Hi Everyone,

I am getting MANY mixed answers even from dealerships about the main bearing cap bolts being Torque to Yield.

I have a 98 F150 with a 4.6l Romeo engine and I cannot find a definite answer about the bolts. I have read that they are TTY and then I have read only the 01 and up engines have tty main cap bolts.

Any input would be GREATLY appreciated. I don't want to spend the $75.00 to replace them if they are not TTY.

 

Spend $10 for a service manual CD or DVD for your truck.

 

All 4.6L and 5.4L main cap, rod end cap and headbolts are TTY if my memory is correct. Give yourself piece of mind and replace them anyways. Its worth it to not have to worry!

 

Yes what Thomas said except I personally would reuse them. Have built hundreds using the same bolts over with never a problem. If it makes you sleep better at night then buy new ones..Just remember if you do use new bolts they must be prestretched before performing final torque.

Here is the factory service method;

Starting with the middle maincap #3 then in sequence.

1. torque main bolts 1-10 37-43 NM
2. rotate main bolts 1-10 65-95 deg's
3. torque jackscrews 11-20 9-11 Nm ( clockwise)
4. torque sidebolts 21-30 19-23 Nm

 

I've read before that you need to pretension (prestretch) the bolts. How to you go about doing that? I'm planning a rebuild, and need some of the answers the OP is needing.
Thanks.

 

There's some good info. I would use them again. As long as nothing over heated.

 

I was thinking about looking that up, just out of curiosity lol.

 

The 98 5.4L =

Vertical



Tighten the bolts in two steps in the sequence shown.

* Step 1: Tighten to 40 Nm (30 ft. lbs.).
* Step 2: Tighten an additional 90 degrees.

Side Bolts



Install the side bolts and tighten in two steps, in the sequence shown.

* Step 1: Tighten to 27-33 Nm (20-24 ft. lbs.).
* Step 2: Tighten an additional 85-95 degrees .

 

Dynotech posted this already, I'll thro in a few diagrams with it -

98 4.6L Romeo -

 

I just found some information I had in a Ford engineering 543 build folder regarding the reuse of the main bolts, It says. Note; the main bearing cap fasteners (bolts) may be torqued to yield a maximum of (5) times. In other words they can be reused a max of five times. Another thing is that the side bolts are not torque to yield and should not have a step 2 which states the bolts are to be rotated an additional 90 deg after the initial torque as shown in your second top post diagram jbrew. If that is attempted those bolts could break.

 

Edit:

Sorry I was getting off topic

 

Not so much......

I know the the ARP head studs require 5 stretch cycles before before final torque: they are not TTY. I believe other ARP fasteners, rod caps and cracks bolts require the same.
There, that's off topic!

 

Thanks

 

Only going from my experience and the actual Ford engineering sheets that I followed for over 20 years. I am refering to the OEM bolts and the advice from the fastener manufacturers that sat in our meetings. The head bolts can also be reused a max of 5 times as stated right from the suppliers. Have reused them to that degree many times while building slave engines for component testing with never a failure. Would I personally use them after 3 or more installations in my or anyone elses vehicle,no but I have used them over for a second application in many engines with never a problem. The OEM torque to yield bolts only require one (1) prestretch application. I hate even mentioning these numbers here because this is usually the response and believe me I completely understand.. As far as rotating the side bolts another 90 deg. we did not perform that process during PV, DV, or any other assembly of these engines. In fact during PV and DV teardowns (every bolt torque recorded every engine componet measured) engineering requested that we perform breakaway torques on the side bolts using a clockwise (tightening) fashion like the torque to yield bolts were. When the guys attempted to do this we were snapping the heads off the bolts. The direction was corrected and a counterclockwise breakaway was used on those bolts and sparkplugs only. Don't be shy about questioning my posts as I in no way think that I know it all about anything. But I am simply relaying to everyone here my experience with the hopes it can help someone out. You guys know about race/performance application here more than I ever will and with that in mind I try to pickup whatever I can from your knowledge. Take care.

 

Thanks everyone,

I went ahead and reused them. Ive personally never heard of having to replace main bolts before. I have rebuilt a bunch of chev motors and never had to. Engine is back together so I will get it into the truck this week and cross my fingers. You never notice how much you need a truck until you can't use yours. LOL. Its gotta be done by labor day. Not camping or taking the jet ski's out this year is killing me .