Step by step engine compressiom test

[Duduglanza]

the test was done with wide open throttle. is it possible to be purposely done? and be that low? would a teaspoom of oil raise compression by 50psi? :/

[AdamB]

Have you got any engine build data? Spec sheet? How many miles / km's on the motor?

It can be purpose built to be that low, but that's just daft in my eyes.

If there's a ring sealing issue then yes it can raise the pressure.

[Duduglanza]

thats what im suspecting.

[glanzadude]

Lads i did the same test pulled out the plug for the fuel pump and removed one spark plug at a time and only turned over the engine with the key and got 155 across all 4 and was started for 20mins before test? What you think lads ??? Stock engine lads running 1bar with td04

Edited February 12, 2016 by glanzadude

[russ78]

That kinda compression result is consistent with an old stock engine

Imo I would say rings are nearing the end of there life

Has it had an Uprated Headgasket by any chance ?

[gorganl2000]

Have you got any engine build data? Spec sheet? How many miles / km's on the motor?

It can be purpose built to be that low, but that's just daft in my eyes.

If there's a ring sealing issue then yes it can raise the pressure.

adamb, by any chance do you faintly recall a car from australia/new zealand way back in the late 1990s or early 2000s belonging to a guy name dale (10sec rx7 forum name)?

if my memory serves me correctly, it was some kind of 11.8 sec black ep82 which was rather simply built (stockish 4efte) but delivered on the drag strip...again, iirc they had like 100-125psi cylinder pressures but ran a ton of boost...for some reason i'm thinking either 2-3mm headgasket, but controlled with autronic (or microtech)

that's too far a trip down memory lane to recall all facts lol

[AdamB]

Lads i did the same test pulled out the plug for the fuel pump and removed one spark plug at a time and only turned over the engine with the key and got 155 across all 4 and was started for 20mins before test? What you think lads ??? Stock engine lads running 1bar with td04

That's fine, I take it you on a 4E?

That kinda compression result is consistent with an old stock engine

Imo I would say rings are nearing the end of there life

Has it had an Uprated Headgasket by any chance ?

It's had low compression pistons fitted, so it's been apart before. Must have had new rings.

Hard to judge without a full spec list.

adamb, by any chance do you faintly recall a car from australia/new zealand way back in the late 1990s or early 2000s belonging to a guy name dale (10sec rx7 forum name)?

if my memory serves me correctly, it was some kind of 11.8 sec black ep82 which was rather simply built (stockish 4efte) but delivered on the drag strip...again, iirc they had like 100-125psi cylinder pressures but ran a ton of boost...for some reason i'm thinking either 2-3mm headgasket, but controlled with autronic (or microtech)

that's too far a trip down memory lane to recall all facts lol

I faintly remember the chap you're on about, I don't know any specifics about it though.

Was that on a 5E though? Have to remember the larger displacement of the 5E makes up for the lack of pressure compared with the 4E. I can imagine a 4E being on such low pressure, but not a 5E.

Like I said, need more of a spec list to judge, or to do a leak down test which will provide more accurate reading.

Edited February 12, 2016 by AdamB

[gorganl2000]

That's fine, I take it you on a 4E?

It's had low compression pistons fitted, so it's been apart before. Must have had new rings.

Hard to judge without a full spec list.

I faintly remember the chap you're on about, I don't know any specifics about it though.

Was that on a 5E though? Have to remember the larger displacement of the 5E makes up for the lack of pressure compared with the 4E. I can imagine a 4E being on such low pressure, but not a 5E.

Like I said, need more of a spec list to judge, or to do a leak down test which will provide more accurate reading.

from my memory it was a 4efte...with a lot of boost at that time in starlet history

i had the specs on paper,,,but disposed of a lot of stuff when i moved a while back...

i had documentation on starlets (builds, specs, turbos, power, etc) from the 1990s from austarlet, ttgt, tercelonline, wheelsjamaica, ivan's site, bajanchameleon, hardcoreep, etc....tons of info in folders...lol

all gone now...smh.

Edited February 13, 2016 by gorganl2000

[AdamB]

from my memory it was a 4efte...with a lot of boost at that time in starlet history

i had the specs on paper,,,but disposed of a lot of stuff when i moved a while back...

i had documentation on starlets (builds, specs, turbos, power, etc) from the 1990s from austarlet, ttgt, tercelonline, wheelsjamaica, ivan's site, bajanchameleon, hardcoreep, etc....tons of info in folders...lol

all gone now...smh.

I can imagine 4E's going down to compression ratio's of like 7.4:1 maybe even less, but I think to get a 5E that low would need some serious work.

Damn that's a shame ! I bet there was some great history there, those names bring back some memories haha.

[glanzadude]

Thanks AdamB yes 4E