Help with compression test #’s and spark plug reading

[Mr.Spool]

Ok engine brought up to temp, wide open throttle, same gauge as previous cold compression test, temp gauge reading about 145 at time of testing.

1- 150#
2- 155#
3- 155#
4- 150#
5- 155#
6- 150#

thats a good cold test for stock motor

 

[1984 t-type]

Ok vacuum brakes are now disconnected from the manifold and manifold plugged off and no change in vacuum so we can scratch bad gauge and leaking brake system off the list what next ?

 

[NOKA72]

I found one time that I was having a low vac issue, and through the egr I was having some type of leak . Maybe something you can look into

 

[1984 t-type]

No EGR on mines port has been welded closed

 

[1984 t-type]

I’m out here testing everything I can think of that’s vacuum related, not done yet ( maybe for the night ) but here’s where I’m at so far. Vacuum ball holds a vac, cruise control holds a vac, there is a line that splits off a tee that shares the same line going to the cruise and vac ball that goes into the interior on the pass side by the ac box ( I’m guessing for the ac controls ) that is not holding a vac so I capped it for now but still no change in vac reading. I disconnect the vac line going to the PCV valve ( RJC valve with not manny miles on it ) and cap that vacuum line and vac gauge goes to around 14 idle 12 in gear. What does this point to a bad PCV or possibly something else ? If PCV which ones are you guys having good luck with ?

Thanks

 

[captndave737]

are you sure your vacuum gauge is reading in psi and not hpa? 10 hpa comes out to 14.5 psi.

 

[1984 t-type]

Vacuum is reading in IN/HG

 

[captndave737]

well it was worth a try.

 

[dank GN]

So did u gave up on the leakdown test and just calling your compression results good enough ? Have you check to see if your cam is getting full lift? You could have a cam lobe going flat .

 

[1984 t-type]

As far as using this harbor freight tester yes I gave up on that, when I can get my hands on a more reliable one I will retest the leakdown. I feel like I am moving forward in the right direction with this so far chasing and eliminating vacuum leaks. I have to dig up my records to get my cam specs but from my reading cars with larger cams and ported heads/ intakes ( which I have ) will have a lower vacuum just not sure it should be this low. So far I have gone from 9 to 14” on vacuum so I will keep on this path before I start pulling parts back off the engine. Seems like I may have a leak on the heater controll vacuum, that line will not hold a vac but the vents will switch so I’m not sure on that one, so for now it’s unhooked.

 

[captndave737]

Make sure you plug the line and zip tie it if it's disconnected.

 

[Chuck Leeper]

Shoot some start fluid under the t/b, right along the gasket on the intake/plenum.

 

[earlbrown]

I'd be more worried about that, than the compression numbers at the moment.

 

[1984 t-type]

I'd be more worried about that, than the compression numbers at the moment.

More worried about what ?

 

[earlbrown]

The low vacuum