I'm going to try the 4.1->4.9 conversion - Page 9
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 9 of 11 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 LastLast
Results 121 to 135 of 152
Like Tree1Likes
HT4100 4.1, 4.5, 4.9 Discussion, I'm going to try the 4.1->4.9 conversion in Cadillac Engine Technical Discussion; The top pulleys seem fine. The other possibility that we are considering is that the old AC compressor may be ...
  1. #121
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    The top pulleys seem fine. The other possibility that we are considering is that the old AC compressor may be off a little, since it's the only thing that isn't from the 4.9

  2. #122
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    We've decided that the water pump housing is probably deformed. I have a digital angle finder around here somewhere and will check it out.

    We tried setting the base timing to 12 degrees but the engine had some miss and stumble issues under load. I reset base timing to 14 degrees and now it only has a little bit of flutter when I'm cruising around 55 MPH. It feels like a car that needs a tune-up. I sliced into one of the plug wires somehow and I think I only went into the insulation but I may have cut the core. I kept my Accel 8.8 plug wires and will probably try swapping one or all of those at some point to see if it ignition is cleaned up. It's also possible that fuel isn't getting delivered properly but symptoms suggest otherwise--I can stomp on it and get solid burn, and the O2 output on the diag shows fluctuation between rich and lean as the engine maintains balance--but I will keep an open mind. It's also possible that I have a vacuum problem and/or EGR is not working correctly, these are other things I will have to look into.

    Anyways the car is back home and just needs this kind of minor attention. Otherwise it's drivable and fine. I'm willing to declare the project a tentative success at this point but won't know for certain until I get the bugs squashed.

  3. #123
    aeronca36606 is offline Cadillac Owners Enthusiast
    Automobile(s): 1985 Coupe Deville 4.1 & 1970 Eldorado 8.2
    Join Date
    Sep 2005
    Location
    East Tennessee
    Posts
    594

    Re: I'm going to try the 4.1->4.9 conversion

    In thinking about your project i had the thought. The one sensor that may give you the most trouble with a false signal to the ecm would be the MAP sensor. By changing the Volumetric Efficiency of the engine relative to what the ECM expects. The map sensors signal will be quite a bit different than what the 4.1 reported. The MAP sensor modifies the Timing quite a bit. If you are having drivability issues with the base timing set according to spec, I submit the problem may be that the MAP is reporting a signal that the ECM is interpreting incorrectly. This may be advancing the timing incorrectly. I am not sure how to correct this without modifying the MAP tables in the prom. Possibly playing with the base timing will allow smooth operation? Maybe a MAP sensor with a different output curve? (If one is available) Anyone else?

    I am sure there will be a fair amount of tweaking to get things running to your satisfaction. Good luck and keep us informed.

  4. #124
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    Final recipe:

    4.9 block and heads
    4.5 TBI intake manifold
    4.5 TBI throttle body
    Chevy 305 TBI injectors
    4.1 sensors (for computer compatibility)
    4.1 ignition parts (for computer compatibility)
    4.5/4.9 front exhaust manifold, 4.1 rear exhaust manifold, 4.1 crossover and intermediate pipes (may be able to use 4.5 TBI pipes everywhere)
    4.5/4.9 alternator bracket
    mix-n-match other parts as needed or desired

  5. #125
    dennis93coupe's Avatar
    dennis93coupe is offline Cadillac Owners Connoisseur
    Automobile(s): 1993 Coupe Deville 2006 XLR Infrared, Ebony
    Join Date
    Feb 2010
    Location
    Orange County, CA
    Age
    60
    Posts
    2,465

    Re: I'm going to try the 4.1->4.9 conversion

    ehall,
    Just a thought, have you capped the port where you are getting vacuum? Did you said it takes a long time to build up the vacuum reservoir? So this could affect the MAP sensor.... Have you measured intake manifold vacuum?

  6. #126
    aeronca36606 is offline Cadillac Owners Enthusiast
    Automobile(s): 1985 Coupe Deville 4.1 & 1970 Eldorado 8.2
    Join Date
    Sep 2005
    Location
    East Tennessee
    Posts
    594

    Re: I'm going to try the 4.1->4.9 conversion

    My thinking on the MAP sensor is as follows.

    The 4.1 is notorious for not having much manifold vacuum. This is reinforced by the fact that Cadillac saw fit to install an electric Vacuum pump.

    The 4.9 is known to have a lot more vacuum and does not have the added electric pump.

    This would indicate to me that the 2 engines have a radical different manifold vacuum profile through the power range.

    Where as the oxygen sensor will compensate for variations in mixture, MAP is normally a set factor in the design of the engine management firmware.

    MAP is used as one of the primary signals along with RPM to set the correct ignition timing. (Ref an old mechanical distributor with both centrifugal and vacuum advance mechanisms)
    Manifold absolute pressure is an excellent way to determine engine work load.

    I wonder if this becomes an issue whether or not someone on one of the early GM ODB1 tuning sites could be of help.

    This may not be an issue as careful adjustment and tuning of the engine timing may be enough for the OP to be happy with the results.

  7. #127
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    The map sensor has it's own vacuum line and sees engine vacuum immediately. This is true for a couple of other systems that need to monitor engine vacuum directly, such as the transmission and the fuel system The reservoir is only used with systems that need stable vacuum sources, such as cabin HVAC and cruise control (and the booster has its own reservoir), which suffer from fluctuating vacuum.

    FWIW the 4.1 only used the pump to feed the cabin, cruise, and brake booster vacuum circuits, so basically the pump just replaced the reservoir for the systems that need stable vacuum pressure. The pump is better than the reservoir since it provides immediate constant vacuum pressure. I'm sure it was deleted to save money, not because of better vacuum in the later years (possible but unlikely--the 4.1 produced 15-20 hg inches the same as every other engine).

    Sometimes a vacuum leak on one circuit will affect another circuit, since it allows the manifold vacuum pressure to drop, so it may be the source of my uneven combustion at speed, but that's about as far as it goes.

  8. #128
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    I think I tracked the stumble to a vacuum leak at the EGR solenoid.

    edit--there was also a small leak at the rubber connector for the tranny vacuum modulator and it expanded out when the engine got warm. I think the modulator itself also needs to be replaced

  9. #129
    aeronca36606 is offline Cadillac Owners Enthusiast
    Automobile(s): 1985 Coupe Deville 4.1 & 1970 Eldorado 8.2
    Join Date
    Sep 2005
    Location
    East Tennessee
    Posts
    594

    Re: I'm going to try the 4.1->4.9 conversion

    Just a thought. An adjustable modulator valve (if available) would give you the ability to tune the transmission to your new engine and driving preferences. The modulator on your THM440-T4 transmission controls the shift firmness. The cable controls the shift point.

    Hope all is progressing well.

  10. #130
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    I sent some of the oil from my 4.1 to Blackstone for a follow-up analysis. In the 16k miles since the previous analysis, potassium parts-per-million went from 14 to 30, and sodium went from 17 to 48. These are indicators of a coolant leak and it was getting worse. Since I had replaced the throttle body and intake gasket in between those tests, it's pretty clear that the old 4.1 was working up to a full-blown head gasket leak. So it's a good thing I replaced the engine.

    I should have replaced the trans too. My trans is slipping when shifting from 2nd to 3rd and slipping all the time in 3rd now, after about 60 miles of driving on the new engine. I have replaced the vacuum modulator and clamped the vacuum lines (which did fix some other problems), and I've adjusted the TV cable about 20 times, so there's no getting around it the tranny internals need some work. I'm pretty mad since I was told by two different independent tranny shops to leave it alone... now I have to pull everything back out to do the rebuild we could have done while the engine was already out. I am going to do a couple of other things as last-gasp efforts but otherwise I expect to need a rebuild and won't be doing anything more on it for a while.

  11. #131
    Sevillian273's Avatar
    Sevillian273 is offline Cadillac Owners Connoisseur
    Automobile(s): 69 Thunderbird | 90 Seville | 89 Marquis | 72 Torino
    Join Date
    Oct 2008
    Location
    Palm Bay, FL
    Posts
    2,022

    Re: I'm going to try the 4.1->4.9 conversion

    That's a bummer. Looks like the extra power pushed it over the edge. I wonder if the trans shops just didnt wanna do the job.

  12. #132
    aeronca36606 is offline Cadillac Owners Enthusiast
    Automobile(s): 1985 Coupe Deville 4.1 & 1970 Eldorado 8.2
    Join Date
    Sep 2005
    Location
    East Tennessee
    Posts
    594

    Re: I'm going to try the 4.1->4.9 conversion

    You might try disconnecting the modulator valve vacuum line. This will cause the transmission pump to go to full pressure all of the time. This will cause a maximum firm shift. The see if the trans still slips. Unfortunately you probably have a toasted trans. I have seen quite a few 440T4's available with low miles since rebuild. People have there trans go bad, Get it rebuilt, and have there engine fail shortly thereafter. They get flustered with the cost and scrap the car. Maybe you could get lucky and find one of these. I also hear that they are not to difficult to rebuild with a kit.

    I had a similar experience with my Diesel. I rebuilt the engine only to find that my trans went out within 10 miles of the engine replacement. Talk about frustration! I was lucky enough to find one in a local wrecking yard that had just been rebuilt. (GM Rebuild) This was lucky as the diesel 440-T4 is extremely rare.

    The transmission is easier and much less costly to R & R than the engine. A local shop only charged me $200 to do the swap. I do however live in an area where labour rates are low.

  13. #133
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    Sorry for leaving this hanging but I had to go out of town and do some other stuff. Anyways I've been doing some more testing and research and my guess is that the transmission probably just needs some cleanup and adjustments.

    First of all, disconnecting the modulator does produce complete (harsh) shifts with no slipping, which indicates that the clutches are alright and the slipping is probably due to the long slow shifts that never fully complete. Second, I noticed that the car was slipping a little when we did the first test runs right after the swap, and the problem with constant slipping came on strong after I fixed the two vacuum leaks. Both of these factors suggest that there is too much vacuum pressure at the modulator that is interfering with fluid pressure for the shifts.

    However I have measured vacuum at the modulator inlet and it is a little higher than recommended, maybe 18ish at full warm idle, but that should not be too high. I replaced the modulator a week or two back and that did not change anything. It was an adjustable modulator from NAPA, and I have turned the screw as far as it wants to go and that has not had any effect either. So either the new modulator is bad or there is some other contributing problem. I will probably go buy a cheapo adjustable unit at autozone and see if it will work any better.

    I have also bought a new TV cable (found an aftermarket on ebay) but have not figured out how to install it yet. The FSM says to just pull the cable up through the opening but I can't seem to get it that far.

    So that's where things stand. My work project came to a sudden stop so I am going to have to slow down on this for a bit but will try these two things as soon as I can get around to it. These hydraulic trannies use fluid pressure for everything and a little bit of variance in the inputs can cause a lot of change in the outputs. I am longing for solenoids I can tell you that.

  14. #134
    aeronca36606 is offline Cadillac Owners Enthusiast
    Automobile(s): 1985 Coupe Deville 4.1 & 1970 Eldorado 8.2
    Join Date
    Sep 2005
    Location
    East Tennessee
    Posts
    594

    Re: I'm going to try the 4.1->4.9 conversion

    You may want to put the vacuum gauge back on and see if and how much the vacuum drops when the car accelerates. It should drop off pretty quickly. I am wondering if the correct port is being used on the throttle body (If this is even possible). The lower the vacuum the higher the pump pressure in the trans. The higher the vacuum the lower the pump pressure and softer the shift. The modulator valve connects directly to the pump offset to control pressure. It is the only input that controls the overall pump pressure. It is also possible that the pump is worn. At worst a rebuild kit would probably fix it. Maybe a new pump.

    When we talked a while ago you said you had an oil filter mounting adapter from a 4.9. You said the oil cooler lines where different. Are they bigger? I wonder if they increased the size of the lines to improve oil flow. Anyway i could use one. If you are so inclined let me know how much you want for it.

    Have a great day!

    PS: When you replaced the modulator valve was it for the 85. I wonder if the 85 4.1 modulator is calibrated different then the 89 4.5. The part numbers are different. The 4.1 and 4.5 engines have a different vacuum curve under power. Maybe?

  15. #135
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,487

    Re: I'm going to try the 4.1->4.9 conversion

    I have watched the vacuum and it does move around quite a bit, but the tranny chapter in the FSM says you need to monitor vacuum and fluid pressure at specific RPMs and I'm not really setup for all that. I have confirmed vacuum specs in ALLDATA for 92 Deville and 85 Deville are the same basic range so I should be okay there. I have been reading a lot on the other GM forums and they all say that tweaking the modulator should make a big difference but it doesn't make hardly any difference. All of the different modulator brands appear to be the same unit just different label on the box--they are "universal" for the 440 and 4T60 and so on, just different fittings on the end depending on the year. I suspect there is something else going on. Fluid levels are fine and the filter and fluid was refreshed a couple of years ago. The TV cable might have been stretched out. We replaced the input seal so maybe something went wrong there. It's possible that I have made some stupid mistake or that the replacement modulator is damaged or something like that but honestly I think I need to take it to a pro and ask them to put their gauges on it and go from there.

    I exchanged some PMs with edahall about his 4.1->4.9 swap and the shift kit stuff. He said he did it because he wanted to not because he needed to.

    On the OFA, the fittings look like the same thread (different fittings same thread) but they are positioned different so they will not mate to existing lines. I have not looked for it yet, PM with the details and we'll figure something out .

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting