Need Help With Force Motor

[maxum_man]

Re: Need Help With Force Motor

Timing shoud be checked at cranking speed at WOT in neutral with plug wires pulled off. I bought a little spark tester plug from Advance Auto Parts and put it in #1 wire to complete circuit. Clip your timing light onto #1 plug wire. Connect black and red clips on timing light to battery. Put your shifter in neutral and WOT. Have someone crank the key and shine your timing light on flywheel side where the "window" is for checking timing. You will have a mark on a pointer/plate to compare the marks on the flywheel to. I think by the Clymer manual, Prestolite ignition is 28* and Thunderbolt is 32*...not 100% on that though. Oh, I put my water hose on the motor just to be safe with the impeller while cranking!

 

[pnwboat]

Re: Need Help With Force Motor

Maxum_man pretty much says it all. You mentioned earlier that when you put your throttle into neutral, it does not advance the throttle plates on the carbs. What you can do to get around this problem is wrap a piece of electrical tape around the neutral safety switch (the little switch that has two yellow wires going to it on your linkage) to hold the little white button in. Just put it in gear as you would normally. With the neutral safety switch "rigged", it will engage the starter and you can crank it. You do not want the motor to start, so the plugs should not be installed in the motor as you would normally. If you don't have an adapter like Maxum_man, you can connect the spark plug wires to the plugs, and wrap a piece of wire around the metal body of the plug. Connect the other end of the wire to ground. You should see the spark jump across the gap on the plugs when you crank the motor.

The little red wire on the top of my motor goes to a temperature sending unit that I installed for a temperature gauge in the dash.

 

[brianvolt7]

Re: Need Help With Force Motor

Thanks for the info on the timing light. I will try this tomorrow.

I have a 4" piece of wire with spade lugs that I have connected to bypass the neutral start switch. I will remove it once the motor is running.

I should be getting my compression tester this week as well, any tips on using this, or I should say, can you tell me how to use it? What compression should I see?

Is it important to have a temp guage? Are they hard to install?

 

[pnwboat]

Re: Need Help With Force Motor

Gauges are pretty much personal preference. I actually have a water pressure gauge and a temperature gauge. Sometimes it helps in pinpointing a problem.

Recently I had a situation where my water pressure went from 10 LBS to about 2 LBS at around 2500 - 3000 RPM's. My water temperature went from 130 degrees to about 90 degrees. These indications told me that my engine was over cooling. I pulled it out and sure enough, there was a piece of debris caught in the opening of the thermostat that was preventing it from closing all the way. Had to drop the thermostat into a pan of hot water to get it to open wide enough to remove the debris.

 

[73Chrysler105]

Re: Need Help With Force Motor

Awesome Thread can't wait to hear that it is running again. I am crossing my fingers for you.

 

[maxum_man]

Re: Need Help With Force Motor

On compression check, pull the plug wires again and just remove which plug from the cylinder you want to test. Find the right adapter for you plug hole and screw it in. Then screw in your Hose/Tube that goes to your gauge, and hook your gauge to it. Then crank for a few seconds, 2 or 3 and check what your gauge says. It should have a "Memory" to it so you dont have to have 2 people working on this at the same time. Then pull everything out and do it to the next cylinder.

A lot of books give you compression specs, but if you talk to someone that has done this stuff for a while they will tell you to look for a 10-12% difference in the compression readings from the highest to the lowest reading. I.E.-110, 120, 120, 115 The difference is 10 psi.

 

[brianvolt7]

Re: Need Help With Force Motor

OK team Force Motor,

Getting ready to check timing and compression tonight. How do I know if I have prestolite or thunderbolt ignition? Also my flywheel does not have numbers on it only three lines, should it be lined up with one of these?

Should the piston pressure be between 110 and 120, I have no idea what is normal for this motor?

So everyone knows, my reed gaskets just shipped today I ordered these on Saturday last week. They are coming from FL so I hope to have them by next weekend.

 

[PaulO]

Re: Need Help With Force Motor

Post #45 page 2 answered your question.

1990 - 1991c = prestolite so set 28? if cranking it over

1991d-1995 = Thunderbolt so set 32? if cranking over.

of the three marks located together the one on the left would be 32? centre 30? and right 28?

Prestolite has 2 cd boxes that each control 2 ignition coils.
Thunderbolt has 1 switch box that controls all ignition coils.

 

[brianvolt7]

Re: Need Help With Force Motor

Well I think this is really bad news:
Piston 1 90#
Piston 2 0#
Piston 3 123#
Piston 4 0#


My carbs and reeds are off, would this cause these compression readings?

 

[PaulO]

Re: Need Help With Force Motor

That does not sound good. Carbs and reeds will have no effect on readings. I guess inspection after head removal may reveal one of a few things. Are you sure the compression screw was well seated against the head to make a tight seal?

 

[brianvolt7]

Re: Need Help With Force Motor

Yes, I disconnected and reconnected the 0# pistons twice.

 

[maxum_man]

Re: Need Help With Force Motor

Hmmm...that's not GOOD news. Might be time for a complete rebuild. Just shooting in the dark, but you might get lucky and just have some broken rings. A teardown, quick honing of cylinders, and new pistons and rings and you'll be good to go. Hopefully it'll turn out good for ya!!

 

[Jeremy90bay]

Re: Need Help With Force Motor

This story line just took a devistating turn for the worse! Sorry for the bad news Brian. Pull the head off and post some pics, it doesnt sound to good though.

 

[brianvolt7]

Re: Need Help With Force Motor

UGG pull the head, hone the pistons, broken rings

Is there any way possible it is just the head gasket? Is there a way to check so I wont need to do a full rebuild? Does anybody know what a rebuild would cost at a shop for this?

One more question, if I were to take it on, how difficult is it?

 

[PaulO]

Re: Need Help With Force Motor

The motor is of no use to you in its current capacity so you have nothing to lose if you pull it down. I did that with mine. I took of most of the covers leaving the bare minimum for the machine shop to pull apart and put back together. I took a lot of photos of all components before and after dis-assembly. and put nuts and bolts in bags relevant to its particular component.

 

[brianvolt7]

Re: Need Help With Force Motor

Thanks PaulO. This may be the way to go, this would at least save me a little money.

I purchased a manual and I am going to read the section on rebuilding the motor to see if I want to take it on. I will be calling some local shops to get a quote on the work as well.

The main thing I want to figure out is if it is the head gasket, this looks to be fairly simple to replace. Does any one have a good way to determine this?

 

[pnwboat]

Re: Need Help With Force Motor

Very easy to replace the head gasket. For a compression reading of 0#, the gasket would have to be completely destroyed. You can usually see a bad head gasket.

 

[brianvolt7]

Re: Need Help With Force Motor

I can see what appears to be rust on the gasket in several spots. Do you think this is an indication of a leaking gasket? Also, do you think the rings need replaced? Should I just replace the gasket?

 

[brianvolt7]

Re: Need Help With Force Motor

pnboat do you think this will fit my motor?

http://cgi.ebay.com/ebaymotors/New-Chrysler-Force-4-Cylinder-Head-Gasket-27-F476529-4-/280319815736?cmd=ViewItem&pt=Boat_Parts_Accessories_Gear&hash=item41445cf038

 

[brianvolt7]

Re: Need Help With Force Motor

Here are my pics. There is not any scratches on any piston walls that my fingernail catches on, in fact the scoring on the walls is light even on the trashed pistons. My main concern is the chip, and I have no Idea what is up with #4