My Weekend at Willow Springs

That looked like a lot of fun! What kind of camera did you have in the car?

- Robert

A friend of mine has 2 chase cams he let me borrow.

Was the the oil pressure gauge? Looks like it went to 0. Bummer! Keep us posted on the diagnosis.

Seen your car there. what happen did the pin let go in the distributor gear?

Yep, it was the oil pressure gauge. I haven't pulled the distributor out yet but the motor sounds normal when it turns over however the rotor doesn't turn so I am pretty sure that is the problem. The funny thing is, I read about this issue when I built the motor so I did double roll pin the gear but I am thinking that maybe the roll pin I used wasn't hardened. What do you think? Are there different strength roll pins?

what are the specs on the motor. So most of those laps are in 3rd and 4th?

The motor is a 351c, 30 over with 4v open chamber heads. I used pop-up pistons to bring the compression ratio up to around 10.5 to 1. I used a Lunati hydraulic cam that has .565 lift on intake and .588 lift on exhaust. The advertized duration is 300 intake, 310 exhaust. 234 intake and 244 exhaust at .050 tappet lift. It pulls pretty good until about 6000rpm.

Yes, mostly 3rd and 4th for the whole track. 2nd a couple of times but as I become a better driver maybe I wouldn't need 2nd.

quote:

maybe the roll pin I used wasn't hardened

Scott,

You may have gotten a Chinese roll pin, or your oil pump may have sucked up a piece of something that was in the oil pan. If the pin were too hard, it would be brittle and shatter easily.

Try looking for a roll pin at an aircraft parts supply. All of the aircraft parts are supposed to have traceability. Try Aircraft Spruce. They are located near you in Corona.

A spiral roll pin is available. McMaster-Carr has them, but I don't know where they get their pins.

John

Scott, there are other possibilities which you'll find when you pull the distributor. First and most common is the roll pin. I've not heard of a double roll pin breaking so it may well be one of the others. #2 is breaking the pump driveshaft between the pump and distributor gear; hardened drivershafts are less than $15. #3 is actually shearing badly worn gear teeth off the distributor drive from a couple of causes, one of which is metal incompatibilty and the other is a cam with its integral gear cut on the wrong tooth-angle. The last has happened from all known cam grinders since they all buy cam-blanks from one of only about 3 manufacturers. I'll be waiting to find what the root cause actually was. On the good side, if dropping the pan and checking #1 or #2 rod bearing shows only light bearing wear, you dodged a bullet. Good luck-

Well, I pulled the distributor out today. It was extremely difficult to get out. The double roll pins held. The gear however didn’t do so well. The gear had broken teeth. There appears to be slight damage to the cam gear so I guess I am going to have to change the cam.

The bottom of the distributor shaft has several hairline cracks around where the oil pump drive shaft inserts. The top of the oil pump drive shaft looks damaged and doesn’t look centered in the hole. I have an oil pump prime tool that will not engage the oil pump drive shaft so there is definitely damage in that area.

So the question is what happened. The motor only has about 3000 miles on it. The oil pump was new, cam was new, oil pump drive shaft was new. If the oil pump sucked up something where did it come from. Could the shaft at the bottom of the distributor have cracked first and seized in the hole?

I guess I am going to be pulling the motor out…

quote:

If the oil pump sucked up something where did it come from

It could have been any number or things including (but not limited to) a small piece from a gasket, a hardened piece of sealer, a small piece from the distributor gear or cam gear. When you get the oil pump out and apart, you should be able to tell.

One of the problems with increasing the distributor's roll pin shear value is that it won't shear easily should something get sucked up into the oil pump.

John

A few possibilities:
1- If you've recently changed distributors from any source, be aware that a 351W distributor WILL fit in a 351C..... but the smaller diameter Windsor gear will only engage the outer 0.060" of its teeth on a 351-C cam. This may (if you're lucky) last for 200 miles before the gear teeth on the distributor rip off.
Second possibility: some aftermarket cams were made with the 'pressure angle' of the distributor gear on the new cam ground at the wrong angle. The result is, the distributor gear teeth fail; one wore to razor thickness in only 5.0 miles.
Third: there is an oil passage in the front of the block that comes off the second drilling of the front cam bearing. If the front cam bearing is installed wrong, that passage will be blocked and no oil will squirt onto the distributor gear/cam gear mesh. I have heard of distributors siezing from lack of this oil.
4- engines that run high pressure or high volume oil pumps put far more load on the distributor gear than a std pump. In some cases, this is enough to radically increase gear wear.

All these scenarios will pump metallic slop through the engine and do bad things to bearings and the oil pump. It may be a good thing to drop the pan and check #1 or 2 rod bearing (most likely to fail in a Cleveland), #1 main bearing, the crank journals on those bearings checked and the oil pump body, all for deep scratches.

The problem was a little worse that first expected.

Good thing you have a 4 day weekend coming up to put it all back together

So whats the problem?

quote:

Originally posted by Scott Bell:
The problem was a little worse that first expected.

I hate it when that happens!

Michael

quote:

So whats the problem?

I have no clue what caused the problem. Something got into the reciprocating area at the front of the motor and did extensive damage. I found this in the bottom of the oil pan...

I have gone over EVERY part with a fine tooth comb and cannot find where this metal came from.

Here is a shot of some block damage...

Another...

Oil Pump Drive...