improving flow for the 3FE’s top end (3 Viewers)

[RockDoc]

I'll run it up to 4500 for sure, likely try to keep it below 5000. From what MarkW has posted, 5000 should be safe with the stock 2F rod bolts. I'm hoping for a nice broad power curve, but would like more bottom end over more top end. The port cross-section hasn't been opened up in any appreciable way, just smoothed and improved around the guide and machined seat transition.

The valves aren't that much larger (I think you can get the idea from the photos, but really minimal) but will allow for the existing seats and guides to be cut fresh without the need for replacement (per Jim C).

The cam will be a MAF RV grind that I got from a blown HiPo 2F that D'Animal came into. My understanding is that that bottom end went boom with around 5 or 6 k miles on it due to the oiling system being botched on rebuild. IIRC from the MAF site, the total duration should be 260* and lift about 0.42" or 0.43".

The bottom end will be a slightly refreshed '83 2F. I'm going to give it some coatings (piston top, piston skirt, bearings? ....) but don't have the funds to do a full machined rebuild.

You might notice that the theme here is putting time and thought into the build rather than significant money. I'm a grad student, so my budget is limited.

 

[RockDoc]

A few more pics. Started working on the intake manifold last night, hopefully will have some photos of that tomorrow.

A couple pics of the exhaust manifold finished better than the last pics, they went through carbide burr, dremel grinding stone and flat file to get to here:

Using a pair of valves (just the right size) to index the manifold gasket and mark out an idea of how much working room there is for "port matching"... more on that later once I get it further, there will be an anti reversal ratchet that effectively crosses the mating surface (stock layout has a touch of this feature on the head side of the contact):

 

[RockDoc]

Some pics of what I'm doing at the head/manifold mating surface of the intake.

In stock form, the port openings on the head open slightly, presumably to account for any misalignment between the manifold and head. The gasket openings match the larger head opening rather than the tighter manifold opening. This gives a touch of anti reversal character relative to traditional port matching. I'm exaggerating this by cutting more "ratchet" into the manifold. First step is to use an inverted cone burr to cut the sharp step end (burr cuts at 25* I believe), then smooth out from the deepest portion of the notch to a matched port opening (6* angle with a 4mm deep cut is ideal according to Dalton).

Again, the benefit of the ratchet here is to negate any reversion during valve overlap (not likely much of an issue with either the stock cam, or the one going in) and make the port act as one with a smaller cross-section during low rpm by constricting flow aerodynamically and keeping velocity of the intake charge up (which should help with this engine). More explanation can be found back in posts 104 and 106

Here are a couple of the intake runners right now, cut with the burr, but not yet smoothed to a port match:

Once I get this "ratchet port matching" done, I think I'll sand blast the rest of the runner length to smooth it out a touch and match the joint between the 2 pieces of the manifold.

 

[RockDoc]

A few pics after the first step towards "port matching". Looks like I still have a bit to go before I get out the sandpaper to finish by hand....

I got the opening to the plenum behind the throttle body opened up and smoothed down some too, no pics yet though.

 

[PabloCruise]

This thread is money!!!

Thanks Doc.

What program are you doing in grad school?

 

[RockDoc]

Shaping pretty much done. Think the next will be attacking the AFM, and sand blasting the rest of the intake manifold, and the exhaust manifolds.

 

[RockDoc]

Just getting some notes together to go with the head and crank to the machinist. I've decided to request a chamber volume of 73cc, which should put the dynamic compression ratio at 7.4:1 with the cam I'll be using. This lies between the stock DCRs of 7.24 for the 3FE and 7.55 for the late 2F. Hopefully things go smoothly with the valves..... I've decided against coating the intake runners since blasting and air-brushing on the coating inside them doesn't seem feasible. The head/chambers and pistons will be done though.

The piston-rod assemblies have been balanced to a spread of about 3g (starting at 39g spread ) I'll take in the crank to be balanced so I have a smooooooooth operator.

 

[Cruiserdrew]

I don't really know how they balance a motor at the machine shop, but I thought it involved balancing the components like you are, and then bolting the rotating assembly together and balancing the entire unit. That would include the flywheel and clutch.

Still-what you have is better than what you started with. When will this be running? I'm expecting at least a YouTube vid.

 

[ntsqd]

Machine shops balance the rods by weighing the big ends only (special scale fixture) and grinding on them until they're within what ever tolerance employed. Then they weigh the whole rod and grind on the small ends until they are all within tolerance again.

The pistons are balanced by milling the underside bosses until they all weigh within the tolerance of the lightest unit. Once that it done the some special "bob-weights" are assembled that represent the weight of the rod (& piston?; never been clear on that step even though I've watched it 100's of times) by adding or removing thin fender washers to a double 'V' block assembly that clamps around the rod journals of the crank. Depending on if the flywheel and damper/front pulley are neutral balance or not they may or may not be assembled to the crank for balancing. Some engines have eccentric mass on their flywheels and dampers ("External Balanced"). Those need to be balanced assembled. Other engines are "Internal Balance" engines and do not need for the damper & flywheel to be assembled to the crank to balance it. In this case the crank is brought to within tolerance by either drilling the counter-weights or by drilling a counter-weight and then filling the hole with a very dense metal known as "Mallory Metal" ($$$$). I would expect an inline six to be internally balanced.

As an aside, if Mallory Metal has to be added it is best done in holes that are parallel to the crank centerline and not in holes that are perpendicular to the centerline. That pretty much limits the counterweights that this can be done on to just the outer most pair.

Once an internally balanced crank balances within tolerance the damper and flywheel will either be assembled to the crank and balance checked again (ideal?), or they will be balanced within tolerance on a mandrel.

 

[lehiguy]

Machine shops balance the rods by weighing the big ends only (special scale fixture) and grinding on them until they're within what ever tolerance employed. Then they weigh the whole rod and grind on the small ends until they are all within tolerance again.

The pistons are balanced by milling the underside bosses until they all weigh within the tolerance of the lightest unit. Once that it done the some special "bob-weights" are assembled that represent the weight of the rod (& piston?; never been clear on that step even though I've watched it 100's of times) by adding or removing thin fender washers to a double 'V' block assembly that clamps around the rod journals of the crank. Depending on if the flywheel and damper/front pulley are neutral balance or not they may or may not be assembled to the crank for balancing. Some engines have eccentric mass on their flywheels and dampers ("External Balanced"). Those need to be balanced assembled. Other engines are "Internal Balance" engines and do not need for the damper & flywheel to be assembled to the crank to balance it. In this case the crank is brought to within tolerance by either drilling the counter-weights or by drilling a counter-weight and then filling the hole with a very dense metal known as "Mallory Metal" ($$$$). I would expect an inline six to be internally balanced.

As an aside, if Mallory Metal has to be added it is best done in holes that are parallel to the crank centerline and not in holes that are perpendicular to the centerline. That pretty much limits the counterweights that this can be done on to just the outer most pair.

Once an internally balanced crank balances within tolerance the damper and flywheel will either be assembled to the crank and balance checked again (ideal?), or they will be balanced within tolerance on a mandrel.

I watched the machinist do my 2F. He drilled and welded on the crank untill is would spin on the balancer without bouncing. Then he added the flywheel and spun it again, drilling on it untill it too spun without bouncing. Then he added the dampener and started over, drilling on the dampener untill nothing bounced. This ensured that every part was balanced by itself and I could swap them as needed. This is the right way to do it. Spinning the whole assembly together and drilling or welding on the crank will get it balanced, but when you swap the flywheel or the dampener, it will almost certainly be off.

 

[PabloCruise]

Machine shops balance the rods by weighing the big ends only (special scale fixture) and grinding on them until they're within what ever tolerance employed. Then they weigh the whole rod and grind on the small ends until they are all within tolerance again.

The pistons are balanced by milling the underside bosses until they all weigh within the tolerance of the lightest unit. Once that it done the some special "bob-weights" are assembled that represent the weight of the rod (& piston?; never been clear on that step even though I've watched it 100's of times) by adding or removing thin fender washers to a double 'V' block assembly that clamps around the rod journals of the crank. Depending on if the flywheel and damper/front pulley are neutral balance or not they may or may not be assembled to the crank for balancing. Some engines have eccentric mass on their flywheels and dampers ("External Balanced"). Those need to be balanced assembled. Other engines are "Internal Balance" engines and do not need for the damper & flywheel to be assembled to the crank to balance it. In this case the crank is brought to within tolerance by either drilling the counter-weights or by drilling a counter-weight and then filling the hole with a very dense metal known as "Mallory Metal" ($$$$). I would expect an inline six to be internally balanced.

As an aside, if Mallory Metal has to be added it is best done in holes that are parallel to the crank centerline and not in holes that are perpendicular to the centerline. That pretty much limits the counterweights that this can be done on to just the outer most pair.

Once an internally balanced crank balances within tolerance the damper and flywheel will either be assembled to the crank and balance checked again (ideal?), or they will be balanced within tolerance on a mandrel.

Awesome detail - thank you!!!

 

[ntsqd]

I watched the machinist do my 2F. He drilled and welded on the crank untill is would spin on the balancer without bouncing. Then he added the flywheel and spun it again, drilling on it untill it too spun without bouncing. Then he added the dampener and started over, drilling on the dampener untill nothing bounced. This ensured that every part was balanced by itself and I could swap them as needed. This is the right way to do it. Spinning the whole assembly together and drilling or welding on the crank will get it balanced, but when you swap the flywheel or the dampener, it will almost certainly be off.

Exactly how it should be done when the engine is an internally balanced design. I would be surprised if any of the whole F engine series is externally balanced. When the engine is an externally balanced design the damper and the flywheel will both have eccentric masses on them. There is NO way that the crank by itself will easily balance. Can be done, but it is a large undertaking involving use of Mallory Metal. If I recall correctly SBF's (both 28 oz. and 50 oz. imbalance dampers exist), SBC 400's and BBC are examples of externally balanced engines. They have large(-ish) lumps cast into their flywheels and damper hubs that are not completely circular. Neither will balance by itself, but both assembled to the crank that they are intended to be on will balance as a whole.

All is not lost though, with a replacement flywheel you just have it "Match Balanced." By putting the new and the old together on the same mandrel in the right order and relationship they can have their imbalances matched so that the new bolts on exactly like the old. Not as simple to do as when the engine is internally balanced, but the overall cost is less than converting to internal balance. Would be hard to justify converting based solely on easy flywheel swaps unless the use was unusual and that would happen a lot. Where I've seen the internal balance conversion done the most is with true racing engines. Even then it is usually better to order the crank internally balanced than to invest a bunch of time and money in converting from externally balanced.

Awesome detail - thank you!!!

You're welcome. I'm glad that it helped.

 

[RockDoc]

Well, the head, crank and harmonic balancee/pulley are loaded up to take in. I'm not feeling like tearing anything down to get a flexplate to take in (I assume it wouldn't be very imbalanced). We'll see what they say.... gonna go by the shop that I had originally check the casting, if they don't balance I'll try another place.

 

[ntsqd]

Assuming that the crank is internally balanced, and I fully expect that this is the case, then what they'll do is like Lehiguy posted. The flex plate can be balanced any time and it won't matter.

 

[RockDoc]

Should get a call with a quote in the morning. First shop doesn't balance in house, and seemed to think the seat inserts would have to be bumped up in size after taking some measurements (I think they are slanted towards industrial/heavy engines more than automotive). Recommended a couple other shops to try and the guy at Campbell Automotive didn't seem phased by any of what I was asking for.... I believe I've heard good things about them in the past.

 

[Cruiserdrew]

Appreciate the details.

Roc-post up what they say. ie what exactly they want to do, and how much $$ they want for it.

 

[RockDoc]

Appreciate the details.

Roc-post up what they say. ie what exactly they want to do, and how much $$ they want for it.

Will do, I imagine the prices might seem high based on location. I think the guy was amused when I told him how much out the rods were. He said the worst they usually see is a 20g spread with big block Chryslers (mine had a 39g spread). When I talk with them tomorrow I'll have to make sure they're planning to do a good 3-angle grind and back and top cuts on the valves. I imagine this is fairly standard, but I forgot to ask when I was in.

 

[Clonestocker]

ntsqd,
Are you a machinist or gear head? I'm new to CruiserLand but a gear head. I've replied to a few post that I through a race related curve on and have never got responded too. This stuff is cool on the heads but I'm wondering just how much steam you can get out of one these things. I haven't looked close enough to see if run a quench dome on the heads to make the burn more efiecent(sp). The 5.3 Vortec still has more appeal because of the mileage and cost. If you could get the I6 with today computer management for injection and todays effeicy(sp) it would be cool to see. I would like to go for a ride in a 3FE that has it's "A" game on. Mine is the only one that I have been in so I can't compare it to anything. I know it needs a tune because I can hear the valve lash. It sounds like a sewing machine. Keep going RockDoc can't wait to here how the improvements are working. matt

 

[RockDoc]

Thanks Matt. I feel my 3FE runs pretty strong (especially when the exhaust is sealed and I feel fine stepping into the pedal ) but I've never had anything I'd call high performance (200 CID Ford, 3.1 Grand Prix)...... I'd love to ride in a 62 with a 5-speed to see how much is lost with the torque convertor. I can tell you that having lockup in 3rd gear makes a world of difference.

 

[Clonestocker]

What is this convertor lockup in 3rd gear all about? Different valve body? I don't even want to know about the Cruiser Auto Trans stuff. In my race car I put it in low gear hold a button and mat it. Let go of the button just like a clutch at 5000rpm. I do want to learn more about these trannys because I can't afford to pay someone to fix it. I bet a fancy T/C can get expensive. I love the way my Cruiser works offroad stock but the popup camper we want to get might be hard on the old girl. Hense the looking into a 5.3. Tell me what you kknow about the transmissions in these things. thx matt