3800 rocker arms

[Barney Eaton]

The 3800 engine had standard stamped steel rocker arms thru 1992.    In 1993 one of the changes was roller rocker arms.

has anyone converted their pre '93 engine to roller rockers?  

I do not have a parts book later than 1991,   I checked Rockauto and they show the same push rod for 1991 and 1993 which leads me to believe

the roller rockers could be added without changing any other parts.

[padgett]

Always thought the roller lifters were more important.

[2seater]

I don’t remember the exact year rocker arm I purchased but several years ago I bought one new one at the dealer. It looked more like a casting than a stamping but it is a roller trunnion only with a standard sliding tip. A couple things made it a non bolt-in, the bolt that attaches it to the head is smaller diameter and something is different about the distance from pivot to pushrod as well as to the valve tip. The ratio is supposed to be the same but it looked like the rocker was located slightly differently. I haven’t opened up the 95 s/c engine to see if the same

[ChrisWhewell]

That's be one of the few mods that'd actually deliver a noticeable power gain, the use of roller rockers with a ratio slightly higher ratio than stock.  If I could find a set, I'd install em and it would also motivate me to remove the exh. manifold on the left and grind that huge obstruction out.  Is that all it takes to get me off my dead @$$ ?  hahaha 

[padgett]

Wonder if anyone makes a 1.65 rocker for the 3800. Believe the 88 has a slightly less-ded cam.

[2seater]

2 hours ago, ChrisWhewell said:

That's be one of the few mods that'd actually deliver a noticeable power gain, the use of roller rockers with a ratio slightly higher ratio than stock.  If I could find a set, I'd install em and it would also motivate me to remove the exh. manifold on the left and grind that huge obstruction out.  Is that all it takes to get me off my dead @$$ ?  hahaha 

I agree it would be nice to find higher ratio rockers but there seems to be precious little for our orphan engines. There is stuff for the later Series I & 2 but something is different about the geometry as mentioned earlier. I looked at some Ford stuff too, which use a 1.6 ratio as standard too but so far no soap. The ratio increase to ~1.7 would net valve lift similar to what the original '88 cam had but without having to get into the engine internals. 

 

Get yourself a spare manifold and start cutting it up and modify as you will. Probably make little difference without other mods but may sound different. Eventually I will install this one, which is now ceramic coated, probably on my future s/c variant or the half turbo one.

[2seater]

[2seater]

I don't know why I am having such a tough time uploading photos but that's the reason for the multiple posts. In any case, this is a comparison of a rocker from a '95 s/c engine on the right and an LN3. The '95 rocker is a bit of a surprise as I had purchased a single rocker from a local Buick dealer and it was clearly a casting, not this stamping, so maybe they gave me something from a Series II? In any case, the differences still remain even though these look like clones. The '95 rocker with the roller trunnion is slightly wider and longer. The roller assembly will not drop into the older model stamping. The guideplate is more of a single piece and less robust than the  hardened steel plate we have. Since the rocker is different than what I saw before, it may be possible the whole late model assembly could be retrofitted if the stud holes are bushed smaller to accept the new rocker. That experiment will need to wait for now.

[padgett]

BTW the problem with the exhast manifold is a right angle turn from both directions into this: