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Any progress on the modded head? curious hows it going
Also what spark plug do you find works best for a 75 2L twinspark?
Im running on in my Berlina and feel they are due
 

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Discussion Starter #22
Any progress on the modded head? curious hows it going
Also what spark plug do you find works best for a 75 2L twinspark?
Im running on in my Berlina and feel they are due
Nothing to update. Decided to try to find a complete 75 Twin Spark engine (or at least a block and crank) to build. Proving to be a lot more difficult than I thought.
 

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Steve Hannaford in Washington State is experienced in twinspark head work, including porting. I've found him good to work with.

Progressive Automotive
3036 68th Avenue West # H
University Place, WA 98466
Phone: (253) 565-3633

Lawrence
 

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I may be wrong about this but I think Hanniford has something like a 2 year waiting list?
 

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Wes Ingram is up there as well and seems to be a good resource for TS builds as well
Just spoke with him last night about mine
 

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I think Wes uses---or at least used to use---Hanniford for his cylinder head work. I've seen a couple of his heads and he does nice work. Cylinder head porting is definitely a cottage industy, about half science and half art. What's cool about putting a well-ported head on an Alfa is finding that you suddenly have a fatter torque curve and more power throughout the range. It's sorta like getting free hp . . . only it ain't exactly free . . .
 

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Jim steck uses a CNC mill so it is more engineering and less art.
 

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Not sure if this is the right place to ask. Has anyone fitted the Jim Evans 11.2mm Nord cams from Classicalfa in conjunction with the 2 Litre CA 10.4.1 high compression pistons. I have, via an engine builder in the UK and am having problems getting it set up ( fuel standoff, miss fire and generally gutless to 2500rpm, surges a bit to 4000rpm, then flies to the 7000 rev limit on a 123 usb tune ignition. It been suggested the the 10.4.1 compression isn’t enough for the 11.2 cams. Any advise anyone please.
 

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It been suggested the the 10.4.1 compression isn’t enough for the 11.2 cams. Any advise anyone please.
You need to set up your LCA's different to get a bigger LSA, I guess you're running now way to much overlap.

With 10.4 pistons (in reality less static CR) you're loosing dynamic CR by excessive overlap. Which LCA's are now set?

That's the key to get it run properly, as well as your ignition curve and carb set must be adjusted to different cams than stock.

Those 'Jim Evans' cams are stock CatCams cams, properly set up your engine will run fine and provide WOT from 1.800rpm on with a nice, wide torque band.
 

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It been suggested the the 10.4.1 compression isn’t enough for the 11.2 cams. Any advise anyone please.
[/QUOTE]

I doubt your compression ratio is a problem since there are lots of performance Alfa builds running 10-10.4 (more or less) compression ratios. Do you know the lobe centers at which your cams are set? Timing curve and/or max advance? It might be a good idea to talk to Classic ALfa and get their recommendations for cam timing. Even better you could contact Jim Evans and/or CatCams for timing information. Then talk to he guy who built your engine as ask how he set things up. Lots of unknown variables here.

Something else to consider. Are you using the same camshaft design on both the intake and the exhaust side? If so you might consider using a milder cam the exhaust side.
 

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This may sound stupid of me but what is LCA and LSA and WOT = torque I guess. Yes lots of overlap. It’s been to two rolling rd firms both are struggling to set it up. I’m talking to a third RR firm who sound as though they are good with old Alfa’s. Thanks for the reply.
 

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180OUT. Thanks, yes they’re a matched pair as recommended by CA who sold them to me/ engine builder along with the pistons. Iv just e mailed Cat Cams for info. Unfortunately Jim Evans is quite hard to get hold of as he’s retired but a third RR firm I’ve just spoken to maybe able to contact him. Yes lots of variables, I’m hoping this third firm who do sound as though they know Alfa nords will be able to sort it out. The biggest problem is I’m out of my engineering depth!
 

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If you've been to a rr firm then they will have produced a performance print-out showing how your ignition timing is set up. Let's start there. Once we have an idea of what exactly your running, there is a lot of informed opinion available here on the bb to help get you running right. I wouldn't recommend spending any more money on rolling-road/dyno tuning until you know what you have.

For raference, I'm running an engine that is similar to yours---10:1 (more or less) compression, Centerline 11.1 mm lift x 254 @ .050 duration intake cam combined with a very mild stock 2 liter exhaust cam---9.6 mm lift x 222 degrees at .050. My ignition timing is set at 36 degrees and is "all in" at about 3400 rpm. We used this combination more as an expedient since we didn't have another exhaust cam available and we wanted to get my car out of my friend's shop. This combination gave a whopping 32 degree difference in duration between the intake and exhaust cams. The result, however, was quite surprising providing both very satisfying torque and power across a much wider power band.

Attn: mods. Since this is Scot's TS head thread, maybe we should move this to RJ's thread?
 

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This may sound stupid of me but what is LCA and LSA and WOT = torque I guess. Yes lots of overlap. It’s been to two rolling rd firms both are struggling to set it up. I’m talking to a third RR firm who sound as though they are good with old Alfa’s. Thanks for the reply.
As long as you don't know how cam timing has been set it's time and money wasting to consider a 3rd RR. Like Jim and I suspect, you need to know that first.

And when terms like LCA, LSA and WOT are unknown it points exactly to that. Lobe center angle, lobe separation angle and wide open throttle.

Cam timing is all about before you even should consider to try 3rd RR.
 

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Thanks all.

180OUT. is your engine a 2L on Weber 40’s or Dellorto’s. Mine is Dellorto 40’s with 34mm chokes, 50 idle jets, 7772.5 main jets. The chokes where 32mm. Not sure about the idles. Which idle jets and chokes do you have? There isn’t any timing info that I can see on the print out from the RR but I’m reasonably sure it’s 35 degrees. It peaks at 5862rpm 145 bhp and 133 lbs. The cam sheet says lash ramp .20mm. Duration @ 0.1mm 284 degrees. Duration @ 1.0mm 252 degrees. Valve lift / cam lift 11.40 mm. Centreline 108 degrees. Timing @ 1.0mm 18/54 degrees. Valve lift @ TDC 3.65mm. Overlap looks like 18degrees but not sure if that’s 18degrees x 2. If I could work out how to get a picture of the Cam spec sheet on the BB I’d post it.

I spoke to Cat Cams tech dept today who said these cams should start to work at 3000 (ish) rpm, which is what is happening. Maybe I need different cams?
 

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My engine is a 2 liter with Motronic style 10:1 (relative) pistons, mildly ported head (intakes only), Alfaholics exhaust. It has 40mm Webers with 33mm chokes. I don't remember offhand how my jets are set up. I'll have it all written down. . . somewhere. As mentioned my distributor (MarelliPlex) goes to full 36 degrees advance at about 3400. Basically this is a fairly conventional engine build only with a surprisingly good camshaft combination. I've already mentioned the cams we used. I don't think that I mentioned that we timed both cams at 102 degrees. I'll leave any further comments about your hardware to others who are better informed than I am.
 

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I spoke to Cat Cams tech dept today who said these cams should start to work at 3000 (ish) rpm, which is what is happening. Maybe I need different cams?
You don't need to post the data sheet. You do need to know how they are set!!

And yes, the combination of a milder exh cam with an inlet cam works as well better.

As long as you don't know which LCA's have been set in your application (or, even which lift at TDC?) you will only waste time and money.

But what do I know having built a minimum of 30 engines with CatCams in the past decade.....
 

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But what do I know having built a minimum of 30 engines with CatCams in the past decade.....
well your being very polite here, I do know that you know more than you tell, so I will strongly listen to @hunnttheshunt, i will like to know wich kind of dellortos are you using like E. Tube 7772.5 doesnt sound right for a 2L engine
 

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The carbs are DHLA40, the idle jets are 50 set in emulsion tubes 7850.1 the carb tags say 5233.P rear and 5234.A front, which I believe makes them correct for the engine and year. I’m going to speak to Eurocarbs UK and find out what jetting was standard for the 2L engine when new and see if they have any suggestions on jetting it now.
 

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Do start working with logic:

- first get cam timing right
- ignition curve
- finally get carb setting right

Your carbs were coming from 2000 Berlina/GTV/Spider.

Stock jetting data is useless because of it was combined with 32mm chokes.
You are using now 34mm so what is worth the stock jetting with 135mains and 50s idle jets?

Nothing because you're using emulsion tubes 7850.1 from 40 DHLA E, which are emission carbs (5240P/5241A) but your carbs are non-emission 40 DHLA's (5233P/5234A) which should stock use 7850.3! Pump jets are also massively different between those both types. Auxiliary venturis: Type E uses 7848.2 (bigger) than 7848.1 (smaller) which 5233/5234 are using.

You're jumping from one issue to an other one instead of starting with step 1: Cam timing.
 
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