Compression

bjmaddoxbjmaddox Member Posts: 1
edited March 2014 in Dodge
I replaced a blown head gasket on a 91 Dodge Colt 2.5. Now the vehicle crank but want start. When the gasket blew, the engine got real hot, gradually lost power and eventually stopped running. I have checked and re-checked the timing and it is correct..rotor button pointing @ the #1 spark plug wire @ TDC and valves closed. The engine is firing and receiving fuel. I have 65,95,95 and 105 PSI in the cylinders during a compression check. I'm assuming that is adequate compression to start the engine. It is also worth mention that during the check, the needle jumped three times per cylinders prior to producing the max reading. I didn't have the head rebuilt because it didn't appear to be damaged warped/cracked. Maybe I should have. I would appreciate any advice anyone can provide.

Comments

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    65 lbs is not enough for adequate combustion. About 85 would be bare minimum. You may have a warped head (well, not YOU, the car I mean!). How was the warpage checked?

    Still, with fuel and spark you should have gotten some cylinders to fire. Also you'd better check your timing marks on your cam and crank pulleys.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    If this engine overheated badly, you can almost count on warpage. This could account for an end cylinder being low. BTW,can you check the timing marks on crank and cam pulleys without taking the engine cover off, or did you do that? I'm thinking it's a good idea to have someone else check this timing as well. The fact that it won't run at all makes me all the more suspicious
  • spokanespokane Member Posts: 514
    I agree with Shiftright that valve timing is suspect. On this engine it's necessary to look closely to be sure all three marks are correct - crank, camshaft, and the distributor shaft.
  • mastermechanicmastermechanic Member Posts: 31
    image


    Well actually you are supposed to place a steel bar on the head and see if you can slide a (specified thickness) feeler guage at any point between the head and the steel bar. Glass might bend.


    My main concern is, because it is a chrysler, the timing is funny. On a Plymouth I overhauled one time, I had a problem with the timing. Unlike Gm, which the distributor runs off of the camshaft, the Chrysler distributor runs off of the oil pump, which in turn runs off of the camshaft. If you remove the oil pump and put it in any way you can, that while the distributor will only fit into the slot of the oil pump two ways and you have the rotor pointing in the right direction, your timing will be way off. You may have to reset your timing marks from scratch.


    In my application, slot mark parallel with the block, number one piston tdc, rotor pointing just past ther number one wire. Yours may be different. Chryslers are funny with timing.

  • jgmilbergjgmilberg Member Posts: 872
    The distributor on that motor is rotated by the oil pump that is driven by the counter balance shaft, that in turn is spun around by the timing belt. The 2.5 is an OVERHEAD CAM so you can't run anything off the cam. Get a Chiltons manual and check the timing mark alignment, I had a problem like this once, and the marks do not line up like you would think. This is really what it sounds like. This may be wrong but worth a shot maybe. I think the crank shaft and the counter balance shaft have marks that line up with each other, and the cam sprocket has a mark that goes at 12 o'clock. I am shooting from the hip but I am almost positive this is how the marks align. Another tip, while it's all apart get a NEW timing belt, you will thank yourself later.

    Head warpage almost always accompanies these motors to some degree, especially when it gets overheated. It should have been taken to a shop and checked out. Since you have it all back together try to get it running again, if it pops another gasket it is for sure time to have the head overhauled.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    MM---thanks for the informative post. Would you please take the logo out of your posts in the future?

    thank you,

    Mr. Shiftright the Host
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