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Discussion Starter #1
I have a '75 242 with the stock B20. I am going to remove the FI and swap in a rebuilt cylinder head, SU carbs, etc.<p>I have two very similar cylinder heads of unknown origin with subtle differences in casting numbers. Neither has the FI port on top of the head. ANybody have a resource for ID'ing by casting number or other means?<p>Cylinder head #1:<br>(under valve cover on left)<br>25<br>NCG<br>(under cover, middle)<br>1-<br>419305<br>VOLVO<br>(Outside valve cover, behind thermo housing)<br>F197<br>(driver side of head, casting is upside down)<br>2<p><br>Cylinder head #2:<br>(under valve cover on left)<br>28<br>NCG<br>(under cover, middle)<br>1-<br>419305<br>VOLVO<br>(Outside valve cover, behind thermo housing)<br>D2<br>(Outside valve cover, above first intake, exhaust ports)<br>7<br>(driver side of head, casting is upside down)<br>3
 

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Re: Cylinder head ID (roger456)

The 419305 I think is the raw casting part number for the 419304 head that was used on B20A, B20B and B20D engines. All are Carb engines used in the 140.<br>The other numbers may have something to do with time of casting, what mold was used, etc.<br>I'd bet that there are flat spaces where the fuel injectors would go.<BR><BR>
<i>Modified by VolvoBob at 7:44 PM 11-4-2006</i>
 

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Discussion Starter #3
Thanks for the info. My main concern was that these not be B18 heads. Is there a way to determine whether they ar A, Bm or D<p>There are no smooth places on the top of the head that you would expect to see for machining a port for the fuel injectors.
 

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Re: (roger456)

B18 heads and B20B heads are visually pretty similar. B18 heads have seals on top of the valve retainers, while B20 heads have seals under the retainers, around the valve guides -- that's the quickest way to be sure. Even if the B18 seals are missing, there won't be any on the guides.<p>B18 combustion chambers measure 87mm across the widest part, B20B chambers are 90mm (all injection heads and very late carb heads are 92mm). B18 intake valves are 40mm, B20B 42mm (injection and late carb heads 44mm).<p>
 

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Re: (roger456)

The designation B20A, B20B or B20D did not deal directly with the head but rather the engine. The A was a single carb while the B and D where dual.<br>The bearing surfaces are better on the D engine.
 

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Re: (VolvoBob)

Okay, what is a B20D? The very late carb engine never sold in the U.S.? I'm only familiar with these:<p>B18A = low CR, "A" cam, single carb (sold in the U.S. only in the P210)<br>B18B = high CR, "C" cam, dual carb<br>B18D = low CR, "C" cam, dual carb<p>B18C is a tractor motor I don't know the details about.<p>B20A = don't know the CR, "A" cam, single carb (not sold in the U.S.)<br>B20B = medium CR, "C" cam, dual carb<br>B20E = high CR, "D" cam, D-jet injection<br>B20F = low CR, "D" cam, D-jet '72-'73, K-jet '74-'75<p>All these motors use exactly the same crank and bearings except for the '74-'75 B20F, which have the same crank and bearings and the B21/23. Connecting rods were weak '74-'79, substitute '80-'83 rods for those in performance applications.
 

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Re: (Phil Singher)

The bearings were indeed different. The B18B used indiumplated lead-bronze bearing metal while the B18D used Babbit's metal at least in production.
 
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