I believe a Roush 427 SR engine has a 7 quart oil pan. Mine does.

If yours does, than filling it with ten quarts is overfilling it and could result in the symptoms you describe. The excess oil is being churned by the crank and splashed into the pistons overwhelming the rings.
Could be the cause of your crankcase pressure.

Thanks for the info. This is the first time I've changed the oil so the symptoms were pre existing......compression test was done prior to adding the additional oil. Sounds like I need to get under the car verify the oil pan number then drain the oil and add in the capacity that Canton has listed and mark the dip stick. I'm sure people think I'm a goof for doing this but I've lived life by looking as the dip stick and making sure my oil was between the add and full line.....I've never knew the dipstick may not be accurate to start with. Should be an easy fix

Sorry about that,was looking at the original thread starter with the Roush engine.......

Your pan capacity is 7 quarts,you also have to add for how much oil your filter holds and how much oil is in the oil lines/oil cooler ....on a typical PH8 type oil filter,figure one quart....depending on the size of the oil lines/cooler,that could be as little as 1/2 quart,so your total capacity could be as little as 8.5 quarts with an oil cooler.....

Once you figure out the total oil capacity,do an oil change after the engine has been warmed up and add the amount you have figured it will hold to full....crank up the engine,let it run for a minute or two,shut it off,give it a few minutes for the oil to drain in the pan,then see where it is on your dipstick and mark your dipstick accordingly and use that mark from then on and you'll be fine....
As far as the low cranking pressure,I would not worry too much about it right now,maybe it should have more or the gauge can be off,either way your numbers are not bad and the good thing is from the high to the low is only an 8% difference which is a good thing!!!
When doing the cranking compression test,did you remove all 8 spark plugs and hold the carb butterflies wide open???? that is the proper way to get an accurate reading....

David

Out of curiosity I went out to the shop after work tonight and was going to check the oil level on the dip stick as I know for a fact the car has 10 quarts of RP and whatever oil is in the lines and oil cooler. The oil mark is at the "add" line......so you can pretty much say the dipstick is out in left field. Funny thing is when the car had 9 quarts in it on the dyno the dip stick had the same measurement......hence the thought hey it needs a bit more. How in the heck can the oil on the dip stick not change when you add a whole quart? I wonder what its going to look like when I drain all the oil and add 7 quarts back in.....wonder if it will even register on the dip stick. Non the less it doesn't need to be driving around with 10 quarts in a 7 quart pan plus what ever residual oil is in the lines and cooler.

Be sure to measure how much you drain out of it when you do do it,that way,you'll know for sure how much oil was in the pan...

David

As a follow up, I took measurements on my Roush/Moroso oil pan and its external dimensions were exactly what the Moroso 9 quart oil pan was. Since I had it off, I measured the capacity, and at 7 quarts, the oil hit the bottom of the windage tray. At 9 quarts, the level was about a half inch above the tray and extended about halfway up the slope towards the back of the pan.
So, my conclusion is that my pan is a 9 quart pan, not a seven quart pan. Maybe yours is too!

I've got something going on with my dip stick tube or something is moving around......getting fluctuating readings. Checked it again and it was below the add line this time

ACE, as we discussed on the phone, I had similar issues of inconsistent readings of oil level on the dipstick. Turned out the dipstick was not going deep enough into the pan and the add/full mark was actually in the dipstick tube prior to going into the pan. When my engine was out and partially assembled I put 7 quarts in the pan and remounted the pan. Then I cut the top of the dipstick tube until the oil level read full. Since your motor is intact, drain the oil, measure and pour back 7 quarts. Borrow the dipstick from my car as it is longer and see if the oil is on the stick. If it reads on the stick then find a dipstick as long as mine or longer and insert the dipstick back into the pan with 7 quarts, pull out, mark it and use the edge of a file to put a light score mark at the full mark and another to duplicate the add mark. I'll be glad to help. One thing to note. If the dipstick is to long then the stick will hit the bottom of the pan giving you inaccurate readings and possibly the stick popping out of the dipstick tube. Just duplicate the dipstick and cut the dipstick off around 1/2" below (verify) the add line.

Sounds like a plan. With a little time this should be something I can check off the to do list rather easy. Must be very similar experience you were having if I am getting inconsistent oil readings on a car that has been sitting for 24 hours in the garage without running. Going to go by the store tomorrow and pick up a clean oil pan to drain it in.

If you have the stock Roush oil pan it is 8 quarts.
http://www.roushperformance.com/engi...enginePage.swf

This is a Canton pan on a Keith Craft setup. According to Canton's website is says 7 quart capacity.

Are you sure about that part number?????????? when I click on the link is gives a circle track pan with one kick out for a small block chevy engine.....

most likely this is the one you have on your engine.


https://www.cantonracingproducts.com...-STREET-T-PAN/

David

I was referring to what is on my engine and not the link he posted. The Canton pan on my car is the 15-660 T-Pan with a 7 quart capacity listed.

how's the new engine running Jim??

okee dokee, I understood it to be the pan number you had, no harm,no foul....

I have this pan on both my race car and street car (both 65 Mustangs):

https://www.cantonracingproducts.com...-14-GA-RR-PAN/

only difference is it is a little wider and holds 8 quarts....Canton makes a very good pan and I've been very satisfied with them....

Dipstick: could the dipstick tube be loose in the timing chain cover or possible sometimes your not pushing the dipstick all the way down???? I had one dipstick that was too long and would hang up on something in the engine before it bottomed out on the tube, I had to cut about an inch off the end of the dipstick to make it go down without a fight,once I filled the pan with the right amount of oil,I marked the dipstick and it has been like that since....

David

Superb. Brent builds a great engine.

This dipstick tube goes directly into the oil pan. I think a few of the things you mentioned are possible. The plan is to drain the oil and refill the pan with 7 quarts. I will then see what type of indication I'm getting on the dip stick and start cutting down the dip stick tube if necessary. I local friend has the exact same block and oil pan and I can use his dipstick as a comparison as well. My guess is my dipstick has never been calibrated and may not be long enough or the dip stick tube may be too long. With 10 quarts my reading was at the add line and fluctuated a few times with back to back checking on a cold engine which makes me think the dipstick tube could be moving at some point

Yes - bigtime. Imagine this: factory 1967 Corvette with chambered sidepipes & a 427 motor. Cut open the OE sidepipe chambered sections to find the flowpath (core) of them to be 1-5/8". Now how restrictive can that be? You don't have to be a rocket scientist to realize your motor just turned into a "pump" to get the exhaust past the mufflers. That equates to a LOT of lost HP.

I'm late to the party on this thread, but wanted to chime in.

Has the timing been verified and tested on the dyno? I have a DynoJet, and have tuned several Cobras. One guy had a Keith Craft, and swore it was installed just as it was delivered from K.C.

First pass read 408hp at the wheels. I checked the timing, and his initial was at 33BTDC! I kept reducing the timing, and the power kept going up. Finally, at 11.5 degrees initial, power was up to 439. Tweaked the jetting a little, and got it to 442rwhp.

Main Point: SOMEWHERE his distributor got tweaked, and nobody caught it before I worked on it.

As for oil capacity, just because you have a "7 quart" pan, that doesn't mean you NEED 7qt.s in the pan. As has been stated, too much oil WILL cost you HP. Having oil coolers and remote oil filters makes it harder to read the dipstick - reading immediately after shutting off a running motor can show a different level than the reading after letting the motor sit overnight. A dyno is a good place to test for optimum oil fill quantity. Start off with two or three quarts less than you "think" you need, and make a dyno pass - if you see the oil pressure fluctuate, then stop immediately and add a quart. Add a half quart, and make another pass. Repeat until you see the power drop.

LnL what was the total timing on that motor? What heads and cubic inches? Just curious, I'm an information nut.