Main Causes of Camshaft Failure / Damage

I would agree. GA. _{(using Slacks voting system)}

Broken valve spindle in the cam-case?

Incorrect reassembly following rebuild?

How about incorrect timing chain adjustment?

_{Thinks: CR4's voting system could be used to advantage here. With all the possibilities listed in individual replies to the original post, the one with the greatest number of good answer votes is the winner!}

Broken timing chain?

poor lubrication...plus the hammering of excessive spring seat pressure

Is it by any means a JGS320 Camshaft?

Did you repair this one and it failed or is it still the same one?

It is very wise to seek out the reason for the damage before going into repair. What is missing is what actually is the damage and what were the circumstances that led to the error.

More input is needed.

Otherwise google "main causes of camshaft failure"

lots of hit come up.

I liked this one: www.cranecams.com/pdf-tech-tips/cam_failure811.pdf

Sincerely IS

ah... missing 710 cap!

Friction?

Just plain lack of maintenance, these things have a finite life you know.

If it's a GMH 308 V8, then most likely it's a bean counter engineering problem. The bean counters specified a less than ideal material (cheaper)for the Cams, which led to them wearining out quickly usually in under 30,000km( I know of one that lasted just 15,000km). Just outside the new car warranty, but way too early in comparison to the previous production models.

That said, I concurr that poor maintenance is a motor killer every time. If your cam failed shortly after installation then it can be incorrect installation proceedure, specifically lack of moly grease on the tappet riding surfaces, and not running the engine at the specified break in speed for the nominated time. Usually a fast idle of 1850rpm for 15 minutes IIRC.

Greetings.

I had a 70 GMC v-8 and the number one intake and exhaust lobes went flat.

My 3 brother in laws said " oh yea Chevy had soft camshafts"

GMC Trucks supposedly used Chevy small v-8s.

Oh whoppie ding!

Oly

Improper break-in and/or break in lubricant. Cams use special break-in lube and most manufacturers require a break-in procedure for new cams, and some require single valve springs for a certain period after which double springs may be used. Seems every manufacturer I have dealt with have different requirements.

the camshaft is trying to kill the cam-follower and in the ongoing battle one of them wins

Well my experience of listening to Diesel truck engine manufacturer's reps telling me that most camshaft failures were a result of excessively long periods of letting an engine run at a "dead" idle.Of course these were,for example,the old V53,the V71,and the V92 series Detroit Diesels.The cams were splash lubed from what came off the rocker arm assy.,and located right under the head at the top of the block,where oil didn't get to very good to begin with.They recommended idling them up to 1000 RPM if you were going to idle longer than 10 min.That wasn't easy to maintain,because the truck application Detroit governors were temperamental and drifted up and down,especially if they were worn,or improperly adjusted.The answer to that was an air actuated idle control you added on.Or went to a Woodward oil fed gov.Anyway you combine that with poor maint.,E.G.not changing oil like you should,and there you have it.

I would agree that engine speed/pump volume are important at tick over and also Lubrication Methods,Blocked Spray bars or poor Design/Material do come into play.Oil Life and amount of Detergent also play a Significant role assuming the correct material was chosen.Higher wear in Tuned/Peaky Motors is to be expected as they have a pretty rough time.

if it is a complete engine rebuild you should use a oil pump primer to fill the system with oil so you have oil flowing to the cam and lifter interface right away. also fill the carb float bowls so you don't have to crank the engine a lot before it starts. always use moly kote on the lobes and lifter bottoms. as a retired race engine builder i have done this many times

Obviously the henways are out of alignment.

Is it Henway, or Henweigh?

I'm sure that Sir Percival Henweigh, the leading physicist of the 16th century coined the term.

I forget, what's a Henweigh?

Anyway you spell it, it's still about 3 lbs.

Do you mean pound sterling or pounds in weight?

(pun intended)

Engine blocks are line bored for both crankshaft and camshaft. If the engine is overheated, the block can warp and distort the line boring tolerances which will stress all rotating components. There is a similar concern with overhead cam operation.

If it's an '83 through '85 V45 Honda 750 Interceptor, then it is due to excessive pressure in the contact area between the cam lobe and the valve follower. Unfortunately, each lobe actuates a pair of valves and the mechanical arrangement is such that contact point is between the fulcrum and the valve, further adding to the force required to open the valves.

I bought one of the first Interceptors off the boat in March of 1983, and I was back to the dealer in less than a year (21,000 miles) with the hard facing flaking off the cam lobes and followers. Initially Honda of America tried to dismiss my claim, but eventually they agreed to replace them under warranty after I bitched up a storm.

They supposedly issued 'new parts' and a special tool to adjust the valves to 'pre-load' (I still have my tool) to make sure the pressure is even across both valves, but that was basically eye-wash trying to band-aid a fundamental design flaw.

Some claimed the top end lube was too low a pressure but I even went to the trouble of tapping into the main oil journal of the crankshaft and plumbed that to the heads using aeroquip fittings and braided stainless hoses but I still wore out the cams and followers.

Even the spray welded, hard coated Megacycle cams and followers didn't stop the wear. I always ran full synthetic motorcycle oil (Redline) too but I still wore the things out. Basically it was a design for which no material and/or lube could fix. Honda got the message pretty quickly and the VFR was introduced with a completely different valve train in 1986.

I sold my '83 750 Interceptor in 1990 with about 50,000 miles on the clock but my son is now riding my 1986 Honda 500 Interceptor. It's valve train seems to hold up much better than the 750's/700's.

I remember those early Vf's,they were referred to as "Chocolate Cams"over here

I had a Chev Van with a 305 engine. It ate camshafts at a predictable rate. As I did not have the time and or facilities, I had to send it to a local garage that I though I could trust. After the third failure, I chose to give the gallery a good look.

Found a plugged oil feed to one of the cam lifters. Needless to say I never went back to them.

My next van was also a Chev/ GMC. I got over a million kilometers on the engine. Unfortunately the body began to biodegrade.

In most engines, cam clearance is auto adjusted by hydraulic tappets. Malfunction of tappet can cause severe linear speed difference between cam and tappet, the moment they collide, resulting to noisy shocks that today's cams are NOT MADE to survive for long. S.M.