Fresh Engine. Low Compression

[mikestang63]

I will add that when I started my brand new setup for the first time, it was running so rich that my eyes were watering. The plugs were wet and black and the dipstick wreaked of fuel. I changed the oil and there was at least a half quart of fuel in the oil. I leaned things out and started it again and it ran much stronger. No signs of compression issues. I also believe you may have something else going on here.

lol.. ya think?

I think in my earlier post one of the items I said could be the issue was an incorrect adjusted valvetrain or bent valves. Something kept those valves open IMO, as there's no wasy the injectors washed down the cylinders unless you cranked it straight for a day.

 

[a91what]

Ok i checked the valves old school after talkin to my uncle took off the rocker after the intake stroke and poured oil on top of the valve. ( down the intake runner). only #3 had air escape past the valve. what are the chances it bent one valve? im going to rip it down and post pics along the way. gi en the weather holds up. fwiw the car ran great for 30mins or so. but if shes gonna get blown i want it all correct.

 

[mikestang63]

Ok i checked the valves old school after talkin to my uncle took off the rocker after the intake stroke and poured oil on top of the valve. ( down the intake runner). only #3 had air escape past the valve. what are the chances it bent one valve? im going to rip it down and post pics along the way. gi en the weather holds up. fwiw the car ran great for 30mins or so. but if shes gonna get blown i want it all correct.

i thought you did a compression check. if it was one valve the other 7 cylinders would be fine

 

[a91what]

i did. then went and got a new one.... guess i iether did somthing wrong the first time or it was bad. new numbers were around 115 on average wet. thats no good number 3 only gave me 45. sorry i may have built a few engines but im still learnin as i go. This is just a hobby.

 

[gearheadboy]

Now you are making some sense..kinda. Is the #3 injector stuck open? Dripping in? That'll put fuel in the oil in a hurry. And it will wash down one cylinder. PS if it has that much fuel in the oil you DO NOT want it to fire at this point. KABOOOOOOOOOM! Change the oil before you get a good spark somewhere or attempt to start it.

 

[a91what]

changed oil but with the compression comin out the intake valve on #3 im gonna pull it and see what happened.

 

[MikeH686]

You said you checked them all with the rockers off correct? Only reason I'm asking is if you leave the rockers on and close the valves you could have that one #3 cylinder valve shimmed to high where it will never seal up just a thought unless you removed the rockers from the equation before you checked

 

[a91what]

i did remove rockers

 

[MikeH686]

Ok proceed then. That's what I get for speed reading this whole thread

 

[a91what]

ok shes pulled. this is how we do it in plant city.

 

[gearheadboy]

Didn't wanna pull the head in the car I take it?

 

[flstang65]

ok shes pulled. this is how we do it in plant city.

Well, at least it isn't a chain over a tree branch. Lol. Anways, glad you finally decided to pull it. I was just waiting to see what was going on with it. My .02 is that you have several major issues here and you might as well just rebuild it again.

 

[a91what]

lol. not the first time i did it with the tractor. not concrete makes you work outside the box. yeah im gonna just pull the pistons too and see whats really going on. better safe than sorry.

 

[gearheadboy]

Do you have a head off yet?

 

[a91what]

yes.

 

[a91what]

nothing looks damaged. least not to me.

 

[a91what]

looking closely i dont think i got the crosshatching steep enough. looks more like 22* than 45*....... idk what difference that makes.

 

[tb9050lx]

pull the valve out of the head and ck it ck the seat as well . a slightly bent valve may bind in the guide . a poorly cut valve seat can also cause issues

 

[a91what]

ok machine shop is owning up to there work. they are going to pull em apart and recheck..... at least im not paying twice.
Pulled a random piston and the rings look stuck. they dont spin, nor did they spread apart.

 

[madspeed]

Thats a good sign, although I would've hoped theyd've done that during final assembly....