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My 144 has a B20, single Weber downdraft, and IPD headers.
My 142 has a B18, dual SUs, and one-piece cast iron intake/exhaust manifold (dual exhaust ports).
My plan is to swap the motors, ending up with the B20 in the 142, and sell the 144 with the B18. I'd rather run the SUs on the B20, but I'd like to keep the headers on it. Is there an intake manifold that would allow me to do this? Is there an exhaust manifold that would allow me to set up the Weber on the B18 without having to put headers on it?
Is my desire to keep the headers on the B20 completely pointless? If it's not going to help the B20 breathe any better, I'll just swap the whole carb/exhaust systems between motors. Sorry for the rambling questions. And thanks for any input.
TF
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i have a b20b that i bought with a single weber 32/36 and a older IPD 2.5" 4into1 header.
surprisingly even with the restricting weber i could feel the difference in high RPM with the header. it sounded like 4500 was the sweet spot when it would pull fast to 6000rpm
now i swapped both out for OEM parts. i have a P1800 aluminum intake with HS6 carbs and a Fuel injected B20 4-2 exhaust manifold.
prior to the change i had a 3foot section of 2.250 after the 2.5 header. then 2 feet of 2" pipe with it bottle necking down into the original resonator. with no rear muffler and possibly stock 1.875 piping ending with a 2" tailpipe.
now the car finally has low end and mid range. it does not like to rev as high and as fast now but im not concerned with that. my pedal input is far less (going from 1bbl to 2 single bbls constantly feeding. exhaust is 2inch with a straight through resonator and a 16inch glasspack for a muffler
no more "sucking sound" from the single barrel progressive. hated the change from primary to secondary. much better throttle response too. instant starting. the weber always took 2 starter rotations. even though it started better cold (even with no choke)
if you plan on keeping the m40 (no overdrive) and want to hit the freeway 65-70mph id say put a header on it. i got 23mpg driving 65-70 to portland. but i cant tell you how it will work with dual SUs because i never ran that combo.
--
68' 144s B20B M40
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Best is one piece iron B18B intake and exhaust.
2nd choice is butterfly one piece B20B with butterflies deleted.
Last choice is the aluminium manifold, with headers. IPD headers are junk, VPD headers aren't much better.
It takes an awfully good engine to need anything other than the stock exhaust, and then you need custom built headers, not one size fits all headers, take note that the good Swedish companies makes 4-2-1 headers in 3 different sizes.
--
69 142S Overdrive + 69 164S Manual
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Options are:
Procure an aluminum intake SU manifold from a 122 or 1800 ('67 or older)
Cut your cast iron manifold to separate intake and exhaust (not sure on difficulty, never done it, but have seen it done)
Run your weber
Lose the headers. And, honestly, unless you have a pretty heavy breathed upon engine, and you run it at high RPM, the header really won't do you much good. The one piece intake/exhaust with dual down pipe breaths quite well.
This final option is the one I would opt for.
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-Matt I ♥ my ♂
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Option 4 it is. At some point, I'd like to get into some headwork and put a cam in it, but even then , I won't do anything to wild. I'll use the SU/exhaust from the B18 on the B20.
I am curious, though, about the secondary throttle butterflies in that manifold. They don't seem to have a seal where the shaft goes through the manifold. Seems like it'd be prone to leaking there. I ask because I'm chasing vacuum leaks on the SU throttle shafts, and it seems like those other butterflies are also something to address, but I haven't heard anything about them.
Thanks!
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I had a 145 that had a full on race spec motor with DCOE side drafts, a while cam, ported and polished and over-bored.
Sure, a motor that totally could have benefitted from headers, but not having any, it was dual down stock manifold and simple 2" exhaust with a free flow muffler.
Might have had a bit more power with headers, but as it was.. total screamer in that configuration.
--
-Matt I ♥ my ♂
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OP wrote---"I am curious, though, about the secondary throttle butterflies in that manifold."
My suggestion would be to lose the butterflies altogether. I've ground the head of a 5/16 bolts thin--insert from the inside and use a seal and double nut on the outside. If you do continue to use the butterflies open up the flat plate covering the mixing chamber---I've sometimes found the chamber to be clogged with carbon.
The combo manifold will work just fine as matt b has written -- although it is sort of an ugly hulk. I've dressed one up by using high temp paint (white) - following instructions -- but here's a little tip that worked for me--learned the hard way--had to do the job twice ---- DON'T just start the motor and let it get hot when finished. Let the paint dry as instructed -- then run the motor for just a few minutes to warm. Shut the motor and let the paint have time to cure. When I did this the first time the paint disappeared (burned off) after letting the works come to full operating temp on first start up. My second attempt with the "curing" process had the manifold white for a long time. -- Dave
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The secondary butterfly shafts do not have a seal and will leak vacuum.
I regularly remove them and fill the outer holes with the same plug that Volvo used to fill the inner hole.
I used to buy the plugs from Volvo, but they have discontinued them. I used to remove inner plugs from broken manifolds, but I have run out of these, so I found another supplier of the same type of plug.
These plug just tap into the existing hole, no drilling or tapping.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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That's good to hear, as I thought those secondary throttles were kind of goofy. I'm interested in the plugs that you have sourced. Any chance you could sell me a couple, or share your source?
Thanks.
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I have read that the best of all worlds is the one-piece cast iron manifold used only in 1967. It has no butterflies. More interestingly, it has a simple integral cross pipe between the two carbs, i.e. it doesn't have the complication, (and potential flow compromises?), of the flat inspection plate that comes with the 1968-and-later butterfly versions. It mates directly to a dual downpipe exhaust.
Coincidently, Eric refurbished and plugged the OEM butterfly manifold on my '70 142 many years ago and it still works great with the car's Stromberg-Zeniths. That being said, I plan to upgrade (or is it retrograde?) to a '67 manifold and HS-6's when I get around to it.
Glad to hear of other 140's kicking around..
Will
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That '67 manifold does look good. If I keep the HS6's, I'll try to track one down.
My latest thought is to hold off until I can do some headwork and find some dual Solex's to recreate the 140 hp kit that Volvo did.
The bummer about having a 142 that barely drives is that I can change my mind about the car 100 times before making any decisions.
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