new 2/17/03
Welding isn't that bad, i just had mine done this week, by Stealth Automotive in Baltimore (410)-244-9300, ran me $750.00 ... very professional looking welds, nothing crappy, but then again, welds
aren't pretty but this looks very tight... This is the first SHO they have done. But the work came highly recommended...
remember your not going to see the welds, I've been on v8sho.com for about three weeks and
I've learned a lot about the SHO.. Loctite will work, but eventually it may fail, (keyword MAY)....
The cost of labor in either case is a major factor, its going to be just as expensive either way.... id suggest the more aggressive approach and have them welded...
just my opinion ....
Sebastian
97 SHO Black
45k mi.
XM
GPS
Welded (guess i can add this now)
on 2/16/03 6:03 PM, Lee R. Miller at leemille@netscape.net wrote:
since the technique for loosening bolts that have had Loctite applied is to heat them first, i don't think that
Loctite up in the cam area of the heads would be a good fix.
You have to heat them to 450 F. I doubt that your SHO motor will ever get that hot! :)
Take care,
--
Rob Parker
La Porte City, Iowa
AIM rob1parker
97 Black Satin
Bone stock
The opinion on this one seems to be that it's a decent temporary fix, but that to prevent failure, welding or pinning is a must. And I don't think there's a conspiracy among the welders to keep the Loctite solution under wraps, I seriously don't think it'll last nearly as long. I don't think that there have been any recorded Loctite failures, but I also think that the majority of those that have used Loctite only had it in there for a few hundred or a few thousand miles until they could get it welded/pinned. For $500-$600 plus the cost of the trip to whomever you'd take it to, I think that it's well worth the expense. I'm not sure that Loctite buys any time, but it seems to buy a little peace of mind. I keep hoping my cams, unwelded and un-anythinged, will last me until I can get the funds to go to Madison.
I'd read up as much as possible on the v8SHO website about all the options available, and go with the one you feel most comfortable with. But, if I knew there was a problem with the car I had bought my daughter, and I had the means to fix it, I wouldn't want to be responsible if she ended up stranded with a dead car and $6000+ dollars of repairs. I'm not trying to guilt you or scare you, and I don't know your situation, but if you have the means, it's a small price to pay considering the cost of the alternative if it fails.
-John B
I have to agree with John, I used the Loctite 294 as recommended as a temporary fix for about 1500 miles before I could get them welded. I also looked closely at the fact sheet, and it looked like there was a slow breakdown of the holding strength of Loctite at temps the parts would be seeing. I would consider this a temporary fix, mostly to ease your mind until you can get them welded or pinned.
Corey Wilkins
97 ES
welded
Ge42ma@cs.com wrote:
I bought a '96 SHO for my daughter...and put a replacement engine in it...Had the engine analyzed. New plugs and a couple of new sensors runs great. I have the top off the engine again to check the secondary valves (engine has 68K on it) and the runners...they are not binding, and to replace the coolant casting at the back of the block. Want to make sure cam sprockets won't spin....will Loctite really prevent this...I don't like the thought of welding....
Thanks for any input!!
As we learn a little and a little more let me try to explain what I think is occurring. Reports of the cam assembly being made by expanding the cam tube, seem to in error. That is a Torrington method and our cams are made by Krupp Presta.
Krupp takes a cam tube and uses a knurling tool to raise the surface of the surface of the tube. Here is a PDF file on a knurl tool which can give you an idea what a diamond knurl looks like.
The inside of the sprocket has hard splines, like very small gear teeth only on the inside middle hole. The outside diameter of the knurls is slightly larger than the inside diameter Krupp takes a press and presses the sprocket into place on the knurl mounting pad, the splines cut into the knurl surface and seat, they resist in shear against turning but have much less strength in the direction of the long centerline of the cam tube. They don’t need a great amount of strength in that direction but in time impact loads of the valves opening and closing works the sprocket a little lose.
The sprocket can in time travel a little left and right off the knurled perch. Engine valve timing may be sloppy at this point but the engine will still run and damage is limited to the cam itself. Maybe the cam can be fixed with a weld if the camshaft / sprocket relationship can be correctly restored. Parts of the hard splines are chipped of and a repaired cam will never be as strong as a good cam that was welded. This is the point where we tell folks to not drive their car and get it towed to a shop that will weld their cams.
My theory is this, assume the cam has not yet started to move, Loctite may do two things, keep the cam from first working lose and then help it resist from walking off the knurl perch. “How much does it help?” is the unanswered question. I respond “How much does it need to help?”
We know welding lasts about 20 times longer than stock, pinning lasts about 53 times longer than stock. What if Loctite lasts “only” 10% or 30% longer than doing nothing? What if that is long enough to then get them welded? (disclaimer: if the sprocket is at all lose or starting to move I think we all agree Loctite is a waste of time, and will not save the motor)
We do know Loctite never warped a cam and does not require removal of the cams from the car. IT MAY BE OF LITTLE OR NO BENEFIT WHAT SO EVER. Paul Nimz and I were the first two to Loctite our cars, and we soon there after both welded our cams. I am not arguing that Loctite is a substitute for welding or pinning. I am saying it may be slightly preferable to doing nothing, and cost little except your own labor if you can do the job yourself.
As I wrote this Don Mallinson sent his own opinion included below. As always I treasure his informed opinions and suggest you read it and take it to heart. Have an opinions of your own? Send it to me and I'll add it to this page.
BTW, there many be a very few Loctited cars that have not failed, they are so few I assume that proves nothing. There are stock SHOs with 110k on them that have not failed. That comforts little the folks who lose an engine every day.
There is no proof either way that the Loctite solution IS a solution. I think everyone that tried it, eventually went to welding or pinning.
For those that equate the Loctite used with that used on bolts, the Loctite mentioned for the cams is a different stuff. Not sure of the heat range on it though.
As to the cam sprockets only spinning if they "walk" or move down the cam, I don't think this is true at all. What happens is that the sprockets as designed by Ford/Yamaha/who ever, are off-center on their mounting base. This puts the sprocket under a constant torque or twisting pressure. Eventually the press fit mounting starts to loosen, with the eventual result that it starts to work loose and rock, and eventually spin. The sprockets from cars that have been driven some (and reved like heck by ignorant mechanics) have walked both directions on the camshaft like a bit in a lathe. The resulting metal in the system ruins the entire motor.
Don Mallinson
SHO Club
Buford,
On this page, it talks about how loctiting your cams should only be a temporary fix.
Now, I'm no engineer, but I have taken a few engineering courses, as well as being a professional millwright (industrial mechanic for those who've never heard of millwrights) and my opinion on loctiting cams is quite high.
Since there are 20000 (approx) V8 SHO's around, and about 200 have failed camshafts, maybe more that haven't reported, but that's about 1%that have failed. I can't see it being any more than 3% including those who haven't reported to V8SHO.com, although this is still unacceptable.
My point is since not all cams in V8 SHO's will fail before the engine needs rebuilding due to cylinder wear, worn piston rings, worn cam lobes, worn/seized bearings, etc., you can't just call loctiting a temporary fix, since most probably never will fail. I think loctite will be just as effective as welding or pinning in preventing cam failure if your sprockets have not slipped yet. If your cams haven't slipped yet, I can't see them starting to slip now with just normal running conditions if they are loctited. Looking at the specs of loctite 294, strength is increased 4 to 5-fold by the loctite. Now considering most cams will never fail anyways, this is well over the amount of protection needed to keep your cam sprockets in the right place.
My car, a 97, has 151,000 kms (90,000+ miles) on it and reading all this stuff on V8SHO.com has got to me. I have nightmares that the next time I start my car will be my last, no kidding. I'm planning on loctiting my cams myself when I pull it out (these damn Canadian winters and SHO's don't mix too well), but I think it's partially only for peace of mind.
I hope my insight in this issue is useful, and also soothes some people's minds about their cars' reliability. At least anyone can loctite their cams themselves, all you need are a couple of wrenches, 5 mL of 294 and some self-confidence, much less than a 5 day trip and $600.
Mike
97 white
PS, when people are welding, pinning or loctiting, is everyone putting new valve cover gaskets on? Just wondering...