Making a 2.2 into a 2.0
 

I am planning on racing in a class where the top displacement is 2.0 Liters. I have a 2.2 engine and need to reduce the displacement to be legal. Any suggestions?

Thanks,
neilca

The biggest thing you need is just a set of 80m pistons and cylinders. Your heads may have a problem but I'm not sure.

You might need to check the diameter of the spigots where the cylinder rest in the crank. I seem to remember that when you convert from a 2.0 to a 2.2, you need to bore out the spigots to fit the larger cylinders. If this is the case, you might not be able to downsize the cylinders.

You also need to read the rules carefully since they may not allow you to "retrofit" 2.2 heads onto a 2.0 engine since the valves are larger which would be a signficant performance advantage.

Right - the 2.2 and 2.0 share the same crank and rods, which means the cylinder bores are bigger. However, the case bores are the same for the 2.0 and 2.2 pistons/cylinders, so you should not have any problem. Simply bolt on the earlier 2.0 pistons and cylinders.

-Wayne

That is good news. Thanks guys. BTW the valves are free in this class so the larger valves will be a bonus. When using the 2.2 heads on the 2.0 jugs should I use the 2.2 head gasket or the 2.0?

Wayne, your book is on the top of my Christmas list!

Thanks,
neilca

At the risk of embarrassing myself, how would anyone know for sure what displacement any given engine would be?

They can take them apart after the race to verify bore and stroke. This usually only happens if you win big races or if someone protests you. Besides whats the point of winning if you had to cheat to do it?
neilca

I have rebuilt a few 2.0 2.2, 911 engines, I know that the 2.0 head are
flat cylinder head gaskets and the 2.2 are the rings crush type gaskets,
so if you wanted to put 2.0 p/c on a 2.2 you will need new set of heads
without the crush ring type heads, I also know a 2.0 cylinder heads can be machined to 2.2 specs , but never heard of 2.2 style into the 2.0 flat tops. other then that, all the rest of the parts are interchangable, block, crank,rods , cams pump, shafts,
tin, 80mm, 84mm piston cylinders, bearings etc..

Does this mean the cylinder bores are the same for the 2.4 as well? I thought you could drop 2.2S pistonsinto a 2.4 with no machine work for a CR bump...

bores are the same 2.2-2.4 but the stroke changed from 66 to 70.4 which is why the 2.2 pistons provide a higher CR in the 2.4 than they did in the 2.2

I meant the case bores; it sounds like the case bore is the same for the 2.0, the 2.2 and 2.4, then...

Supertec Performance has a conversion that will allow you to run 2.2, 2.4 and 2.7 heads on a 2.0 cylinder.
The cost is $220 per set of six.
This conversion was designed to return 2.0 "S" heads to 2.0 specs after they were converted (cut to fit) 2.2- 2.7 cylinders.
This conversion has been race tested by to of the fastest vintage racers on the west coast and we have seen no collateral problems.
Five years testing with no failures.

We also have good used 2.0 "S" pistons and cylinders in stock for sale. With this conversion a custom made piston is desirable for max compression if that is desired. We can supply this piston and any other JE for a reasonable price.

We also have good used 2.0 heads available. We have 2.0 heads converted to 69 "S" spec for those racers who race with clubs that restrict valve size. I.E. HSR West

Hello chums.

Although Wayne is correct about the case spigots taking any 80 or 84mm jug, the later heads will not fit the 80mm 2L jug.

You need Henry's adaptors,,..

Henry, do these adaptor rings increase deck height..how much please?

Kind regards
David

DECK HEIGHT IS NOT CHANGED.

Excellent!

So, it looks like we can get a useful CR increase by swopping the heads, using thes adaptors on 2L pistons..

The only problem looks like the angle of the valve pockets will be wrong for maximum clearance..

Kind regards
David

I don't believe you will be able to get good CR using stock 2.0 pistons w/ 2.2 heads; it will most likely be low. The best benefit for this setup is to go w/ JEs and twin plugs. The shallower valve angles resist knock better so you can bump the CR higher than the 10:1 you can get w/ stock 2.0 heads and pistons.

"This conversion has been race tested by to (two) of the fastest vintage racers on the west coast and we have seen no collateral problems.
Five years testing with no failures."

Henry - Which fastest racers have been using this conversion for the last five years?

Wayne Baker and Frank Beck have both used this modification in the past with no reported problems.
Generally as a repair for 69 "S" heads that were cut for 2.7 barrels.
PS: "I said two of the fastest racers have tested this conversion " not are using this conversion.

Let's face it, both very fast racers.

We have a special JE piston designed for using 2.2 heads on a 2.0 barrel.

What's a set of those trick JEs run?