Roller Conversion

69PaleHorse · Aug 23, 2007

While in the process of heating up my combo, I was able to pick up a full lifter/pushrod/rocker and spider kit for a hyd. roller cam. However, my understanding is that the older blocks do not have the spider mounting holes machined into the top of the lifter valley. I've been advised by my builder that to machine these holes, I would need to pull the engine and drop the rotating assemblies, as there is a possibility that the cam bearings might get damaged in the process.

With that said, I think there are 2 options:

A) Remove the engine, rotating assemblies etc and get the pider mounting holes machined, or

B) Buy the lifter retrofit kit that has the lifters with the bars that span bewteen the pair.

Cost for option A is being quoted around $350, plus my labor in pulling the block. Cost for option B is quoted around $550 and is virtually a drop in affair.

Are these my only options? Can the spider mounts be machined without removing the block? Are there any limitations in reliability/efficiency/performance in going either route?

D.Hearne · Aug 23, 2007

You can go either way. But the retrofit using the O.E. hardware requires a reduced base circle cam which are expensive and limited in offerings. It can be done in the car, but there is still the risk of drilling too far. The linkbar lifters run about $425 from Crane, plus the cost of the pushrods to match, but can be used with the plentiful 5.0 hyd cams. Either way, neither is particularly cost effective. What cam is in there now ? You may be better off just converting the rockers to full rollers and leave the cam as is. Then use the money saved for an intake upgrade to something better than that Performer you have now. That's only a little more expensive version of the stock 83-85 GT Stang 4 bbl intake.

69PaleHorse · Aug 23, 2007

Thanks for the info , DH. If the OE conversion kit reduces my cam options, then that certainly changes things. You may recall, about 5-6 weeks ago I posted a thread about HCI options, and you mentioned your hyd roller Z303, 6-pack set-up in the Ranger.

While that setup is still a bit exotic for me, my current build list looks something like this:

RPM Air Gap intake
AFR165's with 58cc combustion chamber
custom cam grind, similar to Comp XE274 specs

I'm almost certain that the cam grind is NOT the reduced base cam, so it looks like I may have to get the lifter retrofit kit and new pushrods unless I want to take it all back to the drawing board.

D.Hearne · Aug 23, 2007

If you now have an XE274 in there, you'll gain virtually nothing going to a roller cam. You DO know that your current cam isn't a roller cam don't you? Hard to tell with your last post. It sounds a bit like you're wanting to just swap lifters on it and not the cam too.

69PaleHorse · Aug 23, 2007

Sorry I wasn't clear. MY post several weeks back was about upgrading my HCI. The custom cam I am having ground will have similar specs to the XE274HR, the roller version of that cam.

Here is a link to that spec sheet: http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=35-518-8

Currently the car has a mild hyd flat tappet cam, Performer intake and Windsor Jr. heads.

In the next few weeks I will be installing the custom hyd roller cam, RPM Air Gap and AFR165's.

The purpose of the post was basically to figure out which roller conversion method would be best for my situation.

That clearer than mud now?

D.Hearne · Aug 23, 2007

It's your money, but if it were me, I'd stick with a flat tappet grind.(upgraded of course) The cost to convert to roller in a flat tappet block just isn't worth the money. The power gain vs the money spent will in now way be cost effective.

69gmachine · Aug 23, 2007

D.Hearne said:
It's your money, but if it were me, I'd stick with a flat tappet grind.(upgraded of course) The cost to convert to roller in a flat tappet block just isn't worth the money. The power gain vs the money spent will in now way be cost effective.

I agree with DH, especially for a 302 block. Either start fresh with a roller block or stick with the flat tappet.

69PaleHorse · Aug 23, 2007

My understanding was that a flat tappet needs a larger duration in order to get the same lift/performance as a roller, resulting in choppier idle.

I am looking for as much performance as possible without affecting driveability too much, thus the reason for considering the swap.

I'm sure I am over-simplifying, but are you trying to say there is no efficiency difference between the two cams?

D.Hearne · Aug 23, 2007

The idle smoothness comes from the overlap between the intake and exhaust events. Your choice of a dual plane intake will improve the bottom end anyway. If you were looking to eeek out everylast ounce of performance, yea a roller cam is one way to get there, but you're looking at a $400+ pricetag for not much more power. Like I said before, it's your money. I totally agree with 69gmachine as well, if you want a roller cam, start with a roller block. These are dirt cheap. I can buy a fresh reman 302 roller shortblock here for $400. One more tidbit if you decide to use the stock roller stuff----the lifters are good to 6000 rpms only, in effect putting a cork on the power with a built in rev limiter. If you want to spin it more (and it looks like you do with the components you listed) you'll need to upgrade to Crane's O.E style hyd rollers, that's another $190 to toss in.

mustangdave · Aug 23, 2007

Agreed, roller conversions aren't worth the money. Try sticking that Air Gap on your current combo begore spending any more money: I think u will be surprised. You may need to retune the carb when doing so.

S-Car-Go · Aug 24, 2007

Not trying to talk you out of a roller conversion, but you might want to talk to your cam grinder about the pro's and con's of a tight lash solid flat tappet cam (vs a HR).

'69Stang · Aug 24, 2007

69PaleHorse:

I had a 302 in my 69 Sportsroof before I switched to my current 351 Cleveland, and if I had to do it again I would do the following:
-650 Holley DP
-Weiand Xcellerator Single Plane Intake
-Solid Flat Tappet Cam
-AFR 165 heads

The Edelbrock RPM is a great all-around intake, however. Forget about the hydraulic roller, it's not worth the money. A solid cam for a 302 is great because they make more power and 302's like to spin.

bnickel · Aug 24, 2007

another vote for not using a retro-fit roller, the only time this makes sense is you have a numbers matching block and want to keep it for whatever reason, or you have an engine for which there is no OE roller block, like an FE or Cleveland engine, or possibly a 351w and are unable to locate a 351w roller block, they are not real easy to find but they are out there.

if your block is the original numbers matching block and you want to keep it installed in the car, then a retro-fit roller may not be a bad idea, but it's costly and won't give you a lot more power.

that said, the next engine i build WILL be a roller motor but most likely i will be using a late model roller block, the machine cast the same for either block and in the case of the 69 cougar this engine will be going in i'd rather keep the original numbers matching engine in tact and stuffed in a corner rather than risk blowing it up.

Sicarius428 · Aug 24, 2007

I would suggest sticking with what you have OR start with a fresh roller block. Roller blocks can be had for really cheap... You can probably get a fresh block for just the machining cost of converting yours.
Kevin

Helmantel · Aug 27, 2007

I have a retrofit cam in my 289. It's a custom grind with Comp Xtreme Energy lobes. The custom grinds are not that much more expensive than their stock offerings ($260 vs $230 or so).

If you're careful, I think you can drill the holes for the spider with the engine in place, but there's always a risk of course.

My cam works fine, but actually I'm not a fan of the reduced base circle cams. The base circle diameter is reduced by .30", which makes it more flexible.

I've no proof that this is an issue, but my valve train is rather noisy and starts to complain when the RPM's approach 6000. Although high RPM's have never been a strong point of hydraulic rollers, I think that cam flex makes it worse. My cam also has rather steep lobes, with .533 lift and just 258 deg adv duration (208 @ .050), which probably doesn't help either.

Roller cams certainly have their advantages, but if they're worth the investment is questionable. At least when you already have a good running flat tappet in your engine. If you start from scratch, the situation changes somewhat.

69PaleHorse · Aug 27, 2007

Thanks guys. I appreciate and respect everyones opinions here, so I went back to the builder and asked about getting specs for a flat tappet cam....

This weekend was the tear down, and we had been hoping (assuming rather) that the diagnosis of a blown head gasket was accurate. However, upon removal of the heads, we saw no damage to the gasket. Slowly we turned our gaze on the block and noted a crack running from the water passage to #1 cylinder.

So, when it's all said and done, I'll be gettting that roller cam after all, because I'll be picking up a roller block. I save myself some cash by not needing the retrofit lifter kit, but now I need to fork out some dough for a block and machine work.

While I'm at it, I may as well stroke it - since the machine work costs are going to be the same anyway.

Again, thanks for all the advice!

bnickel · Aug 27, 2007

69PaleHorse said:
Thanks guys. I appreciate and respect everyones opinions here, so I went back to the builder and asked about getting specs for a flat tappet cam....

This weekend was the tear down, and we had been hoping (assuming rather) that the diagnosis of a blown head gasket was accurate. However, upon removal of the heads, we saw no damage to the gasket. Slowly we turned our gaze on the block and noted a crack running from the water passage to #1 cylinder.

So, when it's all said and done, I'll be gettting that roller cam after all, because I'll be picking up a roller block. I save myself some cash by not needing the retrofit lifter kit, but now I need to fork out some dough for a block and machine work.

While I'm at it, I may as well stroke it - since the machine work costs are going to be the same anyway.

Again, thanks for all the advice!

you should seriously consider buying a brand new roller block then, summit has all the leftover NOS ford roller 5.0 blocks and they sell them for around $450, which is about the same price or even cheaper than doing a roller conversion. the only machine work needed would be any clearancing required for the stroker crank and if you've already ordered the pistons oversize or there is not a standard bore piston available for your stroker application then you'll need to bore the block but i'm sure there is probably a standard bore piston for whatever stroker crank you get.

the cost of machine work alone on a used block would be more than the cost of a new block and a new block won't need all of the machine work required of a used block.

69PaleHorse · Sep 18, 2007

UPDATE!!

Sometime ago (July 2004) I posted a thread about noticing a white puff of smoke when accelerating from a stop light. I also posted about a rythmic 'miss' that I couldn't diagnose. After a leakdown test on cylinder 1, we thought we had diagnosed a blown headgasket.

That brought me to H/C/I recommendations and roller conversion. I tore down the engine a few weeks back and found that the head gaskets were in perfect shape! Turned out to be a cracked block instead. No bueno.

So, my builder sourced a late model roller block and we are progressing with the 331 build. Hope to have it complete by the end of the month. So I guess I don't really have to worry about a roller conversion after all.

Thanks to all who contributed!

Roller Conversion

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