Fiat TC Fast Road engine-a few questions.

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Piotrek125p
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Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Mon Dec 03, 2012 6:54 pm

Hello.
I'm looking for info about Fiat TC Fast Road engines. I have a few questions to GC. The first one is about inlet port diameter. On this chart download/file.php?id=1123 I see that 36-35 port with 43.5mm (?) is the best choice for Fast Road engines. Am I right? The second question is about the valve seat prep. On this chart download/file.php?id=997 I see that the best are seats like Test 5. Does the seat prep depend on engine final output and torque curve that I want to achieve and I can prep my seats like Test 5 seats? The last question is about the valve shape. Can I apply a 'tulip' valve if I building a road engine, not a competition engine ? Maybe these are silly questions but please forgive me, I'm a rookie engine builder ;)
Thanks for your advice.
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Mon Dec 03, 2012 8:16 pm

Piotr

give me details of your engine type and setup WITH PHOTOS* and I will tell you exactly how to prep the head.

Give me an idea of the equipment you will use with the engine - carbs, cams, exhaust etc


G

* this is sort-of mandatory in GC Q&A for interest reasons (for readers)
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Mon Dec 03, 2012 8:43 pm

I haven't any photos of my engine, today I stripped it and inspected. If I must show a photos of my engine I will do that, but it's only an old engine that needs repair, nothing interesting at that moment. I haven't yet a full setup, now I'm looking for it. At this moment I have:
-Fiat TC 2.0L engine
-new 1800 GLS piston who aprox CR to 9,6:1-(of course it's has a good oversize)
-2xWeber 44 IDF, but I haven't a manifold for it yet.
-standard inlet cam from 132 2000 and standard ex cam from Argenta
-4372748 head (35-32) from 131 and 4372281 head (36-35) from Lancia Trevi)
I want to build a Fast Road engine because I drive my car everyday, but I like to compete in track dayes, so I want have some extra power. I haven't idea what type od cams I should to use, tomorrow I will call to the two workshops who makes a cams for Fiat TC and I will write here about it. At this moment I have a stock exhaust from 132 2000, but I can do a new manifold and rest of exhaust at my university, I must only to know what diameters and lenghts Imust have an exhaust for my engine. I'm thinking about 4-1 manifold, rest of exhaust will have 50mm with two silencers.
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Mon Dec 03, 2012 9:12 pm

no worries

Fiat TC 2.0L engine
new 1800 GLS piston who aprox CR to 9,6:1-(of course it's has a good oversize) OK!
-2 x Weber 44 IDF, but I haven't a manifold for it yet - don't forget manifolds to clear a block-mounted distributor are pretty rare. Best setup is modified 124 idf 40 one and distributor on ex cam
-standard inlet cam from 132 2000 and standard ex cam from Argenta - OK!
-4372748 head (35-32) from 131 and 4372281 head (36-35) from Lancia Trevi)

Use the big-port Trevi head.


I want to build a Fast Road engine because I drive my car everyday, but I like to compete in track dayes, so I want have some extra power. I haven't idea what type od cams I should to use, tomorrow I will call to the two workshops who makes a cams for Fiat TC and I will write here about it.

Don't worry about special OE cams - if the old ones have about 9.5mm lift or more they will be perfect.

At this moment I have a stock exhaust from 132 2000, but I can do a new manifold and rest of exhaust at my university, I must only to know what diameters and lengths Imust have an exhaust for my engine. I'm thinking about 4-1 manifold, rest of exhaust will have 50mm with two silencers.

Make a 3ft 4-1 like the one shown, 1.5" bore primaries. You can get to over 150bhp @ 6200 approx on your setup if the silencers are big-bore straight-thru.

On the head just open up the ex ports around the valve guide region - at the sides. Shape the short radius nicely.

On the inlet side just smooth the port and shape the short radius to give a good elliptical shape. Don't cut it right back.

When you mod the valves and seats it drops the valves deeper into the head and it can make shimming awkward. The trick is to grind the valve tips down (not too much) and use dual cambox gaskets. Normally the valve tips stand about 40.5mm above the spring platform so you can measure yours and see how much deeper they are. With dual gaskets you need adjustable camwheels. The optimum cam timing is probably the OE 110 deg. If you change it you will have piston-valve clearance problems.

Definitely use GC valve springs. You will easily over-rev the standard ones and bend all the inlet valves.

Hope this gets you going!

G
Attachments
IMG_5976.JPG
IMG_5976.JPG (576.87 KiB) Viewed 4902 times
RL_guides (3).JPG
ex port modified - wider near guide region. Do NOT shave off the guides!
RL_guides (3).JPG (93.54 KiB) Viewed 4902 times
RL_fully finished inlet & ex seats.JPG
seat angle inlet and ex - 30 top cut - 45 deg seat 1.75-2mm wide, throat 70 deg into parallel. Leave ALL edges sharp!
RL_fully finished inlet & ex seats.JPG (123.15 KiB) Viewed 4902 times
11.244 cylinder head (2).JPG
the best inlet valve is the later one not the early 'tulip'design. After lapping the valves put a 30 deg 'back grind' on the inlets - to match the top cut on the seats
11.244 cylinder head (2).JPG (58.21 KiB) Viewed 4902 times
EU_view thru inlet port on overlap.JPG
ideal treatment of inlet port with new guide fitted AFTER porting!
EU_view thru inlet port on overlap.JPG (84.41 KiB) Viewed 4902 times
EU_ triple race springs on race bases.JPG
GC springs. You will NEVER drop a valve with these, eg on a missed gear change...
EU_ triple race springs on race bases.JPG (100.19 KiB) Viewed 4902 times
SK finished SSR with all seat angles 30-45-70 sharp visible.jpg
I can't find a photo of a standard size seat region but this will give you an idea of what the SSR (short radius) on the inlet side should look like. A big port head with 36-35 ports does not have much of a short radius and it tends to be rather sharp, the trick is to give it an elliptical radius - but don't make it too long
SK finished SSR with all seat angles 30-45-70 sharp visible.jpg (109.97 KiB) Viewed 4902 times
SK inlets all back ground.jpg
inlet valve back grind. If you cannot do a 30 deg cut in the chamber on the inlet side (ex do not need a top cut) give it 20 deg but don't give it nothing at all. 20deg in the chamber and 30deg on the valve is better than nothing at all and it makes a big difference to the low-lift flow. Leave the valve back-grind SHARP
SK inlets all back ground.jpg (117.45 KiB) Viewed 4902 times
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Mon Dec 03, 2012 9:50 pm

Once again about cams, what means "special OE cams" ? It's a cams from 1608 ? Or I need to regenerate my cams or buy OE new ones ? I find new polish cams for Fiat TC, 290 degrees with 9.8mm lift, should I be interested in these cams ?

About SSR, are you know an optimum radius ? Or something like that really existing ? I know a CNC genious who can modify SSR ideally as I propably need. The same with exhaust port valve guide region. I have to admit that I really don't know how to do it best, are they need have exact dimensions ?

Of course I know about problems with that types of valves and seat and know how to solve that problem. I will do an adjustable camwheels immediately when I get an new set of OE camwheels.

My friend promise to give me a set of new triple springs set from ex-works rally FSO Polonez. I will check it, if these spring will be wrong I will buy a triple springs set directly from GCRE.

EDIT

which inlet valves diameter I should to choose, a 41.8mm or 43.5mm ? In ex valves approx the radius to 12mm only ? I do not have anything more to do ?
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Tue Dec 04, 2012 12:48 pm

any TC cams will do!

As for porting and valve - seat mods, why not buy my new book? All the photos are there!

G
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Tue Dec 04, 2012 2:09 pm

Of course I will buy your new book, I will buy it after a New Year. Now I use your old book (yesterday gift from my friend) and I'm really content. My questions about details are caused by the opinions of my friends who claim that Fiat TC engine Fast Road cannot have more than 130bhp, I want them to prove it's not a true and I can build more powerful engine :)


You reccomend a intake manifold from 124, is this manifold called "waffle manifold" ?

About SSR and ex port modify I think now I know how to do it, thanks for photos.

Finally, I have the last question, about that chart download/file.php?id=1123 You test a 130TC port with 43.5mm valve ? Based on this graph I think that 36-35mm port with 43.5mm valve is the best for fast road engine, or maybe smaller valve (41.8mm) will be better ? Until I read your book I don't know that this size are very importart, more importat that I thought before.

Have you a place on this forum where I can show a photos and write about progress with my engine, besides of "Readers Cars" ? My car is not suitable for display, I want only write about the engine for my car.
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Tue Dec 04, 2012 3:56 pm

After New Year there may be no books. I have 8 only left.

I suggest you stop asking the opinion of your friends! Even the 124 CSA 1800 had 130bhp with 42/36 valves, 9.9mm camlift, 44 IDF, 9.8/1CR! And that is without 4-1 header (of my style), gasflowed head and race valve/seat angles!

You recommend a intake manifold from 124, is this manifold called "waffle manifold" ?

Yes!

About SSR and ex port modify I think now I know how to do it, thanks for photos.

OK!

Finally, I have the last question, about that chart download/file.php?id=1123 You test a 130TC port with 43.5mm valve ? Based on this graph I think that 36-35mm port with 43.5mm valve is the best for fast road engine, or maybe smaller valve (41.8mm) will be better ? Until I read your book I don't know that this size are very importart, more importat that I thought before.

Bigger valve better if you have the money for the conversion. 36-35mm port. My bhp estimate was based on 42mm inlet.


Have you a place on this forum where I can show a photos and write about progress with my engine, besides of "Readers Cars" ? My car is not suitable for display, I want only write about the engine for my car.

You can post it where you think best Piotr, if I think it is in the wrong place I will move it and tell you. Mainly GC Q&A is for engines but I am not bothered reallly.

The diagram attached will help you to understand the SSR, I hope. The only way to learn how to do it really is with a flowbench - which I have done on a hundred types and makes of cylinder head. The rule is any radius is better than none!

G
Attachments
Airflow in the inlet port_06 SSR.doc
(29.5 KiB) Downloaded 199 times
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Wed Dec 05, 2012 6:46 pm

Today I'm thinking about valve-seat modifications. I came up with this idea. I will modify a new seats and my old valves in a manner that suggest GC. I will use an old valves to test, because I want to do a new valves because it will be cheaper and easier than looking for OE Fiat 43.5mm valves. I now one very good factory who can make for me valves in shape that I want. I thought that I modify my old valves, then I will measure the lenght of valve and check how long is this valve and do new valves shorter and build up it like stock. It's a good idea or not ?
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Wed Dec 05, 2012 7:29 pm

Do it GC style - I have done this for years and shared it so you do not have to waste time proving what I already know based on countless flowbench and dyno tests.

Use the old valves and overhaul/mod them

G
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Wed Dec 05, 2012 7:54 pm

Ok, I will do it GC Style. By the way, I will make some Autodesk Inventor projects with Fiat TC parts eg an exhaust manifold flange for custom manifold, maybe someone need projects like that eg for CNC machining. Where I can share with things like that ?
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Thu Dec 06, 2012 11:23 am

Sales section

G
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Thu Dec 13, 2012 2:55 pm

Today I cut a fuel pump lobe in my auxiliary driveshaft. Here some photos

The next step is to tap a plug and dress out aux-shaft bearings with 1000-grade. I'm going to do it "wet", it's correct ? Or I must do it "dry" ? If I dress out, I will have not a problems with correct diameters ? I need to make my auxiliary shaft shorter for 1 inch belt. The shaft has a length 25mm in a pulley side, I have to cut about 1.5 mm ?

The next thing I did was buy today a set of gaskets. I have question about that type of gasket. You write in your old about cam box gaskets from AE. Whether the gaskets that I bought are good ? The same question about valve caps gasket. In my set was two head gaskets. Both of them have a rust in one place (see photo)

Can I used this gasket or I should buy a new gasket ? At last, is it a Goetze Astadur head gasket ?
Attachments
P1010466GC.jpg
Modified auxiliary driveshaft
P1010466GC.jpg (61.48 KiB) Viewed 4462 times
P1010467GC.jpg
P1010467GC.jpg (57.73 KiB) Viewed 4462 times
P1010468GC.jpg
Valve cap gaskets
P1010468GC.jpg (59.22 KiB) Viewed 4462 times
P1010469GC.jpg
Cam box gasket - any good?
P1010469GC.jpg (62.13 KiB) Viewed 4462 times
P1010471GC.jpg
Rust on a head gasket
P1010471GC.jpg (58.51 KiB) Viewed 4462 times
P1010473GC.jpg
Head gasket - is it suitable?
P1010473GC.jpg (63.78 KiB) Viewed 4462 times
Last edited by Piotrek125p on Fri Dec 14, 2012 1:33 pm, edited 1 time in total.
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Re: Fiat TC Fast Road engine-a few questions.

Post by Guy Croft » Sat Dec 15, 2012 12:38 pm

Do not dress the aux d/s bearings with abrasive paper - the soft material will absorb minute abrasive particles. If you think they need a light 'polish' use the finest grade Scotchbrite and a wetting agent like WD40 or Jizer (water soluble degreaser).

Line up all your pulleys with a 'straight edge' - this will tell you if you need to shorten the aux d/s shaft. If you do you need to machine the back of the pulley too or it will rub on the seal. You might need to 'dry build' the engine to check this. Many years ago I did not do this but I am much more careful and experienced these days.

The head gasket is not Astadur it is the very earliest design and not much good.

The lower cambox gaskets - well - maybe they will leak I do not know!

I sell race grade stuff if you want the best. You get the quality and reliability you pay for...!

G
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Piotrek125p
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Re: Fiat TC Fast Road engine-a few questions.

Post by Piotrek125p » Sat Dec 15, 2012 1:24 pm

I'm looking now for Scotchbrite in shops in my city and I found a green fabric, this is it that I should to use ? I can do a better photo of my bearings, but in my opinion I should polish it, they look quite good, but I spend a hours in your site and saw only full polished, great looking bearings in aux d/s, crancks etc. I will do a GC style so I thinking about polish it. Everything like aux d/s bearings, cranks bearings, cams bearings etc. you polish by Scotchbrite ?
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