Stroker: Titan Engine: My Story

[mhead]

Re: Stoker: Titan Engine: My Story

The same thing happened when I was installing my distributor and I had a hard time coming up with an explanation. The only thing I could think of is that the electrode is on the trailing edge of the plug at TDC because it is just ending the spark sequence. By the time the piston is at TDC the fuel should already have been ignited, so the spark has to occur ever so slightly before the piston hits TDC. Also take into account the spark has to go from the electrode through the wire and plug. There's minimal resistance, but it does take a very small amount of time.

Electrode on rotor looks to be maybe 15 distributer degrees or 30 crank degrees. Using crank degrees the rotor leading edge would be at #1 tower something like 30 degrees advanced and the trailing edge would arrive at #1 tower at just a degree or two advance. I guess it kinda makes sense since engines are run with spark advances of maybe 10 degrees. I bet some careful measurements would make it all plain.

But what really got me is that when attempting to start the engine I did see spark at #1 plug. Seems like any spark would make the engine pop or backfire or something. But it did nothing. Thats what got me. If it had backfired or run really crummy I would have understood. Oh well.. It runs now but I'm going to put in the next reply seperate as you'll understand shortly.

 

[mhead]

Re: Stoker: Titan Engine: My Story

Ok the Titan stroker runs. Doesn't idle all that well. But I can't hear a ping at any throttle setting I've tried. I'm up to about 15 miles now. I've got problems however. It runs hot. Today air temp is about 85 (deg F) Just driving level ground at 45 MPH I'm at a little over center mark 210. If I pull up a hill and then hit a stop signal temperature creeps up to top line just before the red zone. If it's having this trouble now what happens when air temp is 110? I'm just driving normally. Not flying like this motor makes me want to do.

Maybe someone can come up with an idea why. Here's what I know

New Titan 4.0 I6 stroked and bored to 4.6. I didn't check by pulling a freeze plug, but I expect they tanked the block and got it cleaned out. Looked into the head and things seem OK in the water jacket.

Just installed new head after first head pinged, got hot, and bent 2 intake valve. #5, #6

Engine running 14.7 air fuel. At no time does it run lean.

No ping that I can hear. Static compression should be in the lower 9s

New fan viscus clutch. Lotta fan noise on engine start. Seems OK

New fan belt. No slippage noise.

Electric radiator fan comes on at higher temperatures. Seems OK

Thermostat I think is 180 degree. It works. Tested with hot water and thermometer. Also measured engine inlet temp with electronic thermometer and can see temperature ramp up and stabilize at about 170 degrees. I'm measuring the temperature of the thermostat housing and not within the coolant so I expect a slightly cooler measurement. With factory 4.0 temp stabilized just above first line on dash gauge. Now with stroker it stabilizes just a tiny bit above dash gauge center line. This could result from my swapping the temeprature sender unit. I broke the old one.

New water pump

New hoses. Lower hose has wire coil within so I doubt it is collapsing.

New temperature sender sensor at rear of engine. Calibrated its resistance with hot water and thermometer. I think it agrees with factory values. Anyway right now I don't doubt the dash gauge.

My Jeep has a fancy hood with the scoop. I should have better than normal air circulation.

Radiator is maybe 3 years old. Been flushed once.

Coolant color is nice green. No rust color.

Bottom end has 2500 miles on it, put on before valve bend. Should be broken in by now I would think.

Previous engine (factory 4.0) ran with normal temperature. Didn't have an overheat problem. Same radiator.

So I am as usual out of ideas. I've seen suggestions that the water pump is wrong by mistake and is for a different vehicle. Evidentally there's one that looks the same but has a reverse impeller. I think if the water pump went backwards the engine would overheat instantly rather than just running hot.

Since the factory engine ran normally I expect that my problem is related to the stroker in some way.

Been thru 2 heating/cooling cycles. Maybe it still needs to suck in coolant. I'm watching the overflow bottle to see if engine is drawing coolant in but I don't think it is. This is a 1992 XJ and it has the non-pressurized overflow bottle.

So I need out-of-the-ordinary ideas. Anyone having heat troubles with a stroker? I would think that if driven conservatively a stroked motor would need to radiate the same wasted heat as a factory motor delivering the same power. I should see the same dash gauge indications.

This is going to be fun...

 

[corbinafly]

Re: Stoker: Titan Engine: My Story

The same thing happened when I was installing my distributor and I had a hard time coming up with an explanation. The only thing I could think of is that the electrode is on the trailing edge of the plug at TDC because it is just ending the spark sequence. By the time the piston is at TDC the fuel should already have been ignited, so the spark has to occur ever so slightly before the piston hits TDC. Also take into account the spark has to go from the electrode through the wire and plug. There's minimal resistance, but it does take a very small amount of time.

Right. It makes perfect sense that the rotor would be past the electrode at TDC. The spark is advanced at much at 45 degrees BTDC sometimes so the rotor needs to be close enough to the distributor for the voltage to jump to the correct terminal throughout the range of spark advance.

 

[corbinafly]

Re: Stoker: Titan Engine: My Story

Ok the Titan stroker runs. Doesn't idle all that well. But I can't hear a ping at any throttle setting I've tried. I'm up to about 15 miles now. I've got problems however. It runs hot. Today air temp is about 85 (deg F) Just driving level ground at 45 MPH I'm at a little over center mark 210. If I pull up a hill and then hit a stop signal temperature creeps up to top line just before the red zone. If it's having this trouble now what happens when air temp is 110? I'm just driving normally. Not flying like this motor makes me want to do.

Maybe someone can come up with an idea why. Here's what I know

New Titan 4.0 I6 stroked and bored to 4.6. I didn't check by pulling a freeze plug, but I expect they tanked the block and got it cleaned out. Looked into the head and things seem OK in the water jacket.

Just installed new head after first head pinged, got hot, and bent 2 intake valve. #5, #6

Engine running 14.7 air fuel. At no time does it run lean.

No ping that I can hear. Static compression should be in the lower 9s

New fan viscus clutch. Lotta fan noise on engine start. Seems OK

New fan belt. No slippage noise.

Electric radiator fan comes on at higher temperatures. Seems OK

Thermostat I think is 180 degree. It works. Tested with hot water and thermometer. Also measured engine inlet temp with electronic thermometer and can see temperature ramp up and stabilize at about 170 degrees. I'm measuring the temperature of the thermostat housing and not within the coolant so I expect a slightly cooler measurement. With factory 4.0 temp stabilized just above first line on dash gauge. Now with stroker it stabilizes just a tiny bit above dash gauge center line. This could result from my swapping the temeprature sender unit. I broke the old one.

New water pump

New hoses. Lower hose has wire coil within so I doubt it is collapsing.

New temperature sender sensor at rear of engine. Calibrated its resistance with hot water and thermometer. I think it agrees with factory values. Anyway right now I don't doubt the dash gauge.

My Jeep has a fancy hood with the scoop. I should have better than normal air circulation.

Radiator is maybe 3 years old. Been flushed once.

Coolant color is nice green. No rust color.

Bottom end has 2500 miles on it, put on before valve bend. Should be broken in by now I would think.

Previous engine (factory 4.0) ran with normal temperature. Didn't have an overheat problem. Same radiator.

So I am as usual out of ideas. I've seen suggestions that the water pump is wrong by mistake and is for a different vehicle. Evidentally there's one that looks the same but has a reverse impeller. I think if the water pump went backwards the engine would overheat instantly rather than just running hot.

Since the factory engine ran normally I expect that my problem is related to the stroker in some way.

Been thru 2 heating/cooling cycles. Maybe it still needs to suck in coolant. I'm watching the overflow bottle to see if engine is drawing coolant in but I don't think it is. This is a 1992 XJ and it has the non-pressurized overflow bottle.

So I need out-of-the-ordinary ideas. Anyone having heat troubles with a stroker? I would think that if driven conservatively a stroked motor would need to radiate the same wasted heat as a factory motor delivering the same power. I should see the same dash gauge indications.

This is going to be fun...

DId it run hot before you changed the water pump? The correct pump for our xjs are reverse rotation. They turn counter clockwise when looking at it from the front of the engine.

 

[mhead]

Re: Stoker: Titan Engine: My Story

DId it run hot before you changed the water pump? The correct pump for our xjs are reverse rotation. They turn counter clockwise when looking at it from the front of the engine.

Yes, belt turns water pump same direction as fan, CCW. I can't see inside the pump to see if the impeller is designed for this rotation direction so I must assume for now that I was supplied the correct pump.

Factory 4.0 ran normal. Never a heat problem. Since then replaced:

Engine, cam, heads, rockers
Hoses
Water pump
Fan clutch
Temperature sender at rear of motor
Coolant
Thermostat housing
Serpentine belt


Did NOT replace:
Thermostat
Radiator

All replacements (except cam) were done after factory 4.0 came out and before Titan 4.6 went in. Am seeing about the same heat from Titan now as I did before bent valve head replacement.

I am leaning towards believing the new fan clutch has problems. I noticed before the valve bend with Titan 4.6 that the engine got quite warm on level ground in cool air at one location, warmer than my then-recent experience at other locations. The only difference I noted at the time was that I had a tail wind of maybe 10 MPH. Now that shouldn't do anything but if the fan isn't fanning then it might. The other observation from today is that it seems to get really warm if I climb a hill (maybe 150 feet elevation gain in 1/2 mile at 45 MPH) AND THEN STOP for traffic there's a dramatic heat increase indicated on the dash gauge. So here's another hint that maybe the engine isn't forcing air thru the radiator but depending on vehicle motion to do so.

I can easily move the fan with the engine off but very warm just before shutting down. The 'easily' is the part thats hard to quantify. OK, anyone know how to test a fan clutch? Know how to temproarily wire or adjust the thing so it clutches harder?

Thanks for suggestions!
Mike

 

[slipslap]

Re: Stoker: Titan Engine: My Story

Like already stated, your WOT is way to rich. And contrary to popular belief running real rich isn't ok. Flooding the pistons with gas can cause them to cook in fuel will burn them up and could cause your overheating. But if you correct that issue and still have heating issues I would think about a new radiator or an oil cooler.

 

[mhead]

Re: Stoker: Titan Engine: My Story

Like already stated, your WOT is way to rich. And contrary to popular belief running real rich isn't ok. Flooding the pistons with gas can cause them to cook in fuel will burn them up and could cause your overheating. But if you correct that issue and still have heating issues I would think about a new radiator or an oil cooler.

Good idea! But running hot is happening with 14.7 air/fuel. I'm not on it hard enough to drop out of closed loop operation. But I'll remember this for later when, if ever.., I get to performance tuning.

Thanks!
Mike

 

[JJacobs]

Re: Stoker: Titan Engine: My Story

Air in the cooling system would be my bet.

 

[corbinafly]

Re: Stoker: Titan Engine: My Story

Air in the cooling system would be my bet.

Doubt it. With an open system like his as soon as the tstat opens the first time the air will be pushed out into the rad and from there it will end up going out to the overflow bottle within a couple heating/cooling cycles.

Does your tstat have a bleed hole in it or did you drill one in it? That would help.

 

[Gojeep]

Re: Stoker: Titan Engine: My Story

Like already stated, your WOT is way to rich. And contrary to popular belief running real rich isn't ok. Flooding the pistons with gas can cause them to cook in fuel will burn them up and could cause your overheating. But if you correct that issue and still have heating issues I would think about a new radiator or an oil cooler.

Have you ever tested a stock XJ with a wide band O2 sensor? I have done 4 of them and all were in the low to mid 11's stock! Not sure why the factory chooses to do that???

 

[Wayne Sihler]

Re: Stoker: Titan Engine: My Story

Yes, belt turns water pump same direction as fan, CCW. I can't see inside the pump to see if the impeller is designed for this rotation direction so I must assume for now that I was supplied the correct pump.

Factory 4.0 ran normal. Never a heat problem. Since then replaced:

Engine, cam, heads, rockers
Hoses
Water pump
Fan clutch
Temperature sender at rear of motor
Coolant
Thermostat housing
Serpentine belt


Did NOT replace:
Thermostat
Radiator

All replacements (except cam) were done after factory 4.0 came out and before Titan 4.6 went in. Am seeing about the same heat from Titan now as I did before bent valve head replacement.

I am leaning towards believing the new fan clutch has problems. I noticed before the valve bend with Titan 4.6 that the engine got quite warm on level ground in cool air at one location, warmer than my then-recent experience at other locations. The only difference I noted at the time was that I had a tail wind of maybe 10 MPH. Now that shouldn't do anything but if the fan isn't fanning then it might. The other observation from today is that it seems to get really warm if I climb a hill (maybe 150 feet elevation gain in 1/2 mile at 45 MPH) AND THEN STOP for traffic there's a dramatic heat increase indicated on the dash gauge. So here's another hint that maybe the engine isn't forcing air thru the radiator but depending on vehicle motion to do so.

I can easily move the fan with the engine off but very warm just before shutting down. The 'easily' is the part thats hard to quantify. OK, anyone know how to test a fan clutch? Know how to temproarily wire or adjust the thing so it clutches harder?

Thanks for suggestions!
Mike

I notice that you haven,t replaced the radiator cap.Try a 16#. Also if you haven,t pushed any water out ,maybe that motor wants to run hotter.
I do understand your concern for the temp the motor runs,I am sure you want the motor to run for as long as possible considering your time and money investment.
Wayne

 

[Georgia Mike]

Re: Stoker: Titan Engine: My Story

My advice would be to pull the water pump and check it out. You said you are "going to assume it's correct", but it's only going to cost you time, new fluids, and a $2 gasket to find out for certain. If it's right, you can eliminate that off the list for good. If it's wrong, and you continue to run it that way, you could burn the engine down while looking all around an easily checked item.

My $0.02

eace:

 

[mhead]

Re: Stoker: Titan Engine: My Story

JJacobs:

Maybe air in system. It's been thru several heating/cooling and doesn't seem to be drawing in any more coolant. Is there a procedure to get air out?

corbinafly:
Yes. Tstat has a small hole in it. Yes my cooling system has a non pressurized overflow. I think it just draws coolant back in and lets air out each heat/cool cycle. Or so I think.

Gojeep
Like I say, I'll worry about this issue later. I'm running 14.7 air/fuel because I am not driving jeep hard. Still runs hot.

Wayne Sihler
Had not thought about radiator cap. Why would a cap make a difference in engine operating temperature.


Georgia Mike
Yep a pump inspection is definitely on the list.

Last night with engine hot from the road, hot enough to engage electric fan, I shut down and immediately tried turning the mechanical fan by hand. Ok a certain amount of force (torque really) is required to turn the fan by hand. This morning with engine cold at about 68 (deg F) I tried the same test. Takes about the same force as last night! This doesn't seem right. I put a new fan clutch in when the Titan stroker went in. And I've had heat problems ever since.

I'm at the grasping at straws stage. First straw is a new, new fan clutch. Think I'll buy a good one rather than the cheap Pep Boys that's in there now. If this doesn't work then I guess the water pump is next unless someone has an easier straw to grasp at.

Thanks for suggestions!

 

[Wayne Sihler]

Re: Stoker: Titan Engine: My Story

The higher # cap will let the coolant reach a higher temp before boiling,it really will not help with the lowering of the running temp,but offers a margin of safety over a 13# cap.Maybe find one of the caps with the built in thermometer,could help in knowing if the dash gauge is reading off.AutoZone has them here for $25

Wayne

 

[mhead]

Re: Stoker: Titan Engine: My Story

The higher # cap will let the coolant reach a higher temp before boiling,it really will not help with the lowering of the running temp,but offers a margin of safety over a 13# cap.Maybe find one of the caps with the built in thermometer,could help in knowing if the dash gauge is reading off.AutoZone has them here for $25

Wayne

Yes, this is what I thought. So far I've not lost coolant, just don't like seeing the dash temperature gauge at the third line (just before the red zone) on a 85 degree F day.

It seems like I've seen here at some instructions that say how to increase the clutching of the fan clutch. I'm going to try this or swap the clutch. Doing this soon.

Mike

 

[XJ AV8R]

Re: Stoker: Titan Engine: My Story

Would a flex fan or something similar that doesn't EVER stop pulling air work? It might be kind of noisy, but certainly wouldn't malfunction or stop pulling air like a fan clutch might.

It seems that your cooling system isn't extracting the heat from your engine fast enough, allowing the heat to build within the block. Perhaps a higher flow water pump would help as well, although I don't know if the passageways within the engine and radiator would allow you to take advantage of a higher flow water pump due to passageway diameter and the accompanying restrictions. The stock pump may move coolant as fast as is possible with the 4.0L. Others will have more knowledge than I on this one, but just a couple of ideas.

I have spent the last two hours reading this entire story off and on...thinking I might just do a stock rebuild on my 4.0! What a headache! Hope you get it all figured out soon mhead! I will continue to read the progress with interest.

 

[Pharaoh XJ]

Re: Stoker: Titan Engine: My Story

Yes, this is what I thought. So far I've not lost coolant, just don't like seeing the dash temperature gauge at the third line (just before the red zone) on a 85 degree F day.

It seems like I've seen here at some instructions that say how to increase the clutching of the fan clutch. I'm going to try this or swap the clutch. Doing this soon.

Mike

I just adjusted the clutch coil about 45 deg its really an easy job and efficient, but you are going to have your clutch engaged 90 % of the time but still you can always loosen it a bit

 

[corbinafly]

Re: Stoker: Titan Engine: My Story

.........
Last night with engine hot from the road, hot enough to engage electric fan, I shut down and immediately tried turning the mechanical fan by hand. Ok a certain amount of force (torque really) is required to turn the fan by hand. This morning with engine cold at about 68 (deg F) I tried the same test. Takes about the same force as last night! This doesn't seem right........

Sounds about right to me. The fan clutch in the morning when you first start up is basically operating as if it was engaged. That's why it's so loud for a little bit until the viscous fluid in the clutch gets redistributed. So the hot clutch should feel about the same. After about 2500 rpm or so the clutch essentially free wheels no matter how hot it is to prevent damage to the fan blades. It is not safe to mechanically lock the stock clutch so that it cannot free wheel. Fan can fly apart at high speed.

 

[gradon]

Re: Stoker: Titan Engine: My Story

If you can't find a culprit, then I would go ahead and remove the mech fan and buy another stock e-fan(the 97+ are better w/ s-blades) and an adjustable turn-on temp switch kit(or whatever it's called~$30@ your local car parts store).

 

[mhead]

Re: Stoker: Titan Engine: My Story

Thanks for advice.

Here's my plan:

First, I can find no reason why the new Titan stroker should run hot under conservative driving conditioins and with 2500 miles on the bottom end. Therefor something in the cooling system is the cause. So I'll just march thru the cooling system.

#1 - replace the new mechanical fan clutch with a newer one. Replace electric fan with one from '97. Retest
#2 - replace 3 year old radiator with a new one. Inspect water pump tp be sure it is designed for CCW rotation. Replace thermostat. Retest

#3 - there's really nothing left at this point... drive jeep off bridge, purchase Toyota hybird, stay in five star hotels.

Mike