598 SCJ Build

68galaxie wrote:

derek528 wrote:There is so much experience in the shop that there really is no need to flow them. They know what makes power...and it's not flow numbers. For example, laying back the short turn really flat will sometimes kill flow numbers, but almost always picks up power. To me, a flow bench is a tool that has it's place, but the dyno tells the true story. I may be wrong and this thing might be a pig, but I doubt it. It will be dynoed, on a conservative dyno and I'll post the numbers. Bischoff does have a flow bench, which gets used from time to time, but bischoff does not build winning engines based on flow numbers. I have brought up flowing these heads and all the guys in the shop just laugh and say "You need to stop racing the flow bench"

How does one know if a port goes turbulent at certain lifts without the flow bench tool? (regardless of what the "useless" flow number might be?
How do you know if all ports flow evenly? You cannot do this with the naked eye.

Just curious how the "flow bench is useless" people deal with these issues?

I'm just going to keep this as a build thread. I'm not interested in arguing about the importance of flow numbers. The people involved in this build have a reputation that speaks for itself, and cannot be argued with. I have chosen to take their advice on this build.

Sorry, I am certainly not trying to argue with you at all.
I am very curious how one modifies cylinder heads without the aid of testing tools.

As you have said flow bench numbers don't tell the whole story - but are a fantastic development tool.
The flow bench can and is used to measure port velocities at different areas of the port, equalizing port velocity distribution,
measuring flow around the valve into the combustion chamber, determining if a port is stalling and backing up at certain lifts, how well the port "works" with a specific valve seat angle and width program.
2 ports that look identical can easily flow 30 cfm different.

I know you are saying the professionals know what works - trial and error?

68galaxie wrote:Sorry, I am certainly not trying to argue with you at all.
I am very curious how one modifies cylinder heads without the aid of testing tools.

As you have said flow bench numbers don't tell the whole story - but are a fantastic development tool.
The flow bench can and is used to measure port velocities at different areas of the port, equalizing port velocity distribution,
measuring flow around the valve into the combustion chamber, determining if a port is stalling and backing up at certain lifts, how well the port "works" with a specific valve seat angle and width program.
2 ports that look identical can easily flow 30 cfm different.

I know you are saying the professionals know what works - trial and error?

I do agree that a flow bench is a great tool. I also believe that it is not a necessity, especiallay when an individual has been porting heads 8+ hours a day for 25 years, someone with that much experience just knows. For example, Tony bischoff was looking at my intake ports and says "these will never flow good at high valve lift" He has little to no experience with these individual head castings, he can just tell by the design. He was completely right, just at a glance he could gather that info.

derek528 wrote:

68galaxie wrote:Sorry, I am certainly not trying to argue with you at all.
I am very curious how one modifies cylinder heads without the aid of testing tools.

As you have said flow bench numbers don't tell the whole story - but are a fantastic development tool.
The flow bench can and is used to measure port velocities at different areas of the port, equalizing port velocity distribution,
measuring flow around the valve into the combustion chamber, determining if a port is stalling and backing up at certain lifts, how well the port "works" with a specific valve seat angle and width program.
2 ports that look identical can easily flow 30 cfm different.

I know you are saying the professionals know what works - trial and error?

I do agree that a flow bench is a great tool. I also believe that it is not a necessity, especiallay when an individual has been porting heads 8+ hours a day for 25 years, someone with that much experience just knows. For example, Tony bischoff was looking at my intake ports and says "these will never flow good at high valve lift" He has little to no experience with these individual head castings, he can just tell by the design. He was completely right, just at a glance he could gather that info.

How do you know Tony was right about the high lift flow without a flow test?
I am not trying to be an a__ hole here - just asking.

68galaxie wrote:

derek528 wrote:

68galaxie wrote:Sorry, I am certainly not trying to argue with you at all.
I am very curious how one modifies cylinder heads without the aid of testing tools.

As you have said flow bench numbers don't tell the whole story - but are a fantastic development tool.
The flow bench can and is used to measure port velocities at different areas of the port, equalizing port velocity distribution,
measuring flow around the valve into the combustion chamber, determining if a port is stalling and backing up at certain lifts, how well the port "works" with a specific valve seat angle and width program.
2 ports that look identical can easily flow 30 cfm different.

I know you are saying the professionals know what works - trial and error?

I do agree that a flow bench is a great tool. I also believe that it is not a necessity, especiallay when an individual has been porting heads 8+ hours a day for 25 years, someone with that much experience just knows. For example, Tony bischoff was looking at my intake ports and says "these will never flow good at high valve lift" He has little to no experience with these individual head castings, he can just tell by the design. He was completely right, just at a glance he could gather that info.

How do you know Tony was right about the high lift flow without a flow test?
I am not trying to be an a__ hole here - just asking.

Because I've seen these castings flow tested from quite a few reputable sources. They stall out at about .600 lift.

any updates??

I'll be working on it saturday, I'll post updates after that. The goal is to get the heads ready to be cnc'ed. I'd like to get the block honed this weekend also.

sweet. very interested in results.

The block is honed. Did more head work. It should be finished by the end of april.

Any updates ?

Well we skipped last saturday because we ran out of parts. The pistons and cam showed up yesterday so we are going in sat and we should start making alot of progress on the short block. The cam we ended up with is a custom comp. 281, 296 duration @.050 113 lobe sep. Lobe lift is .470 on both lobes which is .813 with a 1.73 rocker.

derek528 wrote:Well we skipped last saturday because we ran out of parts. The pistons and cam showed up yesterday so we are going in sat and we should start making alot of progress on the short block. The cam we ended up with is a custom comp. 281, 296 duration @.050 113 lobe sep. Lobe lift is .470 on both lobes which is .813 with a 1.73 rocker.

Nice build "derek528", any progress lately? THNX MAVMAN

Yeah, the block is fully machined, cleaned, plugged, and the cam bearings are in.. The heads were cnc'ed last week. Tomorrow we are going to pin fit the rods, file the rings, and hopefully assemble the short block. The crank is balanced and ready to go in. I'm ready to hear it run, And see what it does on the dyno. Hopefully It will be done by the end of may.

The short block is now assembled. Cam is in, it's 3.5 degrees advanced. Next weekend we will assemble the heads. Pushrod lengths ended up at 9.050 intake, and 9.150 exh. Geometry looks good with the crane gold wide body rockers, we ended up with .830 gross valve lift, when measured off the retainer.
I did get some flow numbers. They ran the same cnc program on another set of heads. The customer decided to have them flowed. The only difference is that my heads have a 2.25 valve and the ones they flowed use the original 2.20 valve.

I don't have all the numbers, but the heads flowed 377 at .500, and 403 at .800 w/ 2.20 valves. I don't know what mine flow with the 2.25 valve, I'd guess slightly more. The exh ports were less impressive at 220 cfm without a test pipe. The bowls are pretty big on the exhaust, that hurts the flow numbers when not using a pipe, and they didn't have a test pipe handy to use for the test.

All in all I'm very pleased with the headwork, I think it's going to make pretty decent power.

Just another update. We got the oil pump, and pickup tube on. We set the pickup/pan clearance. My brother made a crank scraper for me, it turned out pretty nice.

getting closer, mocked up the valvetrain with got pushrods ordered, working on the intake now. About two more weeks should have it done.

Nice

I have to thank Lem Evans, a lot of the parts used were supplied by him, his service was spot on.

Thanks

any updates ?

Still working at it. It's close, it should be on the dyno in a couple weeks.

It's finished. If all goes well, I will have dyno numbers by the end of next week.

Sweet, Keep us posted.

Nice looking job on the intake. have any pictures of the plenum?

Here are a few