Compression Test G13BA

[Highlander]

Anyone know the specs for compression in the G13BA engine?

Did a bit of Googling but getting all different figures, probably from the different engine types.

[Highlander]

Anyone?

[Ladaman]

Is it just for doing a compression test, or somthing more specific?

If for a compression test I'd think it's about 10:1 so a reading approaching 150 PSI should be expected. The main thing is they are all similar.

Any use to you?

[ScottieJ]

Specs for a G13 1298cc

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[Highlander]

Cheers guys, thats the same sort of range of answers i've been finding, 150-200psi

I've been doing a compression test on my son's engine, he has a broken valve and scored cylinder so we're fitting another engine.

the readings i got from his were 0, 145, 145, 145

I've also measured three of mine now, all 1298cc G13BA and all are pretty much exactly the same, 145psi

None are smokey, use oil or lack power so this 199 psi figure for a good cylinder with a service required below 170 psi doesn't ring true to me.

Is that spec maybe for the DOHC G13B Scottie?

Has anyone else tested their compression?

[ScottieJ]

No that spec is out of a samurai service manual, as long as all cylinders are even I wouldn't worry too much.

[Ladaman]

If you squirt a little oil down the plug hole and the compression rises then that could indicate ring to bore wear.

Are you testing it with all the plugs out so get a better cranking speed?

As I say 150ish doesn't sound too bad for an aging car, 199 sounds high to me. That's about 13:1 compression ratio!!

Have you actually found that anywhere? Multiply the compression ratio by 15 and that will give the max cylinder pressure. (I believe).

[Rhinoman]

Have you actually found that anywhere? Multiply the compression ratio by 15 and that will give the max cylinder pressure. (I believe).

Its quite dependent on camshaft timing so it varies between engines.
Around 170psi is pretty good, 200psi I don't think my G16A made 200psi when it was new. 145 seems a bit low, is that full throttle all plugs out? it may just be the tester, a 10% error would be around 15psi.

[Highlander]

Tried some of your ideas guys cheers

Borrowed the garage next doors compression tester and tried my three again, with the same results, so my tester looks to be ok.

I've now tried it with plugs in and out and with the carb opened up fully and with oil down the plug holes but the same results every time.

145-150psi over all 4 engines seems a big coincidence to me but maybe they all have just worn at a similar rate, most of them are after all 25 years old

[Andrew413]

My poor engine :(!