Volvo Community Forum. The Forums of the Volvo Owners Club

Forum Rules Volvo Owners Club About VOC Volvo Gallery Links Volvo History Volvo Press
Go Back   Volvo Owners Club Forum > "Technical Topics" > PV, 120 (Amazon), 1800 General

Notices

PV, 120 (Amazon), 1800 General Forum for the Volvo PV, 120 and 1800 cars

Information
  • VOC Members: There is no login facility using your VOC membership number or the details from page 3 of the club magazine. You need to register in the normal way
  • AOL Customers: Make sure you check the 'Remember me' check box otherwise the AOL system may log you out during the session. This is a known issue with AOL.
  • AOL, Yahoo and Plus.net users. Forum owners such as us are finding that AOL, Yahoo and Plus.net are blocking a lot of email generated from forums. This may mean your registration activation and other emails will not get to you, or they may appear in your spam mailbox

Thread Informations

B20A With 8 Bolt Crank

Views : 343

Replies : 6

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old Aug 2nd, 2021, 20:49   #1
mike gilbert
Master Member
 

Last Online: Oct 14th, 2021 10:59
Join Date: Dec 2003
Location: Peterborough
Default B20A With 8 Bolt Crank

I've just bought a B20A engine for an upgrade to my '68 1800S. Anyway on removing the gearbox and clutch I see it has an 8 bolt crank. So I know this makes it a late 140 engine and the rods are compatible with B21 pistons but also did these last B20's come with larger inlet valves as per the B20E/F heads? I'm sure I remember reading that all B20's got larger inlets at some point but the exhausts remained the same throughout. Excuse my ignorance but despite owning umpteen P1800's I have have always previously rebuilt and restored to original spec - unimaginative I know - and so never got involved in engine upgrades.
mike gilbert is offline   Reply With Quote
Old Aug 2nd, 2021, 21:20   #2
Burdekin
Chief Bodger
 
Burdekin's Avatar
 

Last Online: Today 20:09
Join Date: Oct 2009
Location: Aberdeen
Default

Yes and you can tell as they have the casting in the top of the head where the fuel injector hole would go. The casting is a P shape, see attached pic. It’s not the best pic but hopefully you can see what I mean.
Attached Images
File Type: jpg 2BCF476F-6FE4-45B9-8B04-AE53D02CAFFC.jpg (53.3 KB, 19 views)
__________________
One day I will get rid of all of the rust.
Burdekin is offline   Reply With Quote
The Following 2 Users Say Thank You to Burdekin For This Useful Post:
Old Aug 3rd, 2021, 16:39   #3
Derek UK
VOC Member
 
Derek UK's Avatar
 

Last Online: Today 13:03
Join Date: Jul 2006
Location: Chatham
Default

The parts book for late B20 in the 140 lists 7 different heads coving carbs and F.I. Interestingly they all list the same part for the inlet valves. Exhaust valves are listed for the carb models B20A/B and another part number for injection models. Pick the bones out of this. That took a while!
B20 Early 140
In #419639 B20 A/B/D
In #419760 B20E/F
Ex #419640 B20 A/B/D
Ex #419735 B20 E/F
B20 Late 140
In #419639 B20B
In #419766 B20 E/F
Ex #419640 B20B
Ex #419735 B20 E/F

All Carb heads after the introduction of F.I. had the blank pad for the Injectors. Numbers above indicate that both early and late carb heads used the same small valves in both positions. Later F.I. engines got the larger inlet valves.
Derek UK is offline   Reply With Quote
The Following User Says Thank You to Derek UK For This Useful Post:
Old Aug 3rd, 2021, 17:43   #4
Burdekin
Chief Bodger
 
Burdekin's Avatar
 

Last Online: Today 20:09
Join Date: Oct 2009
Location: Aberdeen
Default

Quote:
Originally Posted by Derek UK View Post
The parts book for late B20 in the 140 lists 7 different heads coving carbs and F.I. Interestingly they all list the same part for the inlet valves. Exhaust valves are listed for the carb models B20A/B and another part number for injection models. Pick the bones out of this. That took a while!
B20 Early 140
In #419639 B20 A/B/D
In #419760 B20E/F
Ex #419640 B20 A/B/D
Ex #419735 B20 E/F
B20 Late 140
In #419639 B20B
In #419766 B20 E/F
Ex #419640 B20B
Ex #419735 B20 E/F

All Carb heads after the introduction of F.I. had the blank pad for the Injectors. Numbers above indicate that both early and late carb heads used the same small valves in both positions. Later F.I. engines got the larger inlet valves.
That’s interesting Derek as Rob from Amazon cars says in one of his videos if a carb head has the P casting it will have the 44mm intake valves.

Towards the end: https://youtu.be/eZJF2x8ybKw
__________________
One day I will get rid of all of the rust.

Last edited by Burdekin; Aug 3rd, 2021 at 17:47.
Burdekin is offline   Reply With Quote
Old Aug 3rd, 2021, 18:41   #5
mike gilbert
Master Member
 

Last Online: Oct 14th, 2021 10:59
Join Date: Dec 2003
Location: Peterborough
Default

Well that is interesting and theres only one way to be sure. I have been offered a head labelled 'B20A from bigger valve era' and asked the owner to measure the valves for me. Mine definitely has the P shaped castings on the head but I dont want to take the head off yet just to measure the valves. We shall see.
mike gilbert is offline   Reply With Quote
Old Aug 3rd, 2021, 22:34   #6
Derek UK
VOC Member
 
Derek UK's Avatar
 

Last Online: Today 13:03
Join Date: Jul 2006
Location: Chatham
Default

As said, my numbers from the 140 parts books. Amazons and pre F.I. 140's with B20 heads I'm sure don't have the pads. 7 different heads listed which would have different specs of valves along with other fittings for both types of F.I.
As Rob said smaller ports keep the gas flow up, larger valves would slow it down and those heads may have had no extra port work. Some say keep the inlets small and make the exhausts bigger as the exhaust ports are so bad. No mention of raising the exhaust port floor but that takes us out of simple and cheap.
He said that they keep their engines simple. Fair enough, that also keeps the costs down too. £1k for a stage 2 (?) head for little practical gain. Rallying at less than works level and a little less power won't keep your engine from performing well. Lots of tuning things not mentioned. Decking the block to match the lowest piston for instance and that is basic blue printing and not "tuning". This maximises squish to get the maximum amount of fuel into the combustion chamber. Relieving around the inlet valve on the b18 if you fit a larger valve is effective on B20 too but it lowers the CR.
Derek UK is offline   Reply With Quote
Old Aug 5th, 2021, 12:56   #7
mike gilbert
Master Member
 

Last Online: Oct 14th, 2021 10:59
Join Date: Dec 2003
Location: Peterborough
Default

Well I decided to disassemble the engine this morning. The first stamping is 49 8032 which equates to a B20A from 1974 . The head does have 44mm inlet valves. As well as the 'P' shaped castings there is a flat casting on the head above no2 exhaust port which I've read was the same stamping as seen on the B20F head.
mike gilbert is offline   Reply With Quote
The Following User Says Thank You to mike gilbert For This Useful Post:
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 22:36.


Powered by vBulletin
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.