'71 429 cobra jet engine - correct cam shaft to use today...
+9
billandlori
SLord82
supervel45
Scott Foxwell
Super Snake Steve
Straubtech
rmcomprandy
crittersf1
Pastel Blue
13 posters
Page 2 of 2
Page 2 of 2 • 1, 2
Re: '71 429 cobra jet engine - correct cam shaft to use today...
Scott Foxwell wrote:Why is that?rmcomprandy wrote:Super Snake Steve wrote:This would be a good time for the professional engine guys to clear this up as far as the roller set up's go's I've read a few times on this board that a roller set up in the 385 series that a roller up is a lot of maintenance and for a street set up it is normally recommended to go solid and sometimes hydraulic can't remember just how its go's but its recommended to use either hydraulic lifters with solid roller or solid lifters with hydraulic roller like I said can't remember witch way I don't know why you wouldn't use say solid roller cam with solid roller lifters with that said I stopped by Jon Kaase shop about a year ago and I asked him about running roller set up on the street and maintenance and he said not a problem anymore and he had that all worked out and a roller for the street was reliable of course he didn't go into detail of what all he has done to achieve this so anyone wanting to share please do thanks
There WILL be rapid wear on the valve guides or valve stems of a high usage engine when stud / guideplate rocker geometry is used with that extra pushrod side angle.
With the extra side angle of the pushrods, (because of the higher pushrod seat in the hydraulic roller lifter), when using a readily available guideplate type rocker set-up with existing stud locations and the boss angles, the rocker tip/roller will exert sideways motion upon the tip of the valve.
In mid 90's Ford Motor Company testing, the sled type friction, bolt down rocker arm fulcrum and stamped rocker arm would wear beyond allowable limitations simply resisting that rocker from twisting during valve opening and closing.
At just 1,600 RPM this happens 12 times every second.
Bronze guides with stainless valve stems don't wear near as much as cast iron guides with O.E.M. valve stems but, after 20,000 street miles and heat cycles, you'll still be required to resize guides in those heads because of that sideways motion.
EDIT: The less the valve spring pressure will help this situation as the valve tip will not be exerting as much force on that rocker arm tip.
If you're not worried at all about needing a high mileage engine, then have at it.
The short deck Cleveland type engines have the same pushrod angular issues but, none seem to be used for anything requiring "high mileage".
A "BALL" type fulcrum saves the that part but, the sideways motion of the rocker arm tip is still present if valve cant angle is much different than the pushrod angle or, with a sled type fulcrum the boss location and its angularity have not been changed to minimize this happening.
Re: '71 429 cobra jet engine - correct cam shaft to use today...
Thanks Randy. Appreciate the response.
Scott Foxwell- Posts : 419
Join date : 2011-06-23
Age : 66
Location : E Tennessee
'71 429 cobra jet engine rebuild...
supervel45 wrote:http://www.lunatipower.com/Product.aspx?id=2299
That is pretty close to the stock cj cam? looks like it. Would they sell a matching valve train kit for this? After reading all of these posts, giving consideration to the restoration build I am doing, it may be wise just to go stock valve train to avoid any possible issues with roller installation. i havent giiven up on this, would need to know that my machine shop undertands all of the variables before moving forward on a roller install. I will have to discuss with my machine shop when the engine goes in to see what they are aware of when it comes to BBF engines. Not a lot of options in my area for engine rebuilds...
Pastel Blue- Posts : 47
Join date : 2016-02-21
Location : Niagara, Ontario, Canada
Re: '71 429 cobra jet engine - correct cam shaft to use today...
Pastel Blue wrote:supervel45 wrote:http://www.lunatipower.com/Product.aspx?id=2299
That is pretty close to the stock cj cam? looks like it. Would they sell a matching valve train kit for this? After reading all of these posts, giving consideration to the restoration build I am doing, it may be wise just to go stock valve train to avoid any possible issues with roller installation. i havent giiven up on this, would need to know that my machine shop undertands all of the variables before moving forward on a roller install. I will have to discuss with my machine shop when the engine goes in to see what they are aware of when it comes to BBF engines. Not a lot of options in my area for engine rebuilds...
No it is not close to the stock cam. The one Randy mentioned is about as close as you can get with a shelf grid.
SLord82- Posts : 145
Join date : 2011-07-02
Re: '71 429 cobra jet engine - correct cam shaft to use today...
Crane cams makes blueprint replica OEM Musclecar Cams
Super Snake Steve- Posts : 141
Join date : 2012-07-18
Re: '71 429 cobra jet engine - correct cam shaft to use today...
For your stated usage of this engine, why go to the expense and trouble of converting to anything but the factory valve train. You will not see any gains that are worth it. IMHO
DanE- Posts : 90
Join date : 2010-04-01
Re: '71 429 cobra jet engine - correct cam shaft to use today...
A copy of the 429 CJ cam would work well imo.
I have used that in a 460 build and it ran very well - way back in the 80's
I have used that in a 460 build and it ran very well - way back in the 80's
68galaxie- Posts : 351
Join date : 2010-04-13
Location : Edmonton AB
Re: '71 429 cobra jet engine - correct cam shaft to use today...
This is directly from Ford Motor Company Engineering documents:
429CJ hydraulic lifter cam .. FMC part number C9AZ-6250-A
lobe lift ... 289"/.289"
theoretical valve lift ... .500"/.500"
SAE duration ... 282/296
Lobe separation ... 115.5 degrees
intake lobe centerline ... 116 degrees
460 Marine hydraulic lifter cam ... FMC part number D3JE-6250-AA
lobe lift ... .283"/.290"
theoretical valve lift ... .493"/.502"
SAE duration ... 288/292
Lobe separation ... 115 degrees
intake lobe centerline ... 115 degrees
Both cams are right around 216/220 degrees @.050" lifter rise
429CJ hydraulic lifter cam .. FMC part number C9AZ-6250-A
lobe lift ... 289"/.289"
theoretical valve lift ... .500"/.500"
SAE duration ... 282/296
Lobe separation ... 115.5 degrees
intake lobe centerline ... 116 degrees
460 Marine hydraulic lifter cam ... FMC part number D3JE-6250-AA
lobe lift ... .283"/.290"
theoretical valve lift ... .493"/.502"
SAE duration ... 288/292
Lobe separation ... 115 degrees
intake lobe centerline ... 115 degrees
Both cams are right around 216/220 degrees @.050" lifter rise
Re: '71 429 cobra jet engine - correct cam shaft to use today...
Pastel Blue wrote:supervel45 wrote:http://www.lunatipower.com/Product.aspx?id=2299
That is pretty close to the stock cj cam? looks like it. Would they sell a matching valve train kit for this? After reading all of these posts, giving consideration to the restoration build I am doing, it may be wise just to go stock valve train to avoid any possible issues with roller installation. i havent giiven up on this, would need to know that my machine shop undertands all of the variables before moving forward on a roller install. I will have to discuss with my machine shop when the engine goes in to see what they are aware of when it comes to BBF engines. Not a lot of options in my area for engine rebuilds...
I am about sure Lunati can hook you up on spring's ect. A comp Cams 926 single with damper or even a Comp Cams 972 single with damper if you want a little lighter spring would likely work fine too with the right retainers. It's not that complicated like Lem said. Pick your poison and go with it.
PS: Comp Cams list's the 926-16 spring for their 270 Magnum BBF cam which is pretty close to the Lunati CJ Repop. Might be the ticket for it also.
Comp Cams Spring 940-16 for the BBF 268 H-10 which is .494 Lift.
supervel45- Posts : 4498
Join date : 2013-09-04
'71 429 cobra jet engine rebuild...
Thanks all for the continued replies... I am learning.
Randy, I have sent you a personal e-mail message (off your web-site submission page) regarding the rebuilding of my engine. Please take a look at it and let me know your thoughts. Thanks
Randy, I have sent you a personal e-mail message (off your web-site submission page) regarding the rebuilding of my engine. Please take a look at it and let me know your thoughts. Thanks
Pastel Blue- Posts : 47
Join date : 2016-02-21
Location : Niagara, Ontario, Canada
Page 2 of 2 • 1, 2
Similar topics
» PLEASE POST PICS OF YOUR ENGINES !!
» '71 429 cobra jet engine rebuild...
» '71 429 cobra jet engine rebuild...
» '71 429 cobra jet engine - piston identification?
» '71 429 cobra jet engine timing cover WTB
» '71 429 cobra jet engine rebuild...
» '71 429 cobra jet engine rebuild...
» '71 429 cobra jet engine - piston identification?
» '71 429 cobra jet engine timing cover WTB
Page 2 of 2
Permissions in this forum:
You cannot reply to topics in this forum