[chuckies76ta]

Originally Posted by whittp

Would I have the option of changing to flat tappet cam and lifters while keeping my same rockers and push rods? I don't have the specs in front of me right now I attached a picture maybe that'll help.

If you go flat tappet cam and lifters, geometry will change and new pushrods will be required. The rockers will be fine.

Who setup your pushrod length on the roller setup?

[whittp]

The engine was built about 7 years ago and the shop owner has retired. The documentation for the build is at the new shop. Buying a new set of pushrods isn't a big deal for piece of mind and reliability. What are the performance trade offs? Is there a cam that will perform similar to what's in it now?

[76TA462]

Put my Comp Cams roller lifters in over a decade ago (picked them up from SD along with Dave's Old Faithful cam). Absolutely no issues. Had to pull the engine apart last winter for another reason, and used a high performance reputable builder in my neck of the woods. The lifters, cam etc. were all checked over and reinstalled as were.

[Formulajones]

Originally Posted by whittp

The engine was built about 7 years ago and the shop owner has retired. The documentation for the build is at the new shop. Buying a new set of pushrods isn't a big deal for piece of mind and reliability. What are the performance trade offs? Is there a cam that will perform similar to what's in it now?

Without knowing what you have now there isn't a good answer. Generally though with the rollers carrying more lift under the curve, and having a good set of aluminum heads on the engine, it's going to be difficult to get the same performance from a flat tappet cam unless you get pretty wild on cam timing with the flat tappet, and then the whole question of drivability comes into play.
Yes you'll have to swap pushrods, and you'll need a different set of valve springs if you go flat tappet.

Personally, I'd stab a roller back in it, same thing you had since you were so happy with the performance of the engine, and either go with the Comp 857-S lifters or a set of Johnsons.

Sticking with the same cam profile keeps things simple for you. It's already been tuned and running for 7 years, you were happy with how it ran and performed, and you won't have to swap pushrods or valve springs.

[whittp]

I should clarify that it has not been running for the past 5 years. The engine only had about 400 miles on it when it failed.

[leeklm]

Not sure what cubic inch you are running? With 305cfm heads, throw Dave's OF2 cam in and push it up closer to 600hp while still being very streetable

Sent from my SM-G965U using Tapatalk

[whittp]

It is a 68 400 block with an eagle rotating assembly. Cubic inches are 461 with this set up. The crank is also going to have to be replaced due to the thrust bearing and I figured I'd go with the eagle forged crank. Connecting rods and pistons are all in good shape.

This thing is a mess inside and I'd sure like to not repeat this again. Hoping the TKX will solve the issue on the crank getting pushed around (and be a lot more fun to drive). Now I'm worrying about the reliability of the top end as well. What can the shop do to ensure it'll be good the next go round? They did mention that most of the prior build was done well but a few corners were cut. Rings not exactly right, bottom end not balanced, #3 was burning a little oil and it's probably the valve seal.

[steve25]

With crap getting thru the motor from the failed thrust bearing I wonder if some of that got into the needle bearings on that or other lifters and the whole thing was a time bomb?

[Formulajones]

Sometimes builds go that way with some shops. I've had fairly fresh builds in here that were running okay, but when I tore them down and took them to Paul for a going over, all kinds of things were found to be "subpar" even for a mild street build. It was a matter of time before things went south, and just lucky very few miles were put on.

Hate to hear it and very unfortunate for you, but maybe the shop you're at now will do a thorough job and straighten things out.

[whittp]

Steve25 I was hoping that too but the shop said no evidence of that causing the failure. That was the first thing they thought as well. What work can be done to the lifter bores to rule that out as a future issue?

[Formulajones]

The shop may suggest looking at the lifter bore clearance. That's supposed to be pretty tight. Around .0015" at the most if I remember right. Having one too loose and flopping around would certainly be an issue.

Can be bushed if that's the case, a good shop will know what to do.

[Dragncar]

Originally Posted by P@blo

Same here HIS. If you never drive it I'd go roller as it cool to say you have a roller motor even know the bearings are not.

Always wanted a BMW

Roller bearings are one of the reasons Germany lost WWII. Tanks do not need roller crank bearings, but they had them. Cost,time=lose.

OP, first thing you need to do is cut your oil filter apart and see what you have going on.

[P@blo]

Roller bearings lost the war. Nope.

[68WarDog]

Originally Posted by whittp

Would I have the option of changing to flat tappet cam and lifters while keeping my same rockers and push rods? I don't have the specs in front of me right now I attached a picture maybe that'll help.

Solid roller lifters generally requires a lot of spring pressures over the hydraulic rollers and longer push rods. I never liked comps. solid roller lifters design. For about 10 years I have ran Crower Hippo solid roller lifters for street driving. Lash has never changed doing yearly check , but you're going to pay more for Crower. Because of another board member recommendation I had Crower add another oiling hole. Go Crower Hippo solid roller lifters and never look back and enjoy the powwa

[steve25]

The addition of Roller bearings in the main driver’s and rods of Steam locomotives in our country is what helped us win the war when the oil that was previously going by tanker to the east coast had to rerouted by rail due to the tanker losses to German U boats in the Atlantic!

[Dragncar]

Originally Posted by P@blo

Roller bearings lost the war. Nope.

That was not what I was trying to say. The Germans had a habit and still do of making things over complicated when it was not needed to get the job done.
Made equipment hard to produce, time consuming and expensive.
We won the war because we simply out produced them. Their Panzer tanks were far superior to our Shermans but we made 50,000 of them !!
They call that POS Sherman Ronson,s because they lit the first hit, every time.
Operating a Sherman in WWII was horrible duty.

[Scarebird]

^^^^ The Chieftain sez you are full of shiat regarding the M4:

https://www.youtube.com/watch?v=bNjp_4jY8pY

Sherman "deathtrap" myth debunked at 33:30

[steve25]

Yup, I got your point and fully agree, as making repairs by having to change out roller bearings in the field when used as in that case for crank bearings is far too time consuming!

[Half-Inch Stud]

Probably reuse the rockers. If your pushrods are shorter than stock, Might need stock length pushrods to attain contact geometry.

[whittp]

If I decide to go with Crower lifters what is the comparable part number to the Comp 857? Is it wise to use the Comp cam and the Crower lifter combination?