[v8hed]

Originally Posted by cobalt327

I've never enjoyed the luxury of having an engine broken in on a dyno, but I would sure like to.

I'm sure the dyno at a good shop will have a program(s) to cycle the engine through the break in process- you don't just hold the engine at "X" RPM for "X" amount of time- the engine speed has to vary during the process, and the dyno can induce a load for the engine to "work" against as it cycles.

You will want to try a couple different heat ranges of plugs. Start w/a safely cool plug to break in with. Better to be a touch cold than too hot. Then judging by how they look AFA heat range goes, install a fresh set for the pull.

Same thing for the carb jetting. Go w/your best guess, leaning towards the rich side if anything for the break in. Then, make changes as needed for the pull.

There should be someone there well versed in plug reading and you should expect to get advice in this regard as part of the dyno session. You have a real advantage in having this shop well versed in racing engines and dyno'ing/tuning them.

You need not be so hesitant to ask them about things like if they're equipped w/an air line and plug hole fitting to swap out valve springs, etc. If you don't ask, then your only option is to bring everything you need. ASK if there will be someone there who will look at the plugs and give jetting advice, etc. The last thing you want to do is assume ANYTHING.

And it's OK to be new at this, and for them to know it. Say what you don't know, and ask questions. Hell, they didn't come out of the womb w/all the knowledge they have now, either!

Thanks man... sounds like good advice

The dyno is a Superflow 901 with 2000hp load cell.

[v8hed]

Originally Posted by ap72

If you're running the springs spec'd for that cam I wouldn't sweat running them with the inners for break in, assuming you have good oil and the engine was built well. You'll be wasting time removing them and reinstalling them, and it takes well over an hour, you can spend half the day just doing that.

Remove the valve covers, remove the rocker arms, remove the locks and retainers, replace the springs, reassemble. BTW, you need something to hold the valve stem in place when you change springs, if it slips down at all it makes installing the locks near impossible and placing all 16 retainers back on without bumping the valve and causing it to drop is not likely.

Also, I'd be sure to run your initial lash a hair on the tight side.

What intake manifolds will you be changing to/from? What carbs?

You're the first person I've seen say it's not necessary to remove the inner springs for cam break-in... these are Comp 987-16 with 120lbs seat and 320lbs open. I'll be making sure the valvetrain geometry is spot-on... correct pushrod length, correct lateral rocker tip alignment, correct installed height on every spring, plenty of coil bind clearance and retainer-to-seal clearance, etc, etc. Oil will be Joe Gibbs BR break-in oil AFAIK.

Curious, why do you recommend running the initial lash a hair on the tight side? Comp state .022" lash (hot), so I was planning to set the cold lash @ .017". Sound good?

Regarding intakes, I have a Victor Jr and an early Performer RPM (non Air Gap) that I want to compare... I may also cut a notch in the plenum divider in the Performer RPM intake before it goes on the dyno.

Carb is a brand new in the box stock Holley 750 DP (4150) and I also have a Quick Fuel Q-750 DP (similar to the Holley HP series I'm told) to try.

[cobalt327]

I've gotten away w/breaking in a FT cam w/that much pressure on the seat. As long as you're not exceeding the open pressure spec's lift, you might get away w/it, too.

[ap72]

the Vic Jr and the RPM are 2 completely different intakes, you should know which one best suites your engine before you even bolted anything together, If its a street engine I wouldn't even waste your time with the Vic Jr. Comparing carbs could be a good idea, as they can have a significant impact, as would trying different carb spacers.

On the cam, as long as the lifter bores were checked and you use good quality lifters with face oiling i wouldn't sweat it. I also wouldn't run a solid flat tappet cam otherwise. I'd run .015" cold lash, your parts will wear slightly during break in which will add a slight amount more lash and running them tight will minimize bouncing. In all honesty the .002" lash probably won't make a difference but I always go a little on the tight side.

[v8hed]

Originally Posted by ap72

the Vic Jr and the RPM are 2 completely different intakes, you should know which one best suites your engine before you even bolted anything together, If its a street engine I wouldn't even waste your time with the Vic Jr. Comparing carbs could be a good idea, as they can have a significant impact, as would trying different carb spacers.

On the cam, as long as the lifter bores were checked and you use good quality lifters with face oiling i wouldn't sweat it. I also wouldn't run a solid flat tappet cam otherwise. I'd run .015" cold lash, your parts will wear slightly during break in which will add a slight amount more lash and running them tight will minimize bouncing. In all honesty the .002" lash probably won't make a difference but I always go a little on the tight side.

There's quite a bit of testing that disagrees with you on the intake front and my combo has been tested elsewhere with both intakes and the Performer RPM with plenum divider notch v.nearly equalled the Victor Jr up top with some gains lower down. Likewise, there are plenty of people running Victor Jr intakes on street motors as they've found (on their combos) the Victor Jr still gives decent torque lower down. The only way to tell is to test on the dyno. And, FWIW, the guy who recommended this combo to me (the same guy that will be dynoing the engine and who has built hundreds of street and race motors) knows it's a 99% street-driven car and he specifically recommended the Victor Jr. intake as that's what he's seen make results with this combo on the dyno. I just want to try the Performer RPM as I've seen the dyno sheet from elsewhere that suggests it might be a touch better for me. We'll see.

The lifters are Comp Cams regular solid lifters... not the EDM model.

[F-BIRD'88]

This time around I'm going to agree with AP72.

[ap72]

Originally Posted by v8hed

There's quite a bit of testing that disagrees with you on the intake front and my combo has been tested elsewhere with both intakes and the Performer RPM with plenum divider notch v.nearly equalled the Victor Jr up top with some gains lower down. Likewise, there are plenty of people running Victor Jr intakes on street motors as they've found (on their combos) the Victor Jr still gives decent torque lower down. The only way to tell is to test on the dyno. And, FWIW, the guy who recommended this combo to me (the same guy that will be dynoing the engine and who has built hundreds of street and race motors) knows it's a 99% street-driven car and he specifically recommended the Victor Jr. intake as that's what he's seen make results with this combo on the dyno. I just want to try the Performer RPM as I've seen the dyno sheet from elsewhere that suggests it might be a touch better for me. We'll see.

The lifters are Comp Cams regular solid lifters... not the EDM model.

So you've seen the RPM perform better on countless tests and you still want to test something else? Just look at the runner CSA, flow, and length, RPM has street written all over it, the Vic Jr is better suited to small ci circle track engines.

I'd run the RPM and forget about it, spend you time tweaking that combo with carb tuning, ignition tuning, and spacers. JMO though and its probably not worth $0.02.

[F-BIRD'88]

This time around I'm going to agree with AP72.

If the open pressure does not exceed 320#, go with it. Only because you are on the dyno and the engine builder is controlling the break in.
(if low ratio rockers are available go with those too.)
If the open pressure is more than this, remove the inner springs for the run in.
Adding a open spacer to the rpm manifold will show you the same effect as carving the center divider. (you won't have time for carving).
There are many benefits to leaving the center divider intact that you won;t se on the dyno.
The Vic Jr will make a bit more power on the top end above 4500 rpm.
The RPM will make more average torque and may equal the Vic JR with the open spacer. If you will be street driving it most of the time, the RPM is the better intake for sure.
If you don't have the big big gears and 4000+++converter to take advantage of the top end power that the vic JR can make, the RPM will make the car accelerate faster. You cannot see this from dyno testing but drag testing in car will show you for sure.

Do not use cold race plugs for the initial engine break in. Do not use over rich jetting. The engine is only under partial load and the water system keeps the engine temp in check. 32-34 deg timing for the run in is plenty., stock carb jetting,
street perf plug heat range is fine. In "champion speak" thats a 10 or 12. A 10 should be good for dyno runs on pump premimum with under 11:1 cr.

If your engine is over 11:1 use a 50-50 mix of 92 and 110 unleaded. (100 octane mix)

You don't want the engine to plug foul (cold plugs overrich jetting) on the run in.

Oil: Cut the oil filter open after the initial run in. If you don't find anything in it, shiny aluminum, brass or.... (you may see the moly lube)
no need to dump the oil. leave all the good break in anti scuff in, install a new filter and go.

You'll find more usefull, informative info and power gains from swapping cams and carbs on the dyno than intakes. (The rpm and vic JR are known quanties and the difference is predictable.)
if the cam is close to correct for the combo, usually SBC's don't want high exhaust rocker ratio. try it.

As far as what you should bring to the dyno session. Ask. Make a check list before hand. Plugs, carbs, jets gaskets oil, filters, torque wrench tools,. You won't insult anyone if you keep your questions in the terms of what is expected of you to bring and you to do (tuning). You will need compressed air if you swap the springs.


I recommend this stuff. Apparently you can get it in the UK too.
www.molyslip.com

[cobalt327]

Originally Posted by v8hed

There's quite a bit of testing that disagrees with you on the intake front and my combo has been tested elsewhere with both intakes and the Performer RPM with plenum divider notch v.nearly equalled the Victor Jr up top with some gains lower down. Likewise, there are plenty of people running Victor Jr intakes on street motors as they've found (on their combos) the Victor Jr still gives decent torque lower down. The only way to tell is to test on the dyno. And, FWIW, the guy who recommended this combo to me (the same guy that will be dynoing the engine and who has built hundreds of street and race motors) knows it's a 99% street-driven car and he specifically recommended the Victor Jr. intake as that's what he's seen make results with this combo on the dyno. I just want to try the Performer RPM as I've seen the dyno sheet from elsewhere that suggests it might be a touch better for me. We'll see.

And therein lies the usefulness of the dyno. If it were for nothing more than obtaining peak power numbers, hell, you can get a good estimate of that by running the quarter and use weight and trap speed. But being able to do back-to-back pulls w/variables limited to just an intake or just a carb or jet change is what really makes the money spent worthwhile, IMO.

I'm a bit curious about the Vic Jr. as compared to the Super Vic. I've heard around here from at least one member that the Vic Jr. is down on power compared to the S Vic in some cases, and I would wonder if yours is one of those cases- IF it's correct to assume this in the first place.

I asked why the Vic Jr was sometimes passed over in favor of the S Vic HERE. Take the info for whatever you think it's worth.

[F-BIRD'88]

Cam shaft break in: After the run in , cool down, bolt retorque and valve re lash
quickly check for running pushrod rotation when you rev the motor. If they are all spinning, you are good to go.

It's nice to have and use a known working dyno distributor and check yours against it.

[lmsport]

For a street engine, the RPM will drive better regardless of some HP difference with the Vic that is only useful of the dyno. Dynos typically only test WOT performance.

[v8hed]

Originally Posted by F-BIRD'88

If the open pressure does not exceed 320#, go with it. Only because you are on the dyno and the engine builder is controlling the break in. (if low ratio rockers are available go with those too.)
If the open pressure is more than this, remove the inner springs for the run in.

I'm not sure low ratio rockers are available, so I've decided to get some Comp 800-16 EDM lifters to replace the non-EDM 813-16 lifters I already have still sealed in the box. Will lose some money because of this, but it seems most folks have good luck with the EDM lifters.

Originally Posted by F-BIRD'88

Adding a open spacer to the rpm manifold will show you the same effect as carving the center divider. (you won't have time for carving).
There are many benefits to leaving the center divider intact that you won;t se on the dyno.

The problem with running a spacer is hood clearance... I don't have too much. I might be able to fit a 1" spacer, but I wouldn't be able to run a 2". At least, not without a drop-base, slim air cleaner. In fact, thinking about it, a Victor Jr. may not even fit, which could be a deciding factor anyway! I've heard the CNC-ported 4-hole/open hybrid spacers are best? I've just got a regular 1" 4-hole phenolic spacer to try right now.

Interesting that you should point to negatives with notching the plenum divider, as the Performer RPM Air Gap comes with a notched divider from the factory and I haven't heard anyone complain about any aspect of the Air Gap's performance compared to the (un-notched) Performer RPM?

Originally Posted by F-BIRD'88

I recommend this stuff. Apparently you can get it in the UK too.
www.molyslip.com

Yea, Molyslip has been arond for years over here. I still have a tube of Molyslip gear additive from at least 15 years back that I never got around to pouring into a manual trans. I've heard some horror stories about Molyslip though... think I'll just stick to a known FT-friendly oil with the appropriate ZDDP levels.

[v8hed]

Originally Posted by ap72

So you've seen the RPM perform better on countless tests and you still want to test something else? Just look at the runner CSA, flow, and length, RPM has street written all over it, the Vic Jr is better suited to small ci circle track engines.

I'd run the RPM and forget about it, spend you time tweaking that combo with carb tuning, ignition tuning, and spacers. JMO though and its probably not worth $0.02.

Sonds like you're getting a little defensive... I'm simply going-on what my builder recommended. He knows full well this is a street motor and he swears the Victor Jr. is the ticket on this combo. THAT is why I want to try both. This guy knows all about CSA, flow, length and can recite formulas blind folded... he knows his stuff and has built hundreds of engines to prove it. I'm read good things about the Performer RPM though and, as I have one knocking around from my last engine, I may as well try both intakes and see how they behave. It's true, however, that the dyno can't test part-throttle performance or streetability and I have read this is an area that can cause a few headaches with a single plane intake, so I am personally swaying towards the Performer RPM if the dyno shows the 2 are close at WOT.

[F-BIRD'88]

"I've heard some horror stories about Molyslip though... think I'll just stick to a known FT-friendly oil"

Do not confuse so called horror stories With the specific Moly Slip engine oil additive sold by Moly Slip. it is packaged so there is no friggin way it will cause any oil problems. It does not and will not clog a oil filter.
I don't run it all the time but run it for the first oil change (about 1 week of driving) . I do not drain the oil right after the inital run in. (just change the oil filter) You waste all the good of the anti scuff protection that the moly slip and Zddp provides. leave it in.

Your engine takes longer to full break in than 30 minutes.

I run reduced spring pressure for the first week or so too.

I keep rpm below 5000rpm and idle above 1000rpm (for a week) but don;t baby it.
Then after a good week or so of driving I change the oil filter , relash and install the springs to correct pressure.

Think about it, if the stuff works to stop run in wear and scuff there will be no trash in the oil. Thats the whole point of running it.

If there is that much trash/metal in your oil after 30 minutes of running, the engine is trashed. Think about it.

I add it Moly Slip EOS Moly Slip EOS
(its not a paste in a tube) to my oil about once a year (annually) after that during a routine oil change.. (i'm cheap so I use 1/2 a can per year)

No problems with my XE flat tappet cam, either (reguardless of all the horror stories) etc. Yes I've had the pan off to inspect.
slow idleing speed as the engine is breaking in (1 to 2 weeks of driving) is death to a high perf flat tappet cam.
After that you can set the engines idle speed to your hearts desire.

[ap72]

Originally Posted by v8hed

Sonds like you're getting a little defensive... I'm simply going-on what my builder recommended. He knows full well this is a street motor and he swears the Victor Jr. is the ticket on this combo. THAT is why I want to try both. This guy knows all about CSA, flow, length and can recite formulas blind folded... he knows his stuff and has built hundreds of engines to prove it. I'm read good things about the Performer RPM though and, as I have one knocking around from my last engine, I may as well try both intakes and see how they behave. It's true, however, that the dyno can't test part-throttle performance or streetability and I have read this is an area that can cause a few headaches with a single plane intake, so I am personally swaying towards the Performer RPM if the dyno shows the 2 are close at WOT.

I'm not meaning to sound defensive, the victor jr just isn't a good intake for most people imo. Its usually bettered by the rpm or the supervic, across the board. Comparind those two for a dual purpose prostreet type engine would be of some value, I just don't wee why you would want to compare those two. The victor will lose out through 95% of the curve if not all. The open spacer on top is a usual trick and worth a look if you can get or borrow one, a lot of dyno shops have things like that to borrow and test.