Stroker update -- Need advice

[tetsulo]

I estimate I've put approx 2500 to 3000 miles on my stroker. Today while driving home I had sudden drop in power and the idle became rough. Temp was exactly where it should be and so was oil pressure. I was close to home so I drove it. Let the engine cool off and then started pulling the plug wires one at a time with the engine running to see what would happen (I suspected a misfiring cylinder). Pulling #1 made it worse. Pulling #2 didn't make any difference. I removed SP #2 and found a little bridge built up between the electrodes. I pulled 3 thru 6 and they look fine. #6 is a little darker than 3 thru 5 but acceptable.

#1 was close to completely fouled (black and built up), and #2 was shot. I need to fix this. engine seems to run great which to me means it's not the piston rings right? gas mileage is good. blue smoke is not normally apparent from the rear exhaust...but once in a while I will see some usually if I have been running at highway speed for a while, then stop and accelerate suddenly but even then it's not huge clouds of smoke. Is it the valve seals? the stems? The piston rings?

Sorry for the novel, but I'm trying to explain this as clear as possible.

Matthew

 

[spyder47]

I built up my 4.7L stroker last summer and currently have 14k miles on it. What were your break-in procedures? Does it smoke on startup? Or just the described times? When does it smoke?

 

[old_man]

Do a quick compression check.

 

[tetsulo]

I built up my 4.7L stroker last summer and currently have 14k miles on it. What were your break-in procedures? Does it smoke on startup? Or just the described times? When does it smoke?

Break in was per builders documentation. Pre-pump oil, start vehicle and run @ 2krpm for 20min to seat lifters/cams. Allow engine to cool, change oil, etc.

I was there for the initial start/run. It doesn't seem to visibly smoke on startup. I've taken to starting the vehicle while standing outside and watching the exhaust -- very early on it would emit a few puffs of blue smoke on startup.

It certainly doesn't excessively smoke as I mentioned above and is more prone to it after a long prolonged run.

The engine was running a little rich to begin with but not to extremes. Some black smoke could be seen under strong acceleration-- I had the FPR brought back to stock pressure (39 at idle I believe) and that smoke went away. I'm using Accel 24lbs injectors.

Do a quick compression check.

Called engine builder and he asked for same info. And I can't find my darn tester! Will get/borrow another one tomorrow and post #'s Considering the condition of the plugs how much junk will be in cylinders #1 and #2?

Matthew

 

[spyder47]

yeah same thoughts do a compression check and as for the debree you had better hope none. Sad to hear your havin issues that sux hardcore.

 

[rsalemi]

Put a new set of plugs in it and see if the problem recurs. Gas fouled plugs will sometimes not clean up - just continue to foul till you get one completely dead. Also what plug is in there? I am running Autolites one range colder than stock - either stock range plugs or slightly colder is what you need.

 

[tetsulo]

These are the second set of plugs. I checked the plugs early on and had noticed the same fouling pattern. I replaced them at that time. I'm using Autolites as well but don't have the #'s with me as I am at work.

I've been running premium gas since I've gotten it running if that means anything.

I took my car to work today so I have a cool engine to work with this evening getting the compression #'s

Matthew

 

[tetsulo]

Ok...here was my methodology -- warmed up vehicle for 10 mins. unplugged coil from cap and grounded. removed all spark plugs wires, removed all spark plugs.

held throttle wide open and had cohort crank engine 4 times for each cylinder. I'm off to start searching for what the #'s may indicate. My gut instinct says that they aren't unacceptably out of whack but I'm not sure.

Here are #'s

1 - 200
2 - 185
3 - 190
4 - 190
5 - 200
6 - 200

Matthew

 

[red91]

did it reach operating tempature ? if not that might explain the lower # on Cyl #2.

other than that...yeah looks good.

 

[tetsulo]

Vehicle was warmed up. I didn't actually check the Temp gauge. I just let it idle for 10 mins with hood up and then shut it off and started my tests. I started at the back of the block and worked my way forward. Figured I wanted to get those out of the way before it got dark as the plugs are tougher to access. From my readings and searchings compression seems really good. This would indicate valve stem seals? I figure it eliminates piston rings and poorly seated valves. I guess next step is to pop off the valve cover. Is a bad seal recognizable?

Matthew

 

[old_man]

Compression numbers look good. What injectors are you running? Sounds like you are running way too rich. Can you get a tailpipe test?

 

[sidriptide]

matt, i do recall seeing a few puffs of blue when i was following you last week. and a lil on cold start-up too. made me think of valve seals but i dont know how the 4.0L head is set up as far as seals.

 

[tetsulo]

Compression numbers look good. What injectors are you running? Sounds like you are running way too rich. Can you get a tailpipe test?

Hmmm...I've got Accel 24# injectors with stock MAP and Hesco FPR set to stock PSI. I have my original FPR. I could swap that back pretty easy. One thing I don't know about the Hesco FPR is if the PSI increase is the the same curve as the stock unit. Mileage seems good. I don't have a corrected speedo gear but but it's showing about 260 to 280 miles if memory serves me on a tank of gas with 31" tires. True mileage should be greater as I'm traveling a greater distance per tire revolution right?

When you say tailpipe test do you mean checking A/F ratio? I doubt in the area I live I'll find a place with a wideband sensor but I can look around. Emission testing was good if that helps at all. I have those #'s if interested.

Wouldn't way rich show on all plugs? Three Four and Five look perfect to me.

I'll talk with him tomorrow via phone, give him the #'s and see what he has to say. It's not impossible I could drive the truck there and have him give it a go over. He may very well have a wideband O2 sensor. He spec'ed and ordered the injectors. I can get the PN's for those as well if it helps.

matt, i do recall seeing a few puffs of blue when i was following you last week. and a lil on cold start-up too. made me think of valve seals but i dont know how the 4.0L head is set up as far as seals.

Yeah, but not heavy smoke right? Or constant?

Matthew

 

[PeterBuilt]

Check the resistance of the injectors and compare them. Maby one is a little out of wack which would hold it open longer than the others. Dont know what year you have but you can probe the o2 sensor, or sensors (dont konw what year you have) and check if they are working and that you see a steady up and down pattern. Just some thoughts.


Pete

 

[tetsulo]

Check the resistance of the injectors and compare them. Maby one is a little out of wack which would hold it open longer than the others. Dont know what year you have but you can probe the o2 sensor, or sensors (dont konw what year you have) and check if they are working and that you see a steady up and down pattern. Just some thoughts.

Pete

I've got a 1990 MJ. What is indicating rich fuel mixture with the information given? The plugs with problems appear to be burnt oil. The engine is burning oil as well. If it were that rich I wouldn't have compression as the rings wouldn't have seated right? I'm not saying that this isn't the problem, but I'm trying to understand the logic.

Matthew

 

[5-90]

Post your numbers for the smog test - but if you're passing, it's probably not a problem. A "rich" mix is usually indicated by a rise in CO and HC (both are products of incompleat combustion, and these products should both be oxidised by the catalytic converter into CO2 and H2O.)

If you need a set of valve guide seals, I think I have a set or two I can dig up - let me know. Yours for shipping (about $5 - I'll send them in a hurry.) As I recall, they're "umbrella" seals, which means you can change them without removing the valves. Just use an air source adapted to the plug holes to hold the valves up while you're working. Probably take you about 2-3 hours - depending on how good you get at pulling valve springs.

If you're getting extensive oil fouling, I seem to recall that would be mainly HC without much in the way of CO. Your compression numbers are good, which means the rings should be scraping things clean (another indicator in favour of valve guide seals.) If they're a little 'hard,' they'll leak on startup until they get worked in. I like to take a little grease or oil and work it into the wiper lip before I install the seals to make sure they're nice and pliable when they go in - it's also worthwhile to lubricate the valve stem just slightly (run a fingertip, wet with oil, over the surface) to help prevent chafing or scuffing the seal.

General fuel "richness" would show on all cylinders with FI, if it's a metering problem. If it's an injector problem, it would show on the affected cylinder. However, since you're saying your plugs are mainly oily, I'd address that first.

While you could probably get away with changing seals on only the affected cylinders, you're there anyhow and should go ahead and change them all. Besides, wherever I've got them, they're full sets of seals.

Once you get this taken care of, check your HEGO sensor and catalytic converter for plugging - burning oil plays hob with both of those.

5-90

 

[tetsulo]

These are my emissions #'s as tested last month

HC 00.26
CO 2.06
NOx 00.30

I sure hope that the O2 sensor and cat are OK. Replacing those again would be a bummer (less than 3 months on both).

I'm heading out of town for the next few days to check out a couple of concerts.

I'm going to I'll take you up on your offer for the seals. I sent you money via paypal. Are the seals for the intake valve different than the exhaust valve? Napa said they were, they said I need six of each @ 2.79 per piece. I gather I'll need a valve spring compressor tool? I have an air compressor and compression tester. I think I can rig the two together to pressurize the cylinder.

Matthew

 

[5-90]

They may be, but I seem to recall they were all in a bag together.

Gimme a day or so to dig them up - I saw them recently, but I've been reorganising the garage for the last couple weeks, so it's all fluxed up. I'll let you know if I can't find them, and give you yer five bucks back if I can't swing it.

5-90

 

[5-90]

Knew I saw them somewhere!

They're crated up and will be going out shortly (I've got errands to run anyhow - neverending story...) and what do you know? They ARE different!

There are two bags in the box, which are numbered. I'll try to find out which is which, and write it on the back of the box before I ship it to you.

You'll probably see them around Monday.

5-90

 

[dizzymac]

I second new valve seals too.