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Website Statistics Global: Topics: 37,241, Posts: 218,883, Members: 5,366. This forum: Topics: 35,483, Posts: 215,181. Our newest member Neuman Flat Tappet CamshaftsNew Flat Tappet Lifters are ALWAYS required for flat tappet cams. Used flat tappet lifters will have a wear pattern on the face. This wear pattern will prevent the lifter from spinning appropriately. It will cause heavy wear on both surfaces in a very short period of time. The wear pattern on the camshaft and lifters starts during the Break-In Procedure. This is one reason why following the break-in procedure is so critical. Even if the cam and lifters only run for a short time, they are considered used. Roller CamshaftsNew Roller Lifters are not always required for roller cams. If you are planning on reusing roller lifters, you should:
NotesRemember, you can't use roller lifters with a flat tappet cam. You can't use flat tappet lifters with a roller cam. Not to be contrary, but let me expound a little on what Ed said. There are actually 4 different types of cams, because there are 4 different types of followers (lifters): mechanical flat, mechanical roller, hydraulic flat, hydraulic roller. Each cam must be ground for the type of follower to be used - period. Like the Chinese restaurant, no substitutions allowed. The differences come down to this: With a flat tappet (follower, or lifter), you want it to rotate in the bore so that you don't wear a groove into it from the cam. This is accomplished by making one side of the lobe slightly higher than the other, on the heal portion, so that it rotates in the bore a little with every turn of the camshaft. You don't want that little ramp on a roller follower, because the wheel on the bottom of the follower takes care of the wear problem - having a ramp on the lobe would put an unbalanced load on the roller, lunching it. The cam lobe shape is also varied depending upon the type of follower, whether roller or flat, mechanical or hydraulic. The lobe contacts the follower differently on a flat tappet than it does on a roller, so mixing and matching would cause a drastic change in the way the cam opens the valves. And, with mechanical lifters, there is a lash take-up ramp at the opening, which you don't want or need with hydraulic. That's the theoretical side. From a practical standpoint, you can put a flat-tappet cam and lifters in a roller block, but you'll need to use flat-tappet-type timing set and pushrods, because they are different between the two different cam types. You'll be giving up the advantages of a roller cam, but frankly, for the street, the performance differences are minor. You should, though, since the cam is used, reuse the lifters on exactly the same lobe that they were used on before because of the wear pattern that they have made with each other. For roller lifters, that isn't an issue. Joined
Sep 2, 2007 · 321 Posts
Discussion Starter · #1 ·
Apr 13, 2008 Roller surprise I pulled my heads today from my 5.0, I planed to upgrade the cam in that chance and cause it runs on the old fiering order -18736245 (not the H.O) I thought I have a Flat tappet cam and lifters. Can a flat tappet cam run with roller lifters? I didnt know what to do, I thought maybe the old owner of this engine just change the lifters from flat tappet to rollers, I also found out that the new pushrods I ask from summit for a stock 5.0 non roller was 6.876 length while the pushrods on my engine was shorter - 6.25 The cam I bought is Flat tappet
(COMP Cams CL31-234-3 - COMP Cams Xtreme Energy Cam and Lifter Kits - summitracing.com) what should I do?? 1. Leave the roller lifters and 6.25 pushrods in the engine and install the new (flat tappet) cam? I dont know much about this engine except
of this facts: Here are some pics from today:
Joined Oct 30, 2003 · 4,010 Posts
There were two different firing orders use on the 302/5.0 that I am aware of and that isn't one of them. And if all else fails, check the casting numbers on the block in the starter area. Joined Jun 3, 2006 · 991 Posts
Its a roller block by looking at the last pic, no your not going to use a flat tappet cam with a ford hyd roller lifter. Joined Jul 18, 2004 · 1,741 Posts
why not use a roller cam? Joined Nov 6, 2004 · 310 Posts
Its a Non HO roller motor. they used the old 15426378 firing order Joined Oct 3, 2007 · 1,472 Posts
Hey MP I just got up and saw your post and PM.... Roller lifters weren't designed to work with a flat tappet cam so I do not believe that you should mix the two. Have you pulled the cam and checked the numbers to see if it is a roller cam? The HO motor is the only 302 to use the 351 firing order (to the best of my knowledge). The standard 302
uses the 15426378 firing order. Big Pause................................. OK.... I just went out to the Galaxie and pulled the intake on the 302 that the previous owner had dropped in. Based on the intake it is an 88 model and has the non HO firing order......(15426378). Under the intake I found a roller lifter spider (retainer) Based on this I would have to say that when ford switched over to roller cams that they did it across the board (on all 302's) and not just on the
HO engine. Based on this I would say that you have 2 options.... Go forward with installing the performance flat tappet cam and lifters in your block. Or Alice can sit until a new roller cam can come in and you send the flat tappet back. This could be a very expensive option for you as you would have to pay for shipping twice and have already paid duties on the flat tappet setup. Were it me I would install the new cam lifters and pushrods even though they are not rollers. You will
still see performance gains with the new cam over a stock non HO cam, and currently have all the parts needed to do the swap. Good luck with the work on Alice... By the way... did you note the heads when you pulled them off? Were the combustion chambers the 86 heart shaped or the later D shaped heads???? just curious... Take care Keith/Bumble Joined Jul 4, 2005 · 331 Posts
Roller lifters will not work on a flat tappet cam. A flat tappet cams lobes have a profile that is raised in the middle where the lifter and cam touch. On a roller cam the lobe profile is flat with a slight taper to one side. This pushes the cam toward the rear as it turns. Further the ramps on the lobes are much steeper on the roller cam.
This is because of the roller follower. A flat tappet lifter can't follow the steeper profile. As said before. You seem to have a non-HO 5.0 roller block. Joined Dec 7, 2007 · 1,466 Posts
If I see it right there are no valve reliefs in those pistons so be careful. You could probably get a stock HO cam for free and gain a bit. Then sell your stuff. You need to decide now since the valve springs are not the same from roller to flat tappet. Joined Feb 1, 2007 · 376 Posts
Your firing order is 15426378, you just got the distributor rotation direction wrong when you listed it in your post (18736245 - move the 1 after the five and count backwards, you'll see what I mean). Like what these other guys said, roller lifters should not be used with a flat-tappet cam, and vice-versa. Joined Oct 3, 2007 · 1,472 Posts
Hey MP, I just found some interesting reading over at Autozone.com. I was trying to find the specs on the stock cam in an 86 5.0 non HO... They have all kinds of info on their site. Based on the AZ site the non HO 86 5.0 cam (t-bird) has a 0.2375 lift intake and a 0.2474 lift exhaust. It calls the specs "elevation" rather than lift and does
not give duration specs. Just some interesting reading I thought you might be interested in..... http://www.autozone.com/az/cds/en_us/0900823d/80/14/d8/7c/0900823d8014d87c/repairInfoPages Iwantmore, UJT, and guys ... He has bought the cam, lifters, and springs, etc for the swap without knowing it was a roller block. If he had access it
would be easy to run down to the store and exchange but he is overseas and has to order everything and pay a tariff on it once it comes into country. Just figured you may not know his situation. Roy, Keith/Bumble Joined Oct 3, 2007 · 1,472 Posts
MP Iwantmore made a good point! There are no valve reliefs on those pistons. Check valve clearance prior to reassembly! Keith Joined Dec 7, 2007 · 1,466 Posts
MP Iwantmore made a good point! There are no valve reliefs on those pistons. Check valve clearance prior to reassembly! Keith Keith You made my day. Could you call my wife and tell her I made a good point! Also thanks for the update on the the application. There is always more to it than we
know. Under the circumstances I agree with the bee. Agree with the Bee. Nice rhyme? Mark Joined Oct 8, 2007 · 1,436 Posts
Wait a second.... I never heard an answer to this.... Everyone is saying that running roller lifters on a flat tappet cam won't work, but I see that your engine is already in the car, and so i'm assuming that it has previously been working. The shorter pushrods could have compensated for the extra height of the lifters. So, has that engine run before
in it's current configuration, and how did it run? Joined Dec 7, 2007 · 1,466 Posts
The rollers are hard as a rock next to a flat tappet. That is why the distributor gear is a problem. A roller will eat up the gear on an old distributor. So I think the assumption is that it is a non HO roller block. Joined Apr 4, 2001 · 7,506 Posts
The valve acceleration would actually be FAR LESS than it would with the flat tappet lifter. The larger the base of the lifter is, the sooner and faster it moves. The 'point' contact of the roller lifter would be very lazy on a flat tappet camshaft. There is a reason roller lobes look so 'straight up and down'. Good Luck! Joined Sep 2, 2007 · 321 Posts
Discussion Starter · #16 · Apr 14, 2008 (Edited) First thing - Thanks every one for your replies! That engine worked very good with the Flat tappet cam and the roller lifters. I belive this is something the last owner did without considering the cams lobes and profile. ford made all the 5.0 roller blocks with the spider bosses and shorter lifter bores since 1984, and yes, even for
the non roller cams. I know that for sure cause I just bought 2 books (downloadable). I knew my pistons are flat with no valve reliefs befor I bought the cam, I mentioned that to the guy in comp cams and he said that cam is just better then stock, no very high lift (0.477 int./0.484 exh. lift) and there is no problem. I believe I have the opportunity to fix something last owner did the wrong way... I guess there are things you cant know until you open the engine... At least I had the chance to fix that mix and mismatch. I have the desktop dyno 2003 and I have the file to my heads and new cam, I compared it to the H.O and I still have a gain.... I will install the cam today and let you all know what is going on..... Thanks again! Joined Oct 3, 2007 · 1,472 Posts
Hey Mark Negative perspiration bro..... HEY!!!!! MARKS WIFE!!!!!!!!!!!!! HE MADE A GOOD POINT AND HE'S STARTING TO RHYME OR SOMETHING!!!!!!!!!!!!! SEE IF HE HIT HIS HEAD RECENTLY!!!!!!!!!!! Keith/ Bumble Joined Sep 23, 2004 · 34,892 Posts
Roy, it looks like things are looking up for you even with the missmatch Gald to see progress! FE
Joined Oct 3, 2007 · 1,472 Posts
Hey FE!!!! Good to see ya back with the wife and the eyes aint glazed over anymore... guess that cataract surgery worked huh? BYW... them ernge robes wasn't really workin' fer ya Keith/Bumble Joined Jan 30, 2008 · 804 Posts
Someone wrote in to hotrod tech articles asking this same question like two years ago. In short they said you can run roller lifters, but its really completely pointless with no gains. Especially so if you buy roller lifters only to limit them with a flat tappet cam, which is not the case. Time for upgrade get the lifter spider, dog bones, and a
cam. Can you install roller lifters on a flat tappet cam?It is possible to run hydraulic flat-tappet lifters on a solid flat-tappet cam, and hydraulic roller lifters on a mechanical roller cam. The rules in some racing classes restrict competitors to running hydraulic valve lifters. Cheaters have been known to run hydraulic lifters on a mechanical (solid) cam profile.
Can you use roller rockers on a flat tappet cam?The two don't necessarily need to be used together. Roller camshafts and lifters can be used in an engine that features nonroller rockers; by the same token, roller rocker arms can be used in an engine that features a flat-tappet solid or hydraulic camshaft.
Can you replace a flat tappet cam with a roller cam?Flat-tappet cam lobes are ground at a very slight angle to prevent the cam from moving. Roller cams cannot be machined this way, so a roller-cam button is employed to limit cam movement.
Is a roller cam better than a flat tappet cam?The big advantage roller cams have over their flat-tappet cousins isn't the reduced friction most people immediately think of, it's increased tappet velocity (i.e., faster ramp rates). This increased velocity, as much as 30 percent, equates to more power.
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Can you use roller lifters on a flat tappet cam
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