Alex's "New" Stroker Build

[AlexTJ]

If you read any of my threads in the other sections then you may know that I had a Titan built 4.6L stroker that blew up on me.

Since I am building a new motor from the Titan's remains I thought I would start a project thread.

This is what I will be putting together over the next few weeks for my '97 TJ:

I started with the usable parts from the Titan:
93 4.0L block
7120 head
5.875" 707 rods
(The Titan crank was installed .060 under so had nothing left. The distributor gear on the "comp 201" cam was also shot)

Then I added my parts as nesessary:

Remanufactured 3727 crankshaft, .040" under I believe
Sealed Power crank and rod bearings
3241HC .060" pistons (from EngineTech) dished to 20cc's (thanks a bunch Oletshot!!)
Lunati 63502 camshaft. Specs: .507/.527 AdvIVO: 23 IVC: 59 EVO: 70 EVC: 18
Springs set up and chosen by my machinist for the lunati cam
Deck Height set @ 9.4225"
Mopar performance 0.043" head gasket
APN cheap header
'99 intake manifold
24# accel injectors
Stock throttle body (ehhhhh for limited time)
Stock air intake (didnt like my K&N drop in, might be a good idea to get a 'real' CAI?)
Stock 97 TJ OBDII but I did make a MAP adjuster

Machine work: The usual plus:
everything balanced
bored from .040 to 0.60
combustion chambers enlarged to ~60cc.
Machinist said he found a tiny crack in the block by a bolt hole but he fixed it (some sort of sleeve?).
He also said he hit water once while doing the valves but it also wasn't a big deal to fix (glue?).
I was really worried about the lift on the Lunati cam but my machinist said he could set up the head for it no problem. I will find out exactly what he did when I pick everything up next week.

Quench: 0.051" SCR: 9.58:1 DCR: 8.03:1
I'm really hoping this will run decent on 91 because 93 isn't availible in good ole Kansas.

[AlexTJ]

I'll post the info from the old Titan engine as a warning to others :

The Titan engine I bought on ebay was supposed to be set up with a 9.25:1 SCR and run on 89 octane. But once I got the engine I never got a spec sheet on what exactly was in it. The only way I would find out is by opening it up which I of course didnt do til it blew up. Turned out it had terrible piston slap as well as a hole in piston 5 where it melted over the compression ring. All the bearings had a ton of copper. It of course smoked a ton and ran like complete crap.
I also discovered that the cam probably didnt have correct end clearance since the distributor gear was screwed and the back of the cam had worn against the oil plug.

Here is what I found when I tore the thing down:

3235477 crank, .030 and .060 undersize....
.040" 2228s with untouched 11cc dish
The 707 short rods
A completely unmarked cam (markings possibly worn off?) that measures .447/.447 and Chuck @ Titan confirmed he often uses the Comp 68-201-4
Stock 58cc chambers
Didnt bother to check head gasket thinkness, I'll assume it was a 0.051
Stock deck height (was measured to be 9.449)
So I calculate deck clearance to be 0.0465"

Using our compression calc I get SCR: 9.66:1 and DCR: 8.26:1, Quench: 0.0975.....
I ran this engine on 89 octane @ ~900ft for about 20k miles before it went (well more like 18k, I drove it into the ground). Either I don't recognize pinging or it didn't ping using 30# injectors (which i'm replacing with 24#s cause thats wayyy too much).

Still, unless my calculations are wrong, thats far from a 9.25:1 SCR

[AlexTJ]

Future Mods planned after the engine is assembled:
Enlarge throttle body,
Wideband O2 w/ guage,
CAI if needed?
Engine tune, either dyno or splitsecond stuff

[AlexTJ]

I calcluate that I will need pushrods 0.0355" shorter than stock. Does that sound right?

[AlexTJ]

^disregard above post^

Short block is done!!! Had machinist degree the cam for me. On the first few tries he said it was 7 degrees off so he changes slots on the cloyes and measured again. Managed to get a 110 centerline, so not bad

[AlexTJ]

Just took off the head after checking valve to piston clearance. Valves didn't even touch the 1/8" of clay!!! Thats with .507/.527 lift, .008" deck clearance, and .043 head gasket (not completely compressed but I'm fine)

[SilverXJ]

I've checked mine with clay, but I haven't heard of anyone mentioning that the pistons come close to the valves.

[AlexTJ]

I've checked mine with clay, but I haven't heard of anyone mentioning that the pistons come close to the valves.

I hadn't either, but I figured why not be extra sure lol

[AlexTJ]

Haven't updated in awhile!

Changes that happened to my build: Back in August it got a new head after the cam break in, machinist "missed a crack" (he replaced the head and did all teh work for free) I don't remember having him increase head cc's so I believe they are stock at 58. But of course the damn Hylift-Johnson lifters that Topline sent me were really for a Chrysler slant-6 so I had to take the head back off anyway. Got it running for real by the end of September.

The cam turned out to be 6 deg advanced so we brought it down to 2 deg with the Cloyes. I don't think I had ever recalculated my compression for these things, its really SCR: 9.78:1 DCR 8.08:1

It runs really well on 91 with the distributor ears cut off and a GM distributor clamp. If I cut the ears just a teeny bit more I bet it would idle cleaner.

I have run it on 89 when 91 wasn't available. I didn't hear any ping but it didn't seem to run as smooth.

I ended up with this setup for the upper end:
Lunati 63502 Cam .507/.527 retarded 2 degrees (still advanced 2 degrees with the 4 built in)
Hylift Johnson lifters
9.600" chromoly pushrods
"new" stock rocker arms
My machinist chose Comp 981-1 springs

Surprisingly with I notice little/no noise at all. The valve train is damn quiet. My buddy's xj has a Titan with a Comp 68-232-4 and the ticking annoys the crap out of me every time I ride in it. My old Titan motor always had an annoying tick to it. Maybe thats why its dead. This stroker has a very noticeable power increase over my old Titan, especially after 3000+ rpm.

The only issue I have right now is a little oil seems to be mysteriously disappearing....

I thought it would go away after break in but as of 6500 miles I'm using almost a quart every 4-500 miles, but no leaks no smoke. It seems to be losing more after periods of spirited driving (full throttle/4500rpm shifts/engine braking to help slow down) and much less oil used when I'm trying to save gas.

I just bought a oil/air separator for the CCV line so maybe I can get a visual on when its drinking oil. I finally got a mechanical oil gauge too so I can verify my lowish oil pressure is do to the stupid sending unit.

[shawnxj]

have you looked at your air filter lately? losing that much oil it'll prolly be soggy by now

[AlexTJ]

have you looked at your air filter lately? losing that much oil it'll prolly be soggy by now

It's dry I've checked. The PCV system is working correctly so the oil is going into the intake manifold and burned. I want the catch can so I can get an idea of the conditions under which oil starts coming out.

[AlexTJ]

I don't remember if my machinist knew I was using moly rings or not. We could have easily talked about it but I don't know. Therefore he could have honed the cylinders for normal rings, and alot of people say that the roughness will eat moly rings. But hastings' website states "Substantial controversy exists on the correct cylinder roughness for proper seating of piston rings, whether chrome, moly, or plain cast iron. It has been our experience that the use of 220-280 grit stones and achieving proper cross hatch angle produces a finish compatible to all three types of the above rings." So I don't know.

I really don't want to do a leak down test right now because I'm working 72 hours a week on nights until summer starts...

[dwg86]

I had the same problem with my stroker. The problem with my engine was I tried to modify the stock baffles in the valve cover to clear my roller rockers (my home made baffles didn't work). Oil was getting sucked into the intake through the ccv line. The vaccum port for the ccv was right above the #6 intake runner. I fouled a couple of plugs in the #6 cylinder before I replaced the valve cover.

Try looking at your plugs and see if there is a certain cylinder that is the problem or if it's all.