So yah, Fieros don't have rev limiters...

[The Dark Side of Will]

'Cause they're lazy scrudges trying to save a buck wherever possible and because it's a high volume, low performance engine.

[Chase Race]

any disadvantages?

None that I know of.

Factory didnt do it because the tooling was too expensive or what?

I'm pretty sure bean counters were involved.

[Series8217]

Ok.. I did some research into crossdriled cranks because my machinist said he could have it done tomorrow if I brought the page out of the GM performance book. Wanted to make sure I really wanted it done..
The general consensus everywhere else seems to be that its a BAD idea, because at high rpms centrifugal force makes it harder for the rods to get oiled due to the arrangement of the holes in the crank.. obviously the opposite of what we're trying to do (help the rods at high RPM). Apparently lots of engine builders burned up bearings because of the worse rod oiling at 7000+ RPM.
http://www.rehermorrison.com/techTalk/51.htm
http://hotrod.com/tipstricks/34219/index27.html
http://www.merkelengines.com/documents/Buick455.html
http://speedtalk.com/forum/viewtopic.ph ... f48927c4c1

I didn't see anybody that said it should be done. Apparently grooved main bearings are the way to go if full rod oiling is needed..

[Chase Race]

The general consensus everywhere else seems to be that its a BAD idea, because at high rpms centrifugal force makes it harder for the rods to get oiled

Veerrrry interesting.

I checked out all of the articles except the Buick one. Have you found anybody that defines "high" RPMs?

The GM performance parts book recommends cross-drilling the 2.8 crank, and they were turning these about 7000 rpm. I wonder if cross-drilling is better or worse at that RPM? A 3" stroke spinning 7k is a lot different than a 5" stroke spinning 9k.

Again, very interesting. Thanks for the info.

[The Dark Side of Will]

http://www.rehermorrison.com/techTalk/51.htm

I don't doubt that this guy burned up cross drilled cranks, but I think he is WAY off base in the reasoning he gives. Centrifugal force affects all oil equally, whether the crank's cross drilled or not. In fact the maximum RPM which an engine will turn is the deciding factor in how much oil pressure it needs for precisely this reason. The oil pressure needs only be high enough to overcome the centrifugal force at the main bearing and get oil out to the rod bearing. But this is the case with ALL cranks and ALL oil...
Now the guy in the Buick article had an interesting point that the stock oil passage may not go as near to the center of the crank as the cross-drilling does... which would be the ONLY difference in oil pressure requirements. The rest of that ("Pinwheel effect" WTF?) is crap.

http://hotrod.com/tipstricks/34219/index27.html
http://www.merkelengines.com/documents/Buick455.html

Except as noted above, both of these guys just reference and parrot Reher-Morrison.

http://speedtalk.com/forum/viewtopic.ph ... f48927c4c1

Nice reasoning... or lack thereof... Kinda like the guys who talk about 1.75 rod ratio...

Your crank, having started life as a non-crossdrilled crank won't have the same problems as RM cites, because you'll retain the factory oil passage. What Cadillac did was to drill the crank for normal oiling, then drill through the main connecting the two normal oiling holes at the main bearing surface. This method obviously passed GM's dyno torture tests. It won't hurt your crank to do it that way.

[Series8217]

So if I do end up doing this, am I going to have to modify my oil pump to provide higher pressure if I get the crank crossdrilled?
Would you do this to your TDC if you were building one with a redline of 7200 RPM in mind?

Another article (older than the Reher-Morrison one; its actually in regards to crank oiling design for a 70's Jag motor) that mentions the issue of centrifugal force with regards to the additional loss created by having a second hole on the main journal:
http://www.jagweb.com/jagworld/xk-engine/page6.html

Regardless of whether or not my original oiling hole is intact, another hole on the other side of the main journal is getting added, right? And since these holes are continous, I'm going to end up losing more oil through that other hole, especially since only one oiling hole is going to pressurized at any point in time.

[Aaron]

So if I do end up doing this, am I going to have to modify my oil pump to provide higher pressure if I get the crank crossdrilled?
Would you do this to your TDC if you were building one with a redline of 7200 RPM in mind?

No, but I would enlarge the pan.

[The Dark Side of Will]

Regardless of whether or not my original oiling hole is intact, another hole on the other side of the main journal is getting added, right? And since these holes are continous, I'm going to end up losing more oil through that other hole, especially since only one oiling hole is going to pressurized at any point in time.

Not sure you're understanding this correctly... why would you be losing oil?

[Series8217]

Ok, I was making all these diagrams to try and demonstrate how I understood what was being done, but I think I finally figured it out! I was getting way confused by the diagrams in the 60 deg V6 perf book (they are ridiculously confusing). I was making it out to be way more complicated that it is.
Is this whats going on?
Stock crank:

Cross-drilled:


Anyway, the reason I thought I would lose more oil is because only one hole on the main is getting pressurized oil so the connection of the hole under pressure to the hole NOT under pressure (adjacent to non grooved bearing shell) is adding an additional place for oil to be pumped to instead of just going to the rod. It's like adding another power draw in parallel.. they're both connected to the same pressure source. Why does this not occur? Am I missing something obvious (probably)?

[The Dark Side of Will]

Those are good pictures. That's pretty much what ought to go on.

[Series8217]

thanks. Do you think I should be okay with the stock oil pump pressure then?

[The Dark Side of Will]

Should be.