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Well, I put the engine back into the 3 last weekend, only to discover that it wouldn't turn over. I had been able to turn it over by hand easily during reassembly, but hadn't check during the last few steps. So, I started stripping things down, and discovered that my new flywheel bolts from Moss Motors were causing the problem. Apparently, they're a little too long and interfere with the rear of the engine. The Moss catalog says that I shouldn't use them with the tabs washers, but I don't know what else to do. I can't find flywheel bolts from any other source, and my originals are long gone. Any suggestions? Thanks.
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Moss Motors Flywheel Bolts
- Thread starter Palmer
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What he said.trfourtune
Jedi Knight
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if you trim them, please run a cooling fluid on them when you do it. You can just run a water hose on it when you do it. Messy, but you won't ruin the temper of the bolt that way. I know it's just on the tip/end a little, but you need full strength for the entire thread contact surface of the bolt.
IMHO
Rob
ps-"You aren't going to change anything as far as the strength of the bolt to trim them off."
Oh yes you can! When you trim them without cooling there is a heat zone which effects the temper. Depending on how much heat you put into the bolt by cutting it off, you could effect the temper by as much as 1/4" back from the cut if you are not careful. That may be almost all of the treads in contact with the crankshaft.
IMHO
IMHO
Rob
ps-"You aren't going to change anything as far as the strength of the bolt to trim them off."
Oh yes you can! When you trim them without cooling there is a heat zone which effects the temper. Depending on how much heat you put into the bolt by cutting it off, you could effect the temper by as much as 1/4" back from the cut if you are not careful. That may be almost all of the treads in contact with the crankshaft.
IMHO
Thanks for the helpful responses. I tried to call APT, but couldn't get through to them. My son-in-law borrowed my angle grinder, so I don't know when I'll get that back. But, I did find a source for the bolts - Rimmer Bros. has them. First time I've ordered from them, and I realize that it may take awhile for them to get here, but I thought I give it a shot.
trfourtune
Jedi Knight
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you can get the ARP bolts anywhere. For my TR4, the part number is 206-2802. This is listed as the BMC 1600 a-series engine, but it is the same for many british cars. It is a 6-pack.
Rob
PS- "Jegs" on line $21.99 ships in 6 days.
Rob
PS- "Jegs" on line $21.99 ships in 6 days.
AweMan
Jedi Knight
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trfourtune Is absolutely correct about heat changing the molecular structure of those bolts.
A little heat goes a very long way, especially in tempered steel, to change its physical properties. Especially if you reach the point of carbon precipitation {the black scale you see when you heat metal to the red stage.} I realize you most likely wouldnt reach this critical point, but even just a little heat can and will re arrange the molecules. So IF you do cut them do as Trfortune says ... use a quench. Go slow, avoid as much heat as humanly possible.
A little heat goes a very long way, especially in tempered steel, to change its physical properties. Especially if you reach the point of carbon precipitation {the black scale you see when you heat metal to the red stage.} I realize you most likely wouldnt reach this critical point, but even just a little heat can and will re arrange the molecules. So IF you do cut them do as Trfortune says ... use a quench. Go slow, avoid as much heat as humanly possible.
TR3driver
Great Pumpkin - R.I.P
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While it is possible for the heat-affected zone to extend some distance, it's pretty trivial to keep it quite short. Just an occasional spritz of water from a spray bottle (or even the kid's squirt gun) will do fine. Or the WD40 can, if it's closer.
Or you could just leave the bolt a bit long and not worry about it. If you taper the end as I suggested, most of the HAZ will be in the taper anyway. The crank flange is plenty thick, so the last few threads don't contribute much to overall strength anyway. By far the majority of the force is on the first few threads.
Or you could just leave the bolt a bit long and not worry about it. If you taper the end as I suggested, most of the HAZ will be in the taper anyway. The crank flange is plenty thick, so the last few threads don't contribute much to overall strength anyway. By far the majority of the force is on the first few threads.
A proper 1/8th in thick cutoff wheel will not heat the bolt much. or a dremel cutoff wheel.
If it scares you, use the hacksaw as suggested.
This bolt is in shear, you would have to get that puppy pretty hot to affect it to the point that it's shear strength degrades.
If it scares you, use the hacksaw as suggested.
This bolt is in shear, you would have to get that puppy pretty hot to affect it to the point that it's shear strength degrades.
Tabcon
Jedi Warrior
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I've always found that cooling off freshly cut bolts with small pieces of burning finger flesh works great.
At least it always works for me,
I usually buy all my ARP stuff either from Summit Racing or Jegs. Both have great service, great prices and usually have almost any size in stock. I do wish that you could buy individual bolts though. Sometimes I only need one or two, but you're always stuck with five to the pack for 20 some odd bucks.
At least it always works for me,
I usually buy all my ARP stuff either from Summit Racing or Jegs. Both have great service, great prices and usually have almost any size in stock. I do wish that you could buy individual bolts though. Sometimes I only need one or two, but you're always stuck with five to the pack for 20 some odd bucks.
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Are the Moss bolts (or the original ones, for that matter) any different from grade 8 fasteners? If not, you could just get grade 8 bolts from any convenient source.
I realize that the ARP ones are different, and probably the safest way to go in any case.
Also, if you cut them off, is it necessary to make sure they're all the same weight? Because of the small bolt hole diameter, if might not matter. But they will be spun at 5000 rpm plus.
I realize that the ARP ones are different, and probably the safest way to go in any case.
Also, if you cut them off, is it necessary to make sure they're all the same weight? Because of the small bolt hole diameter, if might not matter. But they will be spun at 5000 rpm plus.
trfourtune
Jedi Knight
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a few grams difference is not going to make much difference here but it is always best to match them.
Flywheel bolts are NOT the place to mess around. Critical engine bolts are the connecting rod bolts and the FLYWHEEL BOLTS. I am putting eight (8) ARP flywheel bolts in my modified tr4 because they are THAT important.
Do what you want, but you've been warned.
I totally disagree with just using a spritz container of water. You may find using a hack saw tough going if the bolts are any good-even that generates heat but will not raise the temperature into a transition zone.
Rob
(Engineering designer by profession)
Flywheel bolts are NOT the place to mess around. Critical engine bolts are the connecting rod bolts and the FLYWHEEL BOLTS. I am putting eight (8) ARP flywheel bolts in my modified tr4 because they are THAT important.
Do what you want, but you've been warned.
I totally disagree with just using a spritz container of water. You may find using a hack saw tough going if the bolts are any good-even that generates heat but will not raise the temperature into a transition zone.
Rob
(Engineering designer by profession)
TR3driver
Great Pumpkin - R.I.P
Offline
The originals certainly are. Common grade 8 bolts have relatively short, reduced diameter shanks. The correct flywheel bolts have full diameter shanks, long enough to reach most of the way through the flywheel.Sarastro said:
Also very unlikely the original bolts have the same metallurgy as "grade 8" (which is an American thing).
As a general rule, any Triumph fastener that doesn't have a "standard hardware" part number (starting with two letters) has something 'special' about it. The Triumph engineers were under considerable pressure to use "off the shelf" components, so there is usually a good reason for any specials.