Oregon72 updated compression test 100 miles post Colin visit

[Oregon72]

The last thing Colin told me on his visit was that he wanted to see a compression test on #1 after 100 miles. I've driven the miles and did the test tonight immediately after a warm up drive.

Pulled plug and it looked like this - light tan and seems normal.
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For reference this is the historical date
My results back in early June on #1 just a couple weeks prior to Maupin were 60psi dry and 115psi with oil.
My results with Colin in late June at the beginning of the day on #1 were 60 psi dry then 135 with oil and a dry retest later that same day of 90psi then 95 psi.

Compression test this evening dry on #1 was 75 psi. Added 1 tsp dropper of oil down plug hole and got 105 psi. These figures were done solo-style - in other words I screw in tester and reset to zero, disable ignition at coil, go up front crank engine for 6-8 revolutions, turn off key, run back and read the results. Not sure if this is as accurate as a two person test.

Thoughts on those numbers?? Thoughts in general??

Thanks as always---

[Bookwus]

Hiya Troy,

I'm sure that when Colin finishes up with his Liberace thing down in Pahrump he will weigh in here.

However your new readings sound to me to be consistent with what you've seen in the past. Number 1 sounds like it is sick. Not getting any better and not getting appreciably worse.

[Amskeptic]

Liberace thing . . . .

You are at the cusp of a decision:

If you wanted to dive in and freshen up the engine, it would be delighted to have some attention, and you could gain some power.

If you wanted to wait, I think the engine would patiently await and get you to where you need to go so long as you give it time.
Colin

[spiffy]

A top end rebuild is easy, go for it but spend the money on the best parts you can get.

[RSorak 71Westy]

I concur with Colin, in my experience cyls quit firing when the comp. goes below 60 lbs., so yours is still working, but low.

[AirCooledNut]

A top end rebuild is easy, go for it but spend the money on the best parts you can get.

But aren't those results indicative of bad piston rings? Those aren't a top end item, are they?

[Westy78]

A top end rebuild is easy, go for it but spend the money on the best parts you can get.

But aren't those results indicative of bad piston rings? Those aren't a top end item, are they?

I'd consider anything you can replace without cracking the case a top end item.

[Oregon72]

Yes, it looks like a top end is inevitable. The power is pretty weak when I hit any type of incline. This rebuild/engine pull may be coming sooner than later because I feel I may also have an intermittently failing fuel pump that i believe is causing the cutting out and stalling at speed issues that I've been having. It feels like any small bits of vapor lock and the pump can't work through it. Seems to happen at all times, but happens more during hot weather. Yesterday it happened in the Terwilliger curves here in Portland with the entire family in the bus (a horrible spot to be stalled) Happened about four more times before finally pulling into the driveway and it's just not fun driving around knowing that it could happen at any time. I want to be able to go a trip of decent length and not worry about being stranded. My engine has the mechanical fuel pump and it really looks like the engine must be pulled to remove it on the '72. I'm excited to start in on the rebuild but a little bit bummed that it can't really wait until November or so when the weather starts getting bad. This puts a bit of a damper on camping.

[Amskeptic]

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