40DHLA carbs and further upgrades

[Ridge]

Hi !I'm new on the 4um and posting for the very 1st time.

I'd like to submit my own experiences within some questions.

I recently order a special piping to install two 40DHLA cabs on my 411.And I would tell you that it looks great with the 411 engine position (I would send pictures later)

The carbs are tuned similar to the 40DRLA regarding jets.

Here comes my series of questions:

-I bought a 0.430 x 278°camshaft with according rodes and still have the rest of the parts stock as I do nomore know what comes next (Cylinder bore,heads,clutches ...)

I'd ask for your advices to complete my upgrade and what HP I can expect for !

P.S:I'll send pictures as soon as I know how to do.

[raygreenwood]

Welcome! we look forward to it! Ray

[Wally]

Welcome! What country are you from Ridge?

What are the 'rodes' you speak of? and what is exactly your question? I didn't get it quite well.
Pictures would be great, also from the car itself of course!

[Ridge]

Hi!I still don't know how to attach pictures within the post,if someone could help with it first
I'm from Paris-France.
I mean "push-rods" not "rodes" I bought Scat camshaft and pushrods.

I intended to get 150HP so that is why I ask for the rest of the combination to get it.

- What valve size
- what should be the cylinder bore
- intake and exhaust works
- CR anyway.

But if I'm dreaming too much tell me [/url]

[Wally]

Hi Ridge,

Well, to build a 150 Hp engine with side-draft carbs (I hate that set-up because it always leaves out preheating the manifold which gives bad atomization of the fuel), you may need to buy a full manual and/or buy Jake's video for a good understanding of whats all involved. Just naming a bore and stroke would do the neccesary preparation and understanding of building a tuned engine short.

150 hp is 'easily' doable with a type 4, there are many bore-stroke combinations, but you need to know what you do and spend a few euros, but you're certainly not day-dreaming

[Ridge]

Okay!So I would turn the question in another way then:

Can I expect something around 150Hp with the following parts:

- 96mm cylinder kit (to buy)
- Scat camshaft 0.430x278 and pushrods (bought)
- new unworked 1700 cylinder heads with 39x33 valves (bought)
- new 200mm clutch kit/or 228mm (both bought)
- 2x40 Dell'orto carbs with 32mm venturi(bought)
- 4 in 1 type4 exhaust(bought)

I intended to assemble the engine with those elements when I get to know this forum so that's why I hesitated to go further on.

[Wally]

I really couldn't tell, but my gut feeling is no. Probably the heads need to flow better for that.
Since I already think I know your next question, I suggest to look into the type4rum section for some high performance information
Good luck with the built!

[Ridge]

yes I know what you mean
the heads are just there as basic parts but I really intend to work them to flow better: semi-hemi chambers and bigger valve size,anytime increasing CR by flycutting heads (eg:10:1).

There's so much to do for that but I must start to the beginning
I'll go then test my own experience on aircooled perfo engine

Hey!what about attaching pictures here !my ride is quite nice to see !

[Wally]

There's so much to do for that but I must start to the beginning
I'll go then test my own experience on aircooled perfo engine

Please read up first before you start doing the wrong things. Semi-hemi and flycutting then afterwards for higher CR is NOT the way to get performance/efficiency/structural integraty (sp?) out of a type 4 head!
And this is just the first thing you mentioned...
Not trying to put you down, just trying to help you

[Ridge]

Please read up first before you start doing the wrong things. Semi-hemi and flycutting then afterwards for higher CR is NOT the way to get performance/efficiency/structural integraty (sp?) out of a type 4 head!
And this is just the first thing you mentioned...

Okay !
As I read through the Type4rum posts, I noticed that 3 angles profile of valve seats is the most mentionned regarding heads'work,and also Bigger valve combination.
What would be then the advised valve size within using 40 Dell's with 34venturi ?

My CR adjustment intention was just there if deck heigh was to be adjusted as well,but I think I can skip it !

I think then semi-hemi is NOT necessary for t4 heads in noway !

Not trying to put you down, just trying to help you

great thanks,I know as I read up your replies in the other posts !

[raygreenwood]

The 1.7 heads can only go 42 x 36 maximum. Even with unshrouding teh pockets you are technically undercutting the area under the cylinder seating area with the 42mm valve seat. 41 x 35 and 42 x 35 or 36 work very well with the 1.7.
Slight but careful exhaust porting on one side only and match port and polish the intake side, unshround valves and plug area. Leave teh quench area alone. You still will only have 50cc chambers...but a very nice head for high compression. Ray

[Ridge]

The 1.7 heads can only go 42 x 36 maximum. Even with unshrouding teh pockets you are technically undercutting the area under the cylinder seating area with the 42mm valve seat. 41 x 35 and 42 x 35 or 36 work very well with the 1.7.

Thanks Ray

but in all the way I've got to bore up the head's cylinder seating to fit either the 94mm old kits or the future 96mm I intend to buy.

So shall I have to stay on those valve size anyway ?I wouldn't mind if that's the best size you advise!

Slight but careful exhaust porting on one side only and match port

What do you mean ?

and polish the intake side, unshround valves and plug area.

yes

Leave teh quench area alone. You still will only have 50cc chambers...but a very nice head for high compression. Ray

you mean nothing between?OK!

thanks again!