The Stovebolt Site Forums The Shop Area Engine Shop assembling my 261

Can I get a little clarification? The manual I have is for the 216 and it says the the wrist pin clamp bolt goes TOWARD the cam? Is that right? Is the notch in the piston crown front?

Thanks,

Jeremy

Yes, that is correct on both counts, clamp toward cam and notch to the front.

Thanks!
Just wanted to be certain. With any luck I'll have the engine in the truck in a week!
I hope!

Jeremy

If you need to see anything else specific to the later full pressure engines, here's the engine section of the '55 Second manual.

Thanks or that!
I'm wondering if I have the right oil pump now....
My 261 is cast in 57 but its a replacement for an early block. So it has the High mount water pump.
The crank bearings are of the later type though...
I heard there were 2 different oil pumps.. anyone know the differences?

Jeremy

Jeremy,

If you have the early 261 the
1954 Truck Shop Manual may be useful.

Which oil pump do you have?

There are at least two types. The oil pump for the later engines has a floating pickup. The oil pump for the 1954-55.1 engines has a fixed pickup, which bolts to the third main cap. The Master Parts Manual does not have an illustration of the 1953-55.1 pump, but it is similar to the 1940-52 pump shown in the parts book. I do not know if the later pump can be used on the earlier engine, without modification to the oil pan baffles. The oil pans are not interchangeable, although I've heard that some of the replacement blocks for the 54-55.1 came with the non-straight oil pan sides. However, the three 261 replacement blocks that I have acquired for the early engines used the straight-sided oil pans.

Hoyt

Thanks Hoyt,
I just put the crank in and checked the bearing clearances with plastigauge. I've got .002 so as soon as I find som new main bolts I'll bolt everything in.
Is there an actual 261 manual?
My replacement block doesn't use shims, maybe I should look at the 56 manual instead.
Pan oil pan is straight sided if you don't mean the little bulges coming out of it. but the pan isn't curved or anything.

Jeremy

Jeremy,

I'm not aware of a specific 261 manual. I have two 1954 261 engines that were replacement shortblocks purchased from Chevrolet, one in 1958 and the other in 1964. Both of them came with the later main bearings with tangs and no shims. One of them also came with the elastomeric rear main seal. The original 1954 blocks had main bearings with dowels, shims, and a rear main rope seal.

I believe that pre-68 Dave recently posted an image showing the straight-sided and curved oil pans.

Hoyt

Shims are not always required - they are to be used if necessary.

Yeah, i fell into that issue when I ordered an engine kit from Patrick's. I ordered the bearings for an early 261. Live and learn I guess. The pistons go in today, IF I can get the time to check the end gap on the rings. I balanced the rod and piston assemblies to .7g of each other. It might be overkill for an old I6 but my thinking is better is better.

Jeremy