Bent Push rods

[PGibbons99]

1999 3.0 SG Volvo/Penta was run hot because of bad water pump. I pulled the head and found a blown head gasket. I had a valve job done on the head and replaced the head gasket,thermostat, water pump, flapper valve, and flapper boot. I installed the head and adjusted the valves to the correct specs. All torque specs were followed. When started up it ran fine for about 2 minutes under idle and then started knocking. I pulled the valve cover and found all 8 push rods bent and 4 rocker arms cracked. I checked all valves before installing rockers to make sure none were stuck and they were ok. Any ideas before I tear it back down?

 

[f_inscreenname]

Re: Bent Push rods

With all that damage sound like the pistons hit the valves for some reason. Did you do anything to the timing chain or cam? Just a thought.

 

[Boatist]

Re: Bent Push rods

PGibbons<br />Sorry to here of your bad luck. I have a couple of Questions. How did you adjust your Valves?? I must admit I do not know the Volvo 3.0 but I assume it still a GM block and head with hydrolic Valve Lifters. OMC 3.0 says adjust the valves to zero clearance at top of compression stroke then 1 turn clockwise. I have found this is a bad way to do it. This works great if all the lifter are working correctly but if one is stuck it opens the walve way too far. I set them all to zero clearance on the compression stroke, and start engine and let it warm up. As soon as warm I pull valve cover and start engine and adjust each Valve slowly down until it starts to miss then back off until stops missing then back one turn. This way also centers the lifter but if have a stuck lifter it end up too loose not to tight. Kind of messy but it is the way I do it.<br /><br />When you installed head gasket are you sure you got it on right and it was the right one so it did not block any oil lines to the rocker arms.<br /><br />Last thing I can think of is many shops knerl the valves stems to tighten valves in guides and also shim the valve springs to factory specs. This practice I have seen many times in auto engines either cut the cam out of the engine or bend push rods.<br /><br />Would really like to here what you find as the cause.