4.0 Wont start after new heads installed :-(

[SMART AZZ]

1990 FORD RANGER 4.0

I just installed my new heads and finished installing everything back onto the motor.

It cranks, has fuel, and has spark. (all spark wires are in the right location)

It slowly cranks, and makes a gulping sound and makes no attempt to start.

wtf? anyone have this problem before???

im stumped

 

[JDraper]

You sure that the valve timing is correct? Not 180° out or off by a couple teeth? That can cause what's happening.

 

[SMART AZZ]

I only did an upper rebild, heads only I didnt even touch the timing chain thats why im confused...

 

[mechanix]

A 90 4.0 doesn't have a distributor right?

I would run a compression check on all of the cyl's. This would be a good starting point. Then I would go from there. All the pushrods are all the same length (unlike the 3.1 GM). Might want to charge the bat is could be low, but it should still start. What was the condition of the heads when you pulled them off?

 

[SMART AZZ]

The heads I pulled off were cracked between the exaust and intake valve seats they were the crapy 90TM, I scored an excelent pair of 93TM's on ebay for 50$ couldnt believe it. Had the heads machined and magnafluxed, thems is purty now. I am going to check the compression shortly...

Thanks!

A 90 4.0 doesn't have a distributor right?

I would run a compression check on all of the cyl's. This would be a good starting point. Then I would go from there. All the pushrods are all the same length (unlike the 3.1 GM). Might want to charge the bat is could be low, but it should still start. What was the condition of the heads when you pulled them off?

 

[SMART AZZ]

Found one problem, no compression in cyl #4

 

[BigDakota]

Are you sure you sure you have the valves adjusted right? ..You adjust them by using the nuts on the rocker arms..thus putting pressure on the push rods into the lifters, giving you the correct valve open and closing as the cam and engine crank rotates!!
It could be as simple as that...!!!!! or you had an installation problem during your head gasket install. Is there any coolant leakage into a cylinder?
If all you did was swap out heads on a previously good running engine..well...the list of probable causes gets really short!!

 

[rookieshooter]

Ditto on the valve adjustment. If the valves are too tight and off the seats you wont have compression. I mean valve lash

 

[mechanix]

We talking about a 4.0 or a sbc?

 

[Maniak]

The 4.0 OHV motor doesn't have adjustable valves (I'm assuming 4.0 ohv since thats what the 93TM head is for).. You crank them down as an assembly (rocker arm assembly, no adjustments).

If you not getting compression on 1 cylinder.. Pull the valve cover on that head and double check the pushrods.. On my last head swap one of the push rods didn't seat correctly and popped out. The truck would start but you could tell it was a 5 cylinder.. I pulled the valve cover, pulled the rocker arm assembly off, and put it back on making sure all the push rods are in the right spot. Worked much better after that.

If that isn't your issue, its time to pull that head again.. and sit the head upside down (leave the plugs in) and put some water in the area with the valves. If water leaks through the valve then the head is bad (needs at least a valve job).
~Mark

 

[SMART AZZ]

thanks mark will check

 

[rookieshooter]

like to know? were the heads ever milled.? I have seen heads that were warped, and had to be machined. This will change the valve geometry. it is probably not the cause. But I have had this problem before, were you did not take off the amount of metal taken off the head in ralation to the valve adjsutment. This happened to me a month ago . No compression, once I back off the adjustment... bingo!!! we had comprssion. But u said it was only one cyl. So this is probalbly not the cause. Hope I did not confuse you.

 

[mechanix]

Any updates at to what was the problem of no compression on #5? I am curious as to what the problem is.