Sorry if this has been asked and answered before.. Is a B 20F fuel injected head head inter-changeable with a B 20B head ??? I have a dead cylinder in my old B 20B and over all low compression on the on three.. I had a chance to buy a good B 20F engine on EBay within a 4 hour drive so I bought it just in case my old B 20B needs too much work.. On the B 20F the injectors have been blocked off as the previous owner had dual SU carbs on it.. I assume that the distributor,,starter and everything else is interchangeable.. Thanks for your time !!!

You can go right ahead and use the B20F head if you wish. Originally it had a little lower compression ratio than the B20B so it would pay to measure the height of the head--engine mating surface to top of valve cover surface--that will give you an idea of its present state--post results (measure it in mm) here and I'll bet someone can give you the answer. You'll get better performance and gas mileage the higher the ratio--no need to stay with the very low 8.7 (I think) to 1 of the B20F. Also check to see if the head is late enough to have original hardened exhaust seats (or if they have been added--a worthwhile mod). -- Dave

Hello,

Most pieces are interchangeable.

What you should be aware of is the different flywheels/flexplates in case you need to swap in the entire engine.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

I more than likely will just put the B 20F in my 1967 122S standard transmission car and may use the B 20B head to get away from the plugged injectors if the head is good..Regarding the flywheel and flex plate,, will I have to take them off the B 20B and put on the B 20F to line it up properly ?? Thanks for the tip !!

Hello,

The difference is very easily visible.

All B18 and early B20/B30 engines have 6 bolts to retain the flywheel/flexplate.

Later B20/B30 use 8 bolts.

--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

"Regarding the flywheel and flex plate,, will I have to take them off the B 20B and put on the B 20F to line it up properly ??"

It depends on what year the B20F is... they were sold in the USA from '72 thru '75, and the early engines had the same 6 bolt crankshaft and flywheel as B18's, B20B's, etc. But the later B20F's (I don't know exactly when the change occurred, and probably neither does anyone else) had an 8 bolt crank and flywheel.
--

Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

'74-'75 B20s had the 8-bolt flywheels, and they all had K-jet injection in the U.S. market. The D-jet ones were all 6-bolt (except for the B30, which never got K-jet).

I could have sworn my '73 142E was an 8 bolt flywheel. I owned the car from new for about 12 years, and at one point I put a clutch in it. Admittedly, that was a loooong time ago, but....

Meanwhile, see my reply to George below regarding 4980 series engines.
--

Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

I was told that this B 20F was an early engine so it should have the 6 bolts.. As long as everything lines up everything will be good.. The fellow had it in a 1969 1800 (not the original engine). I think he said it was a 1971 but he may have meant 1972.. I bought the engine in Canada if that makes any difference.. He took out the B 20F and is going to replace it with a BMW engine and trans. Thanks again for all the info!!!

If you will post the motor type number I can give you some info on it.
The number is on the left side of the block at the top above the breather box.
It will be partly cast and partly stamped onto a rectangular boss.
The first two (or possibly 4) numbers will be cast, and the first 2 digits will be 49.
Post the 49 and the following 4 digits, which comprise the motor type.
Examples: 496921, 498031, etc
--
George Downs Bartlesville, Oklahoma

I got these numbers. 49 8048 21958 Hopefully these are what you needed...

498048 is a fairly late B20F but not much more is given on it other than it had 115 hp.
But later ones were used on the 1800E and ES (498273 to 498278). So my guess is that this
is probably a 6-bolt engine. Most likely used D-jet.
You can tell on the head by the existence of the holes to mount the AAV at the front, about a 3/4" hole with a ¼"-20 UNC tapped hole at each side of it.
Hope this is helpful.
--
George Downs Bartlesville, Oklahoma

Hmmm.... my document (1973-74 parts catalog) says the only 4980 series engines used prior to 1974 are the 498058 and 498059, both applicable to the '73 model year only. The 498048 is shown as used in 142/144/145 models in 1974. If that's the case, more likely it's an 8 bolt.

I'd never looked into this before, but if it turns out this (4980 series) engine *is* an 8 bolt, you have to wonder - are all 4980's 8 bolt engines, while the other 49XX series (e.g. 4969, 4982) are 6 bolt? Has anyone ever attempted that correlation? Sure looks like a good possibility from here; the 1974 model year 140's were apparently shipped with nothing but 4980's, with a very light sprinkling of same showing up in the 1973 model year. One could guess those (1973) 4980's may have been late production. The remainder (and vast majority) of 1973 engines shipped in 140 series cars appears to have been 4982 series.
--

Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

As best I can tell where there are two similar motortype numbers, one even and one odd,
the odd number is for the AT version.
I went out to my garage and checked all the blocks I have (B20/30)
and here is what I found:
498284: A 6-bolt D-jet engine in the Yellow Peril (73 145E) NOT the original engine.
498285: A 6-bolt big bore short block I got from Ernie Olsen in Connecticut, 1 bad piston.
498196: Originally an 8-bolt B20A engine. I bought the block bare naked in Panama when the original big bore split a cylinder because of a 5/16" hex nut cocking the piston in the too-thin bore. Now has 6-bolt innards and burnt rod bearings (a long story)
498100 (2 of these) 6-bolt B30E or F blocks believed to be 1972. One came from the mountains of Panama after tradein to the dealer because of FI problems. The other came to me from Bruce Young (Lucid) from a car badly rusted out.
498101: 6-bolt 1972 B30F engine that came to me from Kent in SD. Originally AT but converted to an M410 tranny.
From the above the ONLY 8-bolt one, as best I can tell, is 498196, NOT the latest number.
So apparently later than some arbitrary cutoff number does NOT necessarily mean 8-bolt!
--
George Downs Bartlesville, Oklahoma

Agreed on the manual trans engines having an even number and the AT engines being odd. This is in the 6th digit position, e.g. 498058 & 498059.

And yes, the numbers are not necessarily sequential; as I stated in the earlier post, the 4980 series apparently doesn't exist until 1973, while the 4982 numbers show up in 1972 (the first B20F's).

But now about that 4981 B20A: what does your data say about where that engine was originally installed. 4981 does not show up anywhere in the 140 series parts catalogs, so it must have been installed in something besides a passenger car. Or maybe it was a replacement engine (or block) of some sort? The number is just weird, particularly since it matches known B30 numbers.
--

Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

498196 was weird in a lot of ways. As I mentioned it was identified as a B20A in my Motortypen
file. ONE Zenith Stromberg carb. The bare block was lying in someone's back yard.
I do know that Maquinarias y Equipos Romero SA gave up on FI maintenance and was importing
carbureted Volvos well into the B21 years. All of them that I saw had ONE carb.
This block has M12-1.75 threads on both the rodcaps and bellhousing mount, otherwise Unified
threads like earlier blocks.
It does not show any signs of being a marine engine, and was found for me by a mechanic who
USED to work for M&ERSA. I think I paid $200 for it. (I was desperate at the time.)
--
George Downs Bartlesville, Oklahoma

From what I've read on BB I thought the 8 bolt B20 engines were the ones that crossed over to the first 240's. I don't know of any markets other than the USA that got these, certainly not the UK. Quite why Volvo made this engine spec for the short time it was used, I don't know, but it might have carried on for a while in Penta form.

IIRC, the bottom end of an 8 bolt B20 was the basis for the B21 OHC engine. It was apparently a transitional manufacturing move on Volvo's part. At first I was surprised to hear there were markets that never had 8 bolt engines... but I then realized there were markets that never had the B20F engine, either. This is probably not coincidence. :)
--

Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

Thank you for your efforts,,George.. I wanted to know the HP so happy to hear it is 115.. Thanks

Ok,,thanks,,I will do that.. I will go up the garage tomorrow and get some numbers off the engine and post them.. The compression is 135.5 ,,145.5,,140,,135.5 cold.. and the oil pressure goes up to 50 psi as per the video he sent me when the engine was in the car so it must be in too bad of shape..