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4AGE start problem after build

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GTIRHil
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Tuesday, November 05, 2019 11:02 AM (permalink)
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4AGE start problem after build

Hi
I finally have my 4AGE back in my '89 AW11.  But it doesn't want to start.
 
I checked ignition timing and it is about correct on cranking.  10 BTDC.  And there is a good spark.
 
There's a bit of a smell of fuel but that is always hard to judge.  Plugs are a little wet.
 
The head is reconditioned but pistons are original high mileage.  Compression is 120 on 1 and 130 on 2.  Pretty low.  But the engine has stood for a while.  The head was skimmed 0.8 mm and I put adjustable cams in and advanced them a bit to make up for it.  To my surprise the engine is now interference but I was careful not to crash the valves.
 
So - do people think that the low compression might be that I got the cam timing wrong?  And that might be why it won't start?  But a big drop in compression would mean that the cams were more than one tooth on the cam pulleys wrong, wouldn't it?
 
Thanks!

Hil's car all the way!
North Canberra
#1


5 Replies Related Threads

    kojab
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    Re: 4AGE start problem after build Tuesday, November 05, 2019 11:22 AM (permalink)
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    Its unlikely to start if the plugs are wet. Throw a new set of gaped plugs in.  You might be pleasantly surprised.
    Wet plugs will usually short out the spark.

    92' SW20 3SGTE   GEN2 GT Hardtop Holden Ls1 ECU
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    #2
    GTIRHil
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    Re: 4AGE start problem after build Tuesday, November 05, 2019 12:01 AM (permalink)
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    I'll do that.
     
    It's very easy to create new problems as one progresses!

    Hil's car all the way!
    North Canberra
    #3

    GTIRHil
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    Re: 4AGE start problem after build Wednesday, November 06, 2019 9:52 AM (permalink)
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    OK  - dried the plugs.  Only one was really wet.  Some of the plugs are definitely burning something (they are black) but the engine still doesn't want to fire.   Ignition timing is showing 10 degrees BTDC.
     
    So, I never was sure about the cam timing, as posted before.  The zero marks on the Blox gears put them a bit off from the original gears.  I wanted to stick with the OEM but I was worried about the 0.8 mm head skim.
     
    I tried moving them from what I think was advanced to retarded.  The engine didn't run.  BUT I tested the compression and got 90 PSI on cylinder 1.  So I put them back the other way but a bit more than I had them before and got 130 PSI. 
     
    So, lined up left 120 PSI, right 90 PSI, back further left 130 PSI.
     
    It looks as though I need to keep going left.
     
    I do assume that both cams should be set the same, as with OEM pulleys.  The length of belt between them has not changed.
     
    Please, any thoughts welcome.

    Hil's car all the way!
    North Canberra
    #4
    feral4mr2
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    Re: 4AGE start problem after build Wednesday, December 18, 2019 8:20 AM (permalink)
    +1 (1)
    Put the whole thing at TDC, TDC mark (1st scribe on crank pulley from left) on crank pulley inline with timing pointer.  Check cam timing again, IMO put stock cam wheels on to set.  If using stock cams make sure the dimple in the inlet cam is visible and lined up with the flat edge inside the oil filler hole.  Knock pin on inlet cam should be at 12 oclock and exhaust cam 5 oclock.  The 2 scribe marks on the cam wheels lined up with pressed metal line on backing plate.    Pull distributor out and make sure lined up correctly and re-stab, do with dist cap off so you can be sure the rotor is still pointing at #1.   
     
    Dist being out is the most common issue when people rebuild these engines, i hold the rotor with my palm while inserting it and hold it slightly anticlockwise and twist clockwise as it meshes.  The cogs are not straight cut and the rotor will turn. 
     
    The whole timing setup on these isn't hard.  But needs to be right.    You cannot check timing while cranking, so don't really know what you're doing there... 

    if it's not blown, it sucks
    #5
    Admin
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    Re: 4AGE start problem after build Thursday, December 19, 2019 9:12 AM (permalink)
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    @mr2feral is on the money.
    Recheck everything, and make sure that the dizzy is pointing at #1 at TDC.
    If you have the timing right, fuel and spark, it will fire up.

    Mr Glengineering.
    Please visit my other forums - 
    www.celica.org.au
    www.classic-ford.org
     
     
    My build thread - https://www.mr2australia..m/mr2play/FindPost/47893
    #6

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