F7R valve sizes

[DaveH]

A couple of questions if you will,

1. What are the standard valve specs (sizes) for the williams f7r and the megane f7r and

2. What size do people generally go for when going for big valves in a williams f7r? The megane ones or bigger?

[Andy P]

Think the megane ones are 33mm and the Willy ones are 31mm?

[cliolord]

Hi Dave. Craig has my cylinder head and he suggested 33mm inlets (for big valve head) which the meggy head runs williams clio head runs 32mm inlets 8)

[DaveH]

Ah right as i remember the exhaust valves are the same size? What happens if you go any bigger than 33mm cliolord, lots of seat work? Did craig say what sort of gains you would be able to extract from the head if they were fitted as its a lot of money for valves that are 1mm bigger unless it makes a noticable difference?

[cliolord]

Ah right as i remember the exhaust valves are the same size? What happens if you go any bigger than 33mm cliolord, lots of seat work? Did craig say what sort of gains you would be able to extract from the head if they were fitted as its a lot of money for valves that are 1mm bigger unless it makes a noticable difference?

Well, in my case I am aiming for over 210bhp so the larger inlet valves will probably have more of an impact than say if your running 180bhp. Craig said by having 36mm inlet's, torque would be reduced and that's not what I want in really. The 36mm inlet modification is alot of money yes and is only needed if your going for 240bhp+ really iirc

[DaveH]

Rite so megane valves are the way if its a fast road /trackday engine?

[MAXIBOY]

hi mate.
it depends what your starting with as the 32mm valve can be cut in on standard seats and thus saves you in the region of 300 quid in new seats for an extra 1mm gain. if you have a willy head already stick with that.

[cliolord]

you have a willy head already stick with that.

:lol:

[kj16v]

Slightly off topic: Haynes manual says the exhaust valves are sodium-filled. Are they really sdium filled?

[Lunner]

Yup, helps stop them distorting at the high temps....i think

[DaveH]

Yes its a F7R (williams) head. Im just wondering how much of a difference the 33mm valves would make? Is it not possible to cut meggy valves in to willy seats as its only 1mm difference?

[MAXIBOY]

yes you can but then you get 0% benefit as its the larger seats and valves that give you an improvement rather than the 1mm valve increase.

so ifs a willy head i would stick with that unless your going 35mm/36mm mega head. and associated cams etc...

[robi1000]

I have a similar problem now and I'll just ask here. My valve seats were cut for 34mm valves. Where could I get some 34mm valves (could also be 34,5 or sth)? Are there any valves from other car manufacturers that I could use? Or from 8 valve models? How much does this cost?

Cheers

[stan]

turn some 8v ~36mm ones down to suit.

[robi1000]

Will valve stems fit? What should I do? CNC them down to 34mm? What about Mi16 valves?

[stan]

Mi16 valves are very heavy...ive tried them, and wouldnt use them again for this reason.

replied to your pm pal

[summeh]

I'm running megane 33mm inlet valves in my williams head, moderate porting and my engine was dyno'd at 180bhp, so I think some definate benefit to be had. The standard seats are fine for the megane inlets also, if your doing a rebuild then the megane inlets are even cheaper than the williams items.

[robi1000]

Yeah, Megane inlets are my plan B, if I won't find anything else. I suggested them to my head specialist and he said they'll be ok but there will be almost no gain in terms of power or reliability. So to get more then 33mm I should have Clio 1.4 valves machined down to 34mm. The thing that bothers me the most is because I don't know what has been done with the car before I bought it. I always find some kind of racing modification when I dismantle something (welded subframe to the chassis for instance). And because of that I don't really know what has been done to the head apart from that it appears there were 34mm valves once inside. Inlet ports are much wider where inlet manifold bolts on and then get narrower closer to the valves. Also inlet manifold is modified so it has wider openings. I don't know if there are any gains (to me it looks strange) but I know that car goes like st*nk. My question is what would be the biggest valve size if there was no proper porting done to the head so that I would lose as little power as possible and also have valves as big as possible so that they'll seal well?

[MAXIBOY]

33mm are fine for most engines...34mm or bigger only once your running wild cams solid lifters and upgrade too titanium..in my opinion as they get too heavy...

[robi1000]

Well I'll be running cams from now on. I don't think they are really wild (Catcams 5502225) but might gain something. Especially after remap?

[robi1000]

By 1.4L engine you meant E7J engine from Clio,R19,... 94'?

[summeh]

By 1.4L engine you meant E7J engine from Clio,R19,... 94'?

yeah the energy engine

[stan]

or the 1.2.

I can get FAI part numbers if you get stuck...

Size isnt everything though mate, 33mm is fine...they work well.
They work best on over-size inserts though...i wouldnt fit them on std.

[robi1000]

My head is a bit tired so this is it's last overhaul. In case something would go wrong I would have to buy a new head anyway. So at least I can try what can be done. When I'll want a proper head I'll just contact Stan and order one.

[robi1000]

I'll just ask here where more people will see this post:

I just weighted original Williams valves and my new valves. I weighted them on our kitchen scale so it's not lab precise but at least it's an indication. So Williams valves were 55g and new ones are around 57g, but that's before they are going to be skimmed. So after we skim 2mm from them they should be lighter then original ones. So here's the question. I know that if valves are too heavy they change valvetrain harmonics. But what about if they're lighter? I guess heavier valves have bigger inertia so they can't accelerate so fast. That shouldn't be a problem with lighter ones right?

Another question. My inlet ports were enlarged, but unlike on exhaust side where guides were grinded so they blend in the port shape, on the inlet side they aren't. Would I gain anything if they were grinded also? If yes, what are the problems then?

Cheers

[summeh]

High revving engines tend to use titanium valves (nascar, etc), so these being as light as possible I would take that as a route to go down. Basically the lighter they are, the better, for the reason you give (less inertia).

As for the guides, I would suggest that everything should be as smooth as possible to increase flow and reduce restriction. Some might tell you its worth only a fractional increase... But add all those fractional increases up and we have something called the "compounding effect". I.e. lots of small increases = 1 big increase :wink:

[MAXIBOY]

also i tends to allow use to use a softer spring with these as they need less controlling with very light valves thus decreasing the inertia needed to open them...

[MAXIBOY]

^^^^

as well when combined with titanium retainers too...

[2 live]

not really worth spankin the ££££££££££££s out for the minimal gains tho imo.

unless ur minted of course.

[stan]

they will inherently increase the max rpm ability of the engine, for the reasons outlined above....a necessity if your after decent power.

also on a longevity note, they will increase valve-train life as theres less valve seat pounding, harshness on springs etc etc

[robi1000]

Another question. On std valves for Williams there is a central circular section on the valve dish which is milled out. Is this due to valve weight saving or sth else? I hope you know what I mean.

[stan]

yes, more than likely weight

[robi1000]

Hello everybody and here's another question for you! :D As we discussed in this topic before I installed 34mm valves. Now I'm worried about piston/valve clearance. Are there going to be any issues because valve diameter is 1mm bigger? Because I really wouldn't like to see that my pistons bent my brand new custom made valves... Oh and let's say I have stock pistons. :)

[white16valver]

Do the stock pistons have the cut out bits where the valves would otherwise hit the surface?

Like this: http://www.enginetech.com/2004products/pistons_std1.jpg

If so, you may need to do work to get them to clear as the larger diameter may not fit into the cut out bits!

And if you haven't got cut out bits then you'll have to work out clearance between the top of the piston at TDC and the valve fully open, as if the valves are at an angle to the face of the piston, rather than being flat to it, you may risk them touching!

(I think - I'm no mechanic :oops: lol)

[robi1000]

Well, my pistons are a bit different, but the real question is if on forged pistons like this:

http://www.moj-album.com/slike/10833367/9MQTwclBrx7jNWrw.v.jpg

cutouts for valves are under block height or are level with it? Because my pistons are straight and are levelled with the block:

http://www.moj-album.com/slike/10833367/vd01D2TLHnos5sU6.v.jpg

http://www.moj-album.com/slike/10833367/RTSowQcOMemkECHj.v.jpg

Am I in trouble? :roll:

[robi1000]

Oh and I'm using Catcams 5502225.

[robi1000]

There must be someone who has forged pistons? All I want to know is if cutouts for valves are under block height?

[stan]

you will need cut-outs in those pistons.

Best thing to do is to chack what max lift you have around TDC. Stock engine is about 3mm, meaning you can have say 2mm lift.
With forged pistons there is about 8mm....meanign u have alot more room for lift around TDC.

[robi1000]

Hmmm, valve lift at TDC for this cam is 1.55mm on intake side. So I might just make it. Will have to try. I always forget but if all goes wrong I can install valver head? Until I find myself some forged pistons...

[stan]

thats "about" 3mm which includes the cut-outs in the pistons which you dont have. this is also on 32mm inlets.

I think you will have issues trying to achieve the desired lift at TDC,

Why cant you find any forged pistons? If your stuck I can supply a set...

[Allan]

so what size is recomend for running about 300 bhp ?
the 33 megane ones? or go larger then that.

I.e low comp turbo engine...

[MAXIBOY]

33mm like me are plenty

[robi1000]

Why cant you find any forged pistons? If your stuck I can supply a set...

Ha ha, I really hope I'll not get stuck. Because at the moment I don't have another 1500€ to spend on forged conrods and pistons. Not to mention I have rebuilt BE with just 500km on it. And now I'd have to strip it and rehone it all over again. :? Maybe if I'd find a very good offer for used ones I might consider that. Ahhhh, I guess I'll never respray my car... There's always something coming in the way.

[robi1000]

There's also another way. I could make cutouts in this pistons but I don't know how much would that affect their rigidity. I must say that I don't like this idea too much but atm I don't know what to do.

IIRC I could also use F4R conrods since my car will never rev past 7300RPM so forged items are not really necessary (I think). This way I could just buy forged pistons. My question is if I can use my current conrod bearings on F4R conrods? It's not money issue but my bearings are custom made and I'd like to keep them.

[stan]

i dont see how f4r rods will help, they are essentially the same. What pistons are you using and why did you machine the crowns?

[summeh]

33mm like me are plenty

If I was running boost I'd go for the biggest valves possible :wink:

[robi1000]

i dont see how f4r rods will help, they are essentially the same. What pistons are you using and why did you machine the crowns?

When I bought my car it was a mess. The way I see it someone must have driven the car with with siezed conrod bearings and wasted the conrods. And because it was too hard for them to use F7R conrods again they sourced new conrods presumably from F3R (I'm not really sure from which engine they are). Because conrods were longer they milled off piston crowns. Not only this is stupid, the quality of work was appaling. Disaster! Piston height differed by 3mm. So I balanced them and milled them a little bit so they are all equally high. The car ran fine. It also has higher compression. Then, bolt on my inlet cam snapped because someone must have overtighten it with air gun. :x So if I'm buying new conrods and pistons instead of buying forged conrods (another 700€) I could source Clio Sport ones which they say are a bit lighter and better design then stock F7R ones. Is this true? So this way I could just buy some pistons. And because I already spent a small fortune on new valves and head rebuild with new Cat cams and pulleys I'm really trying to save few €. So if I find used F7R forged pistons, are they going to be ok? Is there a possibility that I wouldn't have to rehone my block. Because stripping it now right after it was put together would be a real pain in the a***?

[robi1000]

Maybe a stupid question but would Clio Sport pistons fit Williams engine? Aren't bore and stroke the same? Reason for not using std pistons is that there is greater chance of finding Sport pistons around here...

[stan]

yes the RS pistons can be used.

Ive got some RS rods (stock) somewhere if you cant find any your way.

Used pistons will be fine, though I would fit new rings and hone the block.

[mode0446]

Hi,

i'm thinking about 34mm inlet valve in williams head with cat cams '208, what about exhaust valve, leave stock or oversize? if oversize which engine valve use.

another question: is 8v engine exhaust valves sodium filled?

Thank's