Straighten pushrod

madtom421

madtom421

Member
#1
#1
I'm building a predator hemi 301 8hp motor. I wanted to upgrade the pushrods and had to buy a cut yourself kit as they don't make a direct size pushrod for this motor. I didn't know the correct way of inserting the ball end into the rod and pressed it instead of hammering it in. Needless to say I put a slight bow in the rod. These are the 1/4" chromoly rods I bent it back straight. Do you think it will be ok to use? Screenshot_20210716-062245_Reddit.jpg
 
madtom421

madtom421

Member
#2
#2
Motor specs predator 301 hemi head 8hp stock length billet rod, billet flywheel, .275 cam, 50# springs? (Gopowersports didn't specify the # in there kit I'm assuming 50#) stock compression.
 
mustangfrank

mustangfrank

Well-Known Member
#3
#3
My experience with those engines is next to nothing but I'm no slouch with stock to high performance builds on other pushrod engines. I say start over, it will bend again with use. Talk to a pushrod shop like Trend Performance, even if they don't have those ends maybe you can just get hardened pre cut tubes and re use your ends. If not I'd make sure all surfaces have a nice chamfer and are started straight before pressing again.

50 pound springs sounds high, aren't the smaller engine guys running 26 pounds with cams, give or take?
 
madtom421

madtom421

Member
#4
#4
I purchased the stage 2 predator hemi 301kit from gopowersports. They don't give you any information on the parts in the description. The rod and flywheel are from a gx270, the cam is from a gx390. The kit came with duel springs which equals 65# and meant for the 308 cam option. I'm just using the single spring for the 275 cam and I'm assuming they're 50#. The springs are real stiff which is why I decided to go with thicker pushrods. I just went and ordered a new set of rods. From the searching I found most people run 35# when they remove the governor and then go to 50# with a cam. Redbeard garage installed this same kit on stock rods with no issues but I don't trust them. Yeah it would be foolish to risk $700 worth of motor over a $20 rod.
 
madtom421

madtom421

Member
#5
#5
This cam only calls for 32# springs, these are 50# springs in the kit (blue stripe) i think i have some 35# springs would those be a better choice?
 
mustangfrank

mustangfrank

Well-Known Member
#6
#6
madtom421 said:
This cam only calls for 32# springs, these are 50# springs in the kit (blue stripe) i think i have some 35# springs would those be a better choice?
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I've always been advised to run the lowest possible spring pressures necessary to avoid valve float, almost always the cam manufacturer's recommendation. Any excess only robs power and accelerates lobe wear for no gain, so I would run the 35# springs.

Hopefully some of the guys with direct experience with your engine chime in too.
 
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desert rat

Well-Known Member
#10
#10
Place the ball end on ice ( really on a ice cube ) OR if your just a little nuts like me you can use liquid propain , but if you don't have exp. with it DON"T. Heat the tube in boiling water. Quickly place both pieces together. Heat makes the part bigger cold make the part smaller. You got to be fast.
 
madtom421

madtom421

Member
#11
#11
New rod installed. Motor runs strong but it seems like the engine makes more noise than before. Everything was torqued down and checked for clearance. Doesn't seem to have any excessive vibrations. Doesn't sound like rod knock more valve train. Maybe it's just how the new cam sounds?
Tommy tech tip- make sure your carb bolts are tight or you'll be pushing her home when your carb loosens from the intake
 
Strigoi

Strigoi

#12
#12
massacre said:
50lb sounds kinda high for that RPM range. I’m no expert tho
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It sounds really high for that cam. My .272 Mongoose cam in one of my engines only calls for 26lb springs, which I have in it.

I'm running dual 60lb springs in my stage 4 engine (.308 cam w/ 1.3 roller rockers) and they're designed for 9,000+ rpm. The 212 in my blue bike with a Hot .265 cam is running 22lb springs and it hits 7,000 rpm.
 
copyman

copyman

Well-Known Member
#14
#14
madtom421 said:
I'm building a predator hemi 301 8hp motor. I wanted to upgrade the pushrods and had to buy a cut yourself kit as they don't make a direct size pushrod for this motor. I didn't know the correct way of inserting the ball end into the rod and pressed it instead of hammering it in. Needless to say I put a slight bow in the rod. These are the 1/4" chromoly rods I bent it back straight. Do you think it will be ok to use? View attachment 280467
Click to expand...
I've straightened both the aluminum & steel push rods many times and they worked fine. They are used in my riding mower with a Briggs twin 20 hp. Reason they kept bending was the damn nuts for the lifters kept coming loose. I finally put locktite on the lifter nuts, so far so good. Keeping fingers crossed:)
 
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