My understanding is that it has to do with the head depth and head gasket thickness. The B20Fs used a thicker head gasket. I have my ‘72’s engine out right now for a total rebuild and part of the performance upgrades is decking the head to increase compression and using the E gasket. Both E & F FI engines for 71 &72 used the D cam I believe.

 

My understanding is that it has to do with the head depth and head gasket thickness. The B20Fs used a thicker head gasket. I have my '72's engine out right now for a total rebuild and part of the performance upgrades is decking the head to increase compression and using the E gasket. Both E & F FI engines for 71 &72 used the D cam I believe.

No on the cams. In North America all the fuel injected cars were equipped with B20F engines starting in 1972 and the B20F definitely got the K grind camshaft as part of the emissions control package for 1972. The K grind has a nudge less overlap which makes it idle better. Max lift and the timing events are the same (when measured at 0.05" lift). Edit - I HAVE BEEN CORRECTED. THE F ENGINE STILL HAD THE D CAM FOR 1972 AND PERHAPS 1973. I FOUND A REFERENCE THAT SUGGESTED THAT THE K CAM DID NOT COME UNTIL VOLVO SWITCHED FROM D JET TO K JET IN 1974.

http://www.1800philes.com/ianr/_superlist_grinds.html

Be careful in your search for a true E head gasket. I found out from Phil Singher that the head gaskets that come in the bundled top end gasket kits for fuel injected B20 engines are all B20F head gaskets, even if it is listed for a 1970 of 1971. This helped explain why my compression tests never came out quite right after I rebuilt my B20E with an Elring gasket set. You can get a gasket of the correct E thickness (check the 1971 service manual for specs) by ordering one from Cometic which are available in a wide range of thicknesses for the B20. Cometics are a tad pricey and require a high quality finish on the block and head surfaces. Phil advised that the budget way to get a head gasket in the correct 'E' thickness was to purchase a gasket for a Volvo 1971 or earlier B20B. I have not checked the service manual to confirm that the thicknesses are the same; but, that is my plan if I ever get sufficiently motivated to pull the head to rectify the problem.

 

For US spec cars, the E was used in 1970 and 71 only; 1972 and 1973 B20s were F; and 1974/75 B20s were F with Kjet fuel injection.

E and F heads are different but use the same gasket.

 

I am aware of the 1971 - 1972 change for US spec cars. What I was curious about was the reference to the B20E version being available in 1972 and that the horsepower had increased from 130 to 135 hp. The 1972 1800 ES owners manual I was looking at was in English so presumably the 1972 E engine was for Great Britain and perhaps Europe? I was really curious about what change was made to the B20E between 1971 and 1972 that resulted in the 5hp increase in peak output.

 

Please post the thickness of the true E head gasket when you find it. Thanks

 

Here you go.

The 1971 factory service manual specifies a thickness of 0.031" (0.028" compressed) for both the B and E gaskets.

I did find the thread in the pushrod performance forum discussing the issue (with the thicknesses).

https://forums.swedespeed.com/showthread.php?270145-B20-head-gasket-thickness

Turns out that the Elring B gasket is still a nudge thicker than the service manual value for the B & E gasket. Phil advises that it crushes to around 0.033 - 0.34" which leaves it thicker than the 0.028" specified for the B & E gasket. If you check the MLS web site they do not differentiate the gaskets between B20A, E and F applications, so the intrusion on the fire ring with the B gasket in the E head that Phil mentioned does appear to be a non issue.

If you want a true 'E' thickness head gasket, I think you are going to have to go with Cometic. The only thing I have not been able to confirm is whether the advertised thicknesses are the uncompressed or compressed thicknesses.

The other uncertainty I have is with the 90mm versus 92mm bore option on the Cometic gaskets. I had always assumed that the 92mm bore option was for people who were installing B21 pistons in their B20 to create a larger engine 2.1 l engine. However, I did stumble across some information suggesting that the fuel injected heads have a larger 92 mm combustion chamber diameter. Once again there is conflicting information as to whether this change occurred starting with the 1970 E head or another source suggesting that it occurred with the 1973 or 1974 F head. Maybe its all conjecture. Maybe the only way to put it to bed is to measure the combustion chamber diameter. As a further side note, the old spec sheet for the B20E/B20F Elring head gasket in my engine specifies a diameter of 91 mm - split the difference????