Jeep Strokers

Ok just joined here, thanks Brent for letting me know about this. I have a Titan 4.7 and have had it for almost 2 years come this summer. I personally have had no problems with it (knock on wood) but I have had a problem with spark knock. I do still run the stock computer and stock fuel pump with no upgrades to it, yet. Once its back from being lifted and all I plan on taking it to a local hot rod shop. I was told he could put a completely programmable piggy back computer on it, but its expensive. I run 93 octane in it and a thing of octane boost and it runs fine till around 3500 rpm or so. I have also run 110 race fuel in it and the same thing. I have a fuel cell, Mallory fuel pump, and a Areomotive fuel pressure regulator to put in it then take it to the hot rod shop and let them do there thing to it. Is there anything else or different that I could do?

Thanks for all the help.

When do you have spark knock? You could need either a piggy back computer or larger injectors or both. Since you say it happens around 3500 RPM I take it happens under WOT. While you could probably install larger injectors and be ok you could be running rich at some RPM points. Since you have a fuel pressure regulator, what is your fuel pressure? You may get away by boosting that.

When my first Titan was running I had an Apexi to adjust the fuel at WOT and a wideband O2 sensor to monitor that. I had the stock injectors and the engine only pinged if I used 87 grade fuel. I would ask you your specs for compression, squish, etc but since Titan doesn't give spec sheets (even thought they promised me one) that is impossible.

SilverXJ wrote:When do you have spark knock? You could need either a piggy back computer or larger injectors or both. Since you say it happens around 3500 RPM I take it happens under WOT. While you could probably install larger injectors and be ok you could be running rich at some RPM points. Since you have a fuel pressure regulator, what is your fuel pressure? You may get away by boosting that.

When my first Titan was running I had an Apexi to adjust the fuel at WOT and a wideband O2 sensor to monitor that. I had the stock injectors and the engine only pinged if I used 87 grade fuel. I would ask you your specs for compression, squish, etc but since Titan doesn't give spec sheets (even thought they promised me one) that is impossible.

I have bigger injectors, Ford Motor sport 24lb from Five-O, I am also running a 62mm RE throttle body and a 62mm Hesco throttle body spacer but I'm still running the stock fuel pump and the computer is still stock. I haven't got the new fuel cell, fuel pump, fuel pressure regulator, or the new fuel line in yet due to it still being in the shop having it lifted and all. Once the lift and all that work is done then I'll start on the fuel upgrade then I will send it off to the shop for the computer upgrade.

gamjunior wrote:
I have bigger injectors, Ford Motor sport 24lb from Five-O, I am also running a 62mm RE throttle body and a 62mm Hesco throttle body spacer but I'm still running the stock fuel pump and the computer is still stock. I haven't got the new fuel cell, fuel pump, fuel pressure regulator, or the new fuel line in yet due to it still being in the shop having it lifted and all. Once the lift and all that work is done then I'll start on the fuel upgrade then I will send it off to the shop for the computer upgrade.

Its not a computer upgrade. They just install a piggy back computer. The stock computer is not modified.

Another option that may be less expensive if you do it yourself would be to look at your camshaft choice. A lot of the ordinary cam grinds that I've seen will be bad for a stroker because they will have very little to no valve opening overlap. A cam with more overlap will bleed off cylinder pressure and lower the dynamic compression ratio. I am no cam guru but I've slowly picked up things over the last few years. So there's a lot more helpful advice on cams to be had here.

BTW I am going to split this topic off and put it in Tech, as trouble shooting ping and fuel management is pretty far from the basics. and is only related to Titan by the name of gam's long block.

Have you tried installing an adjustable map to richen up the WOT?

thats a great idea. didnt think of that. heres go-jeep's write up on building you own adjustable MAP sensor.
http://www.go.jeep-xj.info/HowtoMAPsensor.htm

If it has been pinging sence new then the above would be the best idea.....................If the pinging came along later on......You may have some carbon build up on the piston that is creating hot spots.....................

Take the air cleaner off so you can get the the throttle body, hold the eng at a high idle and slowly pour water down the throttle of it keeping it at a high idle(around 2000 rpm)..........It will literally steam clean the pistons

Running it thru a vac port, hose and a container will work also but there need to be a restrictor in the line so it can be drawn in at a idle.........say a .010 or .020 hole drilled thru a ball baring that is inserted into the vac hose......

You don't want to let the water going thru the vac line with out a restrictor................were trying to get a mist of water in there not Hydro lock the eng


Flash

Flash wrote: Take the air cleaner off so you can get the the throttle body, hold the eng at a high idle and slowly pour water down the throttle of it keeping it at a high idle(around 2000 rpm)..........It will literally steam clean the pistons

Running it thru a vac port, hose and a container will work also but there need to be a restrictor in the line so it can be drawn in at a idle.........say a .010 or .020 hole drilled thru a ball baring that is inserted into the vac hose......
Flash

very cool trick!

I'm currently having a really bad time with a Titan. There is a post at NAXJA about it.

http://www.naxja.org
naxja's technical forms
modified tech discussion
stroker: Titan engine: my story

Or you can search for posts by mhead. It will come up.

Basically I've concluded that the quench height is incorrectly designed in my Titan. The result is ping.

Enjoy!

Mhead, I put in all your specs from the naxja thread into the compression calc on this site and got 9.96:1 static compression. With the stock cam, it was doomed from the beginning. The new clevite 229-2174 cam should help, but I'm not sure that it will solve the problem completely. Based on the spec for piston pin height (1.581") you have silvolite 2228 or 2229 (same piston, different part#'s for 2.5L & 4.0L). The good news is these pistons have enough land in the dish area to machine the piston dish deeper to help lower your compression raio. I've machined my pistons to 23cc's and another set silvolites for someone on the yahoo group to 26cc's (this is a relatively new forum that spawned from a Yahoo group named Strokers-this is another place to look for more info). Some have dished these even more, I believe up to 30cc's but I'm not sure how safe a dish that deep is. I could probably machine yours without removing them from the rod ( it would require a special fixture but I think it could be done). Machining your pistons to 23cc's brings your static compression down to 8.8:1. If you post your engine specs some of the guys here may be able to help more by given dynamic compression ratios of different solutions and advice on how better quench could help you, specifically if you could even get this engine to run on pump gas with better quench alone. I don't believe the block could be machined enough to get enough quench to stop pinging in this engine. I feel lower your compression ratio without making quench any worse is your answer, that leaves piston dish and cam as your most logical choices.

My original Titan with the Comp Cam 68-232-4 pinged when I ran regular gas. The Crane they installed for 600 miles and my 68-231-4 are/were too now to see how they handle pinging.