote: Tue Sep 27, 2022 4:35 am Why not take it back to the "pro" who built it?
Have a call to him. He is a good fellow and expect to hear from him soon.

Thank you.

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Re: It Just Does Not Sound Right

#13 Post by C J Murray »

Dan, If you haven't removed the engine yet, I would try the tests with different gauges. The most important consideration is if there are significantly different readings from cylinder to cylinder. The cheaper leak down testers tend to be inaccurate but do show differences between cylinders. If you truly do have 180psi pumping pressure then you ought to correct that. Other signs of too much compression would be difficult starter function and hot oil temps. Pumping pressures are a combination static CR and cam timing.

If there are not variations of readings then your clicking could be an exhaust leak. It could also be a loose valve but you should always adjust your valves before doing those tests.
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Neil Bardsley
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Re: It Just Does Not Sound Right

#14 Post by Neil Bardsley »

Stupid question but it you do the leak down test on a water engine? Don't some pistons slap a bit until warmed up? That said 20% sounds quite high

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Re: It Just Does Not Sound Right

#15 Post by Martin Benade »

Yes to all of those.
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