Seeking Stroker Kit selection advice.

He is a regular contributor on the DeTomaso BB. As a matter of fact he was just talking about the issues you are asking about.

Thanx but what is the DeTomaso BB ?

Why not a standard stroke 351C that makes 500+ bhp at 6000+ rpm & revs easily to 7000 rpm?

Its possible using ported 4V heads & a solid lifter cam.

-G

I thought that a SCAT 377 or 393 was one of more common stroker kit's. What do you mean if you say a " standard stroke 351C " ? do you mean you can use a standard balanced bleuprinted bottom-end, and just improve heads and valve-train and flow to get 500+ ?

quote:

Originally posted by Dago:
Thanx but what is the DeTomaso BB ?

realbig.com/detomaso

wow Dan Jones times Dan Jones is a awful lot of Dan Jones!!!!!!!!!
I will take a week off to read. Thanx.

quote:

I thought that a SCAT 377 or 393 was one of more common stroker kit's. What do you mean if you say a " standard stroke 351C " ? do you mean you can use a standard balanced bleuprinted bottom-end, and just improve heads and valve-train and flow to get 500+ ?

Yes, George is pointing out that it's not hard to make 500hp with a stock stroke 351C.

I don't think anyone sells a 377 stroker crank anymore. You need to have your stock crank offset ground to get the desired stroke. 393 seems to be one of the most popular options these days.

Yes...

The 351C 4V was designed from its inception to be a race engine. It was designed by Ford to make about 520 BHP at 7000 RPM with 11.0:1 compression ratio. Therefore making 500 BHP with a 351C is relatively easy, you don't have to purchase aftermarket cranks or heads to do it, it can be accomplished with the factory castings.

Enthusiasts have been building 500 BHP Clevelands since the 1970s, with the flat tappet camshaft lobe profiles available today it is possible to make 500 BHP at lower engine speeds (6000 RPM) than what we did in earlier decades.

You are correct that the short block needs to be blue printed to survive at high rpm, the valve train needs upgrading to run at 7000 rpm, and the heads need mild porting to make 500 BHP.

George what kind of lobe profile do you suggest to use for an engine that rev a 7000 rpm? I think I would use a jessel shaft mounted valve train and a high performance damper.( or something simular )

Arno

before I get into specifics please tell me what type of use your motor shall see, i.e. street use (therefore spending very little time at high RPM) or track use (therefore spending significant time at high RPM)?

Also will the car utilize mufflers or have an exhaust system without mufflers?

-G

The car will only see the tracks. Including some tracks with long straights. The engine at this moment is blue printed. It is not super stock, like MSD gnition and a upgraded lob profile but not much has been done.I am using 180 Hall heathers, but I changed them so they come togeter in a single 2 in 2 out flowmaster. On the dyno It was 349 bhp and 421 NM. A nice flat line, but not realy much.

Arno

The limits of the production short block under racing conditions is 450 bhp, 7200 rpm (about 4200 FPM mean piston speed), and 8:1 dynamic compression. Race conditions means the engine is operated WFO down long straight-a-ways lap after lap. Sure owners get away with engines making more power, but not under racing conditions. A street engine is operated 99% of the time at part throttle, and an engine operated at part throttle is not producing anywhere close to its maximum compression or horsepower. Drag racers get away with more power, but the experienced ones know that to go racing with an engine employing the production block making anything close to 500 bhp will require grout in the water jackets. Grout is a viable solution for drag racing, but not for circuit racing. Grout is not ideal for street cars either as it makes the oil run hotter.

The cylinder walls of the production block are the main problem. After that I'd say the connecting rods are weakness #2. The lubrication system is problematic but it is well known how to fix it. The production crank is good for abuse into the mid-7000 rpm range, but since it is not fully counter-weighted it should never see use into the 8000 rpm range. For constant high speed use the crank is normally internally balanced.

The short block assembly of a typical professional level 351C racing engine in the 1970s did not employ production parts, it was assembled completely from non-production parts. A heavy-duty racing block cast by Ford with thicker cylinder walls and thicker bulkheads was available from contractors formerly associated with Ford’s racing programs (Bud Moore Engineering, Gapp and Roush, Holman and Moody, and Bill Stroppe). A fully counterweighted forged steel crankshaft manufactured by Moldex was available from the same contractors. Another fully counterweighted billet steel crankshaft manufactured by Hank the Crank (HTC) was available via the aftermarket. Chromoly connecting rods with doweled caps fastened by 7/16” cap screws and forged aluminum round skirt pistons were available from several aftermarket suppliers. The engines were equipped with tappet bore bushings and lubricated via dry sump style lubrication systems when the rules allowed them.

Someday we hope to have a new heavy duty Cleveland block available, for now to go racing with a Cleveland its best to hunt down an old NASCAR block; or build a hybrid combining a heavy duty 351W block with a 9.2 deck height, with Cleveland heads … what we call a Clevor.

Outside of the durability issue there is certainly no problem building a 351C circuit racing engine making 500 to 550 bhp. The iron heads were made to support that much power in the 7000 rpm range with a single 4 bbl carburetor, a single plane intake manifold, a good open exhaust, and a solid flat tappet camshaft with 250 degrees duration and lift in the 0.600 range. For circuit racing I'd set the lobe centers at 112 LSA. If you're using the stock crank use some aftermarket chromoly 351W rods (5.956 length) and round skirt forged pistons. A nice heavy fully bonded damper on the crank snout and a light weight steel flywheel in the back (Yella Terra). Tappet bore bushings (Cleveland block), dry sump lubrication, and an oil cooler to handle lubrication.


-G

George,

You recommend flat tappet and hydraulic roller lifters. Is there any reason why you do not include solid roller lifters?

Mark

Hi Mark, I hope all is well with you ...

The primary problem with solid rollers is the lash clearance. As the valves close and come to rest on their seats the lifter bounces (chatters) on the cam base circle in the approximately 0.020" lash clearance. This action slowly damages the rollers. The solution to this problem is a rev-kit, springs that hold the lifters in contact with the cam lobe. To my knowledge the only rev-kit manufactured for the 351C is manufactured by Porting Dynamics of Maple Grove Minnesota, but the springs operate with a big bend in them, it doesn’t appear they would last very long that way, so the issue of longevity isn't resolved, it shifts from the roller bearings to the rev-kit springs.

The second problem is spring pressure. Most solid roller cam profiles have very steep opening and closing flanks, and they require extreme "open" valve spring pressure to keep the lifter in contact with the cam lobe over-the-nose. The valves are also closed quickly which requires high seated valve spring pressure to prevent valve bounce. All of this spring pressure wears the roller lifter, rocker arm, valve tips and valve seats prematurely. Most solid roller cams aren't ground with longevity in mind.

The third problem is roller lubrication. All hydraulic roller lifters and most solid roller lifters rely upon splash lubrication of the roller bearings. Below 2000 rpm there isn't enough splash lubrication to meet the needs of a solid roller lifter because it is loaded much more heavily by the valve springs. A solid roller lifter that relies upon splash lubrication will quickly fail when used for stop and go driving situations, or even when a motor idles at less than 2000 rpm. Solid roller lifters featuring pressurized oil supplied to the roller bearings are available, but the real purpose for pressurized lubrication of the roller bearings is to increase the load bearing capabilities of the lifter, not low rpm use.
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Some enthusiasts are attracted to roller cams because there is angst these days about flat tappet cams failing prematurely. But for decades we used flat tappet cams without a worry. AND it is important to realize that during this last decade most enthusiasts installed new flat tappet cams without a single problem, the problems occurred to a small percentage of enthusiasts. The problems occurred for one or two reasons, (1) the reduction of ZDDP in motor oil and (2) quality control issues in the heat treatment or surface finish of "off the shelf" cams and lifters. So the solution to these problems is easy enough, when purchasing a camshaft and lifters don't purchase them off the shelf, purchase directly from the cam grinder and request the cam grinder's best heat treatment and best surface finishing. Then use motor oil designed for racing (off-highway usage) which contains generous amounts of ZDDP. Remember the distributor drive gear also needs ZDDP, so use of a roller cam does not equate to freedom to use whatever motor oil you want without consequence. If we approach building the valve train this way, with a bit of engineering precaution, there is no need to fear the use of flat tappet cams, the cam & lifters should be damn near bullet-proof.

Factory flat-tappet cams were phosphate coated for break-in. It would be nice to have a cam phosphate coated it that were available from a cam grinder.
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In Arno's situation, his power goal is only 500 to 550 bhp, with a 351C we can easily achieve that power with cams having valve lift in the range of 0.570" to 0.650". That certainly doesn't justify the use of a solid roller cam. Solid roller cams are for big lifts and motors that aren't expected to go very many miles before rebuilding the valve train is required.

-G

George,

Thanks for the info..

Mark

George can you expand on the pro's and con's of solid vs. hydraulic flat tappet's lifters and what to choose. For instance I've seen lifters with holes in the lifter surface that meets the cam face...the hole delivers oil to the cam surface to improve longevity. Does that have any negative effect on the Cleveland oiling system? Don't want to hijack this thread, but what you are posting gives a lot of great info on building the upper end of the engine engine. I'm ready to put my engine back together and am selecting parts for the valve train for a 450-500hp motor.

@ Dago

That's a really nice racing De Tomaso you have there. I live in Belgium and I hope that I can see it sometime next year on track. I live nearby the circuit of Zolder so if you go racing there, send me a post.

@ Cowboy form hell

I'm building myself a race pantera at the moment. Last summer I bought a Pantera with a 500 + RWHP with nascar spec's and MSD ignition in the US and I also bought an empty shell. My plan was to transfer the engine into the shell but what's your opinion on that ? If you would like to have some more information about the engine, I can give you all the spec's.

I'll try to post a picture of the engine but I'm not sure that I'm doing this the right way.

Carlo

C:\Documents and Settings\Carlo\Mijn documenten\Mijn afbeeldingen\DE TOMASO PHANTOM\4.JPG

quote:

Originally posted by Tom@Seal Beach:
George can you expand on the pro's and con's of solid vs. hydraulic flat tappet's lifters and what to choose. For instance I've seen lifters with holes in the lifter surface that meets the cam face...the hole delivers oil to the cam surface to improve longevity. Does that have any negative effect on the Cleveland oiling system? ...

Tom, that's a fairly simple choice with a Pantera because adjusting lash in a Pantera is akin to sleeping on a bed of nails. Its not something you want to do unless you are going serious racing. So stay with the juice cam, flat or roller. Hydraulic flat lifters don't have EDM holes, as far as I know, that's a solid flat lifter trick. Perhaps a new thread about selecting a juice cam is in order????? Hint, hint.

quote:

Originally posted by ALFA4FUN:

... I'm building myself a race pantera at the moment. Last summer I bought a Pantera with a 500 + RWHP with nascar spec's and MSD ignition in the US and I also bought an empty shell. My plan was to transfer the engine into the shell but what's your opinion on that ? If you would like to have some more information about the engine, I can give you all the spec's ....
Carlo

Carlo, welcome again to the forums, I'm happy to see you posting. Please start a new thread about your engine, so Arno's thread can remain focused on his engine. Thanks.

-G