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Duk
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Re: Jim K. 3.2 engine

Post by Duk »

I've used Neway seat cutters on my 12 heads. They work very well, but frieght costs to Aus were a killa. Hopefully cheaper to other non-US parts of the world.
Jim K
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Re: Jim K. 3.2 engine

Post by Jim K »

Neway are great cutters, I once put together a minimum list of what I would need for 12v and 24v heads, for valve sizes 32-46mm... 15*/30*/45*/60* in 2 sizes plus 7/8/9mm pilots and price went through the roof! :cry: With a set like that, I'd only need the machine shop for milling! Maybe in another life! :roll:
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75evo
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Re: Jim K. 3.2 engine

Post by 75evo »

True, sometimes even though I like to DIY, some of these items are not worth buying as you use them a few times that's all. I'd rather send it off to a machinist to have it done. But the sense of accomplishment is hard to beat if you DIY.

I bought a mini mill and a small lathe though, but I think I will use it for lots more projects than cars alone. All I need to add is a plasma cutter and TIG (already have MIG and spool gun for alu :mrgreen: )

BTW JK, isn't the CPS 11.5:1? In that case you must have only shaved the heads a bit.
Last edited by 75evo on Wed May 20, 2015 10:16 am, edited 2 times in total.
Jim K
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Re: Jim K. 3.2 engine

Post by Jim K »

To tell you the truth, I DON'T REMEMBER what CR I ordered! I can't find my old emails, so I'll definitely have to cc. :mrgreen: :roll: This is something I would do anyway though.
Jim K.

PS: Hah! I found the email where I asked CPS for 11.3-11.5:1. This weekend I'll find out by measuring. :idea:
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Re: Jim K. 3.2 engine

Post by Jim K »

FLOWBENCH.... Every diy should have one! 8)
Well, took both heads to measure flow today. The top numbers came out more or less as expected but there was a clear disadvantage from ~2mm lift up to ~7mm, compared to my previous 24v heads (on the car). We checked seat work and possible flow restrictions but all was well. Knowing these heads should flow better than the old ones I arrived at the valves and examined them in detail. Rude awakening, std Alfa intake valves are better than Ferrea valves. :shock: I am not talking material here but flow. While they look the same when you hold them next to each other, they are not. The key difference which impacts flow is their thickness. I will soon make a simple drawing so that you can clearly see the vital difference. What I will also do, is to fit the std valves in the heads and return to the flowbench. In technical terms, the curtain area with Ferrea valves is smaller. I will only give you the 11mm lift flow numbers now and will post the entire graph when I complete std valve flow tests. Both B/C heads topped out at 156/157cfm respectively vs 146 for the old head and 139 for the std head. Exhaust flow is ~2% better for both heads but there was an important additional observation here: just putting a short 100mm pipe right against the exhaust port, flow jumped +25cfm to 137cfm! We are only comparing exhaust ports alone though. Intakes were measured with the short manifolds on and a short air-horn bolted on there. Max lift numbers don't mean much, the entire curve matters. Another point is to have flow max out at max lift or before (curve is almost horizontal) and not keep steeply rising.
Until next time (Tuesday/Wednesday?).
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Re: Jim K. 3.2 engine

Post by maxiboy »

Thanks Jim.

Really look forward to these sort of tests as they sometimes disprove every thing you thought should work doesn't.
Amazed at the performance valves flowing less than standard.
I think we previously have had a in depth discussion about valves .. sizes penny on a stick designs rimflow etc all things that can be proved or disproved on the flow bench and dyno .. against the theory.
thanks for the information sharing and looking forward to the finished testing and alfa valve improvement in flow
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Re: Jim K. 3.2 engine

Post by gtv-racer »

Nice info Jim.Did not expected this..... :|
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Re: Jim K. 3.2 engine

Post by Jim K »

After a brief interlude for a few days during which I completed two 105 2liter heads (porting +big valves) I will continue with the 24v heads Saturday (hopefully) to measure CR. It looks like I'll have to remove the engine from the stand, set it down and prop one side up so the gasket surface is horizontal. All this should take me a few hours after which I'll again have to put the engine on the stand... Filling the hydraulic followers with engine oil is not going to be a party either! Inch by inch it WILL finish! 8)
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Re: Jim K. 3.2 engine

Post by Jim K »

Ok, found some free time this afternoon and I got around to measure CR. The chamber took in 52cc of oil. For the 3.2, this works out to 11.2:1 with the old gasket and std (uncut) head. Note the pistons are CPS forged items. Some years ago I very carefully measured the chamber face area on graph paper and its 61cm². Since I want ~11.5:1 I have to lose 1.6cc which means milling the heads 0.27mm. Another very simple measurement showed that there is ~6.5mm of travel before the valves meet the pistons, so there is no problem with any possible cams.
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kevin
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Re: Jim K. 3.2 engine

Post by kevin »

Very intesting info . I would then estimate looking at shape of chamber that I could go from 10.5 :1 to 11,5 :1 I would need to take off nearly 1mm . I would also have to skip setting the tensioner on the mark ( line on mechanical tensioner) but start about 2mm above the mark on Tdc then do physical test on belt . Ahaa I just remembered you using the 164 block and not the original gta block so no tensioner marks .
Can't wait to see your power figures . Pity you can't dyno the car with a silenced side exit pipe just to see how much you could really gain . But yeah I know its also a road car nd you need to compare to your other results with full lenght exhaust .
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Re: Jim K. 3.2 engine

Post by 75evo »

There's a guy on Facebook (he has a group called Best Tuned Alfa 75), 286 on a bench dyno with RON 95 fuel. I think it's just a 3.0. Specs as far as I can see is 11.4:1 CR and 10.9mm cams!!! I guess his heads and valve train must be massaged quite a bit to accomodate such high lift cams. I think JK said stock heads shouldn't go past 10mm or the springs may bind.

But his oil pan was CNC'd! We need to gt the CAD file form him for that!! He used a 156 series engine.

I forgot what cams Marc Van W.'s SZ 3.2 I think he said it was a stock 3.2. He said 300 bhp. That's impressive for just a new EFI on a stock engine.

I will get my engine done by August.
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Re: Jim K. 3.2 engine

Post by Jim K »

If you look around for valve springs, you will find several cars which have suitable springs for use in the 24v for high lift cams. All you need is a spring tester and a garage owner to let you bum around the benches for a few hours! 8)
Power figures are very relative. I can only go by what I see and on which dyno. There are dynos where you measure a car to sell it and others where you go when you want to buy a car! :roll:
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75evo
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Re: Jim K. 3.2 engine

Post by 75evo »

Hey JK, I like this engine stand. Looks professiionaly done. Very down to earth too :lol:
Jim K
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Re: Jim K. 3.2 engine

Post by Jim K »

Yeah, yeah... Your price for ITB's just went up! :twisted: I had to take it off the stand as I couldn't raise one side high enough to measure CR, too much tilt. After I got done measuring, its back on the stand now.

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Re: Jim K. 3.2 engine

Post by Jim K »

Another dirty job done today; oiled/assembled the followers so they are ready for installation -hopefully before this dump goes bankrupt! :roll: There are 4 parts to each follower, not counting the thin steel-wire clip (which is found broken at times and has to be replaced).
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