TOPIC:

Kray-Z wrote: Ed,

...........I have to ask - when you are replacing valve shims - do you oil the cam bearing cap threads?

No, when I adjusted shims I installed the cam cap bolts dry. I always torque to the low end of the range specified (maybe I'm a bit of a chicken ) . Ed

If you're using stainless steel fasteners they should get a dab of anti-seize on the threads.

Kray-Z wrote: Industrial and heavy equipment diesel engine assembly is also much more controlled than the average gasoline engine. The manuals for those would specify threads lubed with everything from engine oil of a specific weight to proprietary thread sealants and lockers, sometimes moly-di grease. Back in the day when Caterpillar was still manufactured entirely in the USA, they manufactured their own bolts, and all Cat bolts were grade 8 or higher. Most often the critical fasteners had multiple tightening sequences, usually starting out with two or three stages of torque wrench settings, finishing with a final turning angle measured with a special dial gauge.

Nothing like a compound #2 and jelly sammich

I'll keep doing my #6 bolts by feel.
Steve

So I reinstalled the covers with no lube using the torque wrench in degrees,started at 45 in lbs and increased it in steps til I reached 65 in lbs and felt like it was enough,a little lower than the charts Ed posted.I'll keep an eye out for any seepage,but I think its tight enough.Thanks for the replies and suggestions.

Although at least 16-17 years old.... I have what once was a rather a high quality, "in lb" torque wrench and almost every time use it to tighten those cam cover screws, using it "set" to the lower range as per the FSM, the damn cover leaks or seeps somewhere.
And I have tried using two of my other back up covers to see if there is a problem with the original... same result most of the time.
If I set it to the max range or a little above....(and I also clean out the holes, leave them dry but lightly oil the screw thread tips), most of the time there is no seepage.... go figure.
Since I have NEVER broken a screw or stripped out any threaded hole in any motorcycle I've ever worked on, I can only assume my $88.00 in lb torque wrench is mis-calibrated at those levels.
Yes? No? Too many ham fisted back yard mechanics? .... probably

Torque Wrenches. It is my understanding you don't want to use a torque wrench set at the upper or lower limits but rather someplace in the mid range. This would mean you might have to own a couple of the things.

I'm sure there is some place a torque wrench could be sent for calibration if there is any doubt of accuracy.

I'll keep doing my #6 bolts by feel.
Steve


Listen to the man, I read this shit daily on Lotus and Ferrari forums, old stretched high tensile bolts in cast ally+ innacurate tourque wreches = lots of forum postings and helicoil/timeset/tig repairs.

Learn by our mistakes

Tyrell Corp wrote: I'll keep doing my #6 bolts by feel.
Steve


Listen to the man, I read this shit daily on Lotus and Ferrari forums, old stretched high tensile bolts in cast ally+ innacurate tourque wreches = lots of forum postings and helicoil/timeset/tig repairs.

Learn by our mistakes

Not everyone has the "feel"....

When I was the toolmaker and designer for a large electronics company, I once sourced an electric / electronic torque limiting screwdriver for $40 000... each, and that was the low quote. Highest was $62 500. Why was such an expensive high tech tool necessary in the first place - simple: the people that worked there could not reliably tighten the screws with any kind of consistency or reliability, and it was costing much more than just money. That was a special application, and in the end we cut back our "needs" list until the price came down to $12 000 each, and I had to further modify each tool myself before commissioning them on the line.

Previously, despite my warnings, the chief design engineer on that project had a bad habit of specifying the torque on various critical fasteners as "hand tight" or "finger tight". One day, after receiving the umpteenth e-mailed customer complaint on the over 90% failure rate of the product, I had that engineer come down to see his production line in person. I lined up two assembly workers from the same line to tighten his fasteners "hand tight", one an 85 lbs. 18 year old Asian girl, the other a 290 lbs. former college football line backer...there was some variance....one fell apart before reaching the next process, the other had bent and broken components.

Following that demonstration, and forwarding some of his B.S. engineering skills e-mails to his superiors, two improvements were made - all product engineers had to meet with the production line managers and supervisors at least once a month and spend an hour on the production line, and all references to "hand tight" or "finger tight" - actually anything other than a # torque specification - were stricken from the company's work instructions....and I gradually stopped receiving those e-mails...

Its all okay.The bolts didnt break,not looking for precise,exact torque.I have a 7 yr or so old Craftsman torque wrench that is rated from about 40 in lbs to about 144 in lbs,dont quote me on those numbers,the wrench is outside but its in that zone.Its accurate enough.Like I say the bolts are okay,hopefully tight enough,if I have any seepage I'll use a small,4 inch ratchet handle and gently try to increase a bit,as long as they are reasonably close enough to put even pressure on the gasket across the head cover it'll be good enough.

stokes wrote: Its all okay.The bolts didnt break,not looking for precise,exact torque.I have a 7 yr or so old Craftsman torque wrench that is rated from about 40 in lbs to about 144 in lbs,dont quote me on those numbers,the wrench is outside but its in that zone.Its accurate enough.Like I say the bolts are okay,hopefully tight enough,if I have any seepage I'll use a small,4 inch ratchet handle and gently try to increase a bit,as long as they are reasonably close enough to put even pressure on the gasket across the head cover it'll be good enough.

Sounds good, I think you have it beat...

Generally the rule for precise work is the torque should exclude the lower 20% - upper 10% of the wrench range - for example, if a wrench is rated for 50 - 250 ft-lb (my Mac Tools 1/2" drive micrometer click wrench, actually) it can be safely used for (250-50) x 20% + 50 = 90 Ft-lbs to 250 - (250-50) x 10% = 230 Ft-lbs...I've gone slightly below that (70 Ft-lbs) and all the way to 250 on wheels and such, but not engines...

Just one recommendation - if you must re-torque the bolts, set the torque wrench just a bit higher and do all the bolts the same - starting at the middle and working outward. If you assembled the threads dry, you will have to back the bolts off about a turn just before re-torqueing them. By nature, the gasket will compress gradually with time and pressure, so setting the wrench to the same torque value and re-torqueing after a few days might do it (stop any leaks). Always run over all the bolts in sequence again after torqueing the last one in the first sequence, as the first ones tightened will be loosened somewhat when the others are torqued and compressing the gasket further.

Anyone with the "feel" for avoiding stripped threads or broken bolts should have the same "feel" when using a torque wrench. In other words - the moment you think / suspect something isn't going right, STOP!

Another tip is to prep the gasket. I know the manual says dry, but i find a soak in a flat pan or transmission fluid to keep gaskets pliable and they won't stick to the mated parts. Some folks use grease or antiseize as well. R