Cylinder walls


#1

Since most of the newer cars have aluminum blocks I would imagine the cylinders must have steel sleeves. Would this be a fair statement? I used to work on older car engines ,but now at 81 yearsI stick to fluid changes & other minor things.


#2

It isn’t worth learning; it’s better to remember things from the earlier days. 25 minute radiator replacement and $50 rebuilt carburetors and alternators that didn’t take all day to change are some of my favorites. Other memories include holding the Chevy 350 type water pump up while tightening the bolts to keep the fan from rubbing the shroud when the engine was started.


#3

Yes, they have steel sleeves.


#4

Not all of them…There is a process where the pistons and rings ride directly on the aluminum cylinder walls…The use a silicone alloy aluminum (alumasil)

"Production of components using know-how carried over from Formula 1.
The engine block featured on the new eight-cylinder comes from BMW’s
light-alloy foundry in Landshut near Munich, which also builds the engine
blocks for the supreme racing machines entered in Formula 1 by BMW Sauber.
The crankcase is made of a special aluminium/silicon alloy eliminating the
need for conventional cylinder liners, since the cylinder surface is formed
instead by exposing the hard silicon crystals integrated in the alloy. The iron coated pistons thus run directly in these uncoated, honed cylinder bores.

Well, while I may have more degrees than most people spent years in College I will admit that absolutely none of them are in ME. However, I do remember some other manufacturers trying these silicon impregnated cylinder liners. The track record is less than great. (OK, say Vega.)

If BMW thinks they can pull this off, who are we to complain about mature technologies like turbos?"


#5

Actually, GM started using the coated aluminum cylinders in '71. On the Vega. Needless to say, they didn’t have the process quite figured out yet.

These days, I think pretty much all the 6-pot and 6-pot engines use the alumaseal cylinders. And, as Caddyman showed, even the performance engines are probably mostly all aluminum now.


#6

According to Wiki, GM uses cast iron cylinder liners in their aluminum block Ecotec 4. According to other info on the internet, their aluminum 3.6 liter V6 also uses CI liners.


#7

Nikasil was used in the 90s as a linerless cylinder coating, successfully in Europe, not so much in the US where sulfur in the gas degraded the coating, resulting in a major engine replacement program by BMW, who replaced them with engines made with Alusil blocks, another linerless system that can handle sulfur.


#8

MB…

When I rebuilt my Vega engine…I sent it out to this machine shop that put in steel sleeves…Great machine shop out of Nashville (Grooms). The original engine with the silicone lined walls the engine started burning oil at 40k miles…When I junked the car at 130k miles the engine wasn’t burning one drop of oil. The problem back then was that if the steel sleeve lining wasn’t done right…there was the possibility of the sleeve to drop.


#9

That issue has not disappeared. They had trouble with the early versions of the Atlas I6 with the sleeves sliding down in the block.


#10

I think it’s a GREAT concept…As long as they can keep the sleeves from dropping…From my limited understanding it was due to the different expansion and contraction rates of the steel and the Aluminum. The Vega engine with the steel sleeves was a pretty good engine for it’s day…Too bad the rest of the car was junk…but I did like that car…


#11

I remember hearing of machine shops that would sleeve the Vega engines.

I agree that Vegas were actually a pretty great car for its day. Its weakness was that every single part, every single thing from the seat plastic to the plastic valance panels, was made a cheaply as humanly possible. It’s too bad, because I really liked the car and still have fond memories of it. If the quality and reliability had at least been on par with other cars of the day I’d probably have become a Chevy afficiado.


#12

Exactly MB…Back then I was a HUGE Chevy fan…And the Vega didn’t send me into buying a Toyota…it did put a bad taste in my mouth. My S-15 put me over the edge.

But I LOVED that car…Handled good…It was a good size for a persons first car…Good gas mileage by the standards of the day…When I washed and waxed that car…it looked GREAT…And to this day I still love the body-style.


#13

The reason that the Vega would burn oil was not due to the aluminum block, but the piston rings. Something was wrong with their design. I do know of some people, two I new personally that ran their Vegas over 100k miles without burning oil, both were very aggressive drivers, foot to the floor all the time types. People who babied their Vegas, or drove them like sane people would, seemed to have oil problems.

It was kind of funny that when the Vegas were getting all the bad press about their aluminum engines cracking, that Mercedes and VW were starting to use this technology in their engines, quietly of course. Like any new technology, there was a learning curve. The alloy developed by GM for the Vega is the most commonly used aluminum alloy in engines today, sleeved or not.


#14

“The reason that the Vega would burn oil was not due to the aluminum block, but the piston rings. Something was wrong with their design.”

No…It was the block…or more specifically the cylinder walls.

What would happen is the silicon would break away from the cylinder walls and destroy the rings…I rebuilt at least 5 of those engines over the years.

When I owned my Vega I just got out of the Army…as a 22yo kid I can guarantee you that I did NOT baby my car.

GM’s problem was NOT the block…it was the cylinder walls. GM did not have a good process of lining the Aluminum with the silicon…That’s where the problem was. Every time I rebuilt one of those engines…the machine shop that re-lined it all agreed that the problem was the cylinder walls.


#15

Amen Mike.

Keith, you had to be there. Mike and I both were. It was the cylinder walls. Trust us.

And the engines didn’t crack. The walls tore up.
The valance panels cracked. And the idle stop solenoids cracked. And the inlets to the heater cores cracked. And the rear axle retainers fell off. And the door hinges sagged. And the seats sagged. But the engines didn’t crack.

The Vega was a fun car to drive. And the market segment that bought them was mostly young people. I knew other Vega owners, including my roommate (I shared a military NCO trailer with two other GIs at the time). None of us babied our Vegas.