monzajhon1968
Monzajhon1968
When changing head gaskets on 6.2/6.5 Should I change the head bolts? I am going to use the newer felpro head set its supposed to be the best head set. This engine has a banks kit on it also.
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head bolts
- Thread starter monzajhon1968
- Start date
Turbine Doc
Just Another Diesel Guy
yes bolts are 1 time use torque to yield TTY not to be reused
midniteplowboyy
Recruit
Yes, replace the head bolts, there one time use. DON'T REUSE THEM, BAD THINGS HAPPEN.
Felpro head bolts are good.
If your going to keep the truck forever ARP head studs are good, and they are reusable if you need to pull the heads again later on, but they cost twice as much. Me myself have studs in one of mine and will stud the rest when the time comes, I have so many 6.5 trucks if I trash an engine I'll just pull them out and stick them in another, I figure its cost effective that way. Plus you can recheck the torque if you have the valve covers off later on.
Either way with felpro gaskets and a good surface you'll be fine for a long time.
HTH,
Felpro head bolts are good.
If your going to keep the truck forever ARP head studs are good, and they are reusable if you need to pull the heads again later on, but they cost twice as much. Me myself have studs in one of mine and will stud the rest when the time comes, I have so many 6.5 trucks if I trash an engine I'll just pull them out and stick them in another, I figure its cost effective that way. Plus you can recheck the torque if you have the valve covers off later on.
Either way with felpro gaskets and a good surface you'll be fine for a long time.
HTH,
Missy Good Wench
Wild Blonde from Cloud Mt
The idiot that thought up the TTY bolt scheme should be tarred and feathered.
MGW
MGW
Turbine Doc
Just Another Diesel Guy
$$$$ was the driver, lots of things little things they went cheap on would have made the 6.5 a much better design
chevyinlinesix
Eyre Flow Headers
Yes, x4 replace the head bolts. Once TTY bolts are... "torqued" to their yield point, they loose their strength.
SLIGHTLY off topic, but aren't the main bolts TTY? The specs I see for them IIRC said so much torque, plus so many degrees.
SLIGHTLY off topic, but aren't the main bolts TTY? The specs I see for them IIRC said so much torque, plus so many degrees.
- Staff
- #7
:iagree:
It was a horrible way to cut corners in my eyes. But, I was always told to never reuse head bolts.
monzajhon1968
Monzajhon1968
I went to arp site and they did not list them are they still avalible.
Ratman
6.5 Diesel NUTCASE
You know, this was the EXACT question I asked one of the guys who works here at the local GM medium duty truck shop (lots of 6.2/6.5 work going through their shop).
The "indirect" answer I got was no, that they are not TTY on the mains, -but then and again, -WHY the funky TTY torque procedure? (the 90 degree part)
The guy I spoke with out in the shop responded to my question by telling me, (verbatim) -"in all the years I've worked here, we have never replaced a set of mainbolts on a 6.2 or a 6.5"
That really didn't answer my question though.
It sure makes one wonder, doesn't it?? :thinking:
monzajhon1968
Monzajhon1968
Cool beans! when I couldnt find them listed I thought they might be discontinued. These engines are getting pretty old. Thanks a bunch!
Non Typical
Roller of the Smoke
X2 on that. thanks! i couldn't find them listed.
DieselSlug
Well-Known Member
I was going to go arp head studs, but running only with a heath chip @ 14lbs. i dont think i need to go overboard....
ak diesel driver
6.5 driver
I was told that after the tty bolts were used and had stretched that they would bottom out causing them to not clamp the head enough.
Turbine Doc
Just Another Diesel Guy
I would venture to guess Rich that it has to do with extreme pressure & heat cycles of cold to hot as the head grows thermally that TTYs material requires replace at reuse, mains will take on/reject heat equally/more slow to grow/cool and once hot stay hot or less hot equally.
In the head you have lots of variables changing exhaust flow, coolant flow, fuel flow, immediate temp variances in combustion chamber temps, we already know differences at power for cooling left bank & right banks as engine speed changes.
Possibly this potenial for uneven torque/warpage reusing TTYs maybe the stretches have to be normalized at time head gaskets are replaced so thermal growth changes aren't negatively tweakd by a reused TTY that wasn't quite as fatigued as one of the other ones were, whacking the torque out.
Or all that is crapo conjecture theory my part &
GM needed the revenue and created the must replace bolts policy, ARPs are on my project engine, only because I may be doing some R&D with heads once I get it installed, TTYs properly installed are not a big deal for lions share of the 6.5ers out there.
Let your cooling system get away from you, overheat the engine a time or 2 then yes it would be handy to have ARPs, both of my 98s have the original TTYs in them 177K on one, (pretty fair service life) 150K on the other engine (also not shabby IIRC from my gasser days 90-130K was service life of head gaskets in those)
mitchedo
Member
I wonder if TTY has anything to do with not having to worry about retorquing the bolts after the engine warms up. Getting the valve covers off these things is nuts! Would it have been so hard to route the fuel lines AROUND the valve covers from the rear?
When the shop put my engine together, they ordered new main bolts. I tried to get ARP studs, but this was just before Heath came out with the kit, and it would have been over $400 for main studs.
I asked the shop about the TTY-like tightening procedure on the mains, and he said he never heard of TTY mains, but he'd be sure to watch for any weirdness when he tightened them up. He said that a couple of them felt like they weren't taking torque properly -- kept needing more torque after the initial pass -- so he ordered new ones.
How could they not be TTY? They're the same grade bolt as the head bolts. They're the same size. They get the same torque and tightening procedure.
The new bolts were only about $75. Now that Heath has a set of main studs, I'd get them. ...of course, if you have a 97+ block with 10mm outers, then you're outta luck for them unless you buy the silly little "girdle" that comes with ARP studs. ...then you're still looking at close to $400 anyway. I'm leaving my engine power at stock levels. It will meet my needs, and when I feel the need for speed, I pull the Chevelle out of the garage and go burn up some rubber.
As far as overheating, after seeing inside my engine at 49,000 miles, I wouldn't dare overheat this thing -- studs or no studs.
Besides, the extra bolts are handy to have around as paperweights.
When the shop put my engine together, they ordered new main bolts. I tried to get ARP studs, but this was just before Heath came out with the kit, and it would have been over $400 for main studs.
I asked the shop about the TTY-like tightening procedure on the mains, and he said he never heard of TTY mains, but he'd be sure to watch for any weirdness when he tightened them up. He said that a couple of them felt like they weren't taking torque properly -- kept needing more torque after the initial pass -- so he ordered new ones.
How could they not be TTY? They're the same grade bolt as the head bolts. They're the same size. They get the same torque and tightening procedure.
The new bolts were only about $75. Now that Heath has a set of main studs, I'd get them. ...of course, if you have a 97+ block with 10mm outers, then you're outta luck for them unless you buy the silly little "girdle" that comes with ARP studs. ...then you're still looking at close to $400 anyway. I'm leaving my engine power at stock levels. It will meet my needs, and when I feel the need for speed, I pull the Chevelle out of the garage and go burn up some rubber.
As far as overheating, after seeing inside my engine at 49,000 miles, I wouldn't dare overheat this thing -- studs or no studs.
Besides, the extra bolts are handy to have around as paperweights.
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monzajhon1968
Monzajhon1968
That would explain why a friend of mine a diesel mechanic years ago had a truck with a 6.2 and could not keep head gaskets on it. No matter what he did they would eventually leak he gave up and got rid of the truck and bought a dodge 5.9 and solved the problem. I would almost like to put a 5.9 in my burb if I did not have a 6.5 with low miles and a banks kit. Its just a matter of $$ I allready have this stuff.
midniteplowboyy
Recruit
The first year or two of the 6.2 had standard head bolts, the TTY bolts was GM solution to the head gasket issue, a great improvement but not the best solution, damn bean counters.
The felpro head gaskets and bolts are light years ahead of what they used in 1982. If they would have used one sized bigger bolt and 1/4" bigger bore spacing we would have alot better engine.
The felpro head gaskets and bolts are light years ahead of what they used in 1982. If they would have used one sized bigger bolt and 1/4" bigger bore spacing we would have alot better engine.
Missy Good Wench
Wild Blonde from Cloud Mt
I have pulled down some 6.5 engines that had some of the bolts come out far easier than others.
I suspect that these bolts, over time and thermal cycles loose some of their ability to hold.
I had two bolts on my Burb build that when tightened the last 1/4 turn just went limp on me.
I scrounged up a broken set and replaced the two that got hinky.
The old BBC chevies never used TTY bolts and there was never issues with heads, gaskets or other stuff.
I'm willing to bet that a good set of real good bolts would work fine in the 6.2/6.5
The ARP studs are definately a good thing
MGW
I suspect that these bolts, over time and thermal cycles loose some of their ability to hold.
I had two bolts on my Burb build that when tightened the last 1/4 turn just went limp on me.
I scrounged up a broken set and replaced the two that got hinky.
The old BBC chevies never used TTY bolts and there was never issues with heads, gaskets or other stuff.
I'm willing to bet that a good set of real good bolts would work fine in the 6.2/6.5
The ARP studs are definately a good thing
MGW
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Missy Good Wench
Wild Blonde from Cloud Mt
Just flipped through my 1994 GM service manual.
The torque specs on the mains is 110 lbs on the inside bolts and 100 on the outside bolts.
No mention at all of TTY procedure.
The later blocks with 10mm outer bolts have a slightly different spec for the outer bolts.
The concept of the TTY bolt is to put the bolts into their stretched mode and that that this will allow them to clamp the heads/gaskets and to endure the heavy stresses of the thermal expansion. The bolts while stretched will clamp well and be able to maintain this clamp all through the range of opperation.
So it says in fine print.
MGW
The torque specs on the mains is 110 lbs on the inside bolts and 100 on the outside bolts.
No mention at all of TTY procedure.
The later blocks with 10mm outer bolts have a slightly different spec for the outer bolts.
The concept of the TTY bolt is to put the bolts into their stretched mode and that that this will allow them to clamp the heads/gaskets and to endure the heavy stresses of the thermal expansion. The bolts while stretched will clamp well and be able to maintain this clamp all through the range of opperation.
So it says in fine print.
MGW