Camshaft selection
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Camshaft selection
Okay. I have a 1986 351w cam gear is stripped. I'm looking for a part number for a quality rv style camshaft. This is my first post here so I'm sorry if it was covered before but when I searched all I found was people that didn't know what they needed. I know what I need. But I'm new to fords and there's too much bodiggity information to sort through. I' have a service truck with a carb and c6 trans . Im trying to get more than 3-4 mpg as well. Cause this truck is pretty bad on it. I know a rv style can and light foot will help. But I'm also carrying a 11ft service box that is 8 1/2 foot tall. Looking for a cam in the 800-4000 rpm range my tach is broken and I did wire it up properly so if anyone can tell me what rpm I should be running at 60-65 mph would be greatly appreciated . As I do not know . I am a mechanic so please talk intelligently to me lol. I know this truck needs a 6bt but I can't afford that. I hear the 351w is a good workhorse . So I'll keep it and convert to efi eventually . I already have the timing chain with the 8* advance . And I understand this is a smog era camshaft with 4* retard, I also hear that the aftermarket cams have the timing set straight up . So with a rv cam in the rpm range I desire I also like to know if I may have valve to piston clearance problems. .
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My cam choice would be something with a duration around 210 Intake degrees at .050 lift. such as https://www.summitracing.com/parts/c...view/make/ford
(Even though this cam has "4x4" in the description - it is a good cam for building torque). Lift is under .500", no concerns over piston -valve clearance.
There are plenty of choices in this range. Stock specs are 206 I/221 E degrees at .050" lift.
Regarding what rpm you "are running" at 60-65mph - that depends on your current tire size and gear ratio. If you want to know what rpm to shoot for (with gearing or a tire purchase) I would say 2500rpm at 60mph is good. Lower rpm will give a little better mileage but would also result in lower power taking off and pulling.
If you are planning to convert to EFI (I assume you are thinking aftermarket EFI) so the straight up timing set and cam will not be a problem.
What Carb do you have now (4bbl)? There may be some MPG room for improvement in the cab selection too, depending on what you currently have.
(Even though this cam has "4x4" in the description - it is a good cam for building torque). Lift is under .500", no concerns over piston -valve clearance.
There are plenty of choices in this range. Stock specs are 206 I/221 E degrees at .050" lift.
Regarding what rpm you "are running" at 60-65mph - that depends on your current tire size and gear ratio. If you want to know what rpm to shoot for (with gearing or a tire purchase) I would say 2500rpm at 60mph is good. Lower rpm will give a little better mileage but would also result in lower power taking off and pulling.
If you are planning to convert to EFI (I assume you are thinking aftermarket EFI) so the straight up timing set and cam will not be a problem.
What Carb do you have now (4bbl)? There may be some MPG room for improvement in the cab selection too, depending on what you currently have.
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I do have a carter aluminum 4 barrel . I have taken apart and cleaned it . My cam timing is set up for 8* advance . I was referring to aftermarket cams being timed straight up and smog cams being 4* retard . I would like to throw this out there this vehicle weighs 12000 lbs and is a commercial vehicle . ...sum-k4400 was my first choice but the one review that wasn't by "mr summits family " was one customer who was very disappointed . Now his was on a fresh rebuild and I know building a motor right is not a Lego set so he could have not plastiguaved or something silly but here's the product description....Cam and Lifters, Hydraulic Flat Tappet, Advertised Duration 280/290, Lift .449/.473, Ford, 5.0L H.O., 351W. If the duration gives me clearance problems I can always retard the cam timing a bit . 8* was compensating for my smog cam . I know a little about selecting the right camshaft and I like the one you selected and will probably get it but I do like the longer exhaust duration of the one I posted as I think it would just give it that brute force just off idle lol . But I'm not a fan of cheap parts and I have no idea if "mr summit" makes his cams in his back yard on a tree stump with a angle grinder outside his single wide and goes in his junkyard and picks out 8 lifters and sends me his home made camshaft . With a clipping of his mullet for good luck
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I would like to know where you are getting this smog retard and cam advance info at? This is the first I have ever heard of this with a 351w. It's well known they monkeyed with the 460 a little bit, but I have never heard that they moved the 351w cam timing around on purpose.
I am assuming if you are moving the cam timing around you have one of those fancy timing gear sets with the egg shaped bushing on a pin?
I am assuming if you are moving the cam timing around you have one of those fancy timing gear sets with the egg shaped bushing on a pin?
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I was planning on doing a factory efi stup.... As far as the intake and possibly fuel rails are concerned. I use these bmw m62 v8 injectors in a few cars with ****ty factory injectors and it's real nice. The spray pattern atomizes very nice. Not sure the lb/hr rate possibly 24 cause it's a very efficient motor . I would use a factory ecm if there was one for mass air . But will probably do a mega squirt and Use map and Maf. Which sucks cause I wanted my first mega squirt to be a performance go fast build . And about the gearing . I think this truck is doing a little more than 2500 at 65.... I'd think 3500-4000. Cause it is screaming along ....
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The 4* retard for smog cams was something I found reading forums ( not as a member ) early years used a retarded timing set and the cam itself was degrees straight up. Then later smog cams used a straight up timing set and the cam itself was retarded 4*........ And I have a aftermarket timing set with multiple slots on the crank sprocket I have the ability to advance or retard cam timing by 8* 6* 4* 2* or straight up for a broad powerbamd . But my service truck is way too heavy to not get the most I can
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Frank do they really sell timing sets with a egg shaped bushing ?? Sounds very prone to failure . Lol I'd rather just degree the cam sprocket and find where I can drill a hole and time it differently . Who knows might be able to make money getting old smog timing sets with the 4* retArd and selling it to the mush tang crowd sayin it's heavy duty construction. And a factory ford piece . Plus the extra stretched out chain retards it a few more * ����������
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A stripped cam gear is a sign of another problem you should investigate, could be a failing oil pump or maybe you somehow got a distributor with a steel drive gear on it. Those are for steel roller cams and should not be used in a motor with a cast iron flat tappet cam, if the distributor gear is relatively unharmed this is likely your problem. A seizing oil pump you can test by hand with a ratchet, normally you won't be able to turn the pump fast(counter clockwise is standard rotation) but it should move smoothly and not stick and you should not need a giant breaker bar to move it. Be sure to tape the socket to the extension so it doesn't fall off inside the motor.
As for a cam I'm gonna suggest something with much shorter duration like the Comp 35-231-3, this is a healthy step up from the stock cam and won't give up any low rpm torque while delivering real gains between 2500-4000rpm.
As for a cam I'm gonna suggest something with much shorter duration like the Comp 35-231-3, this is a healthy step up from the stock cam and won't give up any low rpm torque while delivering real gains between 2500-4000rpm.
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From: Orlando area
The Summit Cam (SUM-K4400) is 204/214 duration at .050" tappet lift. valve lift .449/.473
The Comp 35-231-3 is 206/214 @ .050". Vale lift .448/.483
The one I suggested Comp 35-235-3 is 210/218 @ .050". Valve lift .477/.493
Stock is 206/221 @.050 (according to RockAuto >Melling SBY-35).
So I doubt you will notice much difference, if any, between these cams. They are all a good choice for application.
The Comp 35-231-3 is 206/214 @ .050". Vale lift .448/.483
The one I suggested Comp 35-235-3 is 210/218 @ .050". Valve lift .477/.493
Stock is 206/221 @.050 (according to RockAuto >Melling SBY-35).
So I doubt you will notice much difference, if any, between these cams. They are all a good choice for application.
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Yea I know about the stripped cam gear being a problem and I noticed the gear on the cam when I installed the timing set. The previous owner installed a cheap distributor and it has no wear on the distributor drive gear . So I would assume it would be the cause . The oil pump is fine but I will definitely test it. So I should b able to spin freely fast by hand with no binding whatso ever. Makes sense. I'll prob hook it up to a drill and do a high speed test as well
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Why don't you buy a stock replacement distributor from your local auto parts store, or on-line at Rockauto.com?
1986 FORD F-350 5.8L 351cid V8 Distributor | RockAuto
or
https://www.summitracing.com/parts/a...view/make/ford
Your not going to gain anything buying an expensive aftermarket "performance" distributor. The Duraspark distributor is a very good design and used in many performance applications. It's setting up the internal advance to match the engine that is important. In your case the OEM advance curve is fine.
If you just want a gear - this is the cast iron (stock equivalent) https://www.summitracing.com/parts/m...view/make/ford
1986 FORD F-350 5.8L 351cid V8 Distributor | RockAuto
or
https://www.summitracing.com/parts/a...view/make/ford
Your not going to gain anything buying an expensive aftermarket "performance" distributor. The Duraspark distributor is a very good design and used in many performance applications. It's setting up the internal advance to match the engine that is important. In your case the OEM advance curve is fine.
If you just want a gear - this is the cast iron (stock equivalent) https://www.summitracing.com/parts/m...view/make/ford