Cylinder head stud conversion

[OlDaz]

Has anyone replaced the F134 head bolts with studs? Given that the blocks on these engines are prone to cracking between the head bolt threads and the water jacket, I'm thinking to replace some (or all) of the bolts with studs. You may be aware that the bolt holes go right through the engine casting into the water passage/s, so should have some sort of sealant on the threads, otherwise there's some water seepage around the head bolts. The need for sealant can create a problem when re-torquing the head/gasket. Installing head bolts back into contaminated threads in the block will not help prevent cracks. My thoughts are that if the crack/s are not totally destructive and threads cleaned, new studs could be set with locktite and allowed to "grow" into a permanent position without repairing the crack/s. This should seal the threads and the studs will allow more accurate torque values without any twisting. Thoughts??

[BillT]

I have heard others committing about the studs ‘leaning’. I have never experienced this issue just putting it out there. Are the head bolts/studs longer on a f head than a l head, seems they are.  But I do agree with your reasoning for considering the change. Hopefully someone here has done this changeout and will speak up.

[OlDaz]

Finally located and purchased some suitable studs to replace the 14 long head bolts, still chasing a short one for under the carb. Will see how they go when they arrive. Gaskets have arrived and rings are due to arrive today, so slowly making progress. Will update info as parts arrive and get installed.

[OlDaz]

Many parts arrived since last post. Bottom end closed up a few days ago, biggest issue was repairing the oil pickup float - previously had a hole drilled in it??? so it filled with oil and sat in the sludge in the bottom of the pan. Getting the old oil and sludge out of it was actually harder than repairing it. I bought some T-20 Ferguson tractor head studs 132mm long and fitted them with red thread lock yesterday, I made a new G8 short stud 65mm long to go under the carb and fitted the head today. It was a bit of a bear to fit as some of the studs tilted a little when fitted - future note to self - put head in place before fitting studs, more difficult but possibly a better option. Torqued head to 64ft/lb and set inlet valves at 18 thou. Another issue to be aware of is that the new made G8 nuts are not like old head nuts, they only have around 10mm usable thread where old made nuts have around 13mm usable thread - so IMHO the new nuts will be single use only.

[OlDaz]

The top deck of the F-134 block is a known weak spot in these engines. The head bolts put enormous pressure on the thin cast iron surrounding the water jacket. All but 2 of the head bolts go into the water jacket and suffer from varying amounts of corrosion, making them unsuitable to re-use. In case anyone is interested in reducing the incidence of deck failure (especially in engines that have been decked), the 132mm long Ferguson tractor head studs are the right length to replace the F-head head bolts. ARP makes a small head stud about right for the inlet side under the carb, but I opted to make my own. A couple of pictures attached showing the studs fitted. If you look closely you can see the previous deck repairs and some other fine cracks in the same area - the reason for going to studs. One other thing I learned doing this conversion is that I would advise anyone doing this modification to set the head in place when fitting the studs as some mis-alignment can happen.

[OlDaz]

Engine now complete and finally installed in my CJ3b. A lot of fiddly jobs to do now before I can fire it up. I'll update when I get to that stage.

[OlDaz]

More installation issues sorted, engine bay and under dash electrics sorted, all wiring for the old engine was on the opposite side to the F-134. New ally radiator arrived - it was a 3 core unit for a MB, so I had to make a support to go under it and a brace back to the firewall. Cranked engine over without plugs to get oil circulating, installed plugs and it fired right up. Carb needs an overhaul as a bit of sputtering happening. I'll wait to finish the air cleaner install and see if that makes a difference. All front panels now back in place, had to make up a new shroud between the grille and the radiator as what I had was modified to suit the previous engine. I was surprised how much the gearbox moved when I removed the other engine, seems the people who originally changed the engine must have levered the engine/gearbox assembly about one inch towards the back of the Jeep - pulling that engine allowed everything to de-stress and return to normal, so that was a bonus.
What's left to do is refit the floor panel over the gearbox and refit the shift lever boots, a bit of messing around to make it all fit right now things are more where they should be. And the exhaust, I got a new header pipe made up from the exhaust manifold and it currently ends about level with the back of the gas tank. I need to make up a new pipe to go from there, across the back axle then turn 90 degrees so I can fit a muffler in there somewhere. My aim is to have it on the road around mid year, so on track to get there.