I'm just learning about engines. I was wondering why a stroker is called so,..and what are the pros and cons.
Ruben

Hey Ruben!

Good question. A "stroker" refers to the fact that the motor has a larger than stock crank shaft. For a type 1 engine (1300 cc on up) the stock stroke was 69 mm. So any motor with more than a 69 mm is considered a "stroker." Common aftermarket strokes are 76mm, 78.4mm, 82mm, and 84mm (less common are even bigger ones, like 86mm, even 90mm ). The biggest type 1 motor you can build with a stock 69 mm stroke is a 1915 cc, which is a 69mm stroke X 94 mm bore.

The pro's of a stroker motor are several. The main one is more power and torque. The crank of the motor is the "lever arm" of the system, so for a given force acting on the piston, a longer crank stroke will produce more torque. Also, by increasing the stroke of a motor, you increase its displacement. More displacement means more air flow means more power.

There aren't many con's of a stroker. The most obvious is stroker cranks cost more money. Also, when you upgrade the crank to a stroker, you will usually want to upgrade other parts at the same time to take advantage of the increased displacement, such as better cylinder heads, better valve terrain, etc. Also, there may be some additional machine work required on the engine case to clear the crank and rods once you go over about a 76 or 78 mm stroke.

The Doktor is in..... Brian is the man to talk to about type 1 motors. He is great help so don't be afraid to ask any questions..

FORMULA TO FIGURE FOUR CYLINDER DISPLACEMENT:

BORE X BORE X STROKE X .0031416 = TOTAL CC'S

EXAMPLE: BORE = 92 STROKE = 69

92 X 92 X 69 X .0031416 = 1834.74 CC'S

COMPUTE ENGINE DISPLACEMENT CHART.



S.B.83.....85.5...87...88.5...90...90.5..92 ...94....96.5..101.6
64 1385 1470 1522 1557 1629 1647 1702 1777 1872 2075
69 1493 1585 1641 1679 1756 1775 1835 1915 2019 2075
74 1602 1699 1760 1800 1883 1904 1968 2054 2165 2399
78 1688 1791 1855 1897 1985 2007 2074 2165 2282 2529
82 1775 1883 1950 1995 2087 2110 2180 2276 2399 2659
84 1818 1929 1997 2044 2138 2161 2234 2332 2457 2724
86 1861 1975 2045 2092 2188 2213 2287 2387 2516 2789
88 1905 2021 2093 2141 2239 2264 2340 2442 2574 2789
90 2136 2067 2140 2239 2290 2315 2393 2498 2633 2920

OK then,.I'm just tesing him. Another question. I found the young man who owned my 63 bug before me,.who originally put the car together. He has a 2110 stroker that put in it but spun a bearing after only two weeks. I am trading a progressive carb for the engine. the bearing is still stuck to the crank. He basicly just boxed it up after he dissasembled it and did not try to pull the bearing off. I need to know what damage to look for. Everything was new on the engine. Even the aluminum case. also comes with stainless exhaust and muffler, cooling fan, sump, external oil filter. I would like to get that engine put together one day.

Did you calculate all that? Nice work

nah copy/paste I always use this site it has good tech info
http://www.johnsbugshop.com/TECH_DATA.htm

Once you get the bearing off you will have to assess the damage to the journal. I would have it looked at by an automotive machine shop. Unless it's really FUBAR'd they may just have to take .010" off the journals and polish them up, pretty standard stuff. Which bearing was it?

I once spun a rod bearing in a small block Chevy motor. Had to buy a new crank and rod. Hopefully you have better luck than me.