Topic: Bent valves on 500/550 rocker install

[Master Ted]

Yep, I did it - I may have done a stupid thing but I'm not a stupid guy - just new and inexperienced with MCs. At the very least I suggest bryanj's little squib below be entered into the FAQ's under a special heading as yet another novice will no doubt get burned on this one. FSM was not clear to me at time of reading - I simply blew it. The applicable page is filled with a new, special annotation now !

MOST IMPORTANT
When putting the top cover on get your trained humongous spider to hold all eight rocker arms up via the inspection caps or you WILL bend a valve as you tighten the cover down.

[Einyodeler]

Or if you have a lazy spider....loop a length of string around each rocker arm and keep upwards pressure on all 8 while you tighten the cover On the 500/550 you can wrap the strings around the top frame.

[Jay B]

I think I also did this to my 350f. I've had oil in #2 cylinder, fouls plugs. The rest are fine after my top end job. The last time I had the valve cover off I hooked #2 intake valve on install. I tightened just a tiny bit before I realised my mistake. But dammit, I'll bet 10 bucks I tweaked that valve slightly and took out the guide. At any rate it will be a winter project.

[crazypj]

Its also a LOT safer if you back all the adjusters off so the 'valve' end of screw is level with the rocker arm, then there's nothing to catch on valve tip
(Yep, even I did this once, August, 1977, first time I did a 550)
 Pretty amazing that 'we' remember the screwups so well
 You may find you also cracked the top of valve guide - been there done that
PJ

[Tim.]

Yep - safest thing is to totally back off all the tappets.

I also recommended 4 elastic bands stretched across the valve cover holding the rockers up a while back.

One underlying principle that should always be considered when working on these things - don't force it.  If it doesn't fit, don't make it fit, find out where the resistance is coming from and eliminate it.

Deja-vu from spring 2005:

http://www.sohc4.us/forums/index.php?topic=1155.0

[Master Ted]

I think I read every thread on the matter a couple of days ago after I did the dirty deed. Damn thing is the resistance in tightening down cover did not feel that strong - seemingly just the resistance of valve springs on the cam (indirectly). Heck, I've been twisting wrenches for decades which is why I'm so damn mad at myself on this. It's also why I think the item should be in FAQs - BOLDLY.

As it turns out my low mileage head is in real trouble requiring new guides and valves all around. Although there is no happy ending I have a 550 motor in the basket and went about tearing it down and sent off to shop for cleaning yesterday. The 550 is not nearly in as good shape as my fooked 500 head. Oh well - onward and upward as I'll do as best I can with my backup.

Adjusters will be full out and rubberbands will crisscross top of cover to rockers when this one goes in.

 

[Tim.]

Well, I have a worse problem caused by a more silly mistake - I had my head re-done last spring and gave the shop new valve seals.  2000 miles later, I'm burning oil big time.  Leakdown test showed bad rings, as did compression test.  Pull the engine apart, take the top to another shop, and sure enough, the seals on the head were NOT the new ones - totally worn bust-ass old seals.  Oil coming into the exhaust guides (two of which were worn) getting burned, glazing the cylinder walls lowering my compression, and smoking the neighbourhood.

So, I'm completely re-doing last springs rebuild.  New pistons/rings/seals/exhaust guides.  Boring another set of stock cylinders (0.5mm over piston kit).  Starting from scratch, all because the last shop didn't put on 8 seals.

[crazypj]

Well, I have a worse problem caused by a more silly mistake - I had my head re-done last spring and gave the shop new valve seals.  2000 miles later, I'm burning oil big time.  Leakdown test showed bad rings, as did compression test.  Pull the engine apart, take the top to another shop, and sure enough, the seals on the head were NOT the new ones - totally worn bust-ass old seals.  Oil coming into the exhaust guides (two of which were worn) getting burned, glazing the cylinder walls lowering my compression, and smoking the neighbourhood.

So, I'm completely re-doing last springs rebuild.  New pistons/rings/seals/exhaust guides.  Boring another set of stock cylinders (0.5mm over piston kit).  Starting from scratch, all because the last shop didn't put on 8 seals.

Worn exhaust valve guide seals wont cause the problems you mention as any oil is going directly into exhaust and not cylinder. On the intake side the oil will carbon up cylinder and probably raise compression.
PJ