3.0 24V - your suggestions

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yetyGTA
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3.0 24V - your suggestions

Post by yetyGTA » Fri Jan 03, 2014 5:29 am

As already posted in the Introduce yourself. I am from Slovakia and while not owning a transaxle yet will do so sooner or later.

However I had the chance to purchase a 3.0 24V from an early 166 automatic which I began to strip down following Jims bible and learning at a friend who has one of the first 3.8 Autodelta UK conversions. Anyway my plan is to prepare the engine first and then look for the suitable car.

Image

While reading the book and researching many very useful topics on here I have the feeling of loosing confidence what should I do with it. What I know for sure I want is:
1. to achieve 90 - 100 bhp per liter
2. to have as reliable engine as possible with that figures
3. no turbo or compressor
4. ITB
5. fat road / track day setup

Heaving in mind above mentioned I guess I should definitely:
1. port and polish head internals
2. at least refurbish all internals like crank bearings, seals, oil pump etc.
3. to buy ITB (only found this kit from AHM - http://www.ahmotorsports.co.uk/index2.htm selling for 1450 GBP)
4. re-profile camshaft
5. to get a new exhaust manifold and pipes
6. get an ECU
7. to ha have the oil sump modified

Now what I don't understand / would like to hear your opinion and suggestions about:
1. while porting, should I increase the size of inlet valves?
2. when going for higher lift cam profiles do I need new valves?
3. what CAM profile to choose heaving in mind low rev usability?
4. should I bother with uprated rods or they are well dimensioned on the new 24V?
5. when the answer on new rods and different valves is YES. Would not be better to think about 3.5l conversion? Where to get parts for that?
6. I did not understand the compression issue. Is it always better to have it increased? What values I should be looking at?
7. about the oil pump. I have seen some people playing with it but did not get the point. What is suggested to do on this particular engine?
8. is it possible to relocate the thermostat from the back (FWD design) to the front? I am not there yet but from what I see the block is just an evolution of the old one that had the thermostat on the "right" side.
9. as the OEM 166 ECU won't work in the new setup. What options do I have? Is there anything out of the box? I have also seen some DIY from US.


I apologize for so many questions in advance. However even I have tried to read as much as possible and to go through all the post I found relevant those questions remained open. Most probably because of little experience I have so far.

Nevertheless I will appreciate any input or suggestion.
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Re: 3.0 24V - your suggestions

Post by 75evo » Sun Jan 05, 2014 9:51 pm

I would do these things:

11.5:1 compression (higher is better, right unto the point before it blows up)
Clean the heads, don't port it.
Good cams (ask JK)
Good headers, don't get super short ones, at least something as long as OE 164/166 headers.
Lightened rods, and flywheel.

Race car: short Beninca style runners
Street car: 45mm GTA runners


ITB is good, but I'm sure if we all pooled resources, we can come up with a cad design and use Triumph motorcycle throttle and come up with something that costs less about USD$1K. UKP$1.45K is A LOT of money!!!
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Re: 3.0 24V - your suggestions

Post by yetyGTA » Sun Jan 05, 2014 11:27 pm

Thank you for the advice EVO. I really like your idea about ITBs. Completely forgot about Triumph being a three cylinder. That would make it much easier and cheaper to put things together. In relation to ITB. I was also wondering if the length of the runners make the same difference as in case of one TB.

You also wrote that I should not do any porting. Why is that? Would not that make it easier for the engine to breath / release gases?
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Re: 3.0 24V - your suggestions

Post by Duk » Mon Jan 06, 2014 12:34 am

yetyGTA wrote: You also wrote that I should not do any porting. Why is that? Would not that make it easier for the engine to breath / release gases?
The 24 valve engines ports are larger than they need to be.
Making them larger will do more damage to the engines low rpm torque capabilities and probably won't help it make any more power.
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Re: 3.0 24V - your suggestions

Post by kevin » Mon Jan 06, 2014 11:17 am

As duk said leave the heads . I run over 260 whp and have standard valves and no porting on the 3.7 . You mentioned you want torque at low revs then keep the standard 45 mm 166 intake runners with nice tapered big modified plenum . Try get get compression minimum to 10.5 :1 depending on fuel head for 11.5 :1 as Z said . You need a set of 650mm long headers/ primaries like JK makes or similar posted gatoulle . Note his go upwards to achieve length but not sure if you can put them on with engine in car . There is about 20hp gain at 6000rpm with these primaries over the short ones I use (300mm)
Standard rods have not let me down but I used new rod bolts on rebuild . There are some really good cams around but are pricy . Your hydraulic lifters are are good for 7200 rpm continuos racing ( so I hear ) .
Could use cps pistons . Their about 100g lighter than standard and also ppm rods which are about 60g lighter . Good quality head gaskets from Spesso maybe ? Not sure of your budget . Wossner also make for the Alfa . With the 11.5:1 comp , well balanced engine etc should see 300 hp .
If you thinking of looking for more power easily then find a gta crank . So much easier than going big bore .
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Re: 3.0 24V - your suggestions

Post by yetyGTA » Tue Jan 07, 2014 5:10 am

Interesting thoughts. After reading Jim's book I was convinced porting will be necessary. One job less. By the way this is a comparison of the ported 3.75 Autodelta (UK) engine and the OEM 3.2:

Image

So I will focus on replacing only those internal parts that need to be and save the money for ITBs and reprofiled cams. I am really tempted to have ITB mostly because of the throttle response.

Do you think the OEM con rods and pistons could be lightened?

Regarding the flywheel. As you can see the engine is from a car that was fitted with ZF automatic. I will need to replace it. Which one to look for when planning to use the engine in a GTV6? What is the safe way of lightening it? I heard crazy stories of heaving it cracked and escape from the engine into cabin.
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Re: 3.0 24V - your suggestions

Post by Jim K » Tue Jan 07, 2014 6:22 am

DO NOT port the 24v heads, they flow well enough for anything you may want. They already have a low speed problem, don't make it worse. As supplied, factory heads are good for ~350hp, more than most users will be satisfied with.
DO NOT cut the valve guides as shown in the picture! Its one of the worst things you can do for engine life. What do you think they gained with this atrocity? 3-4cfm? Big f... deal! That is a good picture of what NOT to do! :evil:
The guides are short enough as they come, do not ruin them by making them shorter!
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Re: 3.0 24V - your suggestions

Post by yetyGTA » Tue Jan 07, 2014 6:41 am

Thank you Jim. Others have already made it clear to me. :) That was the reason I posted this question on here as I was not 100% sure about porting. Now it is clear to me you were recommending that for the 12V engine in the book.

How about the rods and pistons lightening? I saw your comments in Alains post. Can you advise me what can be done with OEM parts in DIY environment? Is it worth touching them?
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Re: 3.0 24V - your suggestions

Post by 75evo » Tue Jan 07, 2014 8:49 am

Just put JK or Maxspeeding rods. Larry and I are gonna get for our 3.5 105 GTA replica and my 3.2 75. Only worry is the offset, but Jim said don't worry as the width are the same for small and big end, 82mm. That will buy you peace of mind for 7500 rpm and weight savings too.

Cam wise, ask him for the cams I got from him.

p/s make sure he doesn't ship you a bag of olives instead, can't trust the Greekster these days :lol:
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Re: 3.0 24V - your suggestions

Post by yetyGTA » Tue Jan 07, 2014 9:56 am

Bags of olives. :) Maybe I would not mind as they are expensive due to bad weather or something I heard.
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Re: 3.0 24V - your suggestions

Post by Jim K » Tue Jan 07, 2014 8:05 pm

In my 24v 3liter I have std rods and pistons. I bought new gta rods and they were lightened considerably by removing the lumps from both ends. That is the only operation, NO polishing. Then I balanced them end-to-end. Piston weight was equalized by grinding the inside edge of the pins. Then, since its a rwd application and I changed the flywheel and pulley, I calculated the balancing bobweights required, adjusted the weights I have and balanced the rotating assembly. The car has seen several trackdays, with shifting ~7300-7600rpm for many laps (10-20 at a time, several times per day). It had 272hp with the short headers and I have to remap it with the long ones. If Kevin is right about the 20hp gain, I'll be very happy to see ~290hp, meaning 97hp/liter with the milder than fast road Renault production cam profiles. This exercise, makes me optimistic for a 3.2 with a little better (performance wise) cam. Hmmm, maybe 100hp/liter is within grasp for what is essentially a 'street' engine? :?:
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Re: 3.0 24V - your suggestions

Post by 75evo » Tue Jan 07, 2014 11:59 pm

Jim,

What did your customer from Singapore get as far as cam goes? I asked him to contact you.

Well, im aiming for 320 bhp for 100 bhp/litre

:mrgreen:
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Re: 3.0 24V - your suggestions

Post by yetyGTA » Wed Jan 08, 2014 12:33 am

I believe it is the AO Forum member calling himself Saabretooth. Here is his summary - http://www.alfaowner.com/Forum/alfa-gta ... ost6694081 . I have asked him about his plans and he mentioned being in touch with Jim regarding Cams. Also planning to increase compression.
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Re: 3.0 24V - your suggestions

Post by Jim K » Wed Jan 08, 2014 6:15 am

The reground cams have 10mm lift and 225*@1.25mm, noticeably better than my Renault Williams profiles which are 9.7mm, 222@1.25mm. In my 3.2 I may use the 10mm profiles or a bit more at 10.4mm and a little more duration. There is even the possibility to use different intake and exhaust cams and this will be tried out exhaustively on the simulator! However, some serious thought must be given to the hydraulic follower and valve spring areas before I decide on the 'big' cam. The follower will have to stand out even more because of more cam regrinding and harder valve springs able to cater for ~11.5-12mm before coil bind, will have to be found.
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Re: 3.0 24V - your suggestions

Post by 75evo » Wed Jan 08, 2014 8:37 am

I'm actually quite disappointed with the power, but sabretooth said the shop setup the cams using std. cam locks??? His cams are the same as mine right Jim?

I thought these cams needs to be timed based on the info JimK gives. Like what is lift @ TDC for each cam.

I hope sabretooth comes on here soon.
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