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All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 7:36 pm
by Piotrek125p
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.
Left-41.7mm Beta-Center 43.5mm with Beta shape-Right 43.5mm from Lancia Delta Turbo.jpg
Left-41.7mm Beta-Center 43.5mm with Beta shape-Right 43.5mm from Lancia Delta Turbo.jpg (79.42 KiB) Viewed 2975 times
Lancia Turbo 43.5mm valve head.jpg
Lancia Turbo 43.5mm valve head.jpg (85.3 KiB) Viewed 2967 times
Second type of 43.5mm valve head.jpg
Second type of 43.5mm valve head.jpg (83.62 KiB) Viewed 2967 times
Lancia Beta 41.7mm valve head.jpg
Lancia Beta 41.7mm valve head.jpg (83.71 KiB) Viewed 2967 times


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).
installation dwg 43.5mm inlet.GIF
installation dwg 43.5mm inlet.GIF (20.69 KiB) Viewed 2975 times
Fiat TC 43.5mm valve insert2.GIF
Fiat TC 43.5mm valve insert2.GIF (17.84 KiB) Viewed 2975 times
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.

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 8:36 pm
by Guy Croft
MODEL POST!

Well done Piotr..

I shall shut up for a period of time and see what other readers have to say!

I do know that a GC prepped engine at 2liter 85mm bore on 3D/3A cams, 36-35mm inlet ports, 36" 4-1 header with 45 DCOE on 40 chokes at 11/1CR and 43.5/36mm valve combo can hit 184bhp and that is by no means the limit...

I know because the owner Geoff Ward gave me his rolling road data from Northampton Motorsport and their rig (a Superflow) is very accurate.

G

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 8:40 pm
by Piotrek125p
Yep, I know that 43.5mm valve with 36-35mm port is an excellent way to best performance of TC. Miro engine, Lotus Lada replica engine has very good performance. Hopefully my engine will be powerful too with 36-35mm port and 43.5mm valves.

I think in June I can make some update with my head, so member could see a GC tips on non GC prepped head.

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 8:54 pm
by Guy Croft
Lotus Lada was 42/36 and a very, very modest spec...

G

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 8:56 pm
by Piotrek125p
I wrote about replica who belongs to Ian.
viewtopic.php?f=4&t=2837

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 9:09 pm
by Guy Croft
well that is not the Lotus Lada!

The Lotus Lada is a Lotus registered brand name and Lotus are very protective about names.

GC

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Thu Jun 09, 2016 9:24 pm
by Piotrek125p
Ok, I don't know about it, I called it that because Ian, a owner of this Lada called it exactly the same.

GC, could you have a look for my 43.5mm valve with shape as 41.7mm Lancia valve ? This is OE valve, unmodified, with Fiat logo on a stem, It is a first 43.5mm with this shape that I had in my hands. Could you answer for my question that I wrote in my first post ?

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 6:28 pm
by Guy Croft
I wouldn't walk very far to swap valves. In my job I work with client property if I can (always starting with valve overhaul to save them money if I can). Could be a head with 42mm valves (+/-) or 43.5mm of various sorts.

If I have to get new valves I do my best in a shrinking world..

As for the 43.5mm valve design - Fiat did the tests on these I am sure. The style used in the Strada 130TC made by them (and marked Fiat) was absolutely right for their heads, though I would add that a 30 deg top grind on the inlet seat insert and similar back-grind on the valves DOES yield measureable benefit in the low-lift regime.

But you can't buy the OE 8v TC Fiat valves of any size anymore, they are all gone thanks to GCRE.

GC

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 6:37 pm
by Piotrek125p
I can buy a new 43.5 intake valves from local Lancia dealer with no problem dear GC, but in my engine I will fit fully overhauled and modified used valves according to your spec.

I thought that this unusual shape of 43.5m valve that I showed before is typical for some F&L engines.

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 6:43 pm
by Spider 1969
Piotr,

I have a big valve head, reported from a 105TC, with 43,5mm valves with the beta shape as you describe. Not marked Fiat though. See photo. Head number also on photo. Maybe this is of help.

Regards,

Charles

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 6:53 pm
by Guy Croft
Hi Piotr

I cannot buy them from Fiat in the UK, I am told no more stock, if you can please tell me.

They are a good design and better than the earlier 42mm style. The non-firing side design was changed, different radius-angle.

G

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 6:56 pm
by Piotrek125p
My father works in Lancia official service, he will ask in monday about this type of valves, no problem.

Spider1969, could you make for me a photo of your valve with simillar angle thats mine ? For me, your valve looks as valve from the right side in my first photo.

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 6:59 pm
by Spider 1969
Will do that Monday Piotr.

Regards,

Charles

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 7:03 pm
by Guy Croft
Piotr

the 42mm valves that Charles have a different design. Charles, no need to send new pictures.

Piotr - If you are scanning other web locations and pulling conflicting information together stop it please.

You can trust me to tell the truth.

Thank you.

G

Re: All ? about 43.5 intake valves in Fiat TC.

Posted: Fri Jun 10, 2016 7:08 pm
by Piotrek125p
This is the only thread that I make about 43.5 valves dear GC, please tell me which info that I sent before is wrong.