bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 24, 2006 20:54:02 GMT
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Next on the wish list of things to do to the Monza is a set of cams........
So
anyone got any links to sites that can explain in simple terms how to determine a decent cam profile
or
can explain what all the figures mean
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suffolkpaul
Part of things
Retro Free - just a pug 406 with 230k miles on it...
Posts: 696
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May 24, 2006 20:59:42 GMT
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 24, 2006 21:07:22 GMT
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Mmmm - good start but need more info
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suffolkpaul
Part of things
Retro Free - just a pug 406 with 230k miles on it...
Posts: 696
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May 24, 2006 21:08:22 GMT
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thought so.. lol
recomend a Vizard book on minis..i had that and it explained it all realy well.
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suffolkpaul
Part of things
Retro Free - just a pug 406 with 230k miles on it...
Posts: 696
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May 24, 2006 21:09:27 GMT
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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May 24, 2006 21:16:23 GMT
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What are the choices? The theorys all well and good but you normaly end up choosing beween a couple that are around the right area for the power curve you want.
Normaly just boils down to what rev range they give you the power and that info should be avalible from the company who grinds it. along with all the duration/lift/overlap etc. figures
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 24, 2006 21:28:01 GMT
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What are the choices? The theorys all well and good but you normaly end up choosing beween a couple that are around the right area for the power curve you want. Errr - choices are Easy and relatively cheap - buy a set off the shelf that is ground from an original std cam set Not so easy and a bit more expensive - Get a set ground to my spec from an orginal std camset (I have amassed 22 cams (11 full sets for the 24V engines) so I can afford to try a few different profiles to find a good one) Or go the expensive route - buy a set of Sreck or Cat cams that are machined from new blanks so they can have a wilder profile Normaly just boils down to what rev range they give you the power and that info should be avalible from the company who grinds it. along with all the duration/lift/overlap etc. figures Early days but at the moment I'd like to shift peak power up 500rpm and get a 10 bhp gain
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suffolkpaul
Part of things
Retro Free - just a pug 406 with 230k miles on it...
Posts: 696
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May 24, 2006 22:05:24 GMT
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if your car is a daily drive, id keep it fairly tame. you don't want it too lumpy when your sitting in traffic or nipping to the shops do ya???
or do ya?
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 24, 2006 22:07:53 GMT
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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May 24, 2006 22:48:54 GMT
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Getting a custom profile ground is a huge undertaking. You cant just pluck the numbers out of some equation and find a good profile straight away. You have to keep tweeking it and running dyno tests untill you have something close to what you want. Years of work.
Buy one off the shelf and all the hard works been done for you.
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Nick
Posted a lot
Posts: 2,483
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May 24, 2006 23:06:31 GMT
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one piece of advice, don't choose a profile that the rest of your valvetrain cant keep up with..seen this done many a time,
for EG: mr retard goes and buys cams with a power band from 2500-8500rpm, but the valvetrain starts pooping its pants at anything close to 7k..
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idea stolen from rattely eddie.
this weeks car count "5"
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 24, 2006 23:08:02 GMT
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Getting a custom profile ground is a huge undertaking. You cant just pluck the numbers out of some equation and find a good profile straight away. You have to keep tweeking it and running dyno tests untill you have something close to what you want. Years of work.. Agreed but I've been gathering all the cam profile specs from lot of sources for the 24V engines for a while and now I want to make sense of them........ hence the thread Plus I actually have reduced my valve to piston clearance so extra lift I don't want much - especially at the overlap stage Prefer road test to dyno but either way you need to have a benchmark to compare Buy one off the shelf and all the hard works been done for you. but that wouldn't be half as much fun and I'd learn rugger ball Don't take any of this the wrong way either - you have valid and reasonable points and it's good advice I'm hearing/reading - it's just easy is no fun
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 24, 2006 23:10:30 GMT
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one piece of advice, don't choose a profile that the rest of your valvetrain cant keep up with..seen this done many a time, for EG: mr retard goes and buys cams with a power band from 2500-8500rpm, but the valvetrain starts pooping its pants at anything close to 7k.. Ahhhh right so how does one determine that? Current cams and no rev limiter she'll rev past 7K no probs and still produce reasonable power even thou you are over the peak Peak power is 6300 (ish) from memory I'd like 6800 and I'll set the limiter to 7K then
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Try speaking to someone like Newman Cams who grind to order and customer spec. I've not used them myslef but I've heard good things. They'll recommend you what you need based on the other components in the engine and your use of the car.
You can't beat talking to people with the same engine though, find out what they fitted and what worked and what diddent.
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1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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Try speaking to someone like Newman Cams who grind to order and customer spec. I've not used them myslef but I've heard good things. They'll recommend you what you need based on the other components in the engine and your use of the car. OK - Ta - I'll do a search for them You can't beat talking to people with the same engine though, find out what they fitted and what worked and what diddent. Thats the trouble - I know hundreds of peopl with the same engine in various cars - Only one person has fitted srek cams and ported head etc etc and mine already makes more bhp than his!!!
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More BHP where... This is why you need to consider the engine as a wholistic approach.
Know of a guy had a V8 Ford with a certain set of mods. He slapped in a higher lift cam to get more power. On the dyno he showed an extra 20 horse or whatever so he was happy. But on the road the car was actually slower. See his extra 20 BHP was all at 6000 RPM and he'd got like a 50 BHP drop at 2500 RPM...
Also the guy with the cam and head work may have put it together wrong, got it badly set up, etc. And/or may be nmeasured differently than yours.... Unless you know different?
Sounds a tricky one to know whats best.
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Last Edit: May 25, 2006 9:54:48 GMT by akku
1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
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bstardchild
Club Retro Rides Member
Posts: 14,948
Club RR Member Number: 71
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May 26, 2006 10:18:56 GMT
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More BHP where... This is why you need to consider the engine as a wholistic approach. Know of a guy had a V8 Ford with a certain set of mods. He slapped in a higher lift cam to get more power. On the dyno he showed an extra 20 horse or whatever so he was happy. But on the road the car was actually slower. See his extra 20 BHP was all at 6000 RPM and he'd got like a 50 BHP drop at 2500 RPM... Fair point - more power sometimes isn't more...... Also the guy with the cam and head work may have put it together wrong, got it badly set up, etc. And/or may be nmeasured differently than yours.... Unless you know different? Sounds a tricky one to know whats best. I do but if I rattled on a bout that it would be anal and seem like I was arguing with you and I don't want to do either cos you raised some valid points Biggest problem is you can't vernier the cams up cos steel sprocket/Chains and fixed locations on the cams - Compounded by a piggy back arrangement for the Inlet This means any cam ground from the original OE items has some limitations on what can be done. Any cam grond from a new blank however can have the timing changed My engine can't cope with a lot more valve lift as I am already using the piston pockets at TDC I'm doing a table in xls to compare all the profiles I have found one day I will understand it!!!
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May 26, 2006 16:27:28 GMT
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Nah, it was a genuine question. I'm sure we've all seen it before/done it before. Done a bunch of mods and the car runs like cr@p afterwards. Or gone for the "I'll wang the biggest carb on it that I can find, ooh, why doesn't it idle properly any more?" Hee hee. So the other car has the mods, they're done right and set up properly. Assuming theres no other problems like blow-by occuring thats hurting his output then I dunno what to say really. Unless he's started with a lower compression motor than yours or something? a point of compression could make 12 BHP on your six (admittedly thats a wild guess based purely on what I wildy guess VE to be on those motors!). Or you're just a tuning god amongst men who gets a pile more power out of a stocker than other guys can out of a modded motor! Chose which answer suits you best Its often said that the single most important valve train event is the opening of the inlet valve relative to the rest of the cycle. I always prefer to look at stuff in a wholistic viewpoint, but assuming you have good compression and minimal pumping losses conventional wisdom says the earlyier you open the inlet the more power you make. Thats the whole idea behind advancing a cam. But to my mind just go for a longer duration and you can get earlier opening and keep the exhaust open to fully purge the chamber after combustion. I guess timing gets more controllable on a twink than the old cam in block stuff I play with though.
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1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
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