adjustable rocker arms

[Anonymous]

I recently swapped from a 170 to a 200. I noticed that the 170 has adjustable rocker arms, and the 200 didn't. Before selling the 170, i was wondering if the adjustables are something worth holding on to. thanks.
-Keaton

 

[wallaka]

Might as well. You'll have to get different pushrods if you want to use them on a 200, though.

 

[pedal2themetal45]

If you take the adjustable rockers take the pushrods as well so you well have a set..
tim

 

[rommaster2]

are there any advantages to adjustable rockers?

 

[Gene Fiore]

Yeah, you can adjust them...

 

[mugsy]

When I put a 250 cylinder head on a 200 block I had the block milled 0.030" and the head about 0.040". Now the motor has "0 decked" for better quench and the compression is about 9.4:1 :roll: . Without adjustable rockers the valve train geometry would have been way off. If you are planning on any changes/milling to the block or head, keep the adjustable rockers .

tanx,
Mugsy 8)

 

[Anonymous]

so if you have block or head modifications, you can use the adjustable rocker shaft (with hydrolic lifters) to compensate for push rod length?

 

[xctasy]

No. The rocker at mid point between maximum lift and the base of the cam must be at 90 degrees to the pushrod. If its out even a degree or two, there is a risk of the rocker ball socket will wear, and the valve lift and adjustment will be off.

There are a few pictorial accounts of this happening on some 200 I6's here. (when using bigger cams, non standard heads or roller rockers when you haven't been able to do all the math).

According to wasiii, there are 302/351W lifters which are designed to run with oil through type pushrods and have a 150 thou lower start point than the normal 200 lifters. If you deck a block 80 thou, and the head 40 thou, and use the later rocker tube and oil distribution system as found on the post 1972 heads, you could sort out 120 thou of mismatch with just a lifter change. Then you need to get advice from an engine builder.