Don Terrill’s Speed-Talk

This isn’t likely to cure the problem, but may slow down how long it takes to heat up. A lot of the aftermarket w/p housings have the bypass hole sized way bigger than necessary. Any coolant that flows thru the bypass hole is coolant that’s not going thru the radiator. I usually tap the hole for a p...

Looks like my first thoughts on where the level in the tube ends up when the system is “full” was correct. It’s about 1/2 way up the tube on the one I’ve used for the last 20+ years. The red line is where the level is when everything has stabilized.........about 6-1/2 inches from the top of the towe...

The pump we use for the return is just left running anytime the engine is running, and the tank rarely has much volume in it at all.......... so I can’t really address your particular situation. Seems plausible if the tank was nearly full, the tower would drain slower. I guess I’d try installing a n...

If you can manually drain the tower without issue, then there are no problems with the return line downstream of the standpipe.

11.9 to 12.6 isn't gunna make but so much difference

I believe the original thinking was the motor was more like 13-13.5:1.

What’s the car weight, best ET, best speed?
In what kind of air?
Is the track you race at high-ish elevation?

After thinking about it a bit........ I’d say the normal level in the tube is probably closer to 2/3-3/4 way up the tube.

On the 3 different 901’s I have operated, when filling the system........ the level would get to slightly above 1/2 up the tube before it just overflows into the standpipe(and into the return hose). That’s as high as you can fill the tower. Unless there is something unique to your tower compared to ...

The spring on the vacuum break is pretty weak, but if it’s open when there is coolant pushing upwards, then it’s probably not quite strong enough. That being said......... If you were running something like an electric Moroso belt drive on a std mechanical water pump, I wouldn’t think there would be...

Sounds like there may be something blocking/restricting the flow into, or through, the standpipe.

Is everything you buy today junk?

There sure is a lot of it.

Is more and more of this type of problem occurring in the “mid-level” performance offerings?

You’d think it wouldn’t require stepping up to $1200 HR lifters for a mild street build to get a reasonable level of reliability.

The picture is from 2020?

Edit-
Never mind.
I see from your 512 post that the date on the camera appears to be stuck in 2020.

A couple more: E7E9CC3B-C095-4256-BBD2-4F7AE531C734.png 8425DDE4-340C-4105-B487-C0A8B6025936.png I haven’t seen any pics of the lifters yet. I’ve seen similar pitting(and much worse) on the nose in the past, but those were cams that had been running Schubek or tool steel lifters. On those, the only ...

Glad you got it sorted out!!

Doesn’t look like the best scenario for air flow past those electric fans.

pics I rec’d last week. Cam was broken in with the inners removed, and actual break in oil. Owner was seeing some very minor lash increases(.001-.002) on a couple lobes at 100-ish mile intervals. Several of the lobes have pitting, this is about the worst one. About 500 miles on it. The nose of the s...