970-engine in A+-block. Tech help wanted

[dhenry]

I can deck the block. Call on Monday if you like. 01825 7330060.

Daniel

[Vegard]

I understand and do agree to some degree. However, fit 970 length rods then. Not doing this is silly.

[JCWorks]

Thx to your and others knowledge, Vegard, it turned out I do have 970 rods installed, so no need for shipping out the $$$. Although a revvy engine and, as you stated, 50 year old material, I´ll stick with the originals. The guy I bought the engine from thought it might have 1275 rods with special pistons instead, and I wasn´t aware of the different rods sharing the same markings. So all is good, now it´s just a matter of preparing an A-block instead - all to comply with AppK

Would there be any interest in the A+-block once I´ve emptied it? Since it´s really well prepared and in great condition, it would be a shame not to see it come to use. It´s a Bryan Slark built engine, which should indicate decent build quality

[Vegard]

Have the rods been modified in any way? If not, have the bigends lightened, there are easily 30 grams to be removed from an S rod there. Then have them shot peened. I've had Rod Selby do this for me.
Once this is paid for and new ARP bolts have been purchased $1100 might not be so expensive. You'll get £150 for your 970 rods as well at a guess...

[251 ENG]

Southam Mini Metro Centre 01926 815681.

I spend all day reclaiming knackered old S blocks

[Vegard]

By the way, on lightening rods. I've lightened 8 rods today. I want a mill

[JCWorks]

Vegard, if that´s what´s left of them, I understand you wanting a mill No, honestly, nice work. Mine are lightened much the way you mentioned.

I didn´t get to spend much time in the workshop today, myself. I had to take a long drive to pick up a 22G333 box and MkI body that will donate its roof to my S (please don´t ask why


I´ll reply to the suggestions about machine shops later on, but it´s experience I´m after, so anyone who´s prepared 970-blocks before are on top of the list

[Vegard]

I´ll reply to the suggestions about machine shops later on, but it´s experience I´m after, so anyone who´s prepared 970-blocks before are on top of the list

If I'm not mistaken 251ENG is your man for this. Look above!

[618AOG]

May not be of any use, but when I built a 970 engine some 20 years ago, I used standard AE 1275 Metro pistons - worked perfectly with correct deck height etc.

[251 ENG]

970 pistons are identical to 1275 pistons EXCEPT they are flat top with no dish .

Flat to omegas are available from Swiftune and MED .

If your head has been skimmed to death you could use dished pistons .

[Vegard]

The easiest that hasn't bern mentioned yet, would be to find some SA 1100 pistons. Hardly a performance modification though

[guru_1071]

The easiest that hasn't bern mentioned yet, would be to find some SA 1100 pistons. Hardly a performance modification though

they are monsters, i think they rev to about 5500 rpm!

[JCWorks]

This is how my pistons (Omegas) look:



they´re flush with the block but have a small dish.

[App K]

should be flat top pistons in a 970s, C-AEG 190, or, C-AEG 043043,

[Vegard]

should be flat top pistons in a 970s, C-AEG 190, or, C-AEG 043043,

Should be?
Depends on what CR you want to run, doesn't it?

[Spider]

Just as an option, JP Pistons in Australia make small runs of pistons for one offs. So you could order a set of flat tops from them with a lowered gudgon pin. Not saying that this is the way to go, but is another option.

http://www.jp.com.au/

[sandman]

I see you are located in Sweden

If you're building a FIA App.K race-engine to be raced in Sweden - there's "only one way to do this"... proper!
Meaning; 970-spec crank and rods, flat-top pistons, proper S- or skimmed down A-series block.... and a 4.9++ Final drive!

There are several good chaps in Sweden that can help out with the build (or block prep.).. Niklas Johansson, Malmberg, Roger Svensson and Jana springs to mind.

[App K]

I have been using a machined A series block in my 970 for quite some time...

flat top pistons at +40, 18.5cc in the head, correct "period" crank and rods, 8800rpm regularly. Everything to FIA appendix K regs.

hope Ive just not given it the kiss of death!

[JCWorks]

I was a little surprised to see pistons were dished, actually. I put the engine aside after you gurus enlightened me on the rod issue to consider what to do next. It was built as a race engine, so I suppose it was built with fairly high compression. Guess I have to pull the engine back out again and measure block and head etc to find out the cc. Hopefully its skimmed so much it needed the extra dish to compensate, I´m not in the mood for dishing out for new pistons

[Frogeye61]

Don't pull the engine out, just the head, measure bore and stroke with linear caliper (skydelærer)