There
have been a number of engine swapping books and manuals printed and published
by various companies over the years, and some of them actually can be of
assistance in doing a swap. However, experience is the best teacher by
far, and since we have done over 50 engine swaps on personal cars and several
hundred for commercial purposes, we will pass along some general tips that
may save you some headaches. Of course we must generalize due to the infinite
number of swap possibilities that exist, all with their own individual
problems. Therefore we will list some of the major steps to take and problems
to avoid:
Measure
your engine and engine compartment carefully to determine if, indeed, the
swap is possible and practical.
Check the location of the starter, oil filter, pan sump and transmission mounting points to see if they will clear steering linkage, frame, firewall and floor. Some reworking is usually expected, but beware of major engineering changes that can weaken the structural integrity of the frame and body.
Find out how much weight differential exists between the new engine and the old, especially when going to a V-8 from a four-cylinder engine. The front-end components, brakes and weight distribution of the vehicle may be ruined beyond help if it is too great a difference.
Be sure you will have room for an adequate radiator and transmission cooler (if automatic) after swapping in a bigger engine. Cooling is one of the most common problems.
Consider the rest of the driveline. Is it strong enough, or should it be replaced all the way through the third member? If so, can you afford it? Is there a machine shop in your area competent to narrow the axles? Will you need a proportioning valve for the mixed braking system to work … or perhaps a new master cylinder with more volume? Are you able to wire the motor and accessories in a semi-professional manner or will you have to pay big bucks to someone else to finish the job? If you are not handy with detailing, an engine swap can be murder on your budget.
Most swaps require custom exhaust systems and many muffler shops are either unable or won’t build them. If they do, it seldom comes cheap. Think about how you will route the exhaust and where the mufflers will hang. With headers, will you still be able to retain your clutch linkage or will a slave cylinder work?
Assuming you can make or buy good, strong mounts for the engine, will your frame need reinforcing elsewhere to take the torque of the larger engine?
After the deed is done, will gas mileage go down the drain and your wheel traction be nil, canceling out the advantage of the more powerful engine? If so, can you transfer weight to the rear and find tires and shocks or traction aids that will solve the problem?
If you
find that you have answers for the questions we’ve asked that satisfy you
on an unemotional, logical level, then you can proceed with the swap knowing
it will be a viable and well-integrated vehicle when completed. Too many
swappers take shortcuts, either due to a lack of funding or because they
are in too big a hurry to complete the job. Sometimes it is merely inexperience.
Some of the problems we have seen in swaps include: