MPG Automotive

12/18/2025

Lately, there seems to be a resurgence in interest in repairing problems with the Chrysler/Jeep 4.7 cylinder head.
They have a problem with the Intake seats coming loose and sometimes dropping down and getting stuck under the intake valve. Contrary to popular belief, this can happen even if the engine has not been overheated.
The cause is an insufficient "press fit" of the seat in the head when manufactured. They SHOULD have a .004-.006 interference fit (at room temperature). I have measured some with as little as .002!
Most of them CAN be repaired without machining for an oversize seat. The seat "seals" on the bottom "ledge" of the "pocket" where it sits in the head. As long as this "ledge" is intact, the head can be repaired by heating it to about 300 degrees, and the seat chilled to about 0. Then the seat is coated with "seal lock," which is a high-temp sealant that helps to retain the seat.
The remainder of the seats that have NOT yet become loose are "swedged" tighter into place using an air chisel with a rounded tip to prevent them from coming loose in the future.
I have been repairing these heads successfully using this method for many years!

09/07/2024

FUEL MATTERS!

Which one is more important to the health of your engine - the quality of your motor oil or the quality of your fuel? Let's see what the research and engine ...

09/08/2023

https://www.youtube.com/watch?v=Fj2NSteaPnM

Certified Lubrication Specialist, Lake Speed Jr and Keith Jones share their knowledge and experiences with different brands of engine break-in oils. Spoiler ...

07/10/2023

Quite a few years ago the shop where I worked did a test on the effects of oil control on HP. BBC circle track FI engine. Started out with a stock pan & factory tray. Ended up with a dry sump.
There was very little difference under 6,000. But ABOVE 6,000 the differences started to show up to about 30HP difference at 7,000 RPM.
So street engines less than 6,000 just do what's needed to help KEEP oil in the pan, really no HP gain there.

Lakes Speed Jr heads back to EFI University to see Ben Strader and talk oil – specifically the four “R”s of oil: the Right Oil, the Right Place, the Right Time, and, the Right Amount. But if you’ve figured out the oil and where and when it

06/03/2023

Let's go to crankshaft school!

For episode 42, we step into the classroom with “professor” John Callies for a technical deep dive into crankshafts.Starting with the basic nomenclature, features, and differences between standard and racing cranks, and taking us all the way through the specifics of crank grinding and re-work to...

05/30/2023

A couple of major reasons today's engines last longer and have better performance are cylinder finish, piston ring technology and improved motor oil.
Excellent description of research into all these subjects and how they are related.

Friction and Wear are NOT related. They are actually independent of each other. You can reduce friction and increase wear. You can also reduce wear and incre...

12/30/2022

An Excellent article on Motor Oil.

Many enthusiasts look to diesel motor oil as a high-zinc alternative, but is it the best choice? A certified lubrication expert explains the difference.

05/17/2021

Repairing Cracked Cast Iron Cylinder Heads

This is an example of repairing common cracks found in Chevrolet cast Iron cylinder heads as found mostly on Chevrolet trucks.
I have been doing this for over 25 years with good success. Although there are new castings available this repair can be a lower cost option to replacement.
This is a common failure where the crack has spread into the water jacket on both sides of the seat. This will require repairing the crack with "pins" and installation of a replaceable seat.

04/21/2021

Motor oil 101.
A great explanation of oil "weights". What that number means and the proper use of it.

Can thin motor oils protect your engine? Sponsored by Mobil 1 motor oil – Visit AutoZone to find the right Mobil 1 motor oil for you: https://bit.ly/2P218TW ...

12/05/2019

Recently I have seen quite a few questions on several different pages about oil pressure, or lack of it.
Here's a GREAT page from Chevy Hard Core & Melling describing the basics of pumps, clearances and their effect on pressure. Remember, when working on bearings you're working with a CIRCLE so pie (3.1416) comes into play.
Watch the video from Melling on clearances. EXCELLENT !!

Many feel a high-volume oil pump is a necessity for a high-performance engine. Find out what our professional sources have to say about that.

06/06/2019

The effects of "Quench" on engine performance.
More folks need to include "quench" when setting guidelines for building their engine. This article does a good job of explaining how to produce it and the effects of it.

Quench is the clearance between the piston and cylinder head at TDC. It can affect engine effeciency and performance, if you truly understand it.

02/18/2019