96 Cobra Motor , turning by hand

[aggressionred]

Hey guys,

I posted this at another forumn but thought that i should do it here
too, just so that I can get any other opinions lurking out there.
The background is that I have a 96 cobra motor that is being used
for a swap into a 96 GT. Yesterday i had some problems and posted this
at FastestModulars:

"Hey,

So i have the motor ready to go in, but before i did that i wanted
to change the rod bearings. The motor had been sitting for a little while
in a shop and i thought it would be good insurance.
I got standard size(not over/under) rod bearings , and got the motor ready
by turning it. I uncapped one rod at a time, thouroughly cleaned and dried
the cap, and the inside surface of the rod. I put in the bearings with assembly
lube and torques the caps down to spec. I was also very careful to make
sure everything was aligned the way it came off. Plus all the cracked caps looked good. everytime i would get two rods done i would turn the crank so that
the rod would make 2 full turns so i could see if it was binding. I did
that until i got all of them done.
THEN
i turned the motor over and popped the valve covers off the check the
clearance of the cam base circle to rocker. When i started to turn the crank
to do this - it got to a point and wouldn't turn any further.
I backed up completely the other way and it only went about 270degrees
before it stopped again!
I turned to motor over to check to see if any of the rod/counterweight stuff
was messed up but it all looked fine.
Any ideas what that could be? I'm sure if it doesn't turn freely out of the car
then in won't turn freely inside the car.
Do you think i caused it by my methods listed above? i SWEAR i thought
it was turning complely freely when i was putting the rod bearings in.
I'd appreciate any help, thanks!"

I was wondering if anyone else might have input?
thanks in advance.
-Mitchell

 

[tomustang]

where the heads and timing chains on the whole time?

 

[aggressionred]

the whole time.
I don't think one of the valves could have gotten
stuck while i was doing the bearings. And I'm pretty sure
nothing fellin while i had the motor topside or turned over.
Could something with the chains be causing it?

thanks!

 

[tomustang]

did you clean off the crank and check the sizes?

 

[trinity_gt]

1) From the factory the rod bolts are TTY (torque to yield.) Did you use new bolts when you did this work?

2) Did you turn the engine in the normal direction of rotation? If not, perhaps a chain has jumped and you've got PTV.

 

[aggressionred]

Hey guys,

sorry about my noobness, but
1. what sizes should i have checked?
2. whats PTV?

 

[aggressionred]

Also, i know i shouldn't have - but i did re-use the stock rob bolts. Could it have made that much of a difference alrready? Its like.. HARD stopped.

 

[trinity_gt]

Also, i know i shouldn't have - but i did re-use the stock rob bolts. Could it have made that much of a difference alrready? Its like.. HARD stopped.

The rod bolts aren't causing your locking problem. I mentioned them because, since they are TTY and you didn't mention using new ones, you need to know that they are measurably weaker now. When a bolt yields, as these do by design, they do not return to their original length when the load is removed. They also suffer what's called "necking", where the section area decreases, much as it does when you stretch out a piece of licorice. By re-using TTY bolts in such a critical area your engine is a spun bearing waiting to happen.

PTV is "piston to valve" contact and it may occur if the cams get out of phase with the crankshaft due to the timing chain(s) slipping a tooth or two.

 

[Dan_Soprano]

dumb question. but did you leave a spark plug in by accident?

 

[aggressionred]

Actually, I did have a spark plug in by accident while
changing the rods, but took it out afterwards. With all of them
out it won't turn.

Trinity_gt,
about the rod bolts - i knew that there would be stretch, but
decided to re-use them anyways because after this swap i wouldv'e
been tapped out. I wouldn't have had any money for a blower or nitrous
or cams, so i thought that it would be safe on stock HP numbers.
I know thats not a good excuse, but at least its a reason.
I will get new rod bolts and re-do them.

If i have PTV, and knowing that i can't turn the crank ( i haven't checked to
see if it lets me get to TDC ) - does that mean I will have to take the
chains off and re-time?

again, I appreciate all the help guys - Thanks

 

[billfisher]

be very careful. move the cams to safe position and remove the main chains. turn the crank by hand. it will now turn 360. 90 percent probability is the cam phasing.

with the cams locked safe, they are out of the way. you are going to have to remove the pan and rod bolts anyway. if you don't they WILL break. you can replace them with arp units if you like. you are asking to lose a cap or two at high rpm's. not catastrophic necessarily, but a lot of work to redo and remachine stuff. sorry dude.

 

[aggressionred]

I still have to have the Ford OTC tools that hold the
cam in place and align the cam, right?
Which i believe are -
Ford T93P-6256-AH
Ford Tool T93P-6256-A

lock down&align the cams, undo primary chains, rotate crank and
align the timing marks.

pretty much right?

 

[billfisher]

yes. if it still has a problem it is in the bearings, but i think it is timing. good thing you turned it by hand first.

 

[aggressionred]

UPDATE

well guys,

I was a little frustrated about the whole ordeal because of what i was going to have to go through to get the motor turning again.
My original plan went something like this:
1. buy motor.
2. replace rod bearing.
3. put motor in car.

now my plan was going to have to go something like this:
1. 1+2 from above
2. buy the cam tools ...bleh
3. buy a million gaskets and bolts(cam caps, head, rod)
4. re-time the engine
5. alot of other stuff that makes me sigh

so anyways, a friend and I looked back over all of the rods and caps again, and in the lower main oil groove thing to see if there was anything causing a stop. - there wasn't.
We took the timing cover off and the chains were pretty tensioned - and none of the cam gear teeth looked cracked/broken. - so it wasn't that.
We also shined a light into the oil pump pickup tube while turning the engine and it didn't look like anything in there.
I got mad enough that I decided to undo the cam stuff right there.
I didn't have any of the holding tools or anything like that - but just labeled and undid the cam gears and then the cam caps and the cams themselves(in reverso order of tightening seq.) then i undid all of the chaining and tensioners(taped them closed) and also took that off the engine.
Then all the cam followers and lash adjusters came out and into nice labeled compartments in a box(did all this because we were turning the whole engine upside down and they would have fellout).
Now there was no tension on the valves and they should all have been closed - so no PTV, right?
Wrong! - engine still hit. It would only rotate like 310 degrees each way before stopping. We visually checked all the instake valves to make sure they were close - but you can't really tell about the exhaust valves.
By now we were pretty sure that we weren't dealing with a PTV error and that maybe something had fallen into the bores.
This morning i decided to take the heads off to check(bleh). I flipped a coin and decided to do the driver's side head first. I undid the bolts and carefully lifted the head out and put it down. While i was putting it down I heard somthing fall. i went ahead and put the head down but tilted it so i could see the valves and combustion chambers - didn't see anything, BUT on the floor beside it i saw some little plastic pieces. They were off a fuel injector clip that i had broken while taking the wiring harness off. I was pretty sure they weren't there before this because i had just swept the garage.
I went back to the engine - checked the bores - nothing. with the wrench in one hand and a can of wd40 in the other i started turning and lubing the bores to prevent rust, and guess what! - IT STARTED TURNING!
I turned like 5 full turns to make sure but - that was it!
I'm not sure , but i think that it could have been those plastic pieces i found that were next to the head.
The thing is that i really don't know how they could have gotten in there if the motor was upside down when we were doing the rod bearings and we were turning it freely then.the peices would have to have been in the intake ports to survive that - then when we turned the engine over and started turning the crank - rolled into the bore. Weird, but i'll take it.

So now - i have one head off and all the cam/timing stuff off the motor - when i only expected to have the oil pan and oil pickup tube off to do the rod bearings. I guess i really have no one else but myself to blame for the added expense i thought i was being careful but wasn't careful enough.

anyways - i've never timed a 4v before but read this:
http://www.modularfords.com/forums/4v-modular-tech/official-4v-cam-and-valvetrain-thread-7544.html

any other tips?

also - anyone looking for the cam tools and thinking they were going to
have to spend 300 for them -check this out:
http://www.tooltopia.com/index.asp?PageAction=VIEWPROD&ProdID=10075

and one last question:
anyone know where i can buy all head bolts, rod bolts and camshaft cap bolts for good prices? i read that the camshaft bolts are like 2.95 a piece - and there are like 130 of them.

should i take the other head off and have a shop steam or hot tank them? do the valves have to be out for them to be cleaned?nonono: here we go buying the vavle spring compressor tool ..)


Anyways - as you can see i've been a lurk here for a long time and never really posted. I just wanted to thank all you guys for helping out when i did need it though - i may be calling on you again soon..THanks!

 

[aggressionred]

pics

 

[aggressionred]

more pics

 

[Rick 91GT]

Well while the heads are off you should have them checked depending on the milage of the motor. They can tank them with the valves in them but it would be best to take them apart to get the throughly cleaned, I'd also want to check the seats and the guides.

I am building a 96 Cobra motor for a customer and with 80,000 miles I found bad guides, it needed a valve job in the worst way and the secondary ports were near clogged with crud, damn IRC plates. Keep in mind this was a good running engine before it came apart to be built....

If you take off the valve spring and look into a secondary port I think you will be surprised with the build up.

However be prepared it isn't cheap, actually nothing for that motor is cheap. I am building a very healthy blower motor so I went with ARP main studs, ARP head studs, etc...


What was the main purpose pulling the motor apart? That tool link above is OK but it doesn;t have the tool to remove the springs and retainers, the MAC kit I have requires the cams to be in place to remove the followers. springs and retainers....

 

[aggressionred]

well the original plan was swapping my 96GT motor for a 96 4v.
when i got the 4v i was just gonna do the rod bearings and drop it in.
now this ...

I already did look at the secondary valves and they look carbonized as crap.
I have pics on all the secondary intake ports but they are way to large to post as attachments. The motor was advertised as having 78K on it.
Looking at the bores - i can't really tell if they are in good shape for that mileage or not.

Your right - the toolset above deoesn't have the valve spring compressor tool. but i bought it when i thought i would just be taking the heads off and putting them back on. Now i'm thinking about getting a valve job done so thats why i brought that tool up.