44 replies to this topic

[PACINO]

Good morning folks!. Yesterday I did a compression test on the engine. I was a little curious to see how much it scores. The readings have been exactly the same on all four cylinders (150 PSI).
Two observations;
- I was hoping it would give a little more.
- And there is not a big difference if we compare it with 5 years ago.

Before/ Federal Mogul Pistons, +0'20, with 15 years of use.
Now/ New pistons from Swiftune +0'40

Both tests are done with the same compesimeter, with the engine warm (not hot), all the spark plugs removed and with the accelerator pedal depressed. Any thoughts?

Thanks in advance!

[alpder]

I've never used a compression gauge. Others will surely have more experience. But I see that your gauge has quite a long hose, which may contain significant air volume. If so, that's effectively reducing the compression ratio?

[PACINO]

Waaao! 195 views, 1 reply.

Incredible

[PACINO]

I've never used a compression gauge. Others will surely have more experience. But I see that your gauge has quite a long hose, which may contain significant air volume. If so, that's effectively reducing the compression ratio?

Hello! I don't think the compression ratio is compromised by the compressor tube. This is an approved device built for this.

Luis

[Midas Mk1]

Waaao! 195 views, 1 reply.

Incredible

Do you want a medal? Manners eh. 

[MiNiKiN]

A compression test, even with a professional tool, only gives you an indication or actually more like a comparison of the condition of your cylinders.
A little oil and you will have completely diferent values, for example.
Maybe your piston and bore was not bad with the old pistons?

At least your engine shows equal values over all 4 cylinders - thats good for a start.

Better than a compression test would have been a "leak down test".

[Rubbershorts]

Hi Pacino. Plenty of subscribers check out all the content out of curiosity and in the hope of learning, but have nothing to comment that would be of any use. I'm definitely in that category. Ten times more entertaining than reading the news   

 

Engine bay looks mint by the way!

[stuart bowes]

same here, you read the initial post, then you have the follow up questions that teach you what you might look for in those situations, then you have the answer, pictures etc,  I look at most things even though I'm not involved 

 

not much to add myself except if you used the same tester both before and after than presumably the 'difference' is the query, not the absolute values, i.e. tubing isn't really in question unless you're trying to get accurate values for some reason

[timmy850]

Has the static compression ratio changed? Has the cam or cam timing changed? Was the engine run in properly with the carb tuned lean? 

[68+86auto]

Compression testing is of little purpose as far as I'm concerned. If being used for diagnostics, I find a leakdown test more accurate but still not as good as other (expensive) methods I use.

[coopertaz]

Waaao! 195 views, 1 reply.

Incredible

here's a reply have some manners eh!

[PACINO]

Has the static compression ratio changed? Has the cam or cam timing changed? Was the engine run in properly with the carb tuned lean?

The engine with its new camshaft (Sw5), and double Hs2 (adjusted mixture) runs well.
I have never exceeded 3000 rpm (I don't want to force it. It seems that when it gets there it doesn't want to go any further. Kms done so far; 800). And it throws oil as I already said. Possibly U shapep sael, incorrectly fitted.

[PACINO]

A compression test, even with a professional tool, only gives you an indication or actually more like a comparison of the condition of your cylinders.
A little oil and you will have completely diferent values, for example.
Maybe your piston and bore was not bad with the old pistons?
At least your engine shows equal values over all 4 cylinders - thats good for a start.

Better than a compression test would have been a "leak down test".

You're right. I'm starting to think the old pistons weren't bad. Frankly, I was expecting more compression with these Swiftune 0'40.

Thanks MINKIN !

[PACINO]

 
... tubing isn't really in question unless you're trying to get accurate values for some reason

Cheers Stuart !

[PACINO]

Compression testing is of little purpose as far as I'm concerned. If being used for diagnostics, I find a leakdown test more accurate but still not as good as other (expensive) methods I use.

I don't know how a leak test would be done... but you see what a leak it has. Keith Calver told me: "For some reason, the U-shaped seal has been placed incorrectly. In my professional life I had this problem 2 times. Now that doesn't happen to me anymore. I turn the engine and gearbox over "It's the last thing I put in. This way I make sure that piece is perfectly fitted."


Thank you friend!