351c vacuum reading

[josephqatarcarguy 3]

hey, im getting a vacuum reading of 14 at idle, is this low?as rpm increases the reading goes up .... 351c 2v with edelbrock intake and comp cam 256H camshaft... car starts up and runs real smooth ... there is a slight engine vibration.

Also im losing engine oil... no visible leaks/smoking, could it be the intake is leaking internally?


but the car runs/drives real good.

 

thank you

[RogerC 136]

There's lots of info on these forums. I have saved several threads from them into pdfs. I don't recall what vacuum should be at. For the oil, if your checking oil level right after shutdown, wait a couple of minutes and recheck. You may not be getting good drainage from the heads. Clevelands tend to send more oil to the top end and it may not be draining back to the pan fast enough.

http://351c.net/board/

https://www.tapatalk.com/groups/clevelands/  (old archives)

The Pantera forums have good info also

https://pantera.infopop.cc/

[barnett468 418]

That is not unusually low and it may increase with more timing. I can post one way to check the timing later, but for now you can try advancing it 4 degrees and see if the vacuum and the rpm increases a noticeable amount then report the findings.

Do you have a single or dual diaphragm vacuum advance can?

[josephqatarcarguy 3]

6 hours ago, barnett468 said:

That is not unusually low and it may increase with more timing. I can post one way to check the timing later, but for now you can try advancing it 4 degrees and see if the vacuum and the rpm increases a noticeable amount then report the findings.

Do you have a single or dual diaphragm vacuum advance can?

if i increase the timing rpm increases but the car starts pinging . the car runs perfevt now bt will the oil consumption?

[barnett468 418]

15 minutes ago, josephqatarcarguy said:

if i increase the timing rpm increases but the car starts pinging . the car runs perfevt now bt will the oil consumption?

The car starts pinging at idle when you advance the timing?

Did you do a compression test?

You didn't answer my diaphragm question.

 

 

[josephqatarcarguy 3]

7 hours ago, barnett468 said:

The car starts pinging at idle when you advance the timing?

Did you do a compression test?

You didn't answer my diaphragm question.

 

 

No,  it starts pinging under load if I advance the timing and it has a msd pro billet distributor with vacuum advance  

[barnett468 418]

2 hours ago, josephqatarcarguy said:

No,  it starts pinging under load if I advance the timing and it has a msd pro billet distributor with vacuum advance  

Ok then you can increase your timing at idle then reduce the amount of total timing or delay the onset of the timing if you want but this won't fix your miss.

 

You didn't answer my question about the compression test. It may have low compression in one cylinder.

[josephqatarcarguy 3]

2 hours ago, barnett468 said:

Ok then you can increase your timing at idle then reduce the amount of total timing or delay the onset of the timing if you want but this won't fix your miss.

 

You didn't answer my question about the compression test. It may have low compression in one cylinder.

the car does not miss... runs real nice and yeah , i had a shop here run a compression test and it looked fine 

[barnett468 418]

30 minutes ago, josephqatarcarguy said:

the car does not miss... runs real nice and yeah , i had a shop here run a compression test and it looked fine 

well you said it runs rough, and if an engine is running rough it is typically from low compression in one or more cylinders, an electrical issue like a bad plug wire or bad plug, or a big cam or it could be from an imbalanced engine or imbalanced or bent flywheel.

 

 

 

[josephqatarcarguy 3]

9 minutes ago, barnett468 said:

well you said it runs rough, and if an engine is running rough it is typically from low compression in one or more cylinders, an electrical issue like a bad plug wire or bad plug, or a big cam or it could be from an imbalanced engine or imbalanced or bent flywheel.

 

 

 

cars  starts up , runs and pulls hard no issues there  but im losing oil with no visible leak? could it be a internal intake manifold leak sucking oil in?

[1969_Mach1 333]

8 hours ago, josephqatarcarguy said:

No,  it starts pinging under load if I advance the timing and it has a msd pro billet distributor with vacuum advance  

If you don't have the instructions for that distributor, get them from the MSD website.  It has graphs of timing curves with all the combinations of springs and stop bushings available.  They help take guess work out of selecting the appropriate springs and stop bushings.  As a starting point I set my MSD Pro Billet distributor up as close as possible to the curves in the Ford reproduction service manuals.  By the time you get the initial timing and mechanical advance setup, you likely will not need the vacuum advance.

Do a compression test like Barnett mentioned to help find the oil consumption problem.

[barnett468 418]

5 hours ago, josephqatarcarguy said:

cars  starts up , runs and pulls hard no issues there  but im losing oil with no visible leak? could it be a internal intake manifold leak sucking oil in?

if the intake gasket is leaking in the valley, it could suck up oil. one thing to determine if it is getting excess oil into one or more of the cylinders is to remove the plugs and number them with a felt pen then look at the porcelain and see if it looks wet and oily.

you could also be sucking it up thru the pcv if you have aftermarket valve covers, in which case you can put an oil catch can in the pcv line to see if it gets oil in it. they sell them at summit racing.