Why do b20 sleeves crack

However, this means that extra space is required around each cylinder, and this results in a physically longer engine which is problematic in an engine bay of finite width i.

To keep the engine 'short', designers often 'siamese' the cylinders, i. Heat must then conduct from the areas directly between the bores along a longer path to the water jacket, and as a result the area between the bores tends to be hotter than the areas directly adjacent to the water jacket. Note on the larger bore engine that the cast iron liners are not separated by aluminium, whereas on the smaller bore motor they are and this aluminium is contiguous with the aluminium of the block casting.

Aluminium has a much better heat conductivity than does cast iron, so the aluminium between the bores on the smaller bore engine provides a superior heat path for heat to escape from the metal that is directly between the bores, and on the larger engine the heat path is inferior because it is cast iron. This is compounded by the bigger bore engine also having less thickness of metal between the cylinders, further limiting the effectiveness of the heat pathway to the water jacket.

As a result the smaller CC engine will have a more consistant temp around the circumference of each cylinder it still won't be fully consistant around the cylinders because the WJ is non existant between the cylinders , but the larger CC engine will run significantly hotter between the bores and cooler nearer the water jacket, and there will also be a more abrupt difference in liner temp near where the aluminium begins, right where that crack is Does anyone have pics of engines that do have a water-jacket arond each cylinder?

Does Honda produce any of these engines??? If the block is a closed deck design then you won't see much difference except that cylinders will be more widely spaced. If an open deck then you'll see that each sleeve stands alone with a space between each cylinder that is a continuation of the water jacket.

Other differences might be that the sleeves might be 'wet' sleeves where the cast iron is directly exposed to the water jacket, rather than 'dry' sleeves where the cast iron is surrounded by aluminium as with the engines pictured in this thread.

If you have the choice when designing an engine then you'd go for non siamesed cylinders every time. Not only is this going to be a more reliable design, the cylinders will remain rounder as they heat up which will mean more even ring tension and better ring seal.

The differences may not be great, but the siamesed design is definitely a compromise. With the two engines in the photos, if I were intending to substantially supercharge then for reliability reasons I'd pick the smaller bore engine unless there were other compelling reasons not to.

All other Honda engines have individual cylinder bore liners. Chevrolet cu. It may not display this or other websites correctly. You should upgrade or use an alternative browser. Discussion: B20 sleeve theory. The reason im starting this discussion is because there are members on this site who forget as much as i know at any given time.

With that said. What is safe for the b20 sleeve assuming it has cracking problems? From experiance i personally belive that a rod is more likely to squish before a motor reaches enough compression to crack a sleeve.

Sleeves crack because of detonation. If your motor is not tuned right, or if you run too much boost you will detonate and crack your sleeves. It has nothing to do with how powerfull your motor is, how much psi you are running, or your compression. You could make horsepower in a b20 and if you never detonated, you would be fine B20s get a bad rap but really they are a great motor and make more torque than a type r motor stock And Mod Moderator. Do B20s have frm sleeves Click to expand Well then i got nothing Once an engine goes on the Final Bore and Hone machine, the process begins with diamond hone stone selections in progressive stages to acquire the desired plateau hone dimension and finish.

Typical honing leaves a series of microscopic peaks and valleys in a cylinder. The valleys created during honing act as oil reservoirs to provide lubrication when the engine is running. The peaks, on the other hand, are worn off by the piston rings as the engine is broken in — thus leaving a plateaued surface above the valleys. Instead, when we perform a "Sleeve-Only" job, we rough-cut each cylinder under the final bore size from 0.

We perform the Align Bore service to restore trueness and OEM spec clearances to an engine's crankshaft-bearing bores. Simply put, this is where the crankshaft spins and a proper clearance in unison is key to bearing life.