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Hydraulic roller lifters to solid flat tappets?
Can a SBF 5.0 with hydraulic roller lifters be changed to solid flat tappet lifters with no block mods?
Cheers, Glen |
Yes, but why not use a solid roller cam? The adjustment is in the pushrod length.
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You can make the change without any modification to the block, but you have to change the cam. There are several dimensions on a roller cam that are different from a flat tappet cam, solid or hydraulic. besides, why would you want to make a change like that unless you plan on running at 7500 RPM. A little racing in the future?
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You might want to consider opening up the side clearance on the connecting rods to allow more oil to sling up on the cam/lifters----and or, use rods /bearings with a squirt hole.
Restricting the oil flow to the tappet gallies isn't done because the rollers need less oil--its done usually because the engine has a fully rollerized upper end and doesn't need so much oil flow so it can be directed the excess to the lower end of the engine------- |
Are you building it for your 289 Cobra? If so, the original 289 Cobra “High-Rev” racing engines were roller camshafts…. Maybe you should stick with the rollers – just my 2 cents.
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Just curious...why not a solid roller? You'd get the advantage of the increased opening/closing valve rates the rollers offer, plus the hi-rev advantages of solid lifters...sounds like win/win to me? I like the sound of a good solid lifter, don't mind pulling the valve covers now and then to do the lash adjustments, either..."that sound" is just all part of what I think a good small-block should do! Cheers! Dugly :cool: |
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*PM sent* Cheers, Glen |
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I had a thread last year asking questions about solid/hydraulic/roller lifters, and I think some thought I was a little stubborn for not caving in to the hydraulic majority. Ijust love the revability and the noise, and I'm willing to conpromise on other things to get what I want. Cheers, Glen |
I don't believe you will find any more maintenance issues with a flat, solid lifter set up as you would with a roller, solid lifter set up. Plus, the roller will allow you to run a much more aggressive cam profile and will not require high zinc content oils or additives. I think you will get everything you want and more with a roller cam and lifters.
I say do it and don't worry about the non-solid comments. I had a solid roller in my GT40 and coupled with the 180 degree exhaust set up, it was a real badass! |
Cam profiles are ground with enough ramp up no lifter has issues with the slack. Pushrods against the rocker arm don't either.
Pick a cam for it's profile and intent, non hydraulic have some rev advantages because of the lighter tappet weight. Rollers are limited in the rpm ceiling because of it, but make up with being able to accelerate better in the initial ramp up, where a flat tappet may be slightly restricted to prevent the edge digging in. Conversely, roller tappets may have to endure more side loading. As for zinc, read the spec, even the latest grade SN oil has some, and the API does still test with flat tappet motors because they are still in service. Nissan and Hyundai even dropped their roller lifters for a nitrided flat tappet. API has to rate the oil for flat tappet use because makers haven't quit using them. It's all part of the zinc mythology on the net, which is vastly uninformed. Just read the spec and you will know more than 95% of the posters worldwide. Zinc was reduced - not eliminated. |
Thanks gentlemen. I'm convinced. Solid rollers.
Cheers, :) Glen |
Just wondering....
....if there's any difference in "music" level and "quality" between solid flat-tapper lifters and solid roller lifters? A subjective observation, I know, but it's an important consideration.
Cheers, Glen |
Can't say about solid flat tappet lifters,but on my solid roller lifter engine in my race car with open exahust,I can certainly hear the "music" from the upper valve trane and it is properly adjusted!!!!!!
David |
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the valve racket from flat tappet cam & lifters is quite different from that of solid roller tappet & cam combo. If that matter to you then the prudent course would be to listen to both before coming to a decision.
I confess to being prejudice in favor of the flat tappets and cam, as most of my old Ford experience is with the HiPo 289 K code engine. But I've never been sidelined with a cam or lifter issue, and but have had the great pleasure of passing a few cars that were DNF due to disintegrating roller lifters. They take a beating, especially in a street car where inevitably there is a lot of low rpm use. If you are willing to change them out on a regular basis, then no problem. Otherwise watch out, especially if your car is going to see considerable action. So here's one vote for solid flat tappets. I put over 50,000 miles on my last car, a '66 GT350 with a vintage Paxton and original 289 motor. Most of that milage was just normal "spirited" driving, but on numerous occasions I had the opportunity to run flat out for as long as full tank of gas would allow. No engine issues of any kind. I had a Melling high volume oil pump and was using Mobil 1 15w-50 synthetic oil, and of course a stock Ford HiPo flat tappet cam. Z. |
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