Stroker worth the "trouble" ?

[kris]

Ive been interested for a few years and now have the opportunity to build one. I have all the parts except pistons and a harness ready to go but with all the problems ive been reading about people having the last year, Im having second thoughts...

Problems being the cam/lifter failures, and less than expected power/general sluggishness.

Does a set of domestic lifters and diesel oil really cure the cam failures ?

Are the engines that arent producing the expected power increase just not tuned correctly (dist timing, fuel pressure, exhaust mods, etc) ?


This is meant to be replacing a 360 in a wagoneer. The v8 is toast so something has to go in there. Total reliability is my first concern, and ability to run on 87octane is a close second. Im not really interested in another AMCv8 that gets 10.5mpg on the highway, so outside of a GenIII swap this is it.


Discuss ?

kris.

[AaronJ]

Kris,

I am starting to feel the same way. However, I blame the oil more than the cam manufactures.

[oletshot]

I'll throw in 2 cents here.
I haven't heard of complaints of sluggishness from a stroker, so my only comment beside what you already suggested would be - were the expectations realistic to begin with? Just adding a little over a half liter isn't going to turn this into a 350hp monster!
As far as the cam problems, I don't see how they can be stroker related. By definition a stroker only changes cubic inches by adding a longer stroke crank. No real relation to valve train at all.
I feel the cam problems are related more to any combination of the following:
1. Low ZDDP oil (thought I get that out right away).
2. High valve spring pressures due to high lift cams.
3. Cheap lifters or bad cams(damn Chinese imports - that said I'll probably hitting Harbor Freight for more cheap tools soon).
4. Poor valve train geometry (not buying the right length pushrod or replacing used rockers when lift has changed).
5. Improper engine assembly or cam break in procedures.
6. High volume oil pump (reluctant to list this one as I don't believe it but some are sure this has something to do with it).
Any of these could happen on a build-up/rebuild of a stock 4.0L.
I think if someone built a stoker by only changing the crank for more stroke and pistons for stock compression ratio and left the valve train alone it would prove to be as reliable as a stock 4.0L with a slight performance gain. We get caught up in high lift cams to gain more performance and thats fine, as long as you do your homework. To many people think if the parts will bolt together, they fit (I think that includes some of the rebuilders selling strokers). In many cases that has lead to pinging strokers.

Well, I'm out of time so lets see how beat up I get from this post.

[Alex22]

Have you considered a 318 with EFI? If you already have and don't like the idea then don't be afraid of a stroker, If you build it right then it will make the power. As for the cam and lifter situation, its not the import/domestic issue, because there are only 2 or maybe 3 companies that actually produce the lifters and sell to everybody else to market.
The reason for the cam failures started when the government mandated that all exhaust and emissions control systems were a warranty item until 60k or 6 years (i forgot the exact number since it has changed a few times). The car manufactures didn't want to keep replacing catalytic converters for free and determined the zinc in the oil was plugging the converters up prematurely, those who had not already converted to a roller valve train did so and they told the oil manufacturers to remove/stop adding the ZDDP to the oil. Which as we all know lead to failures of new cams and lifters being broken in on oil without the ZDDP. With the new oils that are available with the ZDDP in them, Joe Gibbs, Brad Penn, I believe Amsoil has one and there are a few additives you can use made by Comp Cams and ZDDP plus. I would not run the diesel oils in a gasoline engine, and they are beginning to remove ZDDP from diesel oils too.

Oletshot, Thanks for mentioning the High Volume oil pump as one of the problems as it can cause a few problems. If you aren't adding a few more quarts to your oil pan and have looser oil clearances then it is a bad thing, It will pump all your oil up into your valve cover and begin sucking air. You probably won't be able to notice it, because the oil pressure sender doesn't know what pressure its reading (oil or air) and will keep giving you a nice number even though parts are being starved. If you want higher oil pressure then get a stronger relief spring or just shim it.

And "bolt on out of the box" is the biggest joke ever

~Alex

[kris]

I aint gonna beat you up oletshot. Thanks for the input.


Im didnt mean to imply that stroking equated cam failures. I realise they have nothing to do with one another...

I do believe, like you, that low zddp and cheap lifters have contributed. I dont believe HV oilpumps have either.
Switching to an aftermarket cam (Im considering the comp 231-4) will work well for my purposes. When I did the initial teardown of my donor a few months back, I took extra care with the stock cam and every lifter is marked in its own baggie. Although a stock cam is an option, I feel that the gains available with the cam change are worth the investment.

I will be cryo treating whatever cam and lifters goes in the engine if I do go thru with this. Im a big believer in the process and have had parts done in the past.

As far as the sluggishness goes, there is a guy in my club that had one installed in his xj and he wasnt impressed with the power. Theres a few others Ive read about that didnt reach expectations. I realise that its not going to produce the power that my 360 did and Im prepared for the outcome. I no longer require the "beefy v8" I did 10 years ago. I run the MPI on a 258 in my wifes yj and am very familiar with it. I trust it to give me what it does.

For my use, if it moves my 5000lb wagoneer up and down the hwy with a small travel trailer behind it at more than 55mph, Id be happy. Im pretty sure it will, so all thats left is reliability.

I only question the cam failures. I dont believe they go over well with spouses.
Since Im without a running 360 and the parts are in the garage for the stroker, the choice is seriously leaning towards the stroker.

The comp cam, their supplied lifters and springs, and liquid nitrogen. Add to that some diesel oil or zddp additive and I guess we'll see how it works.

k.

[Alex22]

I have seen the results of cryo'd parts and agree that it can do some great things for the parts, I do believe it is overkill for the cam and lifters. If you really want to spend the money on a treatment for the cam, have you considered nitriding it?

The High volume pumps can be a problem on many engines, I'm going to use a stock replacement pump in mine and shim the spring for higher pressures.

~Alex

[SilverXJ]

If you are considering the 231-4 Comp Cam does offer a nitriding service.

-Chris

[kris]

Have you considered a 318 with EFI?
If you already have and don't like the idea then don't be afraid of a stroker, If you build it right then it will make the power.

No. My wagoneer v8 is AMC, so a cryco engine is not a native swap. If I were going non-native Id go GenIII Vortec. They are truly a great package.
Ill be staying AMC this way and with what is familiar to me. Wagoneers were offered with 258's so the engine bay is already set up for an i6.

Im not looking for gobs of power, just enough with some reliability.


kris.

[Alex22]

Before you go and spend unnessescary amounts of money on your cam and lifters you should talk with your local machinist and ask him about what he reccomends. Cams, lifters, spring pressure and break in oil.

~Alex

[gradon]

I too noted that a lot of the strokers that failed were using hi-volume oil pumps. I went against my intuition and bought one because it was cheaper and included the pickup. My stroker is meeting my expectations.

[oletshot]

I forgot one. I was just recently reading somewhere (here or the yahoo group) that some or all of the rod bearings don't have notches cut in them for the oil squirt hole in the side of the rod. That squirt hole provides the cam with oil. I'm not sure how true this situation is, but block off that hole and your setting yourself up for failure, unless you supply your cam with oil some other way.

I also believe the gains are worth the cam change. I just tried to choose a cam that didn't have so much more lift that it required stronger valve springs.

Alex22, the HV pump I bought claims a 20% increase in volume. Is that really enough to pump all the oil to valve cover? I also hate to admit it, but I've starved an engine very similar to the 4.0L (2.5L in a YJ). It was very low on oil and would it starve itself while turning. Because I only had a gauge and I'm an idiot, I failed to notice the needle dropping on an expressway off ramp. The crank and bearings gave out long before the cam. Are you sure on the import lifters? The ones I got, came in a small plain white cardboard box. I just reminds me of type of boxes chinese tools come in. I hope your right.

[Flash]

oletshot, My opinion on the stroker failure is the same as you, on every point!

The HV oil pump, i can't tell you why its a factor, Other then the majority of are cam failures.......Had a HV pump...........Coincident...........Maybe

The rod oil lube hole, could be and problem..........with piston scuff as well as a cams early failure!

Some day we will have a enough data to say for positive what failed as well as how to make it live 100......200.000+ miles

Thing like, Chinese lifter, and pour cam manufacturing will NEVER be proven!

Flash

Edit, there is tons of strokers out there, that are surviving just fine............But there is enough that have problems, that we cam improve there durability, by discussion of them.

When there is a stroker failure we take a lot about it........as we try to fine clues to its origination.

[highstumpr]

I think I can confirm the need for the rod squirters needing drilled bearings. I had scuffed pistons and the #1 lobe on the cam starting to wear. About 20K on the pistons and 35ish on thee cam.

[AaronJ]

Does anyone have pictures of the rod bearing oil hole thing??????

[kris]

I forgot one. I was just recently reading somewhere (here or the yahoo group) that some or all of the rod bearings don't have notches cut in them for the oil squirt hole in the side of the rod. That squirt hole provides the cam with oil. I'm not sure how true this situation is, but block off that hole and your setting yourself up for failure, unless you supply your cam with oil some other way.

I also believe the gains are worth the cam change. I just tried to choose a cam that didn't have so much more lift that it required stronger valve springs.

I remember reading the same thing.
When a rod is reconditioned, part of the process is resizing the large end. In use, the large end has a tendency to stretch, or become slightly oval. This is remedied by removing a small amount of material from the mating surface of the cap, reassembling the rod, and honing the bearing surface to a round condition. The process does make the rod slightly shorter, but if done correctly it should be limited to a few thousandths.

On the oil squirter...
The groove that the oil follows from the bearing and out to squirt on the cam is milled into the rod, not the cap. Reconditioning rods should nave no effect on the oil passage. The only time this passage may become blocked is if little care is taken in preparation, such as a defective or incorrect bearing, or possibly a burr or other debris in the passage after replacing rodbolts.

So... Although it is important to check the passage during engine assembly as it is important to check many things, reconditioning a rod and replacing a bearing "should" have no effect on its oil passage...


im hoping to spend some time with myy engine today. Ill see if I can get some pictures of a rod and squirter and get them posted if no one else has any...



Q...
Has anyone considered cross-drilling the mains ?


k.