Procedures for Checking Straightness on 1992-2003 Ford Aluminum Cylinder Heads - Engine Builder Magazine

Procedures for Checking Straightness on 1992-2003 Ford Aluminum Cylinder Heads

The surface quality (finish) of the cylinder head gasket surface is
machined to close tolerances that enable an effective sealing joint for
the MLS (multi-layered steel) gasket. To ensure all head gaskets seal
properly, be sure surfaces are clear of any gasket debris, RTV, oil,
and coolant using Motorcraft Silicone Gasket Remover (ZC-30) and
Motorcraft Metal Surface Prep (ZC-31). Use a lint free rag to mop up
the deck surfaces. Shop vacuums are unacceptable for mop up as the
cleaner is volatile. The block or head surface must be clean and dry
before running a flatness check.

Use a straightedge that is calibrated by the manufacturer to. be flat
with 0.0002? (0.005 mm) per running foot length. For example, the
straightedge may be 24? (61 cm) long. That means the machined edge must
be fiat within 0.0004? (0.010 mm) from end to end.

Special care is requlred to ensure the tool Is not damaged in handling
or storage. Be sure that the machined surface is free of nicks and
dents. If these properties are found, the cost of tool re-calibration
most likely will exceed the cost of a new straightedge. Machine shops
may not be able to hold the specified tolerance within the original
cost of the straightedge.

When checking for flatness, avoid running the feeler gauge butt end
against the straightedge. This action will curl or warpthe leaf and
prevent entry under the straightedge. Erroneous readings will result.

Instead, lay the leaf on the suspect area, placing the straightedge on
top of the leaf. A very easy pull orlbooseness of the leaf under the
edge will indicate a depression in the surface. Turn the edge 90
degrees to the area just checked. Confirm any suspicion by checking the
area more than one time.

Figure 1 and 2 demonstrates a 12 point check-system using a
grid format on a 4 cylinder bank. Important to note is that a localized
area of less than approximately 1.5 to 2.0 will influence the
effectiveness of the MLS gasket sealing capability. Depressions or
marks measured to be over 0.001? deep will not seal properly. The
overall flatness check (head end to other end) is not as critical.

As shown with Planes 1 through 3 (Figure 1 and 2)check
these areas locally with the gauge looking for suspect depression areas
of 0.001 inch or more. Then, check these same areas again,
perpendicular, using Planes 4-12. The second pass will confirm a
suspect area because you are using a shorter span of the straightedge.
The first pass (Planes 1-3) is necessary because the overall end to end
flatness must be accounted for before doing the secondary passes (Planes 4-12).

Ford Motor Company approved straightedges are commercially available
through the Rotunda Tool Catalog at special pricing, or can be
purchased from Ihe local tool distributor or truck at regular
pricing.This edge meets or exceeds the requirements of testing Ford
engine components.

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit
Figure 1 - Driver's sideFigure 2 - Passenger side

You May Also Like

Shop Solutions September 2023

Engine shop tips and tricks.

Engine Builder and Engine Pro present Shop Solutions in each issue of Engine Builder Magazine and at to provide machine shop owners and engine technicians the opportunity to share their knowledge to benefit the entire industry and their own shops. Those who submit Shop Solutions that are published are awarded a prepaid $100 Visa gift card. Submit your Shop Solution at [email protected]. You must include your name, shop name, shop address and shop telephone number. Submitted Shop Solutions not published will be kept on file and reevaluated for each month’s new entries.

How to Properly Crate a Performance Engine for Shipping

PPLUS Global Logistics, a freight management provider, recently released a guide outlining the proper steps for crating a performance engine for shipping. Obviously, given the expense and potential for damage to these high-value engines, shipping them requires careful attention to detail to ensure their safe transportation. Related Articles – Shop Solutions August 2023 – The

Shop Solutions August 2023

Engine shop tips and tricks.

The Best of Both Worlds: Twin-Charged Engines

Not to be confused with twin-turbocharging, twin-charging is the innovative combination of a supercharger and a turbocharger. It’s nothing new – Lancia, Nissan and Volkswagen were among the first to use the combination back in the ‘80s, but it’s hardly common today.

Crank Balancing Update

If there’s anything all of us in this industry have come to understand, it’s that you can never be certain someone else did the job correctly – and when it comes to crankshafts and crank kits that you or a customer might purchase, it’s imperative to ensure a proper balance job was performed and not just trust that it was because it says so.

Other Posts

EFI Timing Control & its Advantages

No one can overstate the fact that EFI timing control has radically changed the ability for anyone to fully, and correctly, optimize an ignition timing curve, assuming they are interested in investing the time.

Rebuilding Chevrolet’s Gen VI Big Block Engine

Following Chevy’s introduction of its popular small block V8 in 1955, the OEM needed something larger to power its medium-duty trucks and the heavier cars that were
on the drawing board at the time. Enter the big block!

Shop Solutions July 2023

Engine and machine shop tips and tricks.

Shop Solutions June 2023

Engine and machine shop tips and tricks.