Potential spun X302 rod bearing

[eschaider]

Originally Posted by C5GTO

An overdrive transmission is definitely required as part of the fix. I've been thinking about a transmission change in this Cobra for several years now but those funds always seemed like they'd be better spent on the homebuilt Ferrari and Lambo project cars. In hindsight, I'd have one less headache now and would have avoided a bunch of frustration in trying to get the Richmond Gear/Hurst shifter combination to have a reliable/smooth 2nd to 3rd gear shift. I've penciled in a new TKX in as a line item on the fix budget.

Painful cost-wise but a definite move in the right direction, Joel.

Originally Posted by C5GTO

If it is a spun bearing, I'm thinking a good fix is likely a 347 rotating assembly kit. Does anyone have experience with the Eagle kit that comes already balanced with a harmonic balancer and flywheel included in the kit?

If you are choosing the 347 rotating assembly because you believe it is more resistant to this type of failure, it is essentially similarly susceptible. It is certainly a step up if you are choosing it for additional power.

Although I have never built a 347, I have built other externally balanced engines. The experience is not a good one, and they are poor high performance candidates because of service parts interchange imbalance issues.

If you determine the 347 is going to be your engine, you should attempt to balance the rotating assembly internally. Assemblies that require matched external pieces like dampers and flywheels never can be balanced as well as the original components when these pieces are changed out for service reasons down the road.

Originally Posted by C5GTO

I'll also look into a windage tray and crank scraper, sounds like cheap insurance to me.

This is cheap insurance, and commercially available pieces are easily found online. If you elect to go the crank scraper/windage tray route, try not to use a scraper that is attached at the pan rails. With only 0.030" or so clearance, it is easy to have a pan rail scraper shift during assembly or later operation and strike the crank.

The most reliable way to attach the scraper to the engine is to bolt it to some fixed location on the block, like the main studs, to preclude movement. As you increase the air gap between the scraper and the crank to avoid counterweight contact, the effectiveness of the scraper diminishes very rapidly.

Originally Posted by C5GTO

I guess another good question is the oil pump. Standard volume or high volume? I'm fairly certain the current engine is outfitted with a standard volume pump since the spec sheet didn't mention high volume. Is there a good way to visually tell if the pump is standard or high volume?

The easiest way to check for a higher volume oil pump is to check the oil pump gear tooth face width against a known standard volume pump. Wider gear tooth faces equate to higher volume pumps. Here is a link to a pretty good explanation of high volume and high pressure pumps done by George Richmond at Melling, click here => Melling Pump Discussion.

When you go to a high volume or a high-pressure pump, you force more oil through the engine's oil system. For illustrative purposes, let's say your engine is capable of returning one quart of oil per minute (I pulled that number out of thin air for this example).

When you use a pump that increases oil flow to the engine by one quart per minute, so you now deliver 2 quarts per minute, you are in trouble. You are retaining 1 quart of oil in various forms of suspension each minute the engine is running.

Let's say you have a six-quart pan that is at 4.5 quarts capacity while the engine runs. That would be one quart to wet the engine internals and ½ quart in transit back to the pan. If you retain one quart of oil every minute in 4.5 minutes, your pan will be pumped dry, and the oil pump will draw oily air. This is a significant simplification of what happens, but you can get the gist of the problem/oiling dynamic.

It would not happen that way in the real world, but eventually, you will uncover the pickup. That fateful moment might be on a long sweeping curve while entering an expressway or just playing around with the car in one of our typical spirited driving moments.

Once you uncover the pickup, the damage is done. It will take some time before you become aware of the damage your engine has just suffered. You could be driving at a steady speed on the highway when the rod bearing finally fails, and you won't be able to necessarily hear the damage until you get off the highway.

High-volume and high-pressure pumps (and car owners) will be happiest with an oil pan with at least 8 quarts over the pickup while the engine is running.

All the words about the crank scrapers and windage trays are still valid. Be sure to use an adequately large pan if you elect to go the high volume or high-pressure oil pump route.