shrike

iTrader: (1)

Ok so I am new at this and my question will sound very newbie.

The application is a 4.8 into a 1987 Cadillac brougham. I want to use the original engine mounts (olds engine) and modify them. I don't want to go with Chevy mounts, no money.

So when you position the mounts in the left to right direction, do you center the crankshaft pulley to be halfway between them? Is this distance always symmetrical? What is an acceptable error on that distance?

bczee

iTrader: (12)

Center the engine between the frame rails.

Not knowing what or how the Caddie is setup. the engine mount locations may or may not be centered or offset between the frame rails

shrike

iTrader: (1)

From my calculations the crankshaft pulley is about a 1/4" more to one side than the other based on the reference I use to measure (edges of oil pan).

I am making the the mounts with the engine out of the engine bay, I don't have a proper engine hoist. But I will check if the distance from the mounts to the frame rails is the same. If it is, then I will center the engine between the mounts. If it is not then I will have to do more calculations.

Thanks!

rumblbu

iTrader: (1)

Do you have the original engine? Seems to me you would want the crank centerline in the same place it was before. The problem with building the mounts out of the car without trial first is that you may need to adjust engine height because of interference issues with the pan. How will you be sure the engine is in the correct position front to rear without a test fitment of the engine before making the mounts? Not trying to sound negetive....just trying to be realistic.

Pop N Wood

iTrader: (1)

Engine doesn't have to be centered. Offsetting it might give some much needed clearance for steering or exhaust. Mine is a full inch to the passenger's side. This helps balance out the weight of the driver (small car)

shrike

iTrader: (1)

I made a plywood template that should be roughly the cross-section of the engine cradle. I plan on using that to determine the height and the left to right position of the engine. My plan is to keep the center of the flywheel at the same height to the engine cradle on the 4.8 as it was on the 307. This might require that the distance of the oil pan to the engine cradle will be different.

I will also compare the dimensions left to right on both engines to try and keep the center of the crankshaft pulley identical (or as much as I can get them).

Hopefully it won`t create any interference problems with steering as Pop n Wood mentions.

Anyways it is a Caddy, I shouldn`t be too worried about weight balance

But I will check for all those points, thanks for mentioning them!

shrike

iTrader: (1)

Front to rear fitment I plan on setting by keeping the same distance from the engine brackets to the engine surface where the transmission mates with the engine. I think that is the most important in order to properly fit the transmission. I could go more forward but this depends on the oil pan.

From the measurements I took (very fast though), the 4.8 seems to be about 3-4 inches shorter. So the gap at the front might be bigger