I had been planning to go with a Crane Cam, recommended by one of the other members, to improve the breathing of my engine, but, on discussion with someone who has a lot of engine experience I trust, am looking for a better alternative: His exact words: "I wouldn't put a Crane Cam in a lawnmower"... I am used to using factory parts, and not really entered the upgrade cam market before...

This past week, I saw the results of one bad Crane cam failure- the "mild" cam in my friend's 454 engine, which I just tore apart(that job is financing my machine work!) Two or three lobes failed, and now look more like a disfigured knuckles than cam lobes, and this actually wore through the bottoms of the hydraulic lifters, causing tappet failure, and broken pushrods! (SNAPPED- not just bent).

When I mentioned this to my friend(former race driver & engine builder) he told me they do not properly harden their cams, and he had no use for them...

Ideas? I would like the improved breathing- but not at the expense of another rebuild anytime soon...

Scott

 

The problem(wiped cam lobes) now appears to be more common with all flat tappet cams and a significant contributing factor is that oil manufacturers have removed the zinc from motor oils which used to lubricate flat tappet cam lobes and lifters. There are zinc(ZDDP) additives available that can be added to motor oil but you're still rolling the dice to some extent with any flat tappet cam these days.
I don't know if Crane has any more failures like this than any other manufacturer but I agree it is a concern, I hate having to do things over again as much as anybody else. But to truely eliminate the possibility of this happening to your motor you will have to use a roller cam and both the cam and lifters will cost a lot more money than the flat tappet versions.

 

Just about all my cars are flat tappet style... I think the 03 Interceptor has rollers in its Modular engine, but the others are flat tappet... Nice thing I found out- STP has ZDDP in it, so I started using it in my others...

What do you think of this cam as an option? Performance Camshafts Cam Card Locator - Edelbrock, LLC.

Scott

 

 

Does anyone have the factory cam specs, so I can compare to a few of the options I am looking at? Valve timing, lift, duration, etc? I can find no solid comparable figures in my 1991 Specification Book, or in the Factory manual, Vol. 2, "Engine"... I'm considering a Sealed Power CS764, https://www.rockauto.com/en/moreinfo...121982&jsn=380 from Rock, and it looks to be close to factory, but I am not sure... While I am trying to improve the breathing, I was recommended against Crane, and looked at Edelbrock, but it only said I had t use their timing set, as factory would retard it too much, etc... I am getting ready to order parts this weekend, and really wanted to get the cam settled...

Help? Thanks!~
Scott

 

The factory 351 flat tappet cam apparently produces 0.416 lift and 260deg seat-seat duration, I don't have the 0.050" specs but if it follows suit with other factory cams it's under 200deg.

 

side note: there are no conventional lifters in the modular, their lifters are used as a cushion/fulcrum for the rocker - on-lobe design.

 

I haven't played much with the modular engine yet... I prefer the older designs... I just have it in my other daily driver...


Thanks
Scott

 

This whole discussion just got academic- I ordered the Sealed Power replacement from Rock Auto, as it was about all I could afford. Guess I'll have to wait till my next teardown to upgrade the cam, etc... I gave a quick inspection to the factory one, and could probably have reused it with new tappets, but figured I may as well go new, although I couldn't afford a better option, and got tired of trying to research where answers were getting harder to find... (I am REALLY sick of Bing and Google answering most of my queries with a bunch of ADS, rather than INFORMATION REQUESTED...) I was really hoping to compare original specs to the options, but could not find what I needed. What I would REALLY like is a spiral chart for each cam, so I could compare them that way- I understand and enjoy spiral charts: they make a lot more sense to me than abstract numbers...

Anyway... If anyone does have the specs for the factory 1991 5.8l EFI cam, please post them sometime- Thanks!

Scott

 

Conanskis suggested specs are above, I don't think you'll get much more info than that for the old flat tappet cams. Rest assured, the flat tappet cams of this era are **** poor.

 

S​​​​​​​Stock 302
* Duration at .050 in.: 210 / 211
* Gross valve lift: 0.421 / 0.447
* Lobe separation: 116°

Stock 351
* Duration at .050 in.: 206 / 221
* Gross valve lift: 0.440 / 0.450
* Lobe separation: 115°

Lightning
* Duration at .050 in.: 198 / 208
* Gross valve lift: 0.416 / 0.445
* Lobe separation: 114°

80s 351 HO
dur 206int./221exh
​​​​​​​​​​​​​lift 444int./452exh.
​​​​​​​ 115 lobe separation

96-01 Explorer 5.0L HO roller
Ford Part numbers: F4TE-6250-BA
* Advertised Duration: 256 / 266
* Duration at .050 in.: 186 / 197
* Gross valve lift: 0.422 / 0.448
* Lobe separation: 116°

 

Those stock 351 specs are the roller cam specs...got anything for the flat tappet? I know duration is much smaller for the flatty

 

[QUOTE=ng19delta;16832941. (I am REALLY sick of Bing and Google answering most of my queries with a bunch of ADS, rather than INFORMATION REQUESTED...)
Scott[/QUOTE]
Firefox and ADBlock+, just sayin

 

I use Firefox and AdblockerPlus- All that comes back as Bing or Google "results" are listings for parts, rather than specs... I have this same problem with 90% of the searches any more...

Thanks!
Scott

 

I tend to use Boolean methods, and that makes it a little less annoying. An example would be if I type in 4.9 and most of the results I get are Cadillac, I'll modify the search text to; 4.9, -Cadillac
That will remove those from coming up. there is more to it than that, worth studying Boolean methods. Works on Ebay some, their algorithm is more screwy than Google / Bing