Low Compression

[lyle bright]

I HAVE A STANDARD 911. recently I was told that I have full compression on the left side of the engine and about half compression on the right. I was told I need a complete engine rebuild. Another says it may just be a valve adjustment. What are your thoughts?

[prschmn]

I would wonder-suspect-that cam timing may have jumped-what kind of tensioners does the engine have?

[gomezoneill]

Year/ Model mileage? What do you mean Standard?

[tharbert]

Hey Lyle, welcome to the forum. It would help if you explained a bit more about the car like model year and mileage. There's a fairly wide range of "standard" compression ratios across years and engine types - T, E, S. Can you post the compression test results? How's it running? Smoke? Oil consumption? Are you a Do-It-Yourself type? Maybe some pictures of the engine would help folks know what you have. Yes, poorly adjusted valves may play into your problem as well as Mark's suggestion of a timing issue. Or, it may be something as easy as carbon deposits on the valves. More info!

[afterburn 549]

Originally Posted by prschmn

I would wonder-suspect-that cam timing may have jumped-what kind of tensioners does the engine have?

ditto

[lyle bright]

The car is a 1968 911. It's not an L or an S. That's what I meant by standard. Sorry. I do not know what type of tensioners I have. The only symptoms I have is that it is hard to start when it's cold. If I use starter fluid it starts up real fast but it takes a while to warm up. The choke on the floor next to the gear selector does not appear to be connected to anything. Once it warms up, it runs pretty good. No real hesitation and no real smoke that I can see. If I drive it a while....turn it off and then let it sit for a few hours....like at a car show its hard to start again.

[lyle bright]

I don't have any print out of the compression results ..I was told the left side of the engine is normal and the right side is at about 60% on each cylinder.

[pemz0r]

the knob on the floor is not a choke, it's your heater adjuster.

[theiceman]

wow beautiful car !!!

I imagine mechanical tensioners..
do you have any history of engine work on the car ?

[lyle bright]

no history on the cars mechanicals. It only has 65,000 original miles. No rust on the floors. the car is all original except for the outside color.

[darrin]

Originally Posted by pemz0r

the knob on the floor is not a choke, it's your heater adjuster.

Believe the 68 has a throttle adjuster between the seats for the MFI -- see, Porsche 911E (B Series) ~ 1968-1969

[pmax]

Originally Posted by lyle bright

no history on the cars mechanicals. It only has 65,000 original miles. No rust on the floors. the car is all original except for the outside color.

Nice car !
No history means the miles are really unknown however.

Adjust the valves and do a leakdown.

[pemz0r]

Originally Posted by darrin

Believe the 68 has a throttle adjuster between the seats for the MFI -- see, Porsche 911E (B Series) ~ 1968-1969

I believe the MFI started in 1969 in LWB cars, that were built in post August 1968. I will look deeper into this.

[pemz0r]

I was correct, the B series were built from August to July serial 619001 to 6392126, classified as the first LWB 1969 models. You are correct about the added "hand throttle" for MFI engines.