What is the difference between resin and rubber?

Question

They are both byproducts of plants.....

Answer 1

There are few mysteries about the engine employed in the MGB.

During the era in which the B Series engine was designed, hydraulic lifters for automotive applications were still in their

technological infancy, therefore the engine was designed to use solid lifters. This offered the designers the opportunity to wisely

leave the camshaft exposed to the crankcase so that its lobes could be lubricated by a spray of oil emitting from the lower ends of

the connecting rods. This desire to lubricate the lobes of the camshaft and the lower sections of the tappets dictated the thickness

of the connecting rod big end. Adequate bearing support was achieved by using a large diameter big end design.

Its Heron-type head used Weslake-patented combustion chambers which were a marked advance beyond previous

technology, allowing for superior flow characteristics while permitting excellent flame propagation. The incoming fuel/air charge

was directed toward the spark plug and away from the hot exhaust valve, minimizing preignition and allowing less ignition

advance to be used. The siamesed intake ports, like some other features of the engine, were largely the result of production

economics. By using siamesed intake ports the intake manifold could be of simple design and thus be inexpensive to produce.

The tappets and pushrods could also be neatly situated between the ports, thus keeping the head as narrow and light as

possible. The placement of the intake and exhaust manifolds on the same side of the head meant that only one mating surface

need be machined, and fewer manifold mounting studs and their attendant threaded bores were required. It also allowed the

distributor and generator to be placed on the opposite side of the engine, thus greatly simplifying maintenance.

There are also some distinct engineering advantages to this approach. By placing the intake ports with their cool fuel/air

charge next to the hotter exhaust ports, this area of the head is better cooled than it would be in a crossflow design, precluding

warpage and possibly extending the life of the exhaust valves, although this configuration allows more heat to accumulate in the

walls of the intake ports and thus is detrimental to intake charge density and hence lowers power output potential. The small-bore

long-stroke configuration gives better thermal efficiency and thus better fuel economy. The bore centers are the same as those on

the earlier, smaller displacement versions of the engine, so the new engine could be produced on much the same tooling, thus

keeping costs within reason.

Although the B Series engine design is truly a compromise, it's a brilliant one that modern mechanics recognize as one that

was far ahead of its time when introduced. It was further improved with the introduction of its 5 main bearing version. A higher

capacity Holbourne-Eaton oil pump was provided to supply the bearings which were 1 1/8" wide for the front, center, and rear

bearings, and 7/8" wide for the intermediate bearings. They all had diameters of 2.125", a full 1/8" greater than that of the previous

1622cc three main bearing version. This produced an almost unbreakable crankshaft with lots of overlap between its journals and

counterweights. Certainly there were other new engine designs that were even more advanced in the mid-to-late 1940s, but this

one was intended to be available in cars that ordinary people could afford to own and operate. In those days, that made it special,

and its designers had every reason to be proud. During an era when full race engines struggled to reliably produce 1HP per cubic

inch, when the 18G Series arrived in 1962 it boasted 95HP from a mere 110 cu. in., giving it a specific output of .864hp per cu. in.,

and this was an engine that could reliably be used as a daily driver! In its heyday, it was impressive indeed. Pretty fantastic for a

relic whose design is well over a half century old! A true classic engine for a true classic car!

Everybody who is about to rebuild their tired engine entertains the thought of improving upon the power output of this classic

engine design. However, nobody wants to end up with a temperamental beast. Since you're rebuilding the engine, this is a good

opportunity to do it the Peter Burgess way. As a former professional mechanic who has built custom engines, I can assure you

that I have thoroughly read both of Mr. Burgess' books "How to Power Tune MGB 4-Cylinder Engines" and "How To Build, Modify,

And Power Tune Cylinder Heads," and that his theories are both sound and logical. His reputation as the MGB engine tuner is

well deserved. His books should be in every MGB owner's library. His website can be found at

http://www.mgcars.org.uk/peterburgess/ . If you have not studied his books, they are available from Veloce Publishing at

http://www.veloce.co.uk/newtitle.htm . I wholeheartedly agree with his statement "The entire engine system needs to be

considered as a whole, otherwise the gains from component changes may not be fully realized."

Before you begin, you will need to have a proper Service Manual. I would recommend that you purchase a reprint of the

original factory service manual that the MG dealers had for their mechanics to consult. To my knowledge there is nothing that can

compare with it for completeness. Its actual title is "The Complete Official MGB," although it is often called "The Bentley Manual"

as it is printed by Bentley Publishers. They have a website at http://www.bentleypublisher.com/ where you can order it direct.

If your engine is a post-1967 North American Market model, then it is equipped with an antipollution system. To get better

performance out of the engine, it will be necessary to remove some of the components of this system. Prior to doing this, check

with your State Officials to find out if this is illegal. Be advised that in some states where it is illegal to tamper with a vehicle's

antipollution system it is not required to be maintained once a car has reached a certain age, so specifically inquire about this

issue as well. Be aware that it is desirable to retain certain items of this system, so don't start by simply stripping everything off.

Instead, proceed with the same methodical approach that you would use toward any other part of the car.

If yours is a 1964 through 1969 GA through GF Series engine equipped with a PCV Valve, it should be retained to reduce

atmospheric pressure inside the engine. However, if the compression rings start to fail, oil mist from the engine will saturate the

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This article was written by USA,who certainly knows his 33.000 words so you may want

oil separator tube of the early version of the front tappet chest cover and be transferred into the combustion chambers through the

induction system, the consequent carbon buildup eventually resulting in problems such as preignition, sometimes called "pinging."

The front tappet chest cover from the later 18V engines (18V -797-AE, 18V-798 -AE, 18V-801 -AE, 18V-802 -AE, 18V-883 -AE-L,

18V-884-AE-L, 18V -890-AE-L, 18V -891-AE-L) is preferable due to its better breathing characteristics and for having incorporated

into its cover design an oil reservoir/return chamber which minimizes the transfer of oil mist into the induction system. When

replacing the gaskets on the tappet chest covers, use sealant to glue the gaskets to the covers and allow it to harden overnight so

that the gasket will not move during installation.

If you choose to not remove the hose that leads from the Gulp Valve to the fitting on the center of the intake manifold, it can

be simply blocked with a plug, or, after removing the intake manifold, threads can be tapped into the intake manifold with a 1/4"

NPT tap and a nipple installed.

At this point you may remove both the hoses and the Check Valve that connect the Air Pump to the Air Injectors atop the

head. Next, remove the Air Pump, its air cleaner, and the attendant mounting brackets. When the engine is equipped with the Air

Pump, the Gulp Valve is necessary to prevent backfiring when closing the throttle at high engine speeds, so remove the Gulp

Valve along with its hoses and its attendant hardware as well. At idle the intake manifold vacuum is in the order of 18 to 20 Hg,

while on the overrun it rises to 23 to 25 in Hg without the Gulp Valve. This is not enough to make a significant difference in terms

of the amount of fuel pulled out of the jet, thus the Gulp Valve is unnecessary once the Air Pump is removed. Next, remove the

Air Injectors and replace them with 7/16"-20 fine threaded bolts 3/4" in length. Do not be tempted to use Allen head plugs

because they will have to be bottomed out into the head, projecting into and thus creating an obstruction to air flow in the exhaust

ports. Finally, if your engine is from a post-1974 model, remove the EGR Valve and its hose and control pipe, the fuel shutoff

valve, and the vacuum advance valve.

You should retain the Anti -Run-On Valve fitted on the 1973 and later models as its purpose is to apply such a strong vacuum

to the chamber above the fuel in the float bowls that the fuel cannot exit the fuel jets when the ignition is switched off, thus

preventing the car from running on. When the ignition is turned off the ignition switch energizes this solenoid-actuated valve to

close it, then the oil pressure switch releases it after the engine has stopped and oil pressure has fallen. When the engine is

running the Anti-Run-On valve is open, allowing fresh air to be pulled through the adsorption canister, clearing it of the vapors that

have expanded into it from the fuel tank and the carburetor float bowl chambers, then through the rocker arm cover and  

Answer 2

Resin is what comes out of pine trees, for example.

For a definition of resin check link 1. I'd say that the sap of the rubber tree is a latex (see link 2) rather than resin.

Answer 3

rubber itself is resin

Answer 4

Rubber is a latex and is water based sap. The rubber plymerizes as it dries out and it is no linger soluble in water.

Resins are solnent based saps that have stuff like tupentine in them to keep them liquid. They do not polimerize and remain soluble in the solvent. They can usually be melted at fairly low temperatures too.