Longevity of a stroker?

[Grumpy_one]

Jeepers on the jeep forums seem to think strokers have a short life. It's a mixed bag. One jeeper reports it was due to aftermarket cams that were lasting only 20K that are no longer in business. I've read that some motors will get up 200K. I imagine it's how the skinny pedal gets used. I don't plan on going over 3500 let alone 2500 rpm on the trails. Is this a thing of the past? Short life strokers?

[Cheromaniac]

Mine's still going strong and kickin' ass after 81k miles so you can count mine amongst the strokers that bust the myth.

[jsawduste]

How do I say this politely ?

Oh hell, as it is..........The majority of folks on JF really have no idea what they are talking about...........The few that actually bring something to table are overshadowed by those who talk Parrot...........

[SilverXJ]

x2. Most of those people never had a stoker and just heard of the builds that have had problems. Lots of misinformation going around. I staff off JF, JU, CF and the liked due to what jsawduste said. And if you think those are bad check out some of the facebook groups.

[jeepoffire]

Glad I found this forum as I am looking to possibly stroke my 99 Jeep GC motor that recently crapped a piston into a thousand pieces. First I have to make sure machine shop will resleeve the cylinder, if not, i have a boat anchor. If it can be fixed, definitely leaning toward a stroker build. This engine when built will go into my 2004 WJ. Looking forward to researching different builds and happy to hear the longevity question is debunked for the most part. I alway expect bad apples, afterall, Jeep makes the Renegade now.

[Burnsmacdonald]

My first stroker, but used to be a mechanic in the 70's, so that helps (only a little). I had my engine work done by a master auto machinist who is a known performance builder in this area.

A few humble points to offer from what I have learned in the process, with excellent help from jsawduste, cheromanic and others in this forum and pirate 4x4:
1. Just because a shop does garden variety head work, does not qualify them to do performance engine builds.
2. My builder thoroughly boiled the block to make sure all the oil galleries and water channels were free and clean.
3. We used a 4.2 crank to get the extra 1/2" of stroke. He paid a lot of attention to the oil passages and spent some time chamfering them.
4. We used Keith Black forged allow pistons with a higher pin height to offset the length of the stock 4.0L rods.
5. I used Harland Sharp roller rockers with an after-market cast aluminum valve cover. Trouble is the extra meat on the alloy rocker means that there is no room for for oil baffles on the underside of the cover. That is essential as oil will be suc\ked up into your intake manifold in copious amounts. Especially as having vacuum (negative pressure) applied to the valve cover (as per the stock configuration) is essentially to how the engine runs. My solution (thanks jsawduste) was to install a 1/2" spacer kit that allowed me to install the baffles... problem solved.
6. Kudos to him, he added a baffle in the pan to hold some oil back for the pump on steep declines... a known 4.oL problem.
7. The engine as built is considered a flat tappet cam and therefore must use high-zinc oil, otherwise you won't get the longevity from the engine. After much deliberation and research I settled on Brad Penn High Performance oil. I am using 15W-40 although many folks prefer 10W-30. I don't drive it in the winter up here in Canada so the cold temp thickness isn't an issue.
8. We religiously followed the break-in procedure for the cam. It's fairly well established that failure to do so can result in early cam failure.
9. I am using a BBK 70mm TB, with the intake manifold port-matched to the ported head and the TB. I am also using Accell Racing 24# injectors with 4 orifices each. My AEM air-fuel analyzer says I am running a tad rich and my fuel consumption is higher than I would like it to be, but that is better than running to lean and burning a piston. However, I am currently running the stock ECU. Once the ECU is tuned, I expect an improvement in ignition advance and the fuel mixture (and performance).
10. We have some deepish ponds and streams to cross around here to get to the rocks we play on. At the moment I am running a air induction system to ensure the engine gets enough air volume. However, I am working with Spectre to get the pieces for a custom air box setup that will connect to my snorkel and still provide adequate CFM.

There are a lot of guys here smarter than me that can add to these points (or correct them if needed).

Cheers

[jsawduste]

Been using the 63mm BBK but plan on trying the 70 BBK on the next engine.

[Align=] **along with a minimum 2.5 collector** [/Align]

Most of the headers measure out at 2" a few at 2 1/8" +/- Thorley (who make several Jeep headers) has a 2 1/2 off the shelf that is made of a quality stainless. Coupled to a good exhaust system is going to be about all we can get. AKDM http://www.allkustomdesignmachines.com/index.html can custom make/modify headers so that is an option also.

We are limited in the primary tube diameter because of inference with the bottom of the intake manifold.

Depending on your exhaust routing the Moroso pan would be a wise investment. http://www.quadratec.com/products/51009_1002_07.htm Moroso can cut the drivers side wing if the exhaust is in the way.

Going back to that 70 BBK. The stock cal really needs to be tweaked to take advantage of that flow potential.
It seems your TJ`s fuel pressure combined with the 24# Accel injectors may be more then what the factory cal can handle with the BBK. I`ll bet Chris pulls some fuel out across the board and lets the injector duty cycle rise a bit. Allowing for a wider latitude for the ECM to work off of.

Really think a good tune will not only wake up the engine but bring the mileage up as well.

[jeepxj3]

What 70mm BBK TB are you using?

[jsawduste]

When I last talked to BBK they would make a 68 or 70 and use the Jeep style linkage.

Best to let Burns answer the question though.

[Burnsmacdonald]

Have to look. Don't remember the part number, but it was pretty much a straight bolt-in other than the port-matching. If you don't port-match it is a waste of money as it is still restricted at the manifold so you won't get any benefit from a larger TB.

Get back to you

[Burnsmacdonald]

Am trying to read the part number, but it isn't easy. It is a BBK PowerPlus TB but now I am not even sure it is 70mm.

It is bigger that the stock TB, as we did have to adjust the manifold port. I'll keep trying to see.

[jsawduste]

Offer an apology to Burns and others.
BBK does not make a 70mm TB for the Jeep. They do not offer anything larger then a 63.
Now having said that. BBK does offer a 70 commonly used in the fox body mustangs that will bolt up. You have to figure out the linkage and of course open the manifold up but the bolt patern is the same.
F&B does offer a 68 and can do a 70. Have never used an F&B so I cannot comment on the quality. BBK is 1st rate and I have never had an issue.
Bring this up as I did try a Jeepers Creepers TB and never got it to work properly. Customer service was super and they really tried to resolve the issues but in the end it was back to BBK.

[jsawduste]

Burns, is the throttle plate zinc in color ? If so that is a BBK trademark of sorts.

[Burnsmacdonald]

It says BBK PowerPlus But I can't get into see the size on the bottom of body. It is behind my PSC reservoir and coilover tower.

I will try when I can look during daylight. Getting dark around 4 or 5 pm here now.

It could well be a 62mm or 63mm by what jsawduste says

[Burnsmacdonald]

I stand corrected. I checked and it is a 62mm BBK PowerPlus TB
Must have been dreaming of a 70mm

Jsawduste was right (as usual)