I Need Engine Experts! 340 Roller Lifter and Pushrod Issue

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HawkRod

HawkRod

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Hi folks. I am a moderator on FBBO, so I'm not over here as much (although I would love to have cool A body one day). For now, I'm asking about my 73 Road Runner with a 340. I figure there may be more small block knowledge here, so hopefully someone can help me out.

I need some help from the brain trust please! First some specs:
* Small block LA 340, bored .030" over
* Stroker crank, so now displaces 416 CI
* HAD a hydraulic flat tappet cam (more on that below)
* Aluminum Renegade brand heads
* 1.5 ratio roller rockers
* New hydraulic lifter cam specs: cam lobe lift .340", so lift is .510" with 1.5 ratio rockers

The engine has run over 18,000 miles with the hydraulic lifter flat tappet cam. We are now replacing the flat tappet cam with a hydraulic roller cam. The issue I am having is that the roller lifters are significantly taller than a flat tappet lifter. The roller lifter is .770" taller than the flat tappet lifter (as measured from the bottom of the lifter where it contacts the cam to the "cup" in the lifter where the pushrod contacts the lifter).

So the lifters are taller - who cares? Well, the angle between the lifters and pushrod is excessive. In general, there is a non-ideal angle on a LA block, but it is made even worse with the tall lifters. See picture below where I am pointing:
20240504_201302.jpg


So I set up and measured the actual lift (or more specifically, valve opening) that the cam was making. See mock up below:
20240505_084703.jpg


In an ideal world, it would measure .510" (and I realize you never have ideal world). Well, it measured .370". Wow - so it is losing .140" lift!!! The picture below shows the valve train geometry and it looks terrible to me.
20240505_084739.jpg


Are there better (less tall) lifters? Other ways to address this? Lots of people have put roller cams into small blocks, so what am I missing?

Any help from those who have experienced this would be greatly appreciated - thanks!
 
First things first, go to b3racingengines.com and get ahold of Mike and have him hook you up with a kit to correct the geometry.

Then you need to relieve the heads where the pushrod passes through. Even a 5/16 pushrod will hit with hydraulic rollers.
 
Second ^^^^ that above. Call Mike at B3. You need to get the geometry squared away and that might take a different lifter, adjusters, and pushrods, as well as a relocation kit.
 
Another thing worth mentioning, most over the counter roller lifters will push the oil band up and out of the chamfer at the top of the lifter bore on an LA block. Check this before installing the intake. Run the pump with a drill and roll the engine over through max lift and see if oil gushes out the top of the lifter bore.
 
Look at the push rod angle difference. Left is the tall standard roller lifter. On the right is a shorter lifter with an offset intake lifter.

lifter7.JPG


lifter1.JPG


lifter2.JPG


lifter3.JPG


lifter4.JPG


lifter5.JPG


lifter6.JPG
 
Newbomb Turk said:
First things first, go to b3racingengines.com and get ahold of Mike and have him hook you up with a kit to correct the geometry.

Then you need to relieve the heads where the pushrod passes through. Even a 5/16 pushrod will hit with hydraulic rollers.
Click to expand...
Thanks for the suggestion. I will contact him on Monday

TT5.9mag said:
Another thing worth mentioning, most over the counter roller lifters will push the oil band up and out of the chamfer at the top of the lifter bore on an LA block. Check this before installing the intake. Run the pump with a drill and roll the engine over through max lift and see if oil gushes out the top of the lifter bore.
Click to expand...
Great suggestion - I will check this to make sure. Visually, it looked OK and not too high, but a quick check by running the pump is easy extra insurance.

Oldmanmopar said:
Look at the push rod angle difference. Left is the tall standard roller lifter. On the right is a shorter lifter with an offset intake lifter.

View attachment 1716245838

View attachment 1716245839

View attachment 1716245840

View attachment 1716245841

View attachment 1716245842

View attachment 1716245843

View attachment 1716245845
Click to expand...
Thank you, and this is what I was looking for. Do you have a manufacturer/ part number of the smaller lifters?
 
HawkRod said:
Thanks for the suggestion. I will contact him on Monday


Great suggestion - I will check this to make sure. Visually, it looked OK and not too high, but a quick check by running the pump is easy extra insurance.


Thank you, and this is what I was looking for. Do you have a manufacturer/ part number of the smaller lifters?
Click to expand...

AFAIK, all retrofit hydraulic roller lifters are that height.

You have to live with it.
 
Morel hydraulic roller lifters, which are what you have in there, are the best hydro rollers you can use in a SB Mopar. The oil band is lower than others, so the band stays in the bore. The ones in my 273 clear just fine, but my saving grace is I used late 80's 302 heads, which have bigger push rod holes, plus my cam is itty bitty compared to the OP's cam. If I had to guess, I would say the ones Steve posted the pic of are solid rollers for a high HP small block race motor.
 
HawkRod said:
Well, I won't have to live with it if the lifters shown by @Oldmanmopar work for LA engines! :thumbsup:
View attachment 1716245910

Having said that, I have been unable to find any in my on-line searches that look similar. :(
Click to expand...

He showed you solid roller lifters. As I said I don’t know if any retro fit hydraulic roller lifters that have the short body.
 
This is a photo of factory hydraulic roller lifters taken from a 1985 LA engine.
little different crossbar arrangement, maybe shorter ? Just wanted to put it out there.
All I got is a photo.

Copy of 88truck_2.jpg
 
Darter6 said:
This is a photo of factory hydraulic roller lifters taken from a 1985 LA engine.
little different crossbar arrangement, maybe shorter ? Just wanted to put it out there.
All I got is a photo.

View attachment 1716245958
Click to expand...
There's another piece to this system that's missing in your picture. A retaining "spider" that bolts to a boss in the lifter valley holds the "dog bones" on top of the lifters. This allows the lifters to be shorter because they don't need to have links quite a bit higher than the lifter bore.

You can see it here:
[SOLD] - OEM LA Roller Lifter Retainer Components
 
Are you using checking springs or the actual valve springs? If you are using valve springs then you are probably compressing the plunger in the lifter. The SB Mopar has a stupid lifter angle design that does cause some loss of lift, but it doesn't cause that much loss so you have another problem. The most likely problem is your measurement process.
 
JDMopar said:
If I had to guess, I would say the ones Steve posted the pic of are solid rollers for a high HP small block race motor.
Click to expand...

Newbomb Turk said:
He showed you solid roller lifters. As I said I don’t know if any retro fit hydraulic roller lifters that have the short body.
Click to expand...

Of course - that makes total sense that they are solid rollers. I just got so excited seeing them that I didn't think it through :poke: Thanks for setting me straight!

JDMopar said:
Morel hydraulic roller lifters, which are what you have in there, are the best hydro rollers you can use in a SB Mopar. The oil band is lower than others, so the band stays in the bore. The ones in my 273 clear just fine, but my saving grace is I used late 80's 302 heads, which have bigger push rod holes, plus my cam is itty bitty compared to the OP's cam.
Click to expand...
Thanks, the Morel lifters are supposed to be great, so it is nice to know they work for the application. I'm not worried about the push rod holes either. I think just a little bit of clearance work will ensure that there is no rub.

I spent some time at B3 Racing Engines and read his tech articles. In my case, my rockers are contacting the top of the valve stems in a good position. I'm sure they can be improved by raising the shaft up, and I think I understand about the improvements that provides for duration and valve actuation. So for sure, I will call him on Monday.

But the lost lift still bugs me. I'm trying to find an equation to calculate distance when pushed at an angle. Been lots of years since I did trigonometry!

AndyF said:
Are you using checking springs or the actual valve springs? If you are using valve springs then you are probably compressing the plunger in the lifter. The SB Mopar has a stupid lifter angle design that does cause some loss of lift, but it doesn't cause that much loss so you have another problem. The most likely problem is your measurement process.
Click to expand...
I don't have a good checking spring so our "spring" was one of us providing gentle upward pressure with our fingers to keep the retainer up. We did check and verify that we were not collapsing the lifter.

I measured off the top of the retainer to see how much it moved down. I set the gauge to zero when the cam was on the base circle, and then measured up until the needle peaked and started going the opposite way. Did it twice and got repeatable results.

Not sure how else to measure this?
 
Run the oil pump with a drill while rolling the motor over with a ratchet/socket. The lifters will oil up if you roll it around several rotations, which is pretty easy with the plugs out. Then check your push rod length as soon as they pump up. You really only need 2 that are linked together to pump, so you can hold a little pressure against only those 2 while another person turns the motor.

Mike @ B3 will be a tremendous help to you in getting the frigonometry figured out....lol.
 
Well, I did some measuring and trigonometry.

First, I put a digital angle finder on the flat of the lifter and rotated the engine stand until it read zero. The I measured a push rod and found out that the push rod is at an angle of about 19* from the lifter.
Lifter_angle.jpg


Doing the trigonometry with my measured .331" lobe lift, I calculated that I should then be getting .313" of lift at the pushrod. This is far more than the estimation I had of .247" lift. So as a couple of you have stated, most likely my measuring was off.

But, no decisions until I speak with Mike tomorrow.

To all that have responded so far: Many thanks - this is very helpful! :thumbsup:
 
If you want to reduce the prod angle & the amount of lift that is lost, you could use sol lifters. They should be shorter because they do not have the internal hyd mechanism. Just lash them tight, 0.006-8" at operating temp.
 
I want to update folks on the status of this:

Regarding the significant angle between the lifter and pushrod:
This is what it is, and there is nothing really that can be done about this given the parts that I have. The angle is made worse by a taller lifter, so a solid lifter is a possibility to reduce the angle (and lift losses), but for this engine, the hydraulic lifter is the right way to go, especially given that this is a street driven car.
My measurement of the losses for this was likely in error. By calculation for this application, it looks like (all other things perfect) that the angle means you only get 94.6% of the cam lobe lift transmitted to the top of the pushrod. Not ideal by any means, but still workable. (Knowing this, I would definitely use 1.6 rockers in the future.)

Regarding rocker geometry:
I called and spoke with Mike at B3 Racing engines this morning. What a super guy and based on our conversation, I highly recommend him.
The rocker arms for this engine are contacting the valve stem in a decent spot, but the shaft is no doubt lower than ideal. His kits (custom made for each application) improve this geometry. The biggest gain, from my perspective, is that the improvement in rocker geometry means the valve will spend more time when it is near fully open. Ultimately, this means better flow, and we all know our engines improve with better flow.
The gentleman that now owns this engine needs to make decision if he wants the kit from B3 Racing. The biggest issue we have now is time so he may go with the geometry as it is and upgrade later in the year. If he does this, the downside will be that he will need to buy another set of pushrods. Either way, I will do some extra clearancing of the heads to hopefully cover any future relocation needs, be it in 3 weeks or 3 months.
(P.S. I will almost certainly order one of these kits for my 400 based stroker motor as I think they will improve my geometry on that.)

Now time to make progress with getting this thing running!
Again, I want to offer a humble and sincere Thank You to everyone that contributed ideas! :thumbsup:
 
Just asking here, but why didn't you use a solid roller from the get go? More power all the way around plus the shorter lifter. Please don't tell me it's the frequent valve adjustment thing, as that's just a myth. With all the high end valve train parts you're using here, if you have to adjust once a year, I'd be shocked.
 
RustyRatRod said:
Just asking here, but why didn't you use a solid roller from the get go? More power all the way around plus the shorter lifter. Please don't tell me it's the frequent valve adjustment thing, as that's just a myth. With all the high end valve train parts you're using here, if you have to adjust once a year, I'd be shocked.
Click to expand...
Glad to entertain the question - here is my take on it:

It is absolutely NOT a "frequent valve adjustment" issue. Done (and tightened properly), they last for years with minimal work required. I have a high lift solid lifter car I haven't had to touch for 5 years so far. In this case with the 340 we've been talking about, there is an adjustment nut anyway, so it could come loose for a hydraulic lifter as easily as it could for a solid lifter.

From my understanding of cams, I am not sure I agree with your statement of "more power all the way around". A hydraulic lifter actually has an advantage off the seat, and you also don't lose the lift from the required lash setting. Finally, although it is not that hard to address, lash gets a bit more variable with aluminum heads since they grow more with temperature.

I am NOT saying a hydraulic cam is better than a solid lifter cam. Solid lifter cams absolutely have their advantages, especially in high RPM applications.

In this case this car used to be owned by me but is now owned by a super nice young guy who is in to hot rods and old Mopars. He street drives the car and is still learning much about engines and these old cars. In this application I felt a hydraulic cam was the better choice.
 
I think most every single dyno would disagree. But honestly, I guess it's coming down to personal choice and there's really no argument for that! Keep us posted on how it turns out.
 
RustyRatRod said:
I think most every single dyno would disagree. But honestly, I guess it's coming down to personal choice and there's really no argument for that! Keep us posted on how it turns out.
Click to expand...

Newbomb Turk said:
So would every race track disagree.
Click to expand...
I'm certainly not looking to start a fight over hydraulic vs. solid. I like solid lifter cams and for real performance I think they are the way to go.

However, saying that every race track would disagree isn't applicable here. This is not a race car, it is a street driven cruiser. For example, every track would prefer a high stall torque converter too but it would suck on the highway with overdrive like this car has. It was built for cruising and reliability. For this application, for this owner, the hydraulic seemed like a better choice.

Having said that, knowing what I now know, I would never build another with 1.5 rockers, and I WOULD put a solid roller in it. But that's me, and not this owner.

I think it'll still run ok...
 
HawkRod said:
I'm certainly not looking to start a fight over hydraulic vs. solid. I like solid lifter cams and for real performance I think they are the way to go.

However, saying that every race track would disagree isn't applicable here. This is not a race car, it is a street driven cruiser. For example, every track would prefer a high stall torque converter too but it would suck on the highway with overdrive like this car has. It was built for cruising and reliability. For this application, for this owner, the hydraulic seemed like a better choice.

Having said that, knowing what I now know, I would never build another with 1.5 rockers, and I WOULD put a solid roller in it. But that's me, and not this owner.

I think it'll still run ok...
Click to expand...
I think it'll run fine. My comment was simply saying IMO, you could kill two birds with one stone by going solid. You would certainly be able to go to the shorter lifter and THAT cannot be argued. Either way, please keep us in the loop. It's a nice project, regardless of lifter type.
 
If you run solid lifters, you can NEVER get two problems that hyd lifters can get:
- they won't pump up & lose power
- they won't collapse internally causing noise & power loss.
 
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