Just put the head on and it cranks like it doesn't have compression
01-09-2010, 08:58 PM
Like title says i just reinstalled the head after getting it back from the machine shop and it cranks as if it doesn't have any compression. It doesn't start or even try too start. Timing is correct. The only two things i can think of is that the lifters are pumped up too tight and are holding the valves open or the valve job has the valves sitting too far up in the head keeping the valves open. anyone else have any insight. Thanks for your help.
01-09-2010, 09:21 PM
It's probably the crank to cam timing, a valve is probably open during a compression stroke.
01-09-2010, 09:27 PM
The timing mark on the crank is on is up and on 0%. The mark on the cam is up with the mark on the valve cover. The distributor only goes in one way.
01-09-2010, 09:45 PM
Maybe the lifters aren't pumped up enough. You may have to crank it a lot to pump up the lifters.
01-09-2010, 09:53 PM
If it wasn't pumped up enough then it would act as if it had compression. It turns over and when you let off the key you can tell it still spins just a little more than usual before it stops.
01-09-2010, 10:19 PM
Check this out! http://en.wikipedia.org/wiki/Four-stroke_engine
01-09-2010, 10:23 PM
Whats your point
01-09-2010, 10:27 PM
4-Stroke X # of cylinders
What stroke are you on?
What stroke are you on?
01-09-2010, 10:37 PM
I still don't fully under stand your point. Iv rebuilt motors before. About 2 years ago i cam swapped with a xfi and didn't have any problems. Things were setup the same then.
01-10-2010, 01:36 AM
When the timing marks are lined up, the distributor rotor should be pointing almost straight up to the #1 post on the cap. If not, you might be 180 degrees off on the crank.
01-10-2010, 05:50 AM
Collapsed lifters will not allow the engine to take in any air, so it will spin faster than normal. The cam and the crank both have keys that connect them to the belt sprockets, one of the other might have sheared. Drop a straw down #1 spark plug hole and turn the engine until the straw is at it's highest point. Crank pulley should be lined up with the 0 on the timing vernier. Cam gear sprocket mark should be pointing straight up at the notch, and the Pin that juts out of the cam to interlock with the sprocket, should be straight down. Rotor should be pointing at #1.
01-10-2010, 11:13 AM
Your luckey, it's not an interfearence type v8 with DOHC.
01-10-2010, 07:25 PM
Well it got were it would try too start but wouldn't. I did a compression test and had about 210 on #1 and maybe 10 on 3 & 4. Pulled the cam out and 1 lifter on 2 & 3 was stuck. I should have known but its the first time dealing with this type lifter. I couldn't get them too bleed off so i ordered all new, should be here tomorrow. Maybe i wont have too worry about burnt valves for a long time.
01-11-2010, 10:10 PM
Got the new lifters today but still had too but them in a vice too collapse them. Anyway i got them installed the car runs great. The smooth-es idle its ever had, at least since ive had it.
Automotive Network, Inc., Copyright ©2024