Measuring for shims.

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parrish
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Measuring for shims.

Post by parrish »

Guy,
ive made a start on measuring and correcting the follower gaps.
Engine is a Strada Abarth unit although i don't believe that makes any difference to the required gaps.
Measured cold i have the following:

........................... Inlet ....... Exhaust
1 front of engine .... 0.70mm ..... 0.60mm
2 .................. ... 0.60mm ..... 0.60mm
3 ...................... 0.75mm ..... 0.60mm
4 ...................... 0.50mm ..... 0.60mm

seems to me all the exhaust are acceptable, however the inlets are way out.
Inlet cam identification is SF Fiat 111587 (number is very difficult to read)
Exhaust cam is un-readable.
I am yet to remove the followers and measure the thickness, i propose to leave the exhaust as they are.
I have a spare head and intend to strip it and see what i have in the way of shims and top hats, maybe i could use some of them, is this advisable?
Any advise before i continue?
Regards
Steve
Parrish 366
Guy Croft
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Re: Measuring for shims.

Post by Guy Croft »

rated settings (OE) for that are:

inlet 0.45
ex 0.50

The ex are loose - too loose really. This can wear the cam nose and damage valve & seat as the tappet misses some of the opening/closing ramp.

You can re-use shims if the worn face is flat but - you invert them to put the unworn face against the cam,

G
parrish
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Joined: June 22nd, 2006, 7:11 pm
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Re: Measuring for shims.

Post by parrish »

Thanks for the quick response Guy,
Ive removed and measured the existing shims/tappets and done the maths, correct me if im wrong but the thickness of shim required is the sum of the existing shim added to the difference required to bring the gap to that required!

Tools used:
Image

eg:
existing gap = 0.70mm
existing shim = 4.60mm
required gap = 0.45mm

0.70mm - 0.45mm = 0.25mm

Required shim thickness: 4.60mm + 0.25mm = 4.85mm

is that correct?
If so i have a list of required shims to send you.

I stripped and revisited the inlet tract and would like your comments on the following air flow:
Inlet trumpets = 45mm
Throttle body inlet = 45mm
Throttle body outlet = 40mm
Manifold inlet = 35 x 38mm blended to inlet manifold
Manifold outlet = 35 x 38mm blended to head
Head inlet = 36 x 45mm

Regards
Steve
PS: ill never use a bent screw driver again!
Parrish 366
Guy Croft
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Re: Measuring for shims.

Post by Guy Croft »

Your shim calcs are OK!

I'll come back to your inlet query,

G
Guy Croft
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Re: Measuring for shims.

Post by Guy Croft »

Inlet trumpets = 45mm
Throttle body inlet = 45mm
Throttle body outlet = 40mm
Manifold inlet = 35 x 38mm blended to inlet manifold
Manifold outlet = 35 x 38mm blended to head
Head inlet = 36 x 45mm


Looks OK to me!

The head inlet size`is not 36 x 48 actually. The hole at the face of the near round port is elliptical because of the slant of the manifold mounting region. The minor axis (you can take a true measurement because the ellipse is rotated around it) is 36mm and the major axis is 48mm. The latter gets bigger the more the ellipse is rotated, or to put it more simply the more slant there is. The minor axis never changes. The true port size has to be measured inboard of the elliptical section and as I said, it will be near-round and appr 36mm dia at entry, tapering to some extent toward the port controlling section which will be somewhat smaller than the rest of your inlet tract - which is how it should be.

G
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parrish
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Joined: June 22nd, 2006, 7:11 pm
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Re: Measuring for shims.

Post by parrish »

Thanks for the reply Guy,
before i order my odds and bobs (ill send e mail) i have noticed something that i think may be of interest and may require a change of direction.
The head on the car is i believe from a Lancia beta FF S62 4372281.
The exhaust cam carrier box to head has 2 gaskets!
Not sure what to do now? should i proceed with the shims? should i be thinking of re-seating the cam box's and re-measure everything?
The shims on the exhaust side i would require are:
3.95mm
4.00mm
4.20mm
3.75mm

and the Inlet cam to head has a single gasket with loads of additional blue sealant?
The shims on the inlet side i would require are:
4.80mm
4.62mm
4.65mm
4.50mm

I have a second head FF S73 5991740 with 42mm inlet and 36mm exhaust (measured with a steel rule) standard cams are fitted, all shims are OK.
im wondering if i should swap the heads and investigate this flowed! head off the car.

The block 138AR1i believe is from a Ritmo Abarth and not the Strada Abarth i originally thought.

Is the addition of gaskets and additional sealant an attempt to increase/reduce the cam/shim gap? if so why?

Regards
Steve
PS: im looking very closely at the two heads you have for sale, thinking it may be a better option than spending money on two unknown heads, however the build up costs of cams etc is making it a very expensive option at the moment.

I should also report that i have identified a manifold air leak (poor brazing!)
Parrish 366
Guy Croft
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Re: Measuring for shims.

Post by Guy Croft »

no problem with the shims if u need to order please ring me 0044 1522 705222

Not unusual to have 2 gaskets on the ex side if the valves are way deep in the head. Using blue goo to seal the inlet side is not the best idea in the world and suggests the gaskets were not 'leak-free' .. which mine are.

Might be best to replace all gaskets but that will throw your shimming miles out.

Yes, a GC head prepped & built ready to fit is definitely what you need but I would say that would I not? It's what we need too as the UK_Eurozone_USA debt crisis is crippling my small firm and set to get far worse. However 2 our heads 4 sale have 43.5mm inlet valve so unless the pistons are made for them you could be in trouble. If the engine is 2 liter and of Strada origin it has those (originally I mean..).

BTW - Ritmo 125TC, Strada 130TC, Strada Abarth 130TC - 99.9% all the same. The 105TC Strada/Ritmo is a 1585 with the big inlet valves but way smaller ports. Can be modded however to 2 liter spec no problem.


G
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