All ? about 43.5 intake valves in Fiat TC.
Posted: June 9th, 2016, 6:36 pm
Hi.
I want to make a thread where every member could get any info about 43.5mm valve int Fiat TC heads.
This is one of the most interesting things, especially for this one who are a beginners with Fiat TC. Almost every site about Fiat TC site has a thread about "Big intake valves", "Abarth vavles" etc. You must know that some of folks on there sites shares with other a not fully correct infos about it. Eg. I read on one of Fiat lovers site that you don't need change a smaller valve seats from 41.7mm valves to do this conversion - totally bullshit, I will write about it later.
In this site we can get every info about it what we need eg. how to make correct big intake valve conversion, which material for valve seat we could use, which and why angles on a seat and valves we need to use.
From my knowledge first Fiat/Lancia twin cam engines with 43.5mm intake valves were Ritmo 130TC heads. Also Lancia Volumex, Lancia Delta etc. has it. If you looking for it with tight budget have a look for quite new heads from 1.8 and 2.0L from Lancia Dedra, Fiat Croma etc. Of corse, you can get a valves from 130TC, but most of sellers want for it extra money because it is Abarth thing, remember about it.
I know two shapes of 43.5mm valves. First is simillar that new type 41.7mm valve, I have one piece of this type of valve, with Fiat marking on a stem, but I don't really know from which engine it comes. GC,could you write from which engine it could come ? Do you make some flowbench test from this type of valve ?
A second, most popular is a quite different than Beta valve, this difference is really easy to notice when you will see this photo.
I wrote before about conversion. If you want to do it, you have money and you know a really good machine shop, check this two drawings (GC is a author of both of them). All info about it you can get from this two drawings. From my experience I could add only that a NECCESARY thing is a valve guides in excellent condition. Worn guides could make a really mess when machinist will be making a place for bigger inserts, I know it from my experience really. This job must be done as most accurately as possible. If you will make a place in head for a bigger insert with worn guides you can make a really out of round hole for valve insert, it could fall out in service and make your beautiful engine scrap.
GC wrote about guides, look this.
viewtopic.php?f=2&t=949
About seat&valves angles preparing GC wrote hear, look at it, it is very helpful.
http://guy-croft.com/viewtopic.php?f=2&t=334
Intake ports of corse should be ported for correct size to get as most as possible flow with 43.5mm valves. Always use a 36mm at a first section of intake port. Venturi could be different. I haven't experence when we should to use a 34mm venturi, when 35mm and when 36mm. In my stage II head GC suggest me to use a 35mm venturi, in his book I read about 8v Turbo head preped by GC and it has 34mm.
GC, could you write in short post how to match a correct venturi size for 43.5mm valves ?
This is a first post about 43.5mm valves, I think a GC and members could post here a stories and questions about it and we can get in a short time a really fully exhaustive thread about big intake valves in Fiat TC heads.
Sincerely
Piotrek.
I want to make a thread where every member could get any info about 43.5mm valve int Fiat TC heads.
This is one of the most interesting things, especially for this one who are a beginners with Fiat TC. Almost every site about Fiat TC site has a thread about "Big intake valves", "Abarth vavles" etc. You must know that some of folks on there sites shares with other a not fully correct infos about it. Eg. I read on one of Fiat lovers site that you don't need change a smaller valve seats from 41.7mm valves to do this conversion - totally bullshit, I will write about it later.
In this site we can get every info about it what we need eg. how to make correct big intake valve conversion, which material for valve seat we could use, which and why angles on a seat and valves we need to use.
From my knowledge first Fiat/Lancia twin cam engines with 43.5mm intake valves were Ritmo 130TC heads. Also Lancia Volumex, Lancia Delta etc. has it. If you looking for it with tight budget have a look for quite new heads from 1.8 and 2.0L from Lancia Dedra, Fiat Croma etc. Of corse, you can get a valves from 130TC, but most of sellers want for it extra money because it is Abarth thing, remember about it.
I know two shapes of 43.5mm valves. First is simillar that new type 41.7mm valve, I have one piece of this type of valve, with Fiat marking on a stem, but I don't really know from which engine it comes. GC,could you write from which engine it could come ? Do you make some flowbench test from this type of valve ?
A second, most popular is a quite different than Beta valve, this difference is really easy to notice when you will see this photo.
I wrote before about conversion. If you want to do it, you have money and you know a really good machine shop, check this two drawings (GC is a author of both of them). All info about it you can get from this two drawings. From my experience I could add only that a NECCESARY thing is a valve guides in excellent condition. Worn guides could make a really mess when machinist will be making a place for bigger inserts, I know it from my experience really. This job must be done as most accurately as possible. If you will make a place in head for a bigger insert with worn guides you can make a really out of round hole for valve insert, it could fall out in service and make your beautiful engine scrap.
GC wrote about guides, look this.
viewtopic.php?f=2&t=949
About seat&valves angles preparing GC wrote hear, look at it, it is very helpful.
http://guy-croft.com/viewtopic.php?f=2&t=334
Intake ports of corse should be ported for correct size to get as most as possible flow with 43.5mm valves. Always use a 36mm at a first section of intake port. Venturi could be different. I haven't experence when we should to use a 34mm venturi, when 35mm and when 36mm. In my stage II head GC suggest me to use a 35mm venturi, in his book I read about 8v Turbo head preped by GC and it has 34mm.
GC, could you write in short post how to match a correct venturi size for 43.5mm valves ?
This is a first post about 43.5mm valves, I think a GC and members could post here a stories and questions about it and we can get in a short time a really fully exhaustive thread about big intake valves in Fiat TC heads.
Sincerely
Piotrek.