What have you done to your Land Cruiser this week? (37 Viewers)

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Just about every machine shop will check and just deck the head per the request of the customer. It's not that uncommon.
 
Installed the PTO winch and rolled up 165' of 5/16" wire rope with original chain and hook. 😁

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RevISK said:
Was rebuilding the head a choice? Seems young to have to.
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I was building what I consider my last motor for this vehicle. Rebuilt short block all new everything.
Valve seals where shot and springs where weak as well. I figured I’d cry once. Wasn’t as bad as I thought.

This 250 went into my defender 90. I love this motor. Wish I swapped my 350 in the fj with a 250 instead but it was there when I purchased my fj.
 
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Grayscale said:
Is this first-hand experience? In one of your rides?
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I owned a dealership for 20+ years.
Machine shops make most of their bread and butter money machining heads flat and flywheel machining.

They are happy to do it. They can also tell you if your valves are leaking or springs are out of tolerance. This is not an area to “save money”
 
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Grayscale said:
Is this first-hand experience? In one of your rides?
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I've done it and worked in repair shops that have done it. You diagnose a blown head gasket and get the heads decked. I had 1 friend that wanted to increase his compression ratio on his 79 sbc on the cheap. He had machine shop cut .050" off the head. I think he went from around 8 to about 9:1.
 
The tolerance for cylinder head warping is .0059-inch, as per factory specs. Let's say that the shop removes a bit of material, when decking the head, okay. But, decking .050-inch for compression chamber modification significantly changes the location of the rocker assembly. The maximum head refacing limit, as per FSM 2F is .008-inch. That means that you only get one chance at head-decking, or it is unnecessary as it is within specifications, as per FSM? Why not save that procedure for when it counts, a full engine rebuild? A head gasket replacement, alone, can be performed multiple times. Because iron castings are excellent in compressive strength, weak in tensile or sheer strength, as compared to steel or wrought iron, tooling used to machine it makes grain-like chips, not pasta or slinkies. The low tensile strength of the material is an issue when the tool encounters edges of the water jacket etc - corners aren't strong, like the blow-out experienced in cutting lumber. Simply changing the HG doesn't directly impose any kind of metallurgical changes, by subjecting the casting to a high-impact process of running a milling machine's fly-cutter over it, especially for those corners and surfaces where cracks begin to propagate.
 
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Grayscale said:
The tolerance for cylinder head warping is .0059-inch, as per factory specs. Let's say that the shop removes a bit of material, when decking the head, okay. But, decking .050-inch for compression chamber modification significantly changes the location of the rocker assembly. The maximum head refacing limit, as per FSM 2F is .008-inch. That means that you only get one chance at head-decking, or it is unnecessary as it is within specifications, as per FSM? Why not save that procedure for when it counts, a full engine rebuild? A head gasket replacement, alone, can be performed multiple times. Because iron castings are excellent in compressive strength, weak in tensile or sheer strength, as compared to steel or wrought iron, tooling used to machine it makes grain-like chips, not pasta or slinkies. The low tensile strength of the material is an issue when the tool encounters edges of the water jacket etc - corners aren't strong, like the blow-out experienced in cutting lumber. Simply changing the HG doesn't directly impose any kind of metallurgical changes, by subjecting the casting to a high-impact process of running a milling machine's fly-cutter over it, especially for those corners and surfaces where cracks begin to propagate.
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So space the rockers up by .050, when you're building a SMALL BLOCK, it's a matter of calling the right guy with a credit card in hand.
2fs get trickier, but I don't think I'd stress about taking .050.
Just check that the adjuster rides the valve close to center and call it good...
 
trainbufftony said:
So space the rockers up by .050, when you're building a SMALL BLOCK, it's a matter of calling the right guy with a credit card in hand.
2fs get trickier, but I don't think I'd stress about taking .050.
Just check that the adjuster rides the valve close to center and call it good...
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I agree that .050-inch isn't something that I'd stress over, either. But, it changes things. The 2F waterjacket has this little .250-inch deep passage. If you remove .050, then you restrict the movement of coolant thru this narrow passage under the spark plug hole. Also, sticking to the book, at .008-inch decking is worth the coin, when you are not racing but instead in it for the long-haul. I'm fairly certain that the condition of the head gasket and the proper torque of the headbolts is all that is necessary, if everything else is in spec. I wouldn't pay to build a tricked-out motor. I'm in it for the long-haul, and I like lesser priced low-octane gasoline, and I respect that the gasket will yield to the headbolt torque.

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Grayscale said:
I agree that .050-inch isn't something that I'd stress over, either. But, it changes things. The 2F waterjacket has this little .250-inch deep passage. If you remove .050, then you restrict the movement of coolant thru this narrow passage under the spark plug hole. Also, sticking to the book, at .008-inch decking is worth the coin, when you are not racing but instead in it for the long-haul. I'm fairly certain that the condition of the head gasket and the proper torque of the headbolts is all that is necessary, if everything else is in spec. I wouldn't pay to build a tricked-out motor. I'm in it for the long-haul, and I like lesser priced low-octane gasoline, and I respect that the gasket will yield to the headbolt torque.

View attachment 3786806
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In my limited experience building engines, it's always worked to my advantage to deck the head and pay up for a full valve job with guides.
You don't generally realize how bad it has gotten until you take a spin with the new head on.
That's why I always start on a unknown engine with a comp/leakdown test. If it's got low comp, there's no point adjusting timing or carburation, the adjustment won't hold, and eventually you bite the bullet and pay the machine shop.
Then you wonder why you didn't do it sooner...
That's been my experience anyway...
My fj55 is probably due, but I'm still driving it...
 
Grayscale said:
But, what shop is going to just deck a head? Do they stand by their work if there are further issues? The head also needs to be cleaned, as the milling process can introduce metal chips into the water jacket. It needs magnifluxing, if the cast iron has yielded anywhere to pressure and thermal exposure. If the head is no longer flat, maybe the block is also no longer flat. Maybe the block and head conformed to each other, that is why they are warped, and bringing the head back to a plane will actually create a mismatch that wasn't there before it was decked? If the head needs resurfacing, maybe the valve seats are no longer round, due to warping. If the valves leak, how can a compression test be used to check the fresh seal on the headgasket? How will the piston rings be properly lubricated, when the cylinder hone is all gone in places; I see obvious deficits in the cylinder walls of that 250 straight-6? The engine builder fixes leaks, both obvious and sub-clincal. I watch the Dave's Auto Center on YouTube, and he always says that customers just want him to replace a piston, or whatever, but every time it is a full rebuild.

@hanzo111 I would love to see more of that 250. I'm intrigued by the tech, and I once had a 250 in a '79 Nova.
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Buffchief said:
Installed the PTO winch and rolled up 165' of 5/16" wire rope with original chain and hook. 😁

View attachment 3786416
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Pretty cool seeing this think work for the first times after the rebuild after setting in a field since 1974!!! Thanks to MUD, I was able to slowly find all the parts to make it work on my 1980 model.
 
Hi Guys, welcome to my twilight zone...an update on the 47, the good news, its still running......l stripped out the dash electrics (again) to find the short (s?) checked for wear & added wiring harness sheathing at all the securing clips, redone any loose/corroded original connections l found, and it no longer blows the engine fuse whenever it wants too, that said now there's an intermittent issue with the utes EDIC/Preheater unit (clicks on/off & ute judders) whilst driving & it either over fuels or it settles down & runs fine, add the self aware wiper wash either working or not & the ignition when turned either switching off or not, & the recent development of the (disconnected) fog light switch lighting up, driving has become 'interesting' there's no burning wiring smell, so it looks like l'll have to get a new harness made. l recently fitted the new water thermostat housing, sender, and hoses & a new HD battery & it starts off the key & lastly l took delivery of crystal headlights & HD Terrain Tamer shocks & a start stop cable today.... next up fitting it all..& continuing my quest to solve the riddle of how is it still... :steer:.. Have a good weekend...:giggle:
 
Chungas Revenge said:
The “Berry” was like the shop cat…What now?
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She’ll be enjoying the dry desert air where every 40 should never have to leave.

Gonna have to get Tank in operable condition,
 
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