Reusing Torque to yield bolts
#1
Reusing Torque to yield bolts
I will be replacing a head gasket on another Escort 1.9L engine, and although it's not a truck perhaps I can get some advice about it here.
I did one of these cars about a year ago, and replaced the TTY head bolts and had the head reconditioned at a shop. I would like to not bother with new head bolts this time, as I will have two complete used sets so I would have spares if any failed during torquing.
The new ones will almost certainly be Chinese anyway, so of dubious quality. My other thought is to just pretend that the bolts are conventional style, and find an appropriate torque value to tighten them to. The head gasket presumably doesn't know how it's being clamped.
I have read also that it's permissible to use TTY bolts twice.
Any thoughts?
I did one of these cars about a year ago, and replaced the TTY head bolts and had the head reconditioned at a shop. I would like to not bother with new head bolts this time, as I will have two complete used sets so I would have spares if any failed during torquing.
The new ones will almost certainly be Chinese anyway, so of dubious quality. My other thought is to just pretend that the bolts are conventional style, and find an appropriate torque value to tighten them to. The head gasket presumably doesn't know how it's being clamped.
I have read also that it's permissible to use TTY bolts twice.
Any thoughts?
#3
Well I agree that they stretch when you tighten them. Then the next time they stretch a little more... it turns out that on some engines the TTY bolts may be reused a couple times, and on others they may not. In reading up on this I found a cryptic reference to the importance of "cycling" the fasteners as a necessary high performance preparation. I didn't find a definition of this practice, but it sounds like tightening them and loosening them a few times... huh? Isn't that what's verboten?
On the Engine Builder's website I gleaned this titbit:
"A well-respected OE engineer specializing in engines tells me that critical fasteners have about six rundowns in their useful life. They use four of those at the OE manufacturing operations, leaving rebuilders just two. One rundown for checking sizes puts us on the last rundown during final assembly. My thinking is: why take the chance? Replace the fasteners! The relative cost compared to the total engine job is small and the peace of mind is high."
So this engineer says that they can be used six times. I don't understand how four of those are used up on the assembly line, nor the "one rundown for checking sizes", but "leaving just two" for the rebuilders kind of says that it's okay to use them.
This seems like a really murky topic and I suppose I should do a bit of testing myself to figure it out. Last year when I did one of these engines I did get the Felpro gasket kit with headbolts, and when carefully retorquing and final turning of the head bolts found that some were really easy to turn, and some difficult. It made me very sceptical of the whole operation, and of the quality of aftermarket head bolts.
Hopefully the bolts will either fail under retorquing or not, so I'll know if they're good or bad.
On the Engine Builder's website I gleaned this titbit:
"A well-respected OE engineer specializing in engines tells me that critical fasteners have about six rundowns in their useful life. They use four of those at the OE manufacturing operations, leaving rebuilders just two. One rundown for checking sizes puts us on the last rundown during final assembly. My thinking is: why take the chance? Replace the fasteners! The relative cost compared to the total engine job is small and the peace of mind is high."
So this engineer says that they can be used six times. I don't understand how four of those are used up on the assembly line, nor the "one rundown for checking sizes", but "leaving just two" for the rebuilders kind of says that it's okay to use them.
This seems like a really murky topic and I suppose I should do a bit of testing myself to figure it out. Last year when I did one of these engines I did get the Felpro gasket kit with headbolts, and when carefully retorquing and final turning of the head bolts found that some were really easy to turn, and some difficult. It made me very sceptical of the whole operation, and of the quality of aftermarket head bolts.
Hopefully the bolts will either fail under retorquing or not, so I'll know if they're good or bad.
#5
Sure, you can reuse them. When you bolt a gate together, when you repair a wheelbarrow, when you want to add weight to the recycle box....
"Penny wise & pound foolish" is the man who invests his time and money in a repair and reuses tty bolts. Unless you want to do it over again a couple more times.....
"Penny wise & pound foolish" is the man who invests his time and money in a repair and reuses tty bolts. Unless you want to do it over again a couple more times.....
#6
#7
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#8
#9
Why reuse them?
I got my 92 Ranger for free from my brother in law: He had the engine replaced with a "factory reman" about 5000 miles before a head gasket failure: The "reman" didn't include new head bolts (corrosion on the shank of several blots) and the head popped off the right front bolt just above the block deck.
New bolts in the "reman" would have meant no free truck for me!
Alan
I got my 92 Ranger for free from my brother in law: He had the engine replaced with a "factory reman" about 5000 miles before a head gasket failure: The "reman" didn't include new head bolts (corrosion on the shank of several blots) and the head popped off the right front bolt just above the block deck.
New bolts in the "reman" would have meant no free truck for me!
Alan
#10
Those pesky TTY bolts
Hey, a vote for reusing the old bolts!
For bolts that I reuse, I always wire wheel them and insure they screw in by finger until they snug up to whatever they're holding on.
I see 302s (5.0) switched to TTY headbolts in the early 90s. The engine had no profound change though, and either style of bolts can be used on any small block, so long as they're all the same.
For bolts that I reuse, I always wire wheel them and insure they screw in by finger until they snug up to whatever they're holding on.
I see 302s (5.0) switched to TTY headbolts in the early 90s. The engine had no profound change though, and either style of bolts can be used on any small block, so long as they're all the same.
#11
I have re-used the bolts with no problems. If the bolt isn't damaged from rust, I run a tap in the holes, brush the threads on the bolt, and lube when putting them back in. If you don't do this, torque readings will be off anyway.
To properly do a TTY bolt, you don't use a torque wrench, you use a gauge. How many have one of these in your tool box. If torque wrenches aren't checked quite frequently, the can be off considerable. Also, all torque wrenches aren't the same quality.
The proper way to set torque on rod bolts is to measure stretch, but how many do that.:jd
To properly do a TTY bolt, you don't use a torque wrench, you use a gauge. How many have one of these in your tool box. If torque wrenches aren't checked quite frequently, the can be off considerable. Also, all torque wrenches aren't the same quality.
The proper way to set torque on rod bolts is to measure stretch, but how many do that.:jd
#12
Unless you want the head to come off suddenly(probably not that violent) But if one
side pops the heads of the bolts off, I am pretty sure it will sound like a grenade
going off since the comb chamber is open. What is another $30.00 just think it will
make you feel better and not have to worry about one day crossing RR tracks and
all the bumps cause the weak bolts to break, Now you are stuck on the tracks!!
side pops the heads of the bolts off, I am pretty sure it will sound like a grenade
going off since the comb chamber is open. What is another $30.00 just think it will
make you feel better and not have to worry about one day crossing RR tracks and
all the bumps cause the weak bolts to break, Now you are stuck on the tracks!!
#13
You have to be kidding. It is not a matter of the bolts breaking, or "popping off," but rather do they still have enough clamping force to properly secure the heads to the block. They will be fine in a stock engine that is not used in heavy duty service. If used for heavy duty service, then new bolts would be used.jd
#14
You have to be kidding. It is not a matter of the bolts breaking, or "popping off," but rather do they still have enough clamping force to properly secure the heads to the block. They will be fine in a stock engine that is not used in heavy duty service. If used for heavy duty service, then new bolts would be used.jd
#15
I would much rather spend the $30 on bolts when the head is off than have to replace another head gasket down the road. Sure, the bolts might be just fine to re-use but there is also the chance that you get burned. $30 is not worth having to tear the engine down again.