Cranks but won't fire

OK heres the measurements. I've checked my new motor as well as an old one that has never been rebuilt. I've checked in the Ford CD for clearance and theres no mention of it that I've found, so here we go.

Cam snout lenght 2.742" from bearing journal face to end.
Cam syncro gear 1.238"
Cam gear 0.618"
Large cam spacer 0.863"
Small shim 0.158"

Total stacked lenght of components. 2.877"
Amount of componets protuding past cam snout end. 0.135"
Heres the important part:
Thrust plate thickness 0.155"
small shim 0.158"
That gives you 0.003" clearance between the cam bearing journal and the big spacer and thrust plate. That is the area that the thrust plate occupies so 0.003" smaller thickness of thrust plate verses the small shim is what you want.
Should your old small shim and thrust plate measure out correctly then you have something else binding up the cam.
The only thing that can cause that is the rear freeze plug in the rear cam bearing jounal. Look at the rear end of the cam for signs of rubbing the rear freeze plug. Try to take a flashlight and look into the block through the cam bearing holes and see if you can see any sings of rubbing on the rear freeze plug or some forieng object that might have been drop into there between the rear cam journal and the freeze plug.
Hope this helps you. :)
 
Last edited:
Still skeptical about Cam Welding

More food for thought here, a long thread, I don't know if it applies to us though?
from v8sho.com

http://www.v8sho.com/SHO/StillskepticalaboutCamWelding.htm

A Sample:

>>Q: Is gear slippage the root cause?

A: It's the best we can come up with. Pictures of spun cams and my personal inspection of my own reveal that the cam sprocket is not welded to the cam shaft. There are splines on the shaft and on the sprocket which make an interference fit. However... the loading on the cam sprocket is asymmetrical.

The theory goes that the uneven loading on the sprocket induces a side load against the splines which they are not designed to resist. Therefore, over time, the cam sprocket is "walked" down the splines, causing them to fail. Also, it is known that the sprocket and the cam shaft are of different (though similar) materials, with different RC's. It is my PERSONAL theory that in addition to the side loading, thermal expansion differences between the sprocket and the shaft splines allow it more "play" thus exacerbating the problem. The spines on my sprocket were fine, but the splines on the shaft were snapped off at the base, which leads me to believe that just like snapping a paperclip, enough play will break anything.
<<
 
The SHO cam problem does'nt really apply here. Those are completely different cams and there built a completely different way. The SHO cams are built by taking a long piece of hollow DOM tubing to make the shaft itself.
They then grind individual cam lobes which are pressed onto the tubing shaft once there placed into posistion and orientated to give the proper opening and closing points of the valves. The cam gear itself is also pressed onto the shaft as well. They then force a metal mandrel ball through the center of the hollow shaft to swell its OD enough to make all the lobes, bearing journals and sprocket fit tightly together.
What happens is all those parts or smetimes just a few of them loosen up and get out of orientation(by spinning on the shaft) with each other resutling in valves opening when they should'nt and coming into contact with the pistons thus taking out the whole motor usualy. None of this applies to the ancient design of our 3.8 as our cam is one solid piece with only the cam sprocket bolting onto the end.
The SHO motor is an interference engine meaning that if the cams get out of synch with the crankshaft the pistons hit the valves and that usualy results in busted pistons sometimes busted heads and definetly bent valves.
The SC 3.8 is not an interference engine meaning that if the cam orientation gets off for whatever reason you do not have to worry about trashing the whole engine.

I rebuilt an SHO engine for this problem late last fall and its pitifull what Ford is doing to the owners of those cars. Many of them are still under extended warranty and Ford is denying all claims pertaining to this problem. The cost just to buy new cams for that motor is $800 and that does not include any labor our any of the other parts that get took out, its a pretty sickening situation really.
 
MIKE 38sc said:
You should have an oil hole in the 6 o'clock 10 o'clock and 2 o'clock positions. They may also put the wrong cam bearings in there.

Mike, I just checked the front cam bearing for the oil hole positions. The bearings DO have a hole at 6 10 and 2 o'clock HOWEVER, when I probed the holes with a small allen wrench, the only hole that is not "blind" is the 6 o'clock position. After verifying that the small spacer was .003" WIDER than the thrust plate, I believe it could have been a matter of reduced oil flow to the inside of the thrust plate. The outside of the thrust plate was not nearly as badly galled as the inside surface was, but it was still galled.

How critical is it to have oil coming out of ALL of the holes? If only the bottom hole was supplying oil, that may have led to the galling of the metal surfaces at only 1500 miles since rebuild. The other question is, "Is there any way to verify oil will properly flow when I put this back together?" The timing sprockets did seem to be a little "dry" when we opened the cover but since the car had not run in three weeks, I was thinking the oil drained off the surfaces. Is there other paths for oil to flow into the timing chain area, or does it mainly come from the front bearing hole(s)?
 
MIKE 38sc said:
You should have an oil hole in the 6 o'clock 10 o'clock and 2 o'clock positions. They may also put the wrong cam bearings in there.

I just checked the front cam bearing for the oil hole positions. The bearings DO have a hole at 6 10 and 2 o'clock HOWEVER, when I probed the holes with a small allen wrench, the only hole that is not "blind" is the 6 o'clock position. After verifying that the small spacer was .003" WIDER than the thrust plate, I believe it could have been a matter of reduced oil flow to the inside of the thrust plate. The outside of the thrust plate was not nearly as badly galled as the inside surface was, but it was still galled.

How critical is it to have oil coming out of ALL of the holes? If only the bottom hole was supplying oil, that may have led to the galling of the metal surfaces at only 1500 miles since rebuild. The other question is, "Is there any way to verify oil will properly flow when I put this back together?" The timing sprockets did seem to be a little "dry" when we opened the cover but since the car had not run in three weeks, I was thinking the oil drained off the surfaces. Is there other paths for oil to flow into the timing chain area, or does it mainly come from the front bearing hole(s)?
 
Rus, I just took a look at the block I have all torn down and I have 3 holes in the front cam bearing but It dose not matter as there is a grove around the entire bearing so it gets oil from one hole in the block then travels around the grove to the other holes so 2 of mine are blind and 1 open. One other thing to check for is crank shaft end play. You never know , maybe he did not install a thrust bearing but I would think it would have caused some other problems as well. Im still thinking it had something to do with the small spacer.
Most of our parts interchange with the NA counterpart.
 
I do not have any groove in the front bearing. Is that a problem? How can I be sure that proper lube is getting to the front bearing? I also attached both the views of the thrust plate damage.
 

Attachments

  • thrust plate outside.jpg
    thrust plate outside.jpg
    49.1 KB · Views: 51
Russ just because your front cam bearing does not have a 360 deg groove in it that does'nt mean its the wrong bearing. The factory bearings are not grooved as evidenced by the first pic here. This old engine was never rebuilt and all original when I tore it down. Since you do have a oil hole in the 6 o'clock position then you should be getting oil to that bearing. Oil is fed to that bearing from the front crank bearing. The only way you could not have oil flow to the front cam bearing is the feed passage in the block from the front crank bearing going to the front cam bearing is plugged up with something. There is one more very possable thing that could cut off that oil flow and thats the front crank bearings are put in wrong. The 2nd pic here shows rod and crank bearings, the crank bearings are on the bottom row in this picture. Notice one half is solid(lower or cap shell) and the other half is grooved with a oblong hole or slot in the groove(upper or block shell). The grooved half with the hole is suppossed to go into the block, that slot or hole lines up with the feed hole for the cam bearing. You can see that "IF" they put the solid half into the block instead of the grooved one that will cut off the oil supply to the front cam bearing.
I realize that an engine thats set for 3 weeks or so most of the oil is going to run back down into the sump, so its hard for me to tell over the internet if the bearing and chain were getting oil or not. Can you get me a pic of that front cam bearing, maybe I can see some tell tail signs if you get a good close shot of it, particuliarly the bottom half of it at the 6 o"clock posistion.
I'm including a 3rd pic that shows the front cam journal itself to show how the front of the thrust plate and the timing chain get oil. Notice the hole in the cam journal, that hole takes oil under pressure from that bearing and it travels through the snout of the cam to that second hole you see. That 2nd hole is posistioned so that it lines up with a groove in the back of the cam sprocket. Oil sprays out of that groove hitting the back of the cam sprocket and splashing all over the front of the block where the thrust plate is. Oil also flows past that 2nd hole to the very end of the cam itself, right on out the bolt hole. Take a look at the washer under the bolt that holds the cam sprocket on, notice it has grooves in it that run from the bolt hole outward. Those grooves should be facing the sycro gear. Oil under pressure srays out of those grooves and splash's all over the syncro gear and the timing chain and sprocket. Think of those 2 oiling points as rotating high pressure spray heads.
There should be alot of oil spraying around in the chain area between the block face and the timing cover.
Post some pics of the front cam journal and that bearing and hopefully I can give you a better idea what went wrong.


OK Russ theres only the 1st and 3rd picture gonna post here because the bearing picture is in another post. Hopefully this link will take you to the thread with those crank bearing pictures.
http://www.sccoa.com/forums/attachment.php?attachmentid=11007
 

Attachments

  • new shop 053.jpg
    new shop 053.jpg
    65.9 KB · Views: 55
  • new shop 065.jpg
    new shop 065.jpg
    56.3 KB · Views: 67
Last edited:
Here's a pic of the front cam bearing. Notice the freshly ground metal flakes resting below it. There was signs of some oil on the parts in question but probably not enough to prevent the damage. I do see the holes in the front of the camshaft and the retaining screw at the end. I also see the "channel" that leads up from the crank bearing to the cam bearing. Is there any way to check the crank bearing positions without getting to the bottom end of the motor? This project has already gotton out of hand. I am waiting for the last parts to come in from Ford.
The timing chain set and cam was ordered from Autozone, the spacers and thrust plate must be ordered from Ford. They have two thrust plates called out for the 3.8, neither one has a SC designation so I had them order both.
 

Attachments

  • front cam bearing.jpg
    front cam bearing.jpg
    70.1 KB · Views: 62
Russ that cam bearing was getting oil or it would'nt look that good. I really do think it was getting oil, there would'nt be any Babbit left on the shell if it was'nt. Another indication of no oil would be metal parts like that cam journal turning blue from overheating, so would the thrust plate. I've been looking at the pics of your parts for an hour or so and nothing jumps out at me screaming no oil. I think something else is going on, what that is though I do not know. I wished I could physicaly be there to see and touch the motor myself.
Since this was a rebuilt engine maybe a small piece of metal or something got bolted inbetween the cam journal and the thrust plate. Maybe the cam they put in had a nick or burr on the face that mates the thrust plate or vice versa. Sometimes things happen.
I really feel for you but at this point the only thing I can think of for you to do is bolt in the new cam ,thrust plate,cam gear,sycro gear and spacers and make sure everything turns nice and smooth and freely before going any further.
I assume you've verified that theres nothing stuck in the back freeze plug that could be pushing the cam forward? But then again if that was the case the timing gear side of the thrust plate would'nt be eat up like it is, the backside yes but not the front side.
 
Mike, I am at the same point you are. I too was thinking that somehow a small metal shaving got in between the plate but why would "both" sides of the thrust plate be damaged? Besides that, there is a total of .003" space between the assembly. There is nothing interfering with the back side, freeze plug is OK, there is space between it and the back of the cam.

I did get the thrust plate from Ford today. The correct one is PN E8DZ-6269-A. The other one called out by Ford was larger in diameter. I am still waiting for the spacers to come in. Figures that now that I have spent around $250, there is a used cam complete with all the front end parts on ebay for $20. Outa buy it just in case...
 
Got it all back together and it runs, just not right. Must keep RPMs above 3000. I think I have a serious vac leak or something simple (I hope) Asking for help from anyone with a 94 or 95 to compare vaccum lines with?
 
GOT IT!!! :D

I forgot the aluminum tube that goes from the PCV valve to the back of the intake plenum. :rolleyes: With that hole open to atmosphere, the engine will turn over for a couple seconds, and then die. Runs smooth except for a slight hesitation when the throttle is opened quickly. It seemed to have the same problem before so maybe it is a IC tube leak or other small prob.
Thanks to all the people at SCCOA, there is hope for this old 95. Still have to pull the driver's valve cover and see why it is leaking (spraying) oil? I did the passenger side, the stepson did the driver's. What do ya expect... Kids.
 
Hey glad to hear you got it up and running again!
Bet you know more about that engine now than you ever wanted to. LOL!!!!
But since you've gone through what you have I bet you can tackle any other engine problem you may have in the future. I know you do not want to but knowledge is king and now that engine is'nt such a mystery to you any longer, so you're ahead of the game now.
Good luck to you. :)
 
Just a quick follow up, after tracking down some last problems, I am very close to declaring success however, I still have some minor hesitation when opening the throttle quickly from a dead stop. It also still detonates pretty badly at WOT with the Spout jumper installed, remove the spout and no detonation AT ALL, but with a little less pull.
The final things I have done are a new cam sensor (solved check engine light) replaced a few old cracked vacuum lines, and most recently, adjusted my TPS to read .8volts. (originally .95volts) I also resealed the IC tubes, cleaned my throttle body's nasty oil caked interior. I wish I would have completely cleaned the inside of the IC tubes and intake when I had it apart!

If I could only figure out why it is detonating with the spout jumper installed? I was planning on selling it but now that it is finally running good... :D
 
Final report...

After struggling to figure out the WOT detonation problem, $85 and a day with Ford determined the MAF signal was "out of range". They serviced the MAF and maybe made an adjustment, it is now running good with the Octane plug in place. Thanks again to all the SCCOA brains.

PS. Now the power steering rack is leaking at the steering yoke... a love of these cars is synonomous with insanity I think?:D
 
Thanks for the follow-up. Note that you can pull the connector off the MAF and the engine will still run. Works well to trouble shoot if the MAF is involved in an issue. With the MAF disconnected, the engine computer just plugs in some default values.
 
Back
Top