GS 455 Engine Tuning?

[GSJason1970]

Hi,
I just recently joined the site. I took my GS 455 out on the highway after putting in a new TH400 and noticed that there was smoke coming out of the passenger side tailpipe. The car has been sitting idle for a little more than three week, but even after driving for an hour there was still smoke coming out. Is this the start of an engine problem or am I just not getting a complete fuel burn? Currnetly runnning on a full tank of 93 octane.
Any info on this would be appreciated.
Thanks
GSJason

[GSJason1970]

I opened up the valve covers on my stage 1 455 engine and found that a push rod had gone through one of the rockers! The rockers on this engine are light weight and are dimpled where the push rod is seated. The push rods are hollow and allow oil to pass through to lube the top of the engine. I then took off the manifold to see if there was anymore damage and found that the push rod had pulled out the sleeve it is seated in. Has anyone else had this happen, what could cause this and how can I prevent it from happening again? The engine was rebuilt a few years ago and has less than 2000 miles on it.
Not a mechanic but learning the ropes as I go.
Thanks

[bob k. mando]

who rebuilt the engine? did they know that Buicks require much tighter tolerances?

what pressures are you running? a Buick should have about 10lbs per 1000rpm.

my father wants to know what kind of a cam are you running, the factory stage 1 or a bigger aftermarket cam?

the only thing he can think of that you might be taking for a 'push rod sleeve' would be if the lifter came apart and pieces of it were coming up around the push rod.

i have seen it mentioned before that all hydraulic lifters, new or not, should be disassembled and checked for metal/shavings before being installed.

big cams will beat up the rockers after a while. 2000mi is really short though.

[fueler191]

well from my personal experiences with a fresh rebuilt engine for the first..at LEAST...at LEEAAST 500 miles needs to be kept under 2.5k rpm. Personally i still stick to the 3k marker for that. Many things can happen if you dont give the engine time to break in, especially with cam bearings, and lifters. Everything may have been fine, but if you beat on it a little theres a chance that something could have gone wrong.

But hey...as i say all the time, when something goes wrong...it just gives you a reason to make it go faster.

best wishes to the 455 and you~

-jeff-

[rcull]

Assuming all you failures are on the same valve.

You are probably running OE aluminum rockers. Perhaps they were not well inspected during installation. When rebuilding it is always a good policy to keep rockers and pushrods matched. If everything is good though it really shouldn't cause fast failure.

The pushrod going throught the rocker is an indicator of lack of sufficient oil. Is the rocker towards the rear of the motor where pressure is least?

The pushrod failure could be as bob k. mando describes or maybe the pushrod threw one of the push in ends.

For the push rod to have gone through the rocker, this would have to be the first event. If all else was well the lifter should have stayed together and with luck the pushrod should have been fine, unless it got itself into a position to be bent. You have a more unusual set of failures

[BigRivy]

My experience in this area, which is considerable, would indicate that you are getting high frequency valve train separation. It could be affected by oil pressure but I doubt it. I would say that your valve springs are not up to the rpm that you are turning. Weak valve springs damage alot more engines than I can count. As an ASE certified master engine machinist I have built a ton of hobby type stock car engines of many sorts and have seen just about every type of valve train failure you can imagine and probably a few that you can't. When the spring can't keep up the the rocker and pushrod can't stay in contact like they should. Then they slam back together like they are being hit with a hammer. This could be the problem or when separation occurs the lifter will pump up to try and compensate for the extra clearance, possibly allowing the piston to contact the valve and again slam everything back together again this will also push a lifter through a rocker (steel or aluminum) and knock the plunger out of a hydraulic lifter. The springs you have might provide thousands of miles of everyday driving but give problems with just one high rpm run. Stock Bbuick valve springs don't have a lot of seat pressure to begin with and if the valves were sunk on a rebuild valve job and not shimmed to compensate you won't have the pressure you need to run high rpm. Springs could also be wore out or damaged.

[GSJason1970]

Thanks for all the replys guys, got a lot of valuable info, answers to questions and a lot to think about.
Looks like I may be heading towards an engine rebuild just for peace of mind.
Bob K. Mando - I'm beginning to question the skills of the engine builder.
Looking back the only time the car has been driven by someone else was about two days before I lost all oil pressure. I left it in the care of my local mechanic to do a minor electrical repair on the rear taillight harness, a simple weld job on the exhaust and a last minute tranny line replacement. Just thinking that they could have possibly romped on it up and down the turnpike just pisses me off.
I looked up my receipts and the Cam is a SP 235 from Torque Tech in Valdosta, Georgia. If I remeber correctly this was a very streetable racing cam, but I couldn't find my old catalog.
My oil pressures were 40psi idling at about 1100 rpm and 60-70psi at 3500 - 4000 rpm, too much???
Since the tranny rebuild I have been driving in 1st gear and letting the tranny shift on its own.
I did mistake the lifter for a sleeve and thankfully it was all still in one piece. However the push rod that went throught the rocker arm was bent at the bottom and the next to it was curved like a banana. I found that the nylon fastener that held the rocker arms in place had come off and the push rod smacked the top of the valve cover really hard.

Fueler191 - You may be right as well. May be the engine didn't get broken in enough, as I recall it took a lot of time and tunning to get the car to do a 12.9 in the 1/4 and even then everyone said it should have been hooking up better with all the parts in it and doing low 12's like my friend Toppers bone stock Stage 1 70 GS.

Rcull - It was the set of rockers on the passenger side header closest to the water pump that went. I have Hi rev 455 lifters, 5/16 CM 455 push rods, the rocker arm assembly came assembled from Torque Tech and I got a 455 hi performance steel billet double roller from TA Performance in Arizona (not quite sure what that is and does, but I'm learning).

BigRivy - You could be right too, I can find no info on the springs used on the valves and it could have been this and or any combination of reasons previously mentioned that caused the failure.

Thanks for all the info Guys, it's been really helpfull for me in understanding how all this stuff comes together. There are only a couple of guys in my neck of the woods with Buicks, I seem to be in a sea of Chevy and Mopar here.
Glad to know you guys are out there. I'll keep you up to date on the progress.
Thanks again
Jason

[bob k. mando]

well if you're going to have the engine rebuilt, make sure your engine man sees these pages on oil mods. even if he's a Buick man he might find something interesting in here:
http://www.buickperformance.com/oilflow.htm

http://www.buickperformance.com/OilingMods.htm

http://www.buickperformance.com/Oilmods.htm

http://www.trishieldperf.com/455_block_mods.htm

i'm thinking BigRivy is onto something. if you've got a big cam and stock (original?) springs that would really aggravate the situation he's talking about.

if the valves were sunk on a rebuild valve job and not shimmed to compensate

what he's talking about here is that the Buick rockers are NOT adjustable like Chevy rockers. you can shim up the entire rocker shaft or you can use adjustable or custom length pushrods.

[BigRivy]

No, I'm not talking about shimming the rocker shaft. I'm talking about shimming the valve spring to maintain the proper installed spring height. Sinking the valves into the head will effect rocker geometry, but you can grind the stems to compensate for this and still not fix the spring height problem. Installed spring ht. is the distance between the spring retainer and the cyl.head. This spec. is available in almost any good manual. Aftermarket springs may require a non stock installed ht. always buy the springs that are reccomended by the cam grinder to match the cam requirements. I wouldn't trust any stock spring with a lot of miles on it to be reliable above 4500 - 5000 rpm. Also once a spring goes into valve float it tends to damage it. They heat up real fast and an overheated spring will lose its ability to do it's job. They will then not even be able to do the marginal job they were doing in the first place.