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EXcappa

EXcappa

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Hi All,

I'm looking for advice to make my small block stroker last with the odd blast to 7500rpm over the 1/4 mile.

I've looked through the post from Guitar Jones. Is there anymore to be added?

Did 3 runs last year and ended up doing in number 8 bearing crossing the line just over 7000rpm

I had a precision high flow blue printed pump and full groove mains.
All drain backs were enlarged
 
I ran my stock bottom 7600 many times and never had a problem, what kind of clearances were you running?
 
EXcappa said:
Hi All,

I'm looking for advice to make my small block stroker last with the odd blast to 7500rpm over the 1/4 mile.

I've looked through the post from Guitar Jones. Is there anymore to be added?

Did 3 runs last year and ended up doing in number 8 bearing crossing the line just over 7000rpm

I had a precision high flow blue printed pump and full groove mains.
All drain backs were enlarged
Click to expand...


Most of that stuff is BS. You need to spend all you time and effort on the inlet side of the pump. You can't make the inlet too big.

You need to at least tube the passenger gallery and block off the drivers side feed. Enlarge the feed to the mains to 9/32 maybe 5/16. I wouldn't use less than 85 pounds of pressure at max RPM and 100 wouldn't bother me.

You will get to a point where you need to correct the oil timing. I've never been able to decide when that happens. I know at 7500 you better have your **** wired tight. At 8000 you need to be all over it and at 8500 one little mistake and it's over.

You also need a high volume pump. You can't get too much oil to the rods to quickly when the oil timing is wrong.
 
BTW, I didn't mean that the Guitar Jones stuff is BS. I haven't read his thread. I meant all the nonsense of turd buffing everything on the outlet side of the pump. Make the holes bigger, get the volume there with enough pressure and that's most of it. You don't need a cross over tube or none of that.

Again, the big gains are on the inlet side of the pump. Make it big. If you want to go past 8000 and make power, you need a dual inlet pick up. I think my pick up is 1 inch. Damn near made it dual but I'm shifting at 7000-7200 with this engine.

One last thing. If you are serious about RPM and making power up there, you can't use a passenger car block. Even if you fill the block they move around way too much under load. You end up making the clearances way too wide to keep the block from grabbing the crank, and that opens up a bunch more problems.
 
Last edited:
Thanks for the replies gents.
It had .0025 clearance on the big ends and .0028 on the mains
 
How fast are you guys going that you have to wind it that high. My Son changed his shift RPM from 6800 to 6500 in his 10.30 running 360 and it ran EXACTLY the same. I shift my 422 that runs 9.42 at 7000 RPM.
 
Crossing the line at around 7000rpm. But with better heads and larger solid roller it will rpm a little higher I assume
The bottom end is apart so I want to spend money now and make sure it's the best it can be.
Don't want to pull the engine again
 
if you are going 7000 you will anyway
bearing clearance is fine- do not go tight in a stock block
windage tray/ scraper and good oil drains
you need to do both inlet and outlet
we did in the 60-70s road race cars
 
After building an oil pickup, modified oil pan, and most of the oiling mods, it makes me just want to go to a dry sump system if I wanted to run over 6500.
 
you got that right, especially for road race, gymkhana, autocross, etc
hard to do a good road race pan with ground clearance and crank clearance- keeping the oil off the crank
 
T56MaxTorq said:
After building an oil pickup, modified oil pan, and most of the oiling mods, it makes me just want to go to a dry sump system if I wanted to run over 6500.
Click to expand...


And it still doesn't fix the oil timing issue. That's what kills bearings at high RPM. At 1965 designed SBC style oiling system will oil the rods efficiently to 10k yet, depending on several other parameters 8000 is about max on a Chrysler without correcting oil timing. And that year SBC oiled the lifters first.

It was a piss poor bean counting decision to time the oil feed the way it was done. You could forgive the thinking somewhat, if you consider the people at that time thought 7000 was in the stratosphere.
 
YR you should do a stickey on correcting the timing. I would find it interesting.
 
yellow rose said:
And it still doesn't fix the oil timing issue. That's what kills bearings at high RPM. At 1965 designed SBC style oiling system will oil the rods efficiently to 10k yet, depending on several other parameters 8000 is about max on a Chrysler without correcting oil timing. And that year SBC oiled the lifters first.

It was a piss poor bean counting decision to time the oil feed the way it was done. You could forgive the thinking somewhat, if you consider the people at that time thought 7000 was in the stratosphere.
Click to expand...

Yes I remember our oil timing conversation. It’s one hell of a modification. If I remember correctly, you must tap into the main caps at 6 o’clock and feed them oil from there instead.
 
we used to groove the block side of the mains and feed from the side plenty of clearance there to form a good wedge
6 o'clock is a tough place to get oil in due to the pressure being down- or moving from side to side depending on which side is firing
half grooved mains you loose a lot of support with full grooved mains
 
Wyrmrider said:
we used to groove the block side of the mains and feed from the side plenty of clearance there to form a good wedge
6 o'clock is a tough place to get oil in due to the pressure being down- or moving from side to side depending on which side is firing
half grooved mains you loose a lot of support with full grooved mains
Click to expand...


We tried all that. I don't know why the knowledge isn't more common. It's settled science. The rods need full pressure, full flow at ~ 70 degrees past TDC. You can't get that with a groove. The hole in the block has to line up with the hole in the main bearing to feed the rod.

The higher the RPM, the more critical it becomes. I first came across this with a T/A block W-2 engine I bought complete in 1984. The guy who sold it to me paid a hydraulics engineer to fix it. He made me promise to never change it. I tuned it 8500 and never hurt a bearing. Broke some valve springs so I decided to freshen it up. Everyone and their mother (none of which knew jack **** about hydraulics) convinced me to change it. It took another hydraulics engineer and a bunch of broken parts to put it back to correct.
 
EXcappa said:
Hi All,

I'm looking for advice to make my small block stroker last with the odd blast to 7500rpm over the 1/4 mile.

I've looked through the post from Guitar Jones. Is there anymore to be added?

Did 3 runs last year and ended up doing in number 8 bearing crossing the line just over 7000rpm

I had a precision high flow blue printed pump and full groove mains.
All drain backs were enlarged
Click to expand...

Something must have been wrong with that bearing or Rod bolt or the big end of the rod because number 8 never goes away

It has its own oil flow from the back of the motor going through that last main cap.

It is not being fed like the other main caps feeding the rods. Because it is being fed more or less directly from the pump. Where the others are all being fed off of the passenger side oil galley.
 
Jadaharabi said:
Something must have been wrong with that bearing or Rod bolt or the big end of the rod because number 8 never goes away

It has its own oil flow from the back of the motor going through that last main cap.

It is not being fed like the other main caps feeding the rods. Because it is being fed more or less directly from the pump. Where the others are all being fed off of the passenger side oil galley.
Click to expand...


That's a good point. Look over your stuff very close. It's usually 3 and 4 that are the last to get oil. All the rods will show some heat from the oil timing being off (when the RPM is high enough) and if you don't catch it 3 and 4 come off the crank and make vent holes in the parts.
 
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