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Just wanted see what everyones thoughts were on camshafts. I have a 68 wagon with a B20 from a 75. Dual SU carbs and exhaust are the only mods. I would like to get a little more power. Not quite to the supercharger or turbo stage yet, but would appreciate some power gains.
What cams work well with this set up? I looked over IPD's selection and honestly they seem overpriced. Through isky the prices are nearly half of IPD......
thank you
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My B20E is bored .030" oversize and is running the "STREET TORQUE" cam ..if I were to do it again,I believe I would op[t for the "STREET PERFORMANCE" grind... it would definitely have more top end than what I have. My carbs are rebuilt HS6s with I believe DX needles and I have the dual downpipe manifold and a 2" exhaust system exiting through a 14" MAGNA FLOW muffler and a bubble type resonator.
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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Your biggest inexpensive gain will be from raising the compression ratio. Shave the head down .050" and put it back on with a Fel-Pro 21176B head gasket, and you'll pick up about 20 HP.
I use the D am you already have for lower-budget performance engines, and it works quite well. Most aftermarket cams require double valve springs (and machining the head to accept them), a metal timing gearset of some sort, and any cam change requires new lifters. It adds up to several times the cost of one the the less expensive "performance" cams.
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I thought a 75 B20 had a K cam?
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Lee 75 244 (80k original miles) 79 242 65 220 project
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Quite right! Slight brain burp on my part, sorry... My advice still stands, though.
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K and D cams are pretty clsoe to each other in any case. Both are quite nice on a mostly stock motor, compared to the C cam.
It's a fairly well known 'secret' that the IPD cams are really resold Isky cams. I think the Street Torque cam is the VV61, and the Street Perf. cam is the VV71. These are rather 'vintage' cam profiles, however, and as such they tend to offer more tradeoff. There are some more modern profiles around with less tradeoff (low rpm torque vs. high rpm power), but they tend to be a bit more expensive. KGTrimning, V-performance, et al.
The trouble with sticking a really racy cam in an engine is that it is just part of the equation. The cam largely tunes the valve timing to optimize it for a certain RPM range. 'Racier' cam tend to put this up at higher RPMs. But if the intake, head, and exhaust can't flow well enough to feed the cylinders at that RPM, then you've probably just made things worse. The cam won't flow quite as well in the ranges the engine can support, and the engine can't flow well at the RPM's the cam is tuned for.
Any effort spent on the heads should probably be concentrated mostly on the exhaust ports. Comparing my R-sport head to a stock 'F' head, the intakes are largely the same (although the R-sport has larger valves). But the exhaust ports are dramatically larger. The 'F' head has what appears to be intentional restrictions just past the valve seats. The port jsut squeezes down. Perhaps it was intended as a sort of passive EGR system where the restriction caused a small bit of reversion for emissions purposes? In any case, that's a rather easy and obvious target. And a larger exhaust valve should be on the list before a larger intake. The main problem with the exhaust ports, however, is the basic geometry where it makes an immediate sharp 90 deg. bend and exits the head just 1/4" or so above the roof of the combustino chamber. That sharp bend makes it so the flow is somewhat counterintuitive. I don't know much about porting at all, but I surmise that is why most Chevy/Ford/Mopar head grinding guys won't do so well on a Volvo head's exhaust ports.
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'63 PV544 rat rod, '93 Classic #1141 245 +t
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And a larger exhaust valve should be on the list before a larger intake.
You'd have to do some pretty effective porting on the exhaust side for a larger exhaust valve to do any good, and make a substantial amount of power before you'd need one. It's only needed for pretty burly engines, and only if you already have the 44mm intake valves.
Remember that in a normally-aspirated engine, you only have atmospheric pressure to propel the intake charge, no matter how effective the porting, cam, and header are, and how much power you can make is ultimately limited by the intake valve size (assuming you get everything else right). The exhaust is driven out under very high pressure, so the exhaust valve size is much less of an issue.
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K and D cams are pretty clsoe to each other in any case.
Untrue. The K cam is very slow off & on the seat, while the D cam is noticeably quicker. From seat to seat the K is the larger of the two, but from .050" onwards, the D is larger. The K is also single pattern, while the D is dual.
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John .... Phil Singher and I were discussing this earlier in the postings and he suggested that doing anything with the exhaust ports with my B20E heads was a waste of time.... He suggested that the work on the intake was worth doing .... I have heard so many conflicting opinions about porting the B20 heads I am getting more and more confused. Could Phil's comment about the exhaust ports be because I am running an E head and not a F or B head??
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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Now, wait a sec... I don't see where I said that porting intakes was worthwhile, but porting exhausts was a waste of time. I may have said that with the mild VV61 cam, you wouldn't gain a lot by porting the exhausts on the E head, although you'd have some slight gain. With a more aggressive cam, you'll get more gain from porting the exhausts than the intakes, which are not bad in stock form.
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I may have said that with the mild VV61 cam, you wouldn't gain a lot by porting the exhausts on the E head
Every single extra CFM found in the exhaust port translates to power everywhere, even with cams as small as the K & the W61. It's also free horsepower.
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I have heard so many conflicting opinions about porting the B20 heads I am getting more and more confused.
I started porting B20 heads in the late 80's & I'm still confused.
There's a myth going around that the F heads are different to the E heads in the exhaust port area but the difference is actually the year that the head was cast.
From roughly '73 onwards, the floor of the exhaust port was lifted adjacent to the valve. It doesn't matter if it's an A, B, E or F. I suspect that the competition department asked for the casting change because the later model head actually flows worse than the earlier head in it's standard form, but is much better after porting.
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I THINK my engine is a '72... definitely an eight bolt flywheel motor. Had I known at the time that the Street Torque cam was a lesser cam than the K/D cams I probably would have gone for the Street Performance version or a K or D camshaft. My motor runs well, but has less top end than I was expecting. The car was always sluggish off the line and I was trying to improve that area of it's performance when I selected the Torque Cam.
So ... with all this new and wondrous information, If you were to replace my cam and do some head work ... what would you do to get the best bang for your buck ? I'm already .030" over with compression at 10.5:1. I am in the process of a ground up restoration of "Ole Reliable" and even though I have only about 10,000 miles on my rebuilt engine, I might want to bite the bullet and give myself more top end.
Not limiting myself to just the 3 camshafts mentioned above, and realizing that most of my driving is highway cruising with some periods of insanity running the cones in parking lots thrown in, what would you "experts" suggest?
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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Had I known at the time that the Street Torque cam was a lesser cam than the K/D cams
The street torque W61 is the same size as the K cam, the only real difference is the lobe centres are tighter together, which, all things being equal, makes it a little more torquier because the inlet's lobe centre is in a much better place.
What have you got for an intake & exhaust system? If you only have twin HS6 SU's, then I would get a head from VPD to match that, i.e., nearly standard intake injected head with all the money spent in the exhaust ports.
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Loved the recommendation to buy parts from Vintage Performance...Don't make me laugh - I've been on the "wait-list" for 18 months and still haven't got either my head or my cam. Buy parts from people that can produce.
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I wouldn't recommend buying a cam from VPD, you can get one of those from anywhere. I should make some recommendations based on what's available to you from other cam grinders that are closer to you. Isky has some profiles that are just fine, but they need to be dual pattern like VPD's.
Example: For a standard head I would use the W-61's inlet, but a longer duration for the exhaust like a Cosworth A3. With dual springs, you can use higher lift on the intake, but keep the duration around 215 degrees @ .050" like the W-61 or the Volvo K cam. With a modified head & dual springs, I'd go with W-71 for the inlet & W-81 for the exhaust, but you'd have to have 2x DCOE's or MegaSquirt to get the most out of it. Elgin & Crane also have profiles suitable for B20's, but I'd avoid Comp Cams, they have too much lift to survive for long in a B20.
VPD's heads: John Parker has showed me flow figures for his heads & they are good to great. I can do similar to his street head, but I can't get near his race head, so if I was in the market for a head & couldn't do one myself, I'd join the queue.
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Paul ... the manifold is a steel dual downpipe unit without the secondary butterflies. The exhaust is 2" into a 14" Magna Flow and a 10" bubble type resonator .... was WAY TOO LOUD with just the Magna Flow ... you can look right through both muffler and resonator so not much in the way of back pressure ...
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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Hey Brett, I'll deave the discusion on teh best cam for others to hash out, but if you want a VV 71, I have a new one sitting on the shelf that I'm not likely to ever use. No lifters or push rods, just the cam. $100
contact me off-list if you are interested
Ron rondame@bellsouth.net
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Thanks Ron, but it's going to be a while before I am ready for the engine work ... have a LOOOOONG way to go body wise and suspension wise .... but I'll keep you in mind and store your message away for future reference .
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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Don't feel bad -- having over-cammed several Chevy V8s many years ago, I also was leery of the SP cam and used the ST in my first attempt at a Volvo performance engine. Power would quit somewhere in the low 4000s, and I think a lot of that was the cam choice, although the engine certainly had other problems too.
On a tight budget, I would put in a D cam and new lifters (the Isky SP feels sportier, but I'm not convinced it makes any more power than the D and has less low end). You'll need new lifters, of course. Valve lash for the D is .015-.016".
I would use a .030" head gasket -- Fel-Pro #21176B would be my preference, even though it's not listed for use with an injection head. That brings the pistons .020" nearer the head, which improves combustion. You'll be able to run a bit less timing advance.
You can bring the compression back into limits by having the chambers milled out slightly. Move the straight edge of the chamber further away from the spark plug side, but do not widen the round sides of the chamber. With your bore, something like 50cc chamber volume is reasonable (I think the E head has 47-48cc chambers, so you don't need to take off a whole lot).
Have hard seats fitted for the exhaust valves, if you haven't already.
Stop here if you're out of budget... If not:
Port the exhaust side moderately. Do NOT lower the highest point of the bottom of the port, just smooth the sharp radius as much as possible, and square out the corners a bit. I don't think any decent porter will have any trouble improving the bowls immediately behind the valves on both intake and exhaust. Leave the rest of the intake alone.
If you have the aluminum intake manifold, grind out the carb side so the ports there are nice and round -- you can do this yourself. Do NOT enlarge the head side of the ports, even though the runners are smaller than the intake ports. If you have the first version of the integrated manifold with the flat balance tube on top, I don't know what helps that one (never tried it myself). If you have the later one with arc-shaped balance tubes and a central plenum, cut the exhaust part off, throw the intake part away, and get an aluminum intake to modify.
See if that doesn't work a lot better.
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Wow. I just learned more about building a budget engine in a few paragraphs than I have been able to glean from months of cruising Google hits. Thanks.
I assume the same approach works on a B18?
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Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 51 year old fat man ;-) -- KD5QBL
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Sounds good Phil. I will file it away for future use after we get the body ready for the drive train reinstall. You got any guess as to how many ponies I might be looking at gaining ?
Thanks
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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With the right head/cam combination, I've heard that producing 130 HP at the rear wheels is realistic. The performance would be out of this world compared to stock.
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You can get quite a bit more than 130 HP at the wheels from a streetable B20, but it's expensive. With the "do what's cheap" tips I gave Brett, he'd be doing very well to get 110 -- but that's still a very noticeable gain over what he's probably got now.
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Hi Phil,
I was giving a best guess for what is realistically acheivable with mild porting/cam and exhaust. For anyone that is considering this avenue of performance upgrades - I think suspension and brakes are required...and I don't want to open up the can-o-worms about the adequacy of the brakes. They could use some help.
Craig
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The single circuit hydraulic systems may be a little scary, but other than the early 122's with drum brakes up front, they have very nice brakes. They were the same brakes used on some heavier, more powerful cars.
http://www.google.com/search?hl=en&safe=off&rls=GGLD,GGLD:2005-13,GGLD:en&q=+site:www.autopart.com+raybestos+pgd4
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'63 PV544 rat rod, '93 Classic #1141 245 +t
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The "E" Head I have has 9.5:1 compression ... probably the highest of any of the stock heads.
Phil, I was wondering what your opinion is of porting and polishing one of these heads. I have always thought that this is where the biggest gains should be able to be made.....
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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U.S. market E heads were 10.5:1 CR, and only on '70-'71 engines. From '72-'75 we had F heads, with 8.7:1 CR and a thicker head gasket to boot. In other markets, anything with D-jet was called the E, and anything with K-jet was the F. I don't know how that went in Canada...
In any case, shaving the head AND using a thinner gasket to bring compression up to around 9.5:1 will result in very noticeable power gains on a U.S. market F engine, and it's cheap.
I'm all for porting, but that's expensive. I don't port my "bottom of the range" engines at all, and customers still seem to think they go quite well. I would very much recommend porting to take advantage of a good aftermarket cam -- it should come first.
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OOPS my Bad ... 10.5:1 ...you're correct sir .... I have heard from several sources that the Volvo pushrod heads don't respond well to porting ... I always wondered why. Too bad Edelbrock or some of the other aftermarket head manufacturers don't make one for the VOLVO gang .... one can dream .... ;-)
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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They respond very well to porting, but it's all too easy to get it wrong and cause turbulence. What looks right may not be right at all.
There have been several attempts to make aftermarket heads for B20, but apparently the coolant chambers in the head make it very difficult to do (and the block requires them to be a certain way).
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So, in other words , a Flow Bench would be almost an essential to getting the job done right ?
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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That's a controversial subject among engine builders. I think a flow bench is a really good way of testing that you haven't screwed up the porting, but I don't think it's a good predictor of what power gains you'll get in actual use. The guy who does porting for me just uses his as a cross-check, and he's hardly got room for all the trophies he's got in his shop.
Experience counts for a lot. The outfit that did the head for the MPPE doesn't have a flow bench at all, but they've been doing Volvo heads for 25 years and know what works. Duane Matejka -- who was absolutely dominant for years racing his vintage P1800 -- doesn't believe in flow testing (he says it's old-fashioned). OTOH, John Parker has put a huge amount of effort developing heads on a flow bench, and that certainly works for him.
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With a good port and polish job how many HP do you think you can gain on the same engine with all other things remaining the same except the head ? I suppose carb jetting would enter into the equation also .....
Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com
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No simple answer. With a mild cam and a relatively low-revving engine, you might not gain a lot, as the stock ports are not a restriction at those flow levels (yes, you would get some slight gain). In your case, figure that the E is the best-flowing of all the B20 heads, and that the Street Torque cam is milder than the Volvo D cam the head was designed to work with.
The more aggressive the cam, the more important porting becomes, in a nutshell. BTW, we don't polish -- the intakes like some roughness (a fine sandblast finish is best), and it makes very little difference on the exhaust side, not worth the trouble, IMHO.
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If you raise the compression, do you have to use those bakelite spacers between the carbs (HS 6)and intake manifold? I've been thinking of raising the CR when I have the head rebuilt on my sedan, and wondering what else I might have to do to support the change.
Bill
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The spacers on the carbs are thermal insulation more than anything else.
With 2 gaskets and the heat shield I feel they are pretty unimportant.
(None of my B18s or B20s, or B30s, for that matter, have ever had them.)
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George Downs, Bartlesville, Heart of the USA!
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