1.7 tuning help - which cam and manifold?

[Q]

Hello all, I need a bit of help.

I’m going to tune my 1.7 340.

I am looking into cams and exhaust manifolds for it at the moment. I have heard that you can use cams from other vehicles that are a little better (more refined and tuned for some power instead of just economy). I‘ve thought about using one from a Volvo 480 or Renault clio rsi, but I wondered if any of you are running any of these cams or know of a better one. Does anyone have any of the cam specifications for any of these models so I know what the duration and lifts are.
I have also been thinking about exhausts. The actual exhaust I will make myself (mainly so I can put a lambda sensor in) but I was thinking that there are also better manifolds as well from similar vehicles as the cam. The clio rsi for example has a 4-1 tubular manifold (admittedly not equal lengths but hey) which would allow the engine to breath a little better and probably give a little hike in power over the standard 'thing' and without me having to build one myself just yet.

http://www.renault-turbo.com/chris/red% ... r%2008.jpg
(clio rsi exhaust manifold)

Again similarly I am asking if anyone knows of anything better or is using one themselves and what they thought of it.

I know that cat cams list cams for the f2 series of engines but I haven’t got the money they want for them (£250) and was after some cheap power that I could easily find at a scrappy for the summer, and for about a third of the price i could pick up both a cam and a manifold.
I know that there is a list of cams and their specifications for other volvo engines but i wondered if their was one for cams that fit in the B172?

thanks for any help

tom

(ps. don't mind if the cam isn't compatible with 1.7's fuel pump... planning on running bike carbs and need a new fuel pump anyway)

[classicswede]

Starting with the exhaust side of thing manifold wise I went for the B18u manifold and made up a custom pipe to match to the rest of teh system. This is now off the car as I have a full custom 4 branch manifold so the old manifold and adaptor pipe are available complete to tehe join by the bell housing.

As to cams I have managed to get an uprated cam - no idea what the spec is but it does work quite well. It was originaly for a FI engine so there is no fuel pump drive and this swas fine for me as running LPG only. I'm swapping the engine so the cam will be available

[Q]

Thank you for the reply kinda given up hope on the thread

In the end i have got a clio rsi manifold really cheaply which i am going to cut'n'shut to get the primaries the right length for the cam and then un it into a 2" side exit system (side exit manily because its cheaper not to go out the back...less bends)

but i am very interested in the cam.... any idea of its valve timing and lift or which engine it originally came from? i am not worried about it not having the take off for the fuel pump becaue i intend to use a set of bike carbs and i will probably buy a bike pump instead of using a regulator.

... only problem is, is that i need to get the cam sorted so i know what the exhaust timings are so i can make the manifold the right length.

ps sorry about the bad spelling my computer has decided it will default to overtype and really annoy me

[Jason B]

What characteristics are you optimising your manifold for?

[jtbo]

I think that, those Renault cars that did hold 1.7 unit in engine bay, had bit better cam than engines in Volvo. But I guess difference is not too large as cars are still small family cars mostly.

[Q]

So far the best cam that i have found is one from an early 1.7 480ES engine code B18E which opens the inlet valve at 16 deg btdc and then closes at 64 deg abdc (I do not have the exhaust times) and provides a lift of 10.49mm.
Although i have tried to locate one with no success

I was wondering if anyone was using an uprated cam or new some of the valve times of a cam which would fit?
I know that cat cams make some nice sounding cams for the f series of engines but i don't have the kind of money that they want for them. and wanted something i could find easily at a scrappy

" think that, those Renault cars that did hold 1.7 unit in engine bay, had bit better cam than engines in Volvo. But I guess difference is not too large as cars are still small family cars mostly "
which renaults in particular? do you have any of the valve times? I have thought about investigating about formula renault cams as i know that a few elder cars used a 2ltr version of the f series engine and could rev to a good 10k rpm (with better internals), but i didn't know were to look for information about the cars/engines.

as for the manifold, I want to build the manifold with a fairly broad power band and tuned for about 6500-7000 rpm (denending on the cam) with a 4-2-1 arrangement to keep the torque up a little bit.

I don't want to build a race engine or anything like that but i think that it can give alot more than the raw 8bhp (i'm sure it used to be 80) that it has at the moment. I am not after big power i just want to build/improve the engine myself and make a responsive little unit.

[Chris_C]

Look at the renault 9/11/19/21 range. My stock 1.7 will rev through to 6500/7000 stock ( though I don't do it often as I'd prefer to see it balanced...) but dyno curve shows the power falling off around 4500.

What are you doing for intake? The 1.7 is already strangled with the 28/34, but trying to run higher RPM will need something else.

[Q]

i am planning to run a set of cbr600 semi flat side 36mm carbs, or if they're too small i have a set of 40mm kehins to try... As for the jet size i am going to use i am not sure. i will probably drill the main jets to 1.5-1.6mm and then set up from their. I'm planning to put a lambda sensor (wideband if i can afford it) in the exhaust to monitor air/fuel ratio to help with this.

I'd rather use the 36mm carbs as i think they will give a better and more useable power curve.

[Chris_C]

36mm carbs or venturis? Don't forget the outer barrel isn't the number you need to look at. Agree that for a 1.7 though, you want a venturi under 40.

Looks like we are doing roughly the same thing atm, I was about to get a set of GSXR carbs last week, until I realised that jetting them was going to be a mission. Soldering and drilling jets is where I was at, I'm guessing you can't buy random different jets for bike carbs?

For the moment, I'm going to leave the exhaust side, just worry about cam and carbs, I was half tempted to just go to the scrappy and see what other blocks they had there with the right fit cam, and grab an armful. Some of the 480T guys have fitted ES cams, I need to check the 400 green books to compare, but the B18U is certainly 440s/460s, not sure what cams it came with in those though.

With all this mucking about, is there a reason that everyone sticks a whole F7P engine in, and doesn't just swap the heads over?

[Q]

mikuni's appear to have a slightly larger range of jet sizes avaliable but still none big enough... i was going to invest in a set of micro drills and start small and keep taking material off until its about right, i don't like the idea of solder/adding material as i don't think i can get it even and will produce different flow rates in each carb and make balencing them a big problem.

The cam from the B18E is pretty much a sports cam an i think is the one to go for but i can't find one. hence i'm trying to locate something similar.

at Chris_C
how were you thinking about making the inlet manifold? i was just going to see if i could find another one and then cut it up a bit and try and weld to it... but i don't think that'll work as there'll be a difference in materials and my welding skills are pretty awful... how were you thinking about doing it?

[Chris_C]

I was thinking of properly bodge speccing it, angle grind the manifold 2-3" from the head plate, then silicon hosing and jubilee clips to the carbs

I'll do something better if I prove it all works, but until that point, I'm not going to spend any significant sum of pennies on this.

[filthyjohn]

Bodge ftw, it'll allow you to check whether it works before you give Bogg Brothers £175 for a manifold. R1 carbs have a large range of jets available and a whole cottage industry around fitting them to cars. However they may be overkill for a 1700
Carbs from a 600 may be about right, and you'll certainly be able to drive the car to somewhere that can tune them.
Another option would be bike throttle bodies, lots of pug/citroen lads use them, and they shouldn't be much more expensive than carbs. You'd need megasquirt, but that'd be handy when you came to upgrade further.

[Q]

"I was thinking of properly bodge speccing it, angle grind the manifold 2-3" from the head plate, then silicon hosing and jubilee clips to the carbs"

was thinking bout something like that.... but engine vibrations? Think it'll just shake its self loose..... I'm sure i can make summat


I don't like the sound of itb's as they sound expensive and i have absolutly no clue about them and the engine management i would need to create, scary.... tho if i were to run itb's, i think yamaha R7 itb's would be my weapon of choice as they have standoff injectors as standard and they're cool as!

as a side, my cam ideas have been put on hold at the mo as i got talking with an engine builder today and he said i would need to address the compression ratio of the engine to maximise its potential, and to check exactly what valve lift i can actually get from the engine before i have to molest the pistons..... so i'm not thinking about that at the mo and i'm just gonna see what making it breath better does.

[Q]

not sure if this is gonna work but i'll try anyway...

here's what i made today.... http://www.facebook.com/photo.php?pid=3 ... 674&ref=mf ....well pleased me

[Jason B]

I wouldn't think there would be any problem with making a short manifold and using proper silicon hose, especially not where vibration is concerned. On a superbike like those carbs were originally fitted to, they would see a lot more motion when leaning into corners etc so I expect they are pretty resistant to vibration.

Interesting strut build, what bits and bobs are you using?