Can anyone recommend a cam that would give my 302 more low and mid range torque? Some people talk of "RV" cams...what is that?

Thanks

 

Sedric:

I have posted twice, quite extensively about torque cams and what I recommend for a 302. I have found my old posts, go here to read.

https://www.ford-trucks.com/dcforum/DCForumID73/3104.html
https://www.ford-trucks.com/dcforum/DCForumID93/2344.html

I hope this helps. If you have any more questions, please let me know!

Cheers, George

 

Thanks, that is very helpful. With the increased lift, I probably have to worry about valve-to-piston clearance, right. What is the best way of checking this before buying the cam? I am not sure what pistons I have...they are the stock '72 ones but I can't remember if they were dished and/or had valve reliefs.

Do I have to worry about valve springs or rocker arms binding?

 

While I am not a Ford engine expert, I think that you do not have to worry about piston to valve clearance. That is an issue for high lift race cams. You can double check with the cam manufacturer of choice. E.g. comp cams will have that info for you if you call their tech line. Think about it, if everybody would have to change the entire valvetrain and modify / change pistons to accompany an RV cam, they would hardly sell them well!

If you compare the lift of an RV cam with yoru stock lift, it isn't much difference, maybe on the order of 50 thousands of an inch at the most? Have you checked your stock lift against the cam of choice? Something you may want to do to get an impression.

Same thing goes on the rocker arms and valve springs. They won't be affected. While you are in there you might consider a roller tip rocker since you pulling the valvetrain apart anyway. Needless to say, new lifters are mandatory. I would probably go with a nice valvetrain setup offered by comp cams, putting new lifters, pushrods and roller tip rockers.

Hope this helps.

Cheers, George

 

I have a engine manual for a '74 F-100 and it list the theoretical valve lift at .37 intake, .38 exhaust. The Comp Cam H260 that I am looking at has a lift of .474 for intake and exhaust. To me that's a pretty big increase. Should make a noticable increase in performance right?

I emailed Comp Cams and they said I should replace everything; push rods, rockers, springs but there is no way I want to spend that kind of money. Do you think they are just trying to sell more stuff? Why would the push rods and rocker have to be replaced?

Besides, replacing the push rods is not that simple since I have different lengths at different valves and I'd hate to start all over again matching push rods.

I think new cam lifters and springs will do the trick.

 

I got a little carried away...the H260 has .447" lift for intake/exhaust.

 

>I have a engine manual for a '74 F-100 and it list the
>theoretical valve lift at .37 intake, .38 exhaust. The Comp
>Cam H260 that I am looking at has a lift of .474 for intake
>and exhaust. To me that's a pretty big increase. Should
>make a noticable increase in performance right?

> I got a little carried away...the H260 has .447" lift for
> intake/exhaust

Hi Sedric:

Well, there you go, it isn't much above a 50 thousands increase then! Don't expect a torque or hp wonder out of your truck but you will sure get much better throttle response and ease of towing / uphill driving!

>I emailed Comp Cams and they said I should replace
>everything; push rods, rockers, springs but there is no way
>I want to spend that kind of money. Do you think they are
>just trying to sell more stuff? Why would the push rods and
>rocker have to be replaced?

Yes, they like to sell stuff. That is how they make their money. But seriosly, I think new lifters are the only thing mandatory and those are cheap.

>Besides, replacing the push rods is not that simple since I
>have different lengths at different valves and I'd hate to
>start all over again matching push rods.

Tell me, isn't your valvetrain adjustable? Why different lengths pushrods? I guess here is where my ford engine ignorance really sets in. I only have done one head gasket job on a 302 2 years ago and don't remember how things were set up!

>I think new cam lifters and springs will do the trick.

You can even skip the springs. They will only run into a limitation if you go to very high rpm, like over 5k RPM (valve float), otherwise I think the stock springs should accompany the tad bit extra lift just fine. Of course, if you go for new springs, it would be a good time to put new valve stem seals, just in case they are old already anyway?

Cheers, George

 

Yeah, the 302 has individual ball type rockers like a small block chevy but you don't adjust it by turning the rocker nut in or out. You just tighten the nut down all the way against the stop. You have to get different length push rods to get the right clearance. It's not very convenient and once you have them set you sure don't want to get them mixed up.

 

Sedric:

Okay! That is what I remember. On that (late EFI) 302 that I was working on, I don't remember adjusting any nuts on rocker amrs, so it must be non adjustable.

I checked: Comp cams makes an adjustable valvetrain kit for the 302, so you would have the same setup like on a chevy and no worries whatever you do to your heads or valves. You can bash chevies, but that adjustable valvetrain is good. Comp Cam sells this kit for oldsmobiles (which has the same non-adjustable setup than the 302). I went and checked on comp cams website. The 302 kit is RP-1431-16 and is listed with the 260H cam as a recommendation.

As far as I know (double check) the kit icludes hardened pushrods, studs, guideplates, locking nuts and roller tip rockers . I checked: It is out of stock with Summit but can be had at under $200! That is what you get for having a common engine. On olds this would set you back $60 more. Summit part number is: CCA-RP1431-16

That adjustable valvetrain kit would be nice. At least I like it a lot. The roller tip rockers make some extra power too, not much but while you are at it you mightaswell! I have the adjustable valvetrain on all my olds V8s and they work great.

Cheers, George

 

OK, I went ahead and ordered a cam shaft from Summit. I went the cheapest possible route...by ordering the Summit house brank shaft at $54. The specs are:

204º intake/214º exhaust @ .05" lift
.448" intake/.472" exhaust

I can buy the lifters locally so I just ordered the cam.

 

Sedric!

Sounds like a cam pretty close to the 260H. The exhaust really is what pays, and it looks great there. I have good success with summit brand products. Er, I forgot, you mighthave wanted to spring in for a double roller chain. I usually buy the Summit brand there over the Cloyes etc.

Good luck with the installation. Take care,

George

 

Just an update on my torque cam. I got my new cam and lifters from Summitt and tore my engine apart down to the cam. When I took the old cam out and compared it with the new one and find that the base diameter of the new one is .06" smaller than the old one. This isn't too suprising since that's probably the only way they can get more lift without the lobes being higher than the bearing journals.

Anyways, this brings up the whole question of pushrod length again. Some of my pushrods are now too short. When I tighten the rocker nut down against the stop some of the pushrods are still loose. Before I go out an buy a set of longer pushrod let me ask a question...how much should the pushrod compress into the lifter? I know on chevies you turn the rocker down until there is no play and then give the rocker nut another 1/2 turn. Is it the same for my 302?

Another idea I had was to put a washer between the rocker nut and the ball thing. Has anyone tried this? I can't see why it wouldn't work.

BTW, the first rocker I took apart and looked at is all scored between the ball and the rockers so I'm probably faced with buying a new set of rockers also. Any suggestions on this?

Thanks

 

Sedric:

Hey, it is X-mas, why don't you bite the bullet and buy an adjustable valvetrain from Comp Cams? Seriously, I think that would save you a lot of trouble. Then you could adjust things just like the chebby folk and you would be flexible for the future (e.g. if you should want another cam sometimes down the road!). I wouldn't put worn valvetrain bits back and if you need new rods and rockers, you already are in for spending some $.

Shimming the way you plan can be done. Again, I think it isn't the clean solution to your problem. I think the valve lash with 1/2 a turn more than 0 lash will work, except that you need to translate turns into shim thickness. You would have to find out what bolt the chevy / adjustable kits have and what 1/2 a turn on that bolt comes out to be in inches. I am sure that info can be found online.

Good luck with the installation. Have a Merry X-mas!

George

 

Does installing that adjustable valve parts involve replacing the stepped rocker studs with 3/8" ones? It would sure be nice to have that but it seems like a lot of work and expense. I was really hoping to not have to take the heads off this time.

Thanks and have a great Christmas