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Old April 20th, 2012, 08:05 PM   #1
DT/NoTime
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Default 1927 Ford Roadster

I'm getting back to a '27 Ford Roadster that I've had for a while and setting it up as a fun daily driver with the emphasis on FUN. The current engine is a high compression big block Chevy (I know, Ford engines should be in Ford cars but I bought it with a dead Chevy installed.) It now has way too much cam, too much carburetion and a too loose torque conveter. This car weighs about 2000 lbs. and won't need a race engine to move it. So here's the plan: a Tall Deck 427 truck engine will get a quickie rebuild, a milder cam, and a single four barrel carb. Details and photos will follow but unlike many of the other engines assembled, this will be an economical build up with a target of 400 horsepower on regular gas and a rowdy idle. Schneider Cams of California, a company that Ive had good luck with in the past, will grind a hydraulic flat tappet cam similar to Comp Cams "Thumper" series but with an even tighter lobe separation angle for more of a chaotic idle. Since this is a Tall deck engine, the single four barrel carb intake for a GM 572/600, another tall deck engine, will be a good street intake manifold. For those not familiar with the tall deck Chevy engines, the distance from the crankshaft centerline to the deck surface on a regular big block is 9.8 inches, a tall deck is 10.2. Usually this helps to fit more stroke, or very long rods, or both, in the engine but such options will not be used here. Those that have seen the difference between a 302 and 351 Windsor Ford motor can appreciate the tall deck principle. Since this engine will not need to achieve high RPM, large port heads won't be needed. Stay tuned. -DT

Last edited by DT/NoTime; April 24th, 2012 at 11:50 PM. Reason: Misspelling
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Old April 24th, 2012, 11:46 PM   #2
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Today the heads and shortblock were dropped off at Island Automotive Machine Shop so that John K.,The Machinist could evaluate it's condition. This will be a memorable build because, after machining tons of engines, some of them for me, John is ready to retire. "Could you do one more? " is all it took to get him focused on another project instead of hanging up his calipers. John was supposed to retire on April first but I brought a couple of small block Chevys by and asked "C. Y. D. O. M. ?" And here go again. One day soon John will retire and I'll miss him and the time spent at his shop, the predictable results when I'd retrieve whatever engine I'd dropped off. John can take a worn out tired engine, wheezing and smoking, and have it ready to turn more dinosaur juice into entertaining propulsion. He gives me credit for picking parts that get along together well but it's his careful eyes, skilled hands, and patient craftsmanship that lets me do what I enjoy with cars. Well, the heads will only need a valve job (grinding new surfaces on the valve seats in the heads and corresponding angles on the valves). The valve springs will be replaced with a set that will work well with the cam. The heads were flat and the valve guides were within limits so they will be returned for assembly at my house and will get new guide seals. The short block seems fine with mild normal wear and will get disassembled, freeze plugs and cam bearings removed, hot tanked (washed in a heated caustic bath) and it's cylinders honed. The connecting rods will be checked for size and any distortion or deviation will be corrected, same for the pistons which will be re-used but get new rings. The crankshaft will be polished on all bearing contacting surfaces and reinstalled with new bearings and rear main seal before re-assembling the short block with new cam bearings and freeze plugs. I'll have some photos when John's work is done. -DT

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Old April 29th, 2012, 08:36 AM   #3
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Can't wait to see some pics of this project, Tom!!! Do keep us updated, please.
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Old April 30th, 2012, 09:19 AM   #4
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Me too! Hope you were able to get everything moved down this weekend. Sorry I wasn't able to get by to help.
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Old May 1st, 2012, 09:55 PM   #5
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Hi Bill, Photo's will be posted for sure. All went well with the weight lifting session, Brian. A friend had a very small hydraulic lift that made moving everything easy. I would have called if I needed a hand. The 427 Big Block Chevy shortblock will be finished by mid next week and I'll finish the heads around the same time. The next project will be a 429 SCJ Big Block Ford that's going into a Ford. Should be interesting. When they're done I can race myself! The Ford will be, hands down, a wilder build than this 427 Chevy though. To be continued. First the Chevy................. -DT
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Old May 2nd, 2012, 01:39 PM   #6
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Default Camshaft

I've always liked the sound of a high performance camshaft. Few things fit the overall effect of a Hot Rod or muscle car like a choppy idle. Comp Cams has their "Thumper" series of cams that use traditional performance cam duration and lift specs but tighten the lobe separation angle for an increase in "overlap" in combination with an early exhaust valve opening. This lengthens the period when the piston is completing the exhaust event and the intake valve is beginning to open as the piston is rising toward top dead center. The longer this time period is, when both valves are off their seats the rougher the idle, if all other specs are unchanged. A camshaft that has a wider LSAngle will have less overlap and a smoother idle, all other specs unchanged. This feature is ground into the camshaft blank at the time of its manufacture and cannot be changed. The Comp Cam Thumper hydraulic cam for a Big Block Chevy, part#11-600-4, Has an intake spec of .498 valve lift/227*duration@.050 and an exhaust spec .483 /241*duration@.050 . This means that as the crankshaft is turning, the valves are open at least .050" for 227* and 241*, and will open the valves up to .498 and .483" at the peak of lift. (See the "Basic Auto Tech" series to clear up any confusion some may have with this.) Comp Cams grinds this cam with a LSAngle of 107*. Many other cams in the Comp Cams line up will produce more horsepower with other LSAs but this series of cams are all about SOUND and good performance. The cam created by Schneider Cams has an intake spec of .510 valve lift/224*, exhaust .510/238*, LSA 105* The lift difference should not result in a performance improvement because of the limited airflow of the truck heads. It was dictated by the duration I requested and the lobe designs available by the manufacturer. The Comp Cams cam has more exhaust duration and an earlier valve opening timing resulting in the still expanding burning fuel/air mix "barking" into the exhaust system rather than still pushing down the piston. The very slightly shorter exhaust event of the Schneider cam, and the tighter LSAngle, delays the exhaust valve opening until the piston has completed more of its power stroke. This change should not allow cylinder pressure to escape as quickly, a factor in designing this cam for a low compression engine that should be happy running on 87 octane. It may well be that the car would run similarly with either cam but I feel that this cam is more accurately tailored to my expected use of the Hot Rod. -DT

Last edited by DT/NoTime; May 2nd, 2012 at 11:49 PM.
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Old May 3rd, 2012, 12:17 PM   #7
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Two things came up in phone calls that should be discussed further. First, why such a big deal about the cam. The cam determines the personality of the engine. Selecting one that best compliments the application you have chosen for it is one of the most important decisions you'll make. Will it be making as much low end torque as possible or it destined to challenge some stratospheric redline in the quest for top end power. Nitrous? Supercharged? Turbocharged? Heavy car or lightweight? Automatic trans? Manual? Overdrive? Gear ratio? Compression ratio? Carbureted or fuel injected? Emissions compliant? Towing? Racing? These are just some of the things to evaluate. A stock cam will allow the engine to run well, but just as you select the color of your car and it's wheels and tires, the cam is at least as important. A milder cam, one with shorter valve opening @.050 specifications and a wider LSAngle would hold even more effective compression in the cylinder than simply making minor alterations in timing and LSA. but it's resulting smooth idle goes against the overall presence of a Hot Rod. Second, Single carb? You're right. Speaking of Hot Rod presence, two small four barrel Holleys on an Offenhauser Tunnel Ram intake will get the job done and look better in the exposed engine compartment. I"ve found that this Tunnel Ram manifold has one of the best port matches to the small port truck heads. I'll have pics when it's back from the powder coater. Stay tuned. -DT
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Old June 18th, 2012, 06:55 PM   #8
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While waiting for the last of the valvetrain parts to arrive I checked the block and head numbers and found that this GMC 427 tall deck engine was built in 1981 and was destined for heavy duty truck use. One of the more consistent customers, according to an internet search, was the Blue Bird Corporation for use in their school bus line. I guess it will be a fitting metamorphosis that after one career hauling a bunch of children to school, it can power a lightweight Hot Rod hauling butt again! I like to use a computer program called "Desktop Dyno" to compare changes in engine components and their overall effect on horsepower and torque curves. Using this tool I built a VIRTUAL low compression 427, trying four different hydraulic flat lifter cams with .050 duration specs of 213*/213*, 215*/225*, 224*/234*, all with an LAS of 112*, and the Schneider custom cam mentioned previously. I also compared different sized carbs on a single plane intake and a dual quad tunnel ram. I didn't consider larger cams because this engine will be run no higher than 5500 rpm. For the heck of it I also ran early passenger car oval port heads (10.5:1 compression vs 8.5:1) with their smaller chambers and larger valves and power was up substantially with all combinations. Since the goal was ping free running on 87 octane, the stock (milled for slightly more compression) truck heads will stay. The cams predictably raised horsepower and torque steadily with increases in duration, and the custom cam was very close to the similar duration (largest) cam which had a wider LSA. The carb size was almost inconsequential, with larger ones and a tunnel ram having virtually no effect on power certainly due to the airflow limiting effect of the truck heads. This set, by the way, has the same size port opening as the passenger car 396/427 heads instead of the smaller "Peanut Port" heads usually seen in truck applications. It does have SMALL valves: intake size 1.85" vs 2.065" for general passenger car use, and 1.65" exhaust valves vs 1.72". The torque curve is pretty flat with over 400lbft from 2500-4500 rpm, and peak hp was 376 at 5000 rpm with this combination, according to this program. PS, more important than whether or not this engine on a dyno will make 376 horsepower is the overall assurance that the parts selected for this build compliment the application. And, it is much easier changing camshafts and heads with the click of a mouse! More to come. -DT

Last edited by DT/NoTime; June 18th, 2012 at 10:20 PM. Reason: Clarity
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Old July 9th, 2012, 11:58 AM   #9
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Default Head Games

When we last left our big block it was time for the heads. I prefer to assemble these myself since any problems can be corrected immediately, and because small easily overlooked details or interferences will quickly result in big problems, and then your building a new engine. Well, maybe I'm picky but it's how I roll. First, it is well known, or at least well rumored, that the earlier Gen-IV big blocks were replaced by the Gen-V and Gen-VI variants because the original tooling was so worn out from producing so many big blocks during it's long production life. Accuracy was unreliable and so a re-make was required. Maybe it's just a rumor, but keep it in mind......... The heads were milled for a little more compression and this resulted in a sharp edge around the perimeter of the combustion chamber which can heat up and stay hot. A Dremel tool with a new grindstone will quickly smooth the edge and remove this potential hot spot from pre-igniting the mixture as the engine runs. Next, the heads and valves were washed, scrubbed and blown dry with compressed air. There is ALWAYS SOMETHING LEFT IN THERE, not just the chips from grinding the chambers. (On heads that have been bead-blasted, I'll fill the water passage openings with shaving cream to discourage any missed stuff from falling into the engine, just prior to assembly.) The valves were checked for fit in the guides, and were fine. The valve seats had been re-surfaced and the contact pattern of the valves on the seats looked good. So far so good. -DT

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Old July 9th, 2012, 12:43 PM   #10
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The truck heads have an exhaust valve rotator installed under the spring on the head that promotes the valve turning in function. This minimizes the chance of the hot valve sticking to the exhaust seat and building up micro welds which will ruin the valve seat and prevent it from sealing because of an uneven surface instead of a smooth seat. These rotators are about .300" thick and have a small raised inner lip that locates the inner diameter of the spring and keeps it centered around the valve. The exhaust valve spring seat is machined .300" deeper to allow the use of the same spring on both intake and exhaust locations. These rotators are removed when installing performance double springs since the lip interferes with the inner spring. A hardened .300" steel spacer replaces them and instead has an outer lip to locate the spring. At the top of the valve stem is a machined groove that grips a ring forged inside a pair of tapered split locks that secure the valve spring retainer which secures the top of the spring. The retainer has a series of round steps under it that center the spring around the valve. Using a telescoping gauge in place of the spring, the height can be determined for all locations and then shims can be used to equalize all heights. The first head had measurements, with the spacers on the exhaust spring seats, that were a little short on the intakes and exhaust, but this could be accommodated by using split locks with +.050" installed height (the inner ring is forged LOWER inside the split lock to locate it higher on the valve stem). The second head had intake measurements that were close to those on the first head, but the exhausts were at least .125" TOO SHORT !! Both heads have the same casting and date #'s and came off the same engine. The reason it never affected the original engine, except for some possible premature cam lobe and lifter wear, was the very low lift of the stock cam and low pressure springs. The fix could have been to cut the four spring seats in the imperfect head, use four longer exhaust valves or just machine .125" from the bottom of four spacers to preserve the locating lip. Not knowing if there was a reason that this head wasn't cut at the factory, in case it wasn't by error, the four spacers were resized. The machine work was quickly performed by Al Fadge, another meticulous Machinist and good friend. The heads will be finished with Federal Mogul valve guide seals and the appropriate springs set at even heights. (Where are the Pics? Here soon I promise! And sorry for the delay.) -DT

Last edited by DT/NoTime; July 11th, 2012 at 03:22 PM.
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