Want to go roller on my mystery motor

[joshua]

I have no idea what cam I have in this engine.

Here is a link about what engine I have. Basically just pictures because the person who had it built passed, and the family had no clue on any of it.

https://classicbroncos.com/forums/threads/boat-motor.316757/

I would like to put a roller cam in it while out. Question is, is it mandatory to change the springs? I would rather not because it’s all brand new. I’m pretty sure I will need shorter push rods. But if I can figure out what cam I have, and try to get roller cam in the same neighborhood would I have to still change out the springs?

I do realize tappet and roller cams are different. But I have no clue if when in the same ball park do they use the same springs.

 

[rocknhorse76]

Generally, the springs for roller cams have higher rates. While not ideal, you can run springs intended for flat tappet cams, as long as the roller cam doesn’t have too much lift. I’d recommend having the heads checked out by a reputable machine shop to make sure everything is compatible.

 

[pcf_mark]

Roller lifters are heavier and need more spring to control them. Roller cams generally have more list which can cause the springs to bind. Both can lead to some pretty terrible engine damage. If you want a roller get the package including springs you can install them with the heads on no problem. Assuming the pistons are flat tops you do not need to worry about piston to valve clearance but check anyway.

 

[Broncobowsher]

More than just lift and mass. Roller cams are more aggressive on opening and closing rates as well. Opens the valve faster, which at speed can float the valve with a spring not heavy enough to keep it under control. then on closing the lifter drops away faster than the spring can keep up. Both cases pushrods and rocker arms get loose, pushrods fall out of place, worst is if the rocker arm turns sideways. Now the rocker is on the valve spring and the retainer can come loose and drop the valve into the piston. You now own a good sized pile of scrap metal.

Yes, you can convert to roller, but with stock heads for a flat tappet cam you have LESS RPM potential than the stock flat tappet cam.

 

[joshua]

Ok I figured I would have to. Just wanted to be sure thanks!

 

[Mark]

You've probably resolved this already, is the motor flat tappet or roller? If your 302 is a flat tappet motor, you can convert it to a roller motor, but it's kind of a can of worms, you will have to change the lifters to roller lifters, which involves either installing a spider to keep the roller lifters oriented correctly, or install barred roller lifters, Also lifter springs will need to be changed, and roller lifters are longer and will require you to remove the heads to install them. and pushrods will need to be changed.

 

[joshua]

No I just picked up a 351 roller cheap. Thinking I would stroke it. But idk. The whole reason I convinced my self to get a roller was reliability. Idk how reliable a 408 is. I want to drive my rig to events. I live in southern MN. Pretty close to right in the middle of the country. Good starting point to get to multiple events! Thanks for the heads up tho!

 

[nvrstuk]

408's are EXTREMELY reliable. I've built many, spec'd many and not had any design issues with them. Of course they can blow up with a bad lifter or a skirt can gall but that is not from the design of the 408, that is from bad parts- china or usa. Doesn't matter if the quality of the part is poor.

I have a couple strokers out there with well over 80K miles w/o issue. Great engine for a Bronco. I've had a couple die young. Two with bad lifters. One was a stock roller Ford Motorsports lifter and the other was an aftermarket link bar lifter. Only other stroker issue was my Ford Performance block that Ford bored my block at .0055" skirt to wall when Mahle Piston manufacturer spec's out .0025" skirt to wall. Ford actually spec'd this out as their website actually stated the clearance numbers that were 2 1/2X the clearance that Mahle requires. (I am not making this up)

So you won't have any issues with the 408 but parts can fail whether they are for a 170 or 501 cuin engine.

Good luck.

 

[joshua]

Thanks nvrstuk. I just finished breaking in rebuilt motor I found for cheap on craigs face. It’s on the run stand. So I’m going throw that in and decide which route to take. Then gather parts for either just a rebuild or a stroker. I have a ton of research to do. As I’ve never put a bottom end together.

But I would like to do as much as possible in putting it the motor together. I’m going to focus on getting the bronco up and running. Been collecting parts for 20 years. Wanted to make a show truck I guess. I’m in my 40s now. And I just want to drive it again. I could careless if it’s perfect anymore. I’m in the process of rebuilding a 44 Collected all the speciality tools I believe. I really appreciate everyone on this site. Could never get this done without ya!

Joshua

 

[nvrstuk]

Glad we can all help out. Such a resource here. I'm learning everyday!


I'm with ya in "driving it". I can drive to town 4x/day 7days/week and never get tired of it.

I have been Broncoless for 8months thanks to Ford Performance but I should be able to pick up my old block today and start grinding piston rings- I hope- this weekend.

I'm so stoked.

Get a build thread going and then you have a record of what you've done and we get to admire your work!

 

[joshua]

I would like to store this block long term in a storage unit. Can I break it all down, smear grease on cylinder wall, lifter walls, bearing surfaces? I’m going to have it hot tanked and honed anyway. How about the oil galleys though? Will they get full of rust and destroyed? Love to hear anyones thoughts in long term storage on one of these.

 

[nvrstuk]

Don't do any honing until after storage.

They make some cool stuff for long term storage.

I think where you live makes a huge difference.

You live down south where you have 95% humidity 300 days a year? You'd better store it inside a climate controlled environment l o l

Where I live, spray some wd on it and put a tarp over it!

 

[joshua]

I wasn’t planning on doing anything but store it. We have very humid summers in mn

 

[bulletpruf]

I would like to store this block long term in a storage unit. Can I break it all down, smear grease on cylinder wall, lifter walls, bearing surfaces? I’m going to have it hot tanked and honed anyway. How about the oil galleys though? Will they get full of rust and destroyed? Love to hear anyones thoughts in long term storage on one of these.

Grease on the machined surfaces - cylinder bores, deck, lifter bores and you should be fine. Oil galleys should have some residual oil; should be fine. Climate controlled storage would be the best, but not absolutely required.

 

[73azbronco]

they make a spray for storage, rotate at least one revolution on each cyl as you spray, spray into intake, done.

 

[Broncobowsher]

Fogging oil. Used when laying up marine engines.

 

[nvrstuk]

Fogging oil. Used when laying up marine engines.

...and snowmobiles and any other seasonal equipment.

I was waiting to see who had found something "new & improved".

My new sleds have a program that automatically "dumps" more oil into the gas mix (2 stroke) so all internal metal parts are now "summerized" and protected. Used to spray fogging oil in.