valves

[thelynx]

Hey

Just picked up a cheap 1.8 head with bent valves, if I were to get it fixed, would it be best to go with bigger valves? If so what size are bigger than standard ?

Cheers

[stan]

williams inlets can be cut onto the existing seats, tho they are a renault only part.

megane f7r inlets will require larger seat inserts to be fitted/cut...more expensive.

in either case you would want to fettle the bowl area to get it to flow properly.

you could just send it to me and i'll sort it :D

[summeh]

When Ben put megane inlets in mine I think it was just the seats cut larger to suit ??

[stan]

yeah...thats the nasty way...FAR better fitting new inserts.

[stan]

yeah...thats the nasty way...FAR better fitting new inserts.

[BenR]

nasty lol.

its 'better' to run a new insert as your right on the edge of the std insert with 33mm valves.

But if you've got the equipment and know how its not detrimential

[stan]

I disagree :D

[2 live]

thin seats have more of a tendancy to get dropped ...in my experience....would always go with larger seats to accomodate the larger valves....recuttin is the cheap/easy way out.

[BenR]

thin seats dont.........thin inserts do, but even recut std inserts do not become 'thin', just the seat margin is moved to the edges where the top cut is part of the parent ally.

TBH i have never seen a renault drop a seat in any form or stage of modification.

Its an option for people who dont want to spend the large amount of money to add larger inserts for the propriety percentage point gain.

Its a wiser idea to add larger inserts, but as many customers see it.......if its not going to gain any bhp, and its not going to be any less reliable in the grand scheme, why spent the extra wad......and its not a small one. Customers thing ££££££££........not engineering ideal, so you have to blend the two.

[stan]

thin seats dont.........thin inserts do

but by taking the internal diameter close to the external, you are making it a thin seat insert.

tho i agree it likely wont fall out...its a risk especially if your using uprated camshafts.

also the lack of meat to play with, means by nature of the profile left, you WILL get increased shear/flow seperation...no matter how good you are or what tools you have :D