Progress Thread Snow - 93 GT Vert. My first Ford, Mustang, convertible, ...

[AeroCoupe]

So there are a lot of different grades of lapping compound. Not sure which one you used but check this site out, should give you some insight:

Polishing Paste & Lapping Compounds - Kemet

Silicon Carbide Lapping Compound for precision lapping, cutting and smoothing of metal surfaces. Simichrome metal polish for use after diamond compound. Removes

www.kemet.co.uk

Granted it’s a UK company it’s good info.

 

[JAA]

So there are a lot of different grades of lapping compound. Not sure which one you used but check this site out, should give you some insight:

Polishing Paste & Lapping Compounds - Kemet

Silicon Carbide Lapping Compound for precision lapping, cutting and smoothing of metal surfaces. Simichrome metal polish for use after diamond compound. Removes

www.kemet.co.uk

Granted it’s a UK company it’s good info.

I had used the basic stuff: https://www.summitracing.com/parts/ptx-80037

Went with both of these. They will give me a three step process.

• Amazon product ASIN B006ZXZYMA
  View: https://www.amazon.com/dp/B006ZXZYMA
• Amazon product ASIN B00HC2LNU0
  View: https://www.amazon.com/dp/B00HC2LNU0

 

[JAA]

Gonna swap to what should be an easy exhaust valve. Will try an extended 3 step process

 

[JAA]

Lol - that 800 grit certainly puts on a polish!!

 

[JAA]

Good news

Forgot to take a picture, but that leaking exhaust valve is now good.

Time to hit an intake valve

 

[JAA]

30 minutes in, not looking good

 

[JAA]

One thing I am going to do for giggles is to hydro test the stock heads I removed. If my lapping is as good or as better as those it’s a different convo.

 

[JAA]

Anyone built and used one of these?


View: https://www.youtube.com/watch?v=5UCU0F8yawk

 

[JAA]

1 hr

 

[JAA]

Really tried to polish this one up

 

[Monkeybutt2000]

Again, you've got options. Spend the money at a machine shop, purchase new heads, or send it. If this was my car,I'm sending it.

 

[JAA]

Again, you've got options. Spend the money at a machine shop, purchase new heads, or send it. If this was my car,I'm sending it.

Send it?

 

[Monkeybutt2000]

Send it?

Bolt heads on and go.

 

[JAA]

Bolt heads on and go.

That what I’m thinking at the moment.

 

[JAA]

Yes I did it. Ive always wanted a vacuum tester and perform a leak-down test

Im going to put in a spark plug and test both valves.

Setup

With vacuum running

Valve shut off

10 seconds after valve shutoff

 

[JAA]

True story - just broke the vacuum gauge. Those plastic things are such garbage.

Here is a cool pic for foxbody folks

 

[JAA]

Initial data
GT heads are 70 and 71. Original e7 are 23 and 24 (for reference). I feel its reasonable to say the GT head I finished and measured this way is better than the e7. Next step is to redo the other GT40 head and measure.

Head	Cylinder	peak Hg	After 10 seconds (Hg)	seconds to 10 Hg
70	1	17.5	16	120
70	2	17.1	15.2	100
70	3	17.5	16	96
70	4	18	16	80
71	1
71	2
71	3
71	4
23	1	17.5	15	80
23	2	13.9	1	1
23	3	19	13	20
23	4	17.1	15.2	53
24	1	18.1	15	44
24	2	18.4	6	8
24	3	18	12	15
24	4	18	8	6

 

[AeroCoupe]

I think you have it whipped man, congrats!

 

[JAA]

Final values

Mental note, and for others who stumble on my hot mess here. The torque of the spark plug plays a significant role in keeping vacuum (as you can see by head 71). Do not just hand tighten those plugs. Im confident this directly translates to actual performance also when folks are changing plugs in general.

Head	Cylinder	peak Hg	After 10 seconds (Hg)	seconds to 10 Hg
70	1	17.5	16	120
70	2	17.1	15.2	100
70	3	17.5	16	96
70	4	18	16	80
71	1	18	16.2	105
71	2	19.8	17.3	126
71	3	19.1	17	151
71	4	18.6	16	120
23	1	17.5	15	80
23	2	13.9	1	1
23	3	19	13	20
23	4	17.1	15.2	53
24	1	18.1	15	44
24	2	18.4	6	8
24	3	18	12	15
24	4	18	8	6

 

[JAA]

Ok - so next steps

1. Get GT40 heads surfaced
2. Clean surface rust off of engine block
3. Install Gt40 heads
4. Remove old rockers from old e7 on cylinder 1 and install on GT40 cylinder 1 wish pushrods
5. Follow firing order and do each cylinder this way

Thoughts?