5.0 supercharged into an LR4?

greiswig

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Oh, I was just suggesting that you might be able to find out what steel ARP uses for the stretch/strength qualities they want, get some rod stock and have it threaded at both ends a la ARP.

Take this advice with a shaker of salt, but...I would guess the head bolts across an aluminum head are more likely to need the TTY-style bolts, because of thermal expansion of a thick aluminum cylinder head. IIRC, the thermal expansion coefficient of Al is almost twice that of cast iron. So it may well be that you can re-use the bearing cap bolts. My understanding is that when you torque them properly, you're not ACTUALLY going outside their elastic range, you are purposely not doing so. So they shouldn't have actually yielded, unless some thermal expansion caused them to stretch past the yield point.

My Unimog, though, had a cast iron head, and they strongly recommended not reusing the old head bolts, claiming they were TTY. I reused them anyway on one trip (out of necessity), and it never had an issue after that. Torque sequence went just like they were new, too. So I suspect it was a CYA thing on the part of Ma Benz.
 

Tapps33

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Hmmm....good idea....now I need to find a jaguar factory manual!

Google machine, here I come!!!
 

Tapps33

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Oh, I was just suggesting that you might be able to find out what steel ARP uses for the stretch/strength qualities they want, get some rod stock and have it threaded at both ends a la ARP.

Take this advice with a shaker of salt, but...I would guess the head bolts across an aluminum head are more likely to need the TTY-style bolts, because of thermal expansion of a thick aluminum cylinder head. IIRC, the thermal expansion coefficient of Al is almost twice that of cast iron. So it may well be that you can re-use the bearing cap bolts. My understanding is that when you torque them properly, you're not ACTUALLY going outside their elastic range, you are purposely not doing so. So they shouldn't have actually yielded, unless some thermal expansion caused them to stretch past the yield point.

My Unimog, though, had a cast iron head, and they strongly recommended not reusing the old head bolts, claiming they were TTY. I reused them anyway on one trip (out of necessity), and it never had an issue after that. Torque sequence went just like they were new, too. So I suspect it was a CYA thing on the part of Ma Benz.
Yeah, I agree, one would think given the difference in expansion coefficients of the dissimilar metals the bolts should be ok....but I also thought the whole point of TTY was you torques them until they yielded....and it was this stretch yield that give you your compression. That said, it the bolts are indeed grade 10.9 or 12.9 like I suspect they're supposed to be, one would think they would rip the aluminum threads out long before they ever stretched to their true yield point. I dunno....it's a bit of a conundrum...albeit a potentially self made one...

Now that I think about it, I re-used head bolts in a lot of my Honda engine builds....and I was even running some decent boost with a lot of them....of course I was also very young...and breaking down wasn't that big a deal....and I couldn't afford pretty much anything at that point....so ARP was definitely out of the question! However! This is my wife's car...and her DD...if the engine leaves her stranded with our twin toddlers....I may have to move in with one of you guys!! LOL!!
 

Tapps33

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Nothing to report right now. Still working on it, I just had to put it on the back burner for a few weeks. I should be finishing the tear down and starting the machining in the next week or so.

Sorry for the delay, I've had to put out a few fires here first...but now, this project is about to become my priority!
 

Tapps33

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SDD tool just arrived!

I'm going to try and install the SC ECU into the LR4 and see if I can get it functioning. Yes, It'll throw a crap ton of engine codes because it's not the SC engine, but as long as I can get the immobilizer to accept the new ECU, it should....and I stress should...be a direct swap once I finish the engine rebuild.

Hopefully @SCV8LR4 is right and this is truly possible!
 

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