MED race head valve guides and seat cutting - an insight

A look at the work involved in refitting new MED valve guides and valves to a Road Competition cylinder head.
Valve spring pressure - • How to test and setup ...

[@stevewelborn8744]

I'm in America and I've worked for a mom and pops automotive machine shop for 35yrs. I work in the head dept. and have reconditioned a lot of these heads.We do race engines but most are American V-8's. Just wanted to leave a very positive comment and say you guys do excellent work. Very Very nice.

[@Uswesi1527]

Undoubtedly, but, definitely, the Master Craftsman knowledge , that even , big engine manufacturers don’t know.

[@Uswesi1527]

The Master Craftsman , actually & physically, demonstrated how a few thous affect balancing, smooth running, and the service life of the engine.

[@ssa9148]

VERY interesting to see the tool head is driven by a ball joint - kind of like a universal (CV) joint to account for minor offset between the spindle and the tool head.

[@nurburgringdreaming2221]

Very very good info on cutting seats The porting on those heads look beautiful

[@mjt-ew8rs]

very cool. definitely would like to see more videos. I use neway hand cutters for my valve jobs

[@ericgeber6145]

Me too😁

[@Dagowly83]

One of the most satisfying things to watch 😎

[@vzrman]

Excellent video.

[@bnellynel]

Those cutters ain’t cheap. Nice tools.

[@ipanemabeach2266]

Love engineering!

[@franktaylor7617]

😎👍

[@bouny01]

By your reamers at magafor they go up with an increment of 0.01. You have them in carbide and HSS. HSS is around 30€ and carbide around 90€. I geuss it will be cheaper than a custom made one.

[@jiritichy6855]

(1.1.2023) Just being old (71+ y.o.) home mechanic I wonder, there has to be some dimensions how deep you can/or have cut these velve seats(in case you have to put new replacement in) to prevent the valves to sink too deep or on other hand to stick out too high in the cylinder, which in extreme cases can cause contact of the valve with piston. Where do you find all this information for one's personal vehice?

[@bodaaymn408]

I work in a cylinder head, there is an available job opportunity for me.

[@Sternhammer89]

What size reamer do I need for cast iron or manganese bronze valve guides. In the video you say yours have been ground to give the exact clearance.

[@Sternhammer89]

To what height do the valve guides get fitted? Did I spot that the press touch on the faced off area of the head? Also what size press would I need for this e.g. 1 Ton, 2 Ton, 10 Ton etc?

[@jiritichy6855]

There are some videos on youtube. The press is achieved not by pressure applied, while pushing it in, but rather by heating the head with torch and freezing(preferably in liquid Nitrogen) of the seat, you are trying to put in. The frozen seat just falls inside of the head opening if done properly. As it cools off/heats up to normal temp, it will create the press fit. It should be-I believe .007" diference between the hole and the seat O.D.at normal temp. You might still use a driving rod and hammer to get it all the way down...but it should be just light tapping.

[@bh-xe2wp]

we are just setting up our workshop were is the best place to buy these tools for a milling machine.

[@gavinivers8941]

This way a good head costs more that a not so good head. Time and labor is money....

[@connorchappell2694]

How do you know what depth to set the valve guides, does it vary between heads?

[@MEDEngineeringTechVideos]

The tops go in flush with the rocker cover deck face. If you see, the press stops when it touches down on the deck face at the back (front).

[@bengunn07]

I was about to ask the same until I saw the last one where the press head was straddling both

[@ProGrindCAMSHAFTS]

Please forgive my ignorance sir, what engine is that?

[@onomatopoeidia]

BMC A-Series 1275

[@shriramvenu]

is there a reason you don't use any cutting oil when doing the rimming or cutting the valve seats?

[@MEDEngineeringTechVideos]

It's not required with this particular job and cutting tool.

[@imalat789]

How do you drill the cylinder head for 11 stud

[@aodhanmaguire8816]

can you buy these cutters anywhere ?

[@billhenning]

I think you went about this all wrong. When the valves are seated they will each have their own height, since as you note they sit a “few thousandths” different than each other after the seats are cut. Therefore each valve stem will be a little different in the height to the spring seat, which means each spring will not be an equal length when fitted to the valve. All that you did cutting the spring seats in the beginning is for naught since the valve seat cutting changes everything. I think you need to do all that seat cutting first and then measure the fitted valve stem height, and then adjust accordingly with spacers under the spring seats rather than cutting away metal that can never be replaced. Then the next time you do a valve job you won’t be cutting away yet more metal, but instead adjusting spacers to get the consistent spring height you want.

[@MEDEngineeringTechVideos]

Sorry, totally disagree with your concept on this. Feel free to give us a call to discuss.

[@billhenning]

@@MEDEngineeringTechVideos Disagree all you want but you never proved what you claimed to have accomplished initially by machining all the spring seats to the same height above the top deck. That was a meaningless measurement (why is the deck height some meaningful standard??) that may have even made the situation worse. If the factory cut the valve seats, installed the valves without springs, and then measured the height of the valve stem to the spring seat they may have intentionally machined each spring seat differently to equalize spring height between all the valves. In not doing this measurement you have assumed that the distance between the valve seat and spring seat inside the head is the same for all the valves. That’s a near impossibility for any casting, so I think it is very likely that after all your work that all your springs sit at different heights from each other. Think about it, then prove it yourself by measuring the installed valve height without spring. That’s the proof, isn’t it?

[@MEDEngineeringTechVideos]

@@billhenning No. Sorry, there's no time to debate with you - more race winning heads to be machined here.

[@pyroboobysmith359]

Hello from CANADA. Let me start by saying it looks like MED has a meticulous service and the product line appears to be second to non. I have owned 13 Minis over the years, late 60s, early 70s, but never one with any power. Retired now and have an opportunity to purchase another Mini for restoration. This time around I want far better performance, so my question is, ( I am not being a dickhead here ) after looking at the cost of aftermarket components to put together an engine, why would one not just buy a used, very reliable, Honda Vtec B18 with approx. 160-170 hp at the wheels and for approx. 500-1000 Cad. dollars ( 300 - 500 gbp ) and call it good.

[@MEDEngineeringTechVideos]

Hello, thanks for the message. There's a few main points to consider. From experience of doing these things, it's rarely as easy or cheap to convert a Mini to a 'modern' engine as you first think. To get the car running well and the engine conversion neatly in place will cost far more in money and time than the initial engine purchase. Converted Minis generally are not worth as much as original A-Series powered cars, usually requiring a subframe change and much cutting of the bodyshell. Gearing dictates that you will usually have to run 13-inch wheels, and again generally speaking, converted cars rarely handle as well as the original Mini setup. There's a limit to how much power can be put down effectively in any case, so we would question the need for 160bhp on the road. Overall a mildly tuned 1275 A-Series is still a good option in terms of drivability, originality and fun. If you can achieve circa 100-110bhp and get the suspension geometry perfected, it will be a very effective road car.