Honda K24 Engine main bearing cap design

[Scout1]

I find it very interesting all the discussion around here on how various engines need different oils and often it gets pretty technical citing things like bearing design. So I got to thinking about my K24 engine in my Accord and wondered what Honda did to make it so reliable on just about any oil? Must have pretty wide bearings, right? So I went looking for pictures and videos and found the YouTube video below showing install of the crank and was surprised to see instead of individual main bearing caps, the K24 has a big plate that incorporates all the main bearing caps that goes on the bottom of the block. Looks a lot like how a motorcycle engine does it with a split case. Is this design typical in other cars? Does that design increase rigidity and maybe is it responsible for the rock solid reliability and longevity of these K24 engines?

https://www.youtube.com/watch?v=9aNu5pylb3g

 

[dan_erickson]

I have never seen that before that that plate must make the whole engine assembly pretty strong.

 

[skyactiv]

That main bearing girdle is somewhat common on newer engine designs. The oil jets that squirt oil to the bottom of the pistons help cool them and is common on modern turbo vehicles and non boosted vehicles to a lesser extent.

 

[AKhan87]

Originally Posted By: skyactiv
That main bearing girdle is somewhat common on newer engine designs. The oil jets that squirt oil to the bottom of the pistons help cool them and is common on modern turbo vehicles and non boosted vehicles to a lesser extent.
+1 I have never done an engine without that design.

 

[Scout1]

Wonder how they make that? Do they cast the block in one piece then make a cut at the crank center line?

 

[Billbert]

This is commonly called a 'skirted' block. Mostly used with aluminum blocks.

 

[Yah-Tah-Hey]

My neighbor has a four cylinder Honda motorcycle that has that setup. Looks like a very strong bottom end.

 

[Hokiefyd]

The bearing plate like this is pretty common in the last 10-15 years. The first engine I owned with one was a Cadillac Northstar, designed in the late 1980s. It was probably pretty uncommon technology back then for a street engine. Indeed -- they had problems with various oil leaks at the joints (called "case half leaks" in the Cadillac world, where it leaks from the joint between the two crankcase "halves").

Yes, bearing plates generally improve the structural rigidity of the engine. It's similar in nature to a cross bolted bearing cap, I guess. Probably easier to assemble, though.

Honda engines typically have pretty strong bottom ends. The R-series (Civics) and K-series (CR-V, Accord) both use a bearing plate. The J-series (V-6) uses cross-bolted main caps, and the bottom end ends up looking like a plated bottom end when it's assembled.

I think the plate and the block are manufactured in two parts. There are sometimes dowels installed to facilitate assembly. I also think the plate is used, to a large degree, to aid in assembly. It's pretty quick to lower a single plate onto the engine and torque it down from the top. Cross-bolted main caps require individual installation and fastening from the top and from the sides, which takes more time.