I recently had my 400 bored 30 over to make a 406 ci for racing. It
has new bearings throughout splayed 4 bolt main caps, steel crank, new
cam, valve springs, pushrods, high volume oil pump and new oil pan. I
had great oil pressure at start up around 40 psi at idle 1000 rpm. I
raced in a 25 lap race on a 3/8 mile oval track and as the race went on
the oil pressure dropped at idle it was 20 psi and while racing only 50
psi at 6300 rpm. I noticed while scrubbing tires going right and left
when I would turn right the psi would drop near 0. I haven't checked
anything yet it's actually still on the trailer. Does anyone have any
suggestions. I have read a few posts that indicate a oil filter bypass,
is this something I should look at or am I doomed for new bearings.
Well I tried a few things with the motor and I believe my transmission
was putting strain on the motor and causing the problems. I pulled the
trans out, started the motor and I have 50 psi at idle and 80psi at
4000 rpm's. Oil still looks great, no metal shavings or anything.
Could the transmission bog down the motor that much? Powerglide with
direct drive shaft.
No, the transmission is not going to make you lose oil pressure.
However as was mentioned by others, a racing engine MUST have a windage
tray or baffling system of some sort in the oil pan to keep the oil at
the pickup in hard turns and slides. On the slides the oil is slopping
up out of the oil pan and leaving the pickup dry. This MIGHT not have
caused damage yet, but allowed to continue it WILL cause damage to the
I still think it's the oil moving away from the sump as you take
off/make a hard turn/make a hard stop.
As others have mentioned, you should have a windage tray of some sort
in the pan that would make sure the oil doesn't run away from the sump
under racing conditions. To continue down the present path (no pun
intended), you are going to eventually cause damage due to oil starvation.
Thanks for the reply's. My oil pan is suppose to have a windage tray
and baffles but it is something I will look into.
I also noticed that I didn't have oil restrictors in the back of the
motor. Would this help keep some of the oil in the pan rather than
filling up the vavle covers.
Our rules don't allow us to use a dry sump system, I wish they did.
So, I put oil restrictors in on top of the cam and now I am getting
good oil pressure on the track all the time. I must have been filling
up my valve covers and draining the pan. Thanks all for the advice.
I now have another problem!
I attempted to put a saginaw three speed stick shift in my car with a
7.25 triple disc clutch and Howe throw out bearing. I could not get
the throw out bearing to move at all. Meaning I could not shift the
car while it was running. Also to note I have a new Girling clutch
master. Anyone have any insight or suggestions.
Check the obvious...then, recheck it.
Did you measure the clearance on the input shaft, VS the assembly you
installed? Its possible you are not able to move the slave enough, OR, the
slaves moving fine, but you just dont have the proper clearance, but first
thought would be to check for that pesky air pocket that wont leave.
I checked and rechecked everything several times. I bleed the system
again, only this time I ran the bleeder line back into the clutch
master using a clear plastic tube then pumped the pedal until there was
no more air bubbles. This worked great and now the throw out bearing
works wonderful. Must have been air locked before. The clearance on
the bearing is right at 1/8".
I have acquired a new problem. I replaced my old worn out distributor
with a MSD hei one part number 8365. I developed a high rpm miss
around 5500-6000 rpm. Checked the timing and it had jumped 3 degrees
so I pulled the dist. cap and the rotor was broken. Looked like the
screws just backed out because the treads were still in good shape. I
replaced the rotor and raced on Sunday and the same thing happened. I
now have it on jack stands and with a new rotor I am still getting a
slight vibration at 5300 rpm's. I have made sure the new dist. is not
longer so thats not the problem. However, when I pulled the old one
out it was rather tough to pull it all the way out. Same thing when I
put the new one in. It was binding a little towards the bottom. The
only thing I think it could be is one of my oil restrictors in the back
of the motor is binding the shaft.
If anyone has any suggestions I would appreciate it.
Thanks in advance
If it were binding, i would have expected it to grind itself free at 5500
RPM in a very short time.
Have you checked/cleaned the advance mechanism/springs etc.
Electrical connections? Good Earth & good Voltage and big enough supply
Does it miss in neutral or under load ?
Other stuff to check ..
Plugs & leads ok ? gapped right.
Fuel supply & filters.
Thats all I can think of ATM, lets know what else you find.
I don't think it would grind itself free because the housing does not
move in the motor. I did have a transmission fire a couple weeks ago
that could have got the wires too hot. I have replaced most of the
wiring to the dist. but this problem did not occur with the old dist.
I will replace the plug wires and reply back. That might be the
problem. btw the plugs are gapped at 35 and timing is set at 36.
Well, I pulled the trans out and backed off the oil restrictor and it
worked. I can now set the dist. with ease and at 6000 rpm it's right
I still have a hesitation at first throttle but I think the fuel filter
is dirty. Does anyone know how to clean the stainless steel filters.
Thanks for all the rely's
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