stroker motors?

Just a quick question. I see that some guys are running stroker engines. Are there any big advantages or dis advantages to going to a stroker setup? Thanks Tim

If you've already got all the stuff in your sig - I wouldn't bother! But seriously, you will find that blower efficiency is increased and torque improves, especially on part throttle. If you go with 4.0 L then you can retain the stock crank, which is good, but if you go to 4.2-4.3 then you have to either get a mucho expensive billet crank or use the truck crank which is cast. As long as you don't intend to rev the motor past 5200, the truck crank would probably hold up OK.

strokers

Thanks Dave,I I was just wondering. It seems that as heavy as our cars are the extra cubes would be an advantage. I wasnt olanning to make any changes to my red 90. I would like in the future to buy a 5 speed car and make it strictly a weekend warrior but that wont be till I get this one all done. These cars are such a challenge. Thanks Tim

XR7 Dave said:

If you've already got all the stuff in your sig - I wouldn't bother! But seriously, you will find that blower efficiency is increased and torque improves, especially on part throttle. If you go with 4.0 L then you can retain the stock crank, which is good, but if you go to 4.2-4.3 then you have to either get a mucho expensive billet crank or use the truck crank which is cast. As long as you don't intend to rev the motor past 5200, the truck crank would probably hold up OK.

Click to expand...

Dave how would you get 4.0L out of a SC engine using the stock crank?

That's easy. Just say you have a 4.0L engine for like 2 years. By then, someone else will have produced one and then you're set.

Overbore your stock 3.8L...

That comes out to around 4.0L right?

A strocker engine doesn't rev as easily as an Overbore engine, that is why it works good with the blower's RPM limit around 6000K.

? about 4.0l strocker

how much do you bore it out to get the 4.0L out of a 3.8?

I'm sorry, I thought we were talking about STROKER motors. I just did not see how you could stroke a motor to 4.0L by using the stock crank.

what do you get

what do you get if you bore it .30 over?

Boring doesn't increase displacement significantly.

.030 overbore goes from 231.895ci to 235.561ci,
or 3.66ci difference.

Might be effective for unshrouding valves, though.

I think XR7 Dave means it will take a little welding and some grinding on the stock crank to get the proper offset for the stroker motor. Not sure the stock crank is up to snuff to get all the way to 4.2 no matter what you do. I believe Dr Fred discovered that the expensive way and went billet!

just for fun

Here's some calculated displacements;

1/8" stroker, .030 over: 3.996L or 244ci
1/2" stroker, .030+; 4.149L or 253ci
.350, .030+; 4.259L or 260ci
3/8", .030+; 4.287L or 262ci
3/8", .040+; 4.309L or 263ci

Now, what rods are readily available to work with
what journal diameters & strokes, i have not researched,
but it seems like i saw a post somewhere that someone
[Wise, maybe?] used 1/8 offset grind [without weld-up?]
and 6.0" Chevy SB rods with custom pistons for a 4.0L....

As George said,
a welded-up/.375 offset crank didn't work out well for Fred;
[I wonder if strange harmonics is a problem at that stroke; and at what RPM??]
and a billet crank is prolly about $2k,
plus another $1k for rods & pistons,
so we prolly won't see very many big stroker SCs.