• Welcome to the Contour Enthusiasts Group, the best resource for the Ford Contour and Mercury Mystique.

    You can register to join the community.

Please chime in with experience or opinions-spun bearings

T

trail brake

New CEG'er
Joined
Oct 30, 2007
Messages
14
Hello all. I've been lurking here and reading through some of the links to old forums until I could post.

I have a 1990 Miata and have been tossing around the idea of using a Duratec 3.0 for an SM2 autocross car. On paper it sounds like a good marriage because of the aluminum block and decent torque potential. In N/A trim a Miata could run with a minimum weight of 2200 lbs and that should be no trouble with the 3.0l. The shorter block length and potentially lighter weight (does anyone know what a long block weighs?) the balance could end up at 50/50 or better depending on set-up.

All that being said, after reading around here I get a little nervous about the Duratec because it looks like most people who do 3L conversions to Contours do so due to spun bearings. I see another thread here that weargle wrote where his new 3L has spun a bearing too. Is this a weak point to the motor? :shocked: Is there anything that can be done to prevent the problem form occuring during build-up?

If I build one I'll want to be able to wind it up during runs. If I'm always worried about spinning a bearing though I don't know how much fun the car would be. Let em know your thoughts.

Doug
 
not to many spin bearings on 3L engines. I would say if you don't want any problems I would completely rebuild the engine and use some clevite (sp?) bearings and you should be good to go.
 
The spun bearings are often a result of oil starvation, usually attributed to a poor 2.5L oil pan design. Sweeping right-hand turns (who hasn't taken that circular on-ramp at 55mph?) are particularly hard on the 2.5, especially when oil is low. But with your car, you'll not only have a 3.0 and the option to use an upgrade oil pan, but you won't have in mounted transversely anyway (I'm assuming).
 
I'm wondering what you're gonna do about the drivetrain, but if you're really worried about the bearings, just overfill the oil, I run about 6.5 quarts as most do, and that will protect it for the most part.
 
PurpleMystique said:
The spun bearings are often a result of oil starvation, usually attributed to a poor 2.5L oil pan design. Sweeping right-hand turns (who hasn't taken that circular on-ramp at 55mph?) are particularly hard on the 2.5, especially when oil is low.
Click to expand...

Good to know there is an attributable cause.

PurpleMystique said:
But with your car, you'll not only have a 3.0 and the option to use an upgrade oil pan, but you won't have in mounted transversely anyway (I'm assuming).
Click to expand...

No, I don't think I want a transverse-mounted anything in a Miata!

In reality tho, the oil pan will likely have to be a hack job for clearances. The lower subframe / K-member of a Miata is a very tight and confining design.
 
DanMyers said:
I'm wondering what you're gonna do about the drivetrain, but if you're really worried about the bearings, just overfill the oil, I run about 6.5 quarts as most do, and that will protect it for the most part.
Click to expand...

There is a Miata in existence with a 3.0L duratec swap, built by Mazda engineers in Cali. They used the Lincoln/JAg IM with a big ugly hood scoop for clearance. I don't remember the details about choice of tranny but I think it was likely RX7 derived. They used a good deal of RX parts in the development. Here, I'll go find the link.

http://www.miata.net/news/v6.html

There, finally found it. RX7 TT tranny & diff I believe.

This swap is actually my favorite but for SM2 rules I believe he is leaving half a liter on the table...

http://forum.miata.net/vb/showthread.php?t=193437http://forum.miata.net/vb/showthread.php?t=193437&highlight=duratec
http://majica.net/JNR/jnr.htm
 
Last edited:
PurpleMystique said:
For what it's worth, the Taurus and Escape 3.0s used different oil pan designs.
Click to expand...

Before settling on any one I would scroung up one of all available variants and choose the best option or cut and weld to make my own.

The biggest problem I see with the KL swap I posted above is the oil pan. If I remember correctly it's goa 2.5" of ground clearance and holds about 3 quarts. :shocked: :nonono:
 
Hm, that's really interesting, thanks for the links, looks like I've got some reading to do. Whatever you decide, good luck with it, and post some after pics.
 
Just to address some of your concerns "Trail":

2.5 Duratec has severe oiling issues due to poor pan baffling AND poor design in drainback holes in the heads. If you were to use a FULL 3L Duratec and run the SVT 2.5 cams, this will yeild the most impressive results and offer that extra bit of reliability due to better oiling designs. Secondly, as for the pan clearance issue, you could always use a remote oil reservior which will get you the added oil you may need if you end up using a custom pan with limited capacity. This will also double as good insurance for the turns. I am thinking specifically of the Moroso Accusump which offers a reservior that can hold up to 2.5 extra quarts IIRC. I'd double check on this capacity before quoting though. You would then be able to run as little as a 3 quart custom oil pan and still retain a total volume of 5.5 qts. The only other thing I'm unsure about is whether the Accusump can run in a continuous mode without burning up solenoids. But being that it is pressure activated I don't know if the custom pan option will be a problem or not. I am guessing it would work ok since you are only changing pan dimensions and not internal oiling dimensions. HMMMMMM?

Here is a link: And it is a 3Qt. Accusump
http://www.moroso.com/catalog/new_products.asp

OH Hell!!! I read the rest of the article. Are you sure they only used the Jag intake manifold and not the entire engine? The reason I ask is because you are here on this site in which everyone runs the 3L taurus/escape/sable engines and the Jag 3L are quite a bit different IIRC AND they are set-up for a rear-wheel-drive tranny as well. The aforemention all being FWD. Wasn't sure if you were aware of this. I guess if you can make a custom bellhousing for for a RXTT to Jag 3L, you could do it for these as well. Nevermind...just rambling.
 
Last edited:
Thanks for the Accusump link Pale Horse. I'd thought about doing something like this and/or an oil cooler to add capacity. Maypo had planned to go with an oil cooler on the KL but had some issues with it.

I came here because there seems to be a pretty healthy knowledge base about duratecs in general here and many active users. For SM2 class autocross I will have to use a Mazda branded block (only fwd applications) if there is a discernable difference between brands. I think the Tribute will be my link to cheaper Ford-branded duratecs thought I haven't confirmed this yet. Regardless, I can't use either Lincoln or Jag version at this point. Would be nice though. I will have to read the SM rules again to verify that because Wikipedia states Ford owns controlling interest in Mazda since 1999. The Block is the only part that has to be compliant to the brand though and I should be able to pick and choose between heads, cams, intakes and oil pans as long as they are compatible.

Regarding the VVT motors, it seems like most people who look at swaps tend to steer away from them but I'd rather have it for the higher low-end torque potential. It does add complexity but heck, power is power.
 
Don't forget about the much looked over Mazda MPV Minivan. Those even have a cast UIM that can be ported IIRC. Does SM2 rules allow you to run engine management systems? If so, going with the mazda6 VVT motor may be the big win. Keep us posted on this thread or PM me with any questions you may have. I'd love to keep track of this progress from start to finish.
 
TourDeForce said:
Didn't that guy from the 'Truck-U' show put a V-8 into a Miata? I think there's a conversion kit available.

yeah, here ya go...: http://www.monstermiata.com/Monster_V8_Kit.asp
Click to expand...
Lotsa variations on the "Monster Miata" but unfortunately Mazda has been conspiciously absent in V8 manufacturing. SM2 rules allow pretty much anything as far a engine management goes so yes, the Mazda6 VVT motor is an appealing option.
 
You must log in or register to reply here.
Back
Top