stroker reliability

[amcinstaller]

you know, it makes me think that maybe the problems had actually have nothing to do with STROKING the engine seeing as all the problems tend to be on the top end of the engine. the only engine failure that comes to mind due to bottom end issues (and i could totally be forgetting somethin here) is turbo toms engine, but his was a faulty piston (so the story goes) and it wasnt a stroker. so i think what needs to be figured out is where the bad geometry is in the head, and how to overcome that, not whether or not to stroke a 4.0

[CobraMarty]

It is interesting that most all problems are centered around the cam. It seem that the 'further' away from the stock cam, the more chance for problems.

Looking around on 505 site, their engines all have a cam bolt. Might be cheap insurance.
http://www.shop.505performance.com/prod ... egoryId=26

[grainofsalt]

It is interesting that most all problems are centered around the cam. It seem that the 'further' away from the stock cam, the more chance for problems.

Looking around on 505 site, their engines all have a cam bolt. Might be cheap insurance.
http://www.shop.505performance.com/prod ... egoryId=26

Pardon my ignorance, But what does that replace/do? Is it just a replacement that goes in the end of the cam (meaning replacing the stock bolt and washer)?

[Retlaw01XJ]

Unsure how the Hesco setup differs from stock.
But the stock spring/pin setup will still allow the cam to move back and forth in the block. It's possible this could disrupt the oil cushion and lead to cam bearing failure.
Jeep eventually went to a cam retention plate to keep cam movement to a bare minimum. Unfortunately, these plates won't fit the earlier or aftermarket performance cams. Solution for those cams is to use a solid pin filed to fit and keep cam end play under 0.005" or so.

[gonridnu]

Stroking the engine has little to do with the failures you are reading about. No one is complaining of failed main & rod bearings, rods or crank failures, or anything else related to the rotating assembly. These other issues you are reading about are not related to the fact that the piston travels up and down an additional 1/4" in each direction.

Almost all of the issues are related to camshaft so it should stand to reason if you use a mild cam with stockish valve spring pressures you may avoid these problems. Other than that it's basically just a stock rebuild. As such it is subject to all the same pitfalls a stock engine would be on replacement (build or installation mistakes) but it has nothing to do with the piston going up and down a little more.

While I only have 7k on mine at this point I fully expect it to have a service life comparable to a stock 4.0 rebuild of a similar quality and it has given me no reason to think otherwise. I would also guess the reason so many have posted and then disappeared is because they are happily enjoying their jeeps on the weekend and have no reason to continue posting here.

[jbain]

I had never built a motor before until this time last year when I decided to build a 4.6 poor mans in my brother garage floor. Sent the thing off and got the machine work done then asked a friend to help me assemble the motor. Once done we reinstalled the cam, bolted on the factory head (with 256k miles) dropped it in and fired it up, I drove it 500 miles then won my first mud bog with it. Since then I've beat it as often as possible and even driven it on and off to work for awhile. Just a couple months ago I drove 6 hours to Harlan KY, wheeled it hard then drove it 6 hours back the little stroker hummed right along hour after hour. I chose to stay with a stock head because I read everything I could and decided that reliablity meant more to me the advantage of additional HP.

[superj]

mine was built two owners ago and myself, nor the previous owner, know exactly what is in it but it has lasted the whole two years i have owned it with zero trouble.

[Dezertxj88]

Well when I started thinking about stroking my motor...I wanted to look at everything..rod ratio, piston speed ect ect...

A 4.2L stroker vs a stock 4.0 is litterally no different.
4.0 rod ratio is like 1.794 & piston speed around 2955 fpm. (assuming a 5200rpm rev limit)
4.2L stroker has a 1.75 & a piston speed around 3050 fpm. (assuming a 5200rpm rev limit)

And if you polished the rods & used ARP rod bolts, the 4.2L will actually have a stronger bottom end. Theres alot of here say as to what keeps reliability and such, but its common to see people say not to exceed 3500fpm & to try and keep a 1.8-1.65 rod ratio, perferably nothing less than 1.700. Honestly if built correctly and not built on to a extreme then yes I think any stroker will last just as long as a 4.0 would!
With strokers though, you can get stronger rod bolts, polish & shot peen the rods, and then have everything balanced out perfectly. So in actuality it should run smooth than a normal 4.0

4.5+ short rod stroker
1.50 rod ratio & piston speed around 3375fpm (assuming a 5200rpm rev limit)

4.5+ long rod stroker
1.57 rod ratio & piston speed around 3375fpm (assuming a 5200rpm rev limit)