Found an unknown fully worked head. Getting it tested this week.

Started by DarkHelmet, September 19, 2024, 04:25:41 PM

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DarkHelmet

The story goes, a man who raced spridgets in the 70s-80s passed on and after an estate clear out, I'm now a lucky man in possession of a, let's say, modified...head. It is thoroughly unknown. Zero documentation of the work was passed along. I made some phone calls and the people who know say the person who probably did the work isn't with us. So I am going to spend some money and discover what I have. It has valves numbered to match each cylinder, multi-angle valve jobs, back-cut as well and definitely ported. This 12g202 is quite different looking for the stock one I have. So before I put it on an engine that it doesn't deserve, I found a shop willing to flow bench it, as they built their work on cylinder head development. This is after a magnaflux tomorrow just to make sure what I have isn't scrap before I spend too much on it....So...

By all appearances, this had a LOT of time spent on it. Unused since machined and then it sat on a shelf.

Any guesses on how will it will flow? I wonder how a calverST small bore job flows....
1978 mini1000, A+ 998 engine.

MiniDave

I'll be interested to see what it does - for some good flow numbers, see if you can borrow one of Vizards bibles, I think it has some pretty good info in it.
Complete failure at retirement - but getting better!

1972 Mini Racing Green
1972 Mini ST hotrod
2017 Audi Allroad - Glacier White - His
2018 Audi Allroad - Floret Silver - Hers

DarkHelmet

Preliminary results are in! (Full results later this week)
Sucker flows 105cfm@.450

Which is about a 70% gain.

Time for unleaded valve seats.
1978 mini1000, A+ 998 engine.

cstudep

I got given a 12G940 head that clearly has had some port work done, at the very least, and I am contemplating having someone look at it to see if it is salvageable or not. I guess I need to hunt down a place to take a look at it one of these days. I can't see any obvious cracks or anything but I have not looked at it all that closely. It has a LJR stamped into it above the thermostat housing area but I have no idea who that would be and just assume that is probably who did the work on it. About what did the magnaflux and flow test cost if you don't mind sharing? I have never had anything like that done so just curious what something like that costs.

DarkHelmet

Magnaflux, dry, was about $35. Guy put it in the parts washer too.

Flowbench is gonna be about $200.
1978 mini1000, A+ 998 engine.

MiniDave

Nolands in downtown KC can do the magnaflux and skim it too to give a good flat surface. Of course they can also do hardened seats and a valve job. They don't have a flow bench AFAIK.

Some of your local parts houses that have (or used to have) machine shops can probably do the magnaflux too. These small block heads were not prone to cracking much unless overheated badly. The only ones I know of that were crack prone were the early Cooper S heads, they would crack between the valve seats......

I met the guy who does the head work for Greg Wold (VERY successful Mini racer) and he charges $2100 for an amateur racer's head, $3100  for an all out race head, but you also have to buy a cam that works with this head. I did not get HP numbers but that gives an indication of what you can spend to get a performance head for an A series.
Complete failure at retirement - but getting better!

1972 Mini Racing Green
1972 Mini ST hotrod
2017 Audi Allroad - Glacier White - His
2018 Audi Allroad - Floret Silver - Hers

cstudep

Thanks for the info guys. I need to pull the valves out of this head and see what the seats look like. Like I said I have not really looked it, I just dug it out of a box with a bunch of other stuff and it was pretty obvious just looking at it that the ports had been well massaged.

I have been going back and forth with Calver for a while as I was contemplating having him work an old cooper S head up for me. He is certainly knowledgeable on the subject of heads and will spend some time chatting with you if you reach out to him. I would imagine he would probably give you some flow numbers on his stuff if you asked. His philosophy is a little different on some things like porting and what not but he has done a lot of flow testing and I have done zero so who am I to argue with anyone about any of it LOL.

94touring


DarkHelmet

The head is back from the shop. Heres the flow.

if the image doesn't load, right click open in new tab.
here's the score card.

28 in.hg. pressure

lift   int/exh
.050   33.7/34.9
.100   52.4/49.6
.150   67.9/69.2
.200   80.0/83.9
.250   91.1/92.0
.300   94.4/96.1
.350   98.5/98.4
.400  102.4/100.3
.450  108.0/102.1
.500  107.6/103.5

so its passing stock flow (60cfm) before it gets to .150" lift.
An SW5 camshaft or kent 266 would see near .400 on a 1.4 rocker...which is near 100 cfm.
(Notes:) This is the head only, no manifold intake or exhaust, no carb attached. of course that would reduce numbers a bit and be more "realistic" but simply put, this is REALLY nice. Also the exhaust flow is right up there with the intake flow which is usually 10% or more less than, and these are STOCK size valves.

so what motor would you put under this? is a 6,000 rpm 1098 or an 8,000 rpm 998 going to benefit? I cant' determine flow VELOCITY, but I can assume it wont be too bad with everything bolted on...such as a nice header and HIF44 on an alu intake.

Thoughts?
1978 mini1000, A+ 998 engine.


MiniDave

No replacement for displacement is my general idea.......however, it really matters what you're going to do with it - is it going on a race engine or a street motor? For a street motor torque is king, and you build for lower RPMs since you rarely will be bouncing off the 6K rev limiter.

A race motor would be where you want those RPM's, but it suffers at anything below say 4K, so you're always wound out.

I think the Evo1, SW5, 266 etc with a set of 1.5 rockers would give you both worlds - torque and revs without the super high RPM, with 1.3 rockers you would have more torque at lower rpms and the 1.4 might be the sweet spot.....according to Vizard, lift over .5 doesn't produce any more gains IIRC.
Complete failure at retirement - but getting better!

1972 Mini Racing Green
1972 Mini ST hotrod
2017 Audi Allroad - Glacier White - His
2018 Audi Allroad - Floret Silver - Hers

94touring

Well we did a 266 cam and Calver 1.4 rockers.  Dyno sheet showed it made great power from the bottom all the way to 6k. With 3.44 gears I could start in 2nd gear if I needed to for some odd reason.  Even super easy to start from a stop with an MED mega light flywheel.  6k rpms in a mini for the street is more than enough. Only time I'm ever up there is our spirited car drives acting like a maniac.

DarkHelmet

Keith Calver replies to my question of what this head would be useful for.

I'm excited now.

" I suspect that head was done by the late and very great Dave Taber,
Comptune? Or possibly the equally legendary Bob Griffith at BHP
Developments, though I am nit sure if Bob is still alive and kicking - a
very long time since I had any communiques with him. A steal at that
price though. Nice one.

Sounds like a candidate for the new small-bore cam developed by my mate
Graham in oz. We have been developing stuff specifically for the
small-bore for a few years now. We both love the little motors and
decided nothing had really been done for them specifically for decades.
Certainly as far as road going use is concerned. We tested it in a
998+80 motor when I was out there a couple of years back. Strong
performance, peaking at 5,500rpm but still going well at 6,500rpm. I
think it will be great in a decent 1098 motor. Cam spec is RE289, not on
my website yet - trying to protect the profile from being copied by all
the usual suspects who can't be bothered to or invest the time and money
in doing real R&D. The cam profile is designed to work with standard
rockers so no fancy high lift stuff needed. Though I suspect from dyno
tests that it would benefit from my  CST3009 1.3:1 rockers.

Cheers, Keith."

So I'm inquiring about prices and with the 1.3 rockets and...maybe the 68mm pistons...
1978 mini1000, A+ 998 engine.

MiniDave

We used his 1.4 rockers on Dan's build, and as he says they worked well,  but it sounds like if you use Keith's cam you don't need them.
Complete failure at retirement - but getting better!

1972 Mini Racing Green
1972 Mini ST hotrod
2017 Audi Allroad - Glacier White - His
2018 Audi Allroad - Floret Silver - Hers

94touring


94touring

Maybe Dave or someone will chime in, but slightly off topic to 1098 cranks.  Can they be used on a large bore A series?  Because I just realized a 1098 crank stroke is the same as what we have in the Inno, making it a 1425cc.  I would love to do another stroker in the 1275 sitting on my shop floor.

MiniDave

Not 100% sure, but I think the major difference other than the stroke is the smaller rod journals, so you have to use early style rods. 1 5/8" instead of 1 3/4" rod journals
Complete failure at retirement - but getting better!

1972 Mini Racing Green
1972 Mini ST hotrod
2017 Audi Allroad - Glacier White - His
2018 Audi Allroad - Floret Silver - Hers

94touring


MiniDave

No, the crank was already in the car tho I had to modify it because the tapered end was damaged. We machined the boss that the primary gear rides on and used a 998 primary gear instead of a 1275 and with the same number of teeth on the gear.

It had Cooper S rods and we bored it to 40 over? (60 over?) Of course you need the smaller rod bearings tho we used the std 2" mains. I also had to custom the thrust bearings as the std set were too thick. I think I used the old ones on the front and mew ones on the clutch side (where all the stress is) to get the right clearance.

We didn't use a vernier on the cam gear, I just used offset keys to get the timing right.

I think a lot of the performance also came because of the head that had clearly been worked over.
Complete failure at retirement - but getting better!

1972 Mini Racing Green
1972 Mini ST hotrod
2017 Audi Allroad - Glacier White - His
2018 Audi Allroad - Floret Silver - Hers