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PostPosted: Thu Jun 28, 2018 3:27 pm 
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Greetings, I have a 1979 Chevy LUV 4x4 with a 1.8L engine. I just went through the head gasket replacement on it and did a carburetor O/H (Hitachi piece seems to be a pretty bad design). I had the engine set at 6 degrees BTDC on #4 per the book and zip tied the timing chain to the camshaft sprocket before removing the head. Upon reassembly, I have no compression. I did adjust the valves according to the book after I installed the head. If I did get the chain off by a tooth, do any of you have any recommendation on how to fix my problem without endangering my valves - its an interference fit. Pictures of an appropriate allignment of chain and cam and crank pulley would be helpful. Also, what does that pin do in the timing chain (see picture)?


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PostPosted: Thu Jun 28, 2018 6:45 pm 
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Lining up on number 4 was for the rebuilding process. For head gaskets I use #1. Thinking the cam timing is off

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PostPosted: Thu Jun 28, 2018 9:40 pm 
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Luvrv8 wrote:
Lining up on number 4 was for the rebuilding process. For head gaskets I use #1. Thinking the cam timing is off

It doesn't really matter where the engine is for a head gasket replacement as long as you don't rotate the crank or the cam while the head is off & put the chain & cam gear back on exactly as they came off. the chain can't fall off the crank gear, the cam gear is tied to the chain, so the only way you can get the timing off is to rotate the cam or the chain/gear combo. The chain & cam gear should have just raised up & slipped right back on the cam with nothing rotating, if they didn't you moved something during the gasket replacement. And the FSM does indeed say to put the engine to #4TDC for a head gasket replacement
That said my opinion is that you should always put the engine to #1TDC before opening it up in any way. There are alignment marks on the crank, cam & timing chain that will only all align at #1TDC plus the dizzy rotor will be pointing towards the #1 plug terminal. It's easy to tell if it's been put back to #1TDC, check that everything points to where it's supposed to.
Luvrv8- the engine should be put to #1TDC during a rebuild, not #4. When the oil pump alignment marks match the crank setting marks the distributor drive shaft will drop into the oil pump timed to #1TDC. If the oil pump is bolted 180 degrees out the dizzy will be timed at #4TDC and the plug wires will need swapped before it will run.
Now to the problem of no compression- I agree you probably have a timing problem & the valve adjustment with the timing off set at least one valve in each cylinder so that it's not closed when that piston is at TDC.
BTW there was no picture. The cam pin ensures the cam gear will only go on one way plus it makes the gear turn the cam.
If you need to rotate the engine assembly with the cam & chain installed loosed the valve adjusters all the way so that all the valves are closed, then the pistons won't hit the valves. The put the crank timing mark to zero- it will be at either #1 or #4 TDC- then look to see what position the cam is in- if the cam alignment dowel is straight up the cam is at #1TDC, if the dowel is straight down it's at #4TDC. If it's somewhere else you definitely have a cam timing problem. You need to get the engine to #1TDC or as close as you can. Now look at the dizzy rotor, see which terminal it's pointed at or closest to. Look at the cam sprocket, there should be a matchmark on the sprocket that aligns with a mark plate on the chain. This occurs only when the crank, chain & cam sprocket are at #1TDC.
If the "book" you are using is a FSM there is a picture of the timing chain with all the marks noted when the engine is at #1TDC- it's in the timing chain replacement section. If need be I can scan & post it, but it will be tomorrow evening late.
What you ultimately need is for the crank & cam to be at #1TDC. You can pull the cam sprocket back off & rotate the cam independently of the crank & chain to get the dowel in the correct position. If the cam sprocket match marks don't align with the chain marks you can try moving the cam gear so that they do align by keeping strong tension on the side of the chain opposite the tensioner. When you get all the marks to align telling you you're at #1TDC rotate the engine at least two complete revolutions to make sure the marks return to the same alignment- this is with the valves still all closed. If the engine readily returns to #1TDC check that the dizzy rotor is pointing to the #1 plug wire terminal. If all matches set the valve lash. If you still don't have compression the problem is likely the gasket or installation, not timing.
Now, if your engine happened to be put together with the dizzy at #4 when the crank, chain & cam says it should be at #1 then you need to make the appropriate adjustments to the valve adjustment procedure. This may be your problem, the pertinent valves were adjusted as if the engine were at #1TDC when it was actually at #4. A quick tell should be if the #1 plug wire from the dizzy cap actually goes to the #4 plug.

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'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.


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PostPosted: Fri Jun 29, 2018 9:46 am 
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That's an excellent thing to try. I am posting this problem on vacation, so when I get back home in a week, I will loosen the valves up. I aligned the engine to #4 firing with the cam dowel straight up (sorry about no picture), which according to your info means I'm about 180 degrees out. I thought that was how I took it off, when it was firing, but maybe not. I'll try doing putting the cam the same way with #1 at TDC. Thanks for your response. I do have the manual, so no need to upload it. I'll let you guys know.


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PostPosted: Sat Jun 30, 2018 8:17 pm 
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From the manual, this is a easy and quick way to check cam timing

Bring the camshaft mark to the mark on the #1 rocker arm shaft bracket. See if the crank is on the TDC mark and distributor is pointing to #1


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PostPosted: Sat Jul 07, 2018 9:01 pm 
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oldestisuzuist wrote:
Luvrv8 wrote:
Lining up on number 4 was for the rebuilding process. For head gaskets I use #1. Thinking the cam timing is off

That said my opinion is that you should always put the engine to #1TDC before opening it up in any way. There are alignment marks on the crank, cam & timing chain that will only all align at #1TDC plus the dizzy rotor will be pointing towards the #1 plug terminal. It's easy to tell if it's been put back to #1TDC, check that everything points to where it's supposed to.Now to the problem of no compression- I agree you probably have a timing problem & the valve adjustment with the timing off set at least one valve in each cylinder so that it's not closed when that piston is at TDC.

If you need to rotate the engine assembly with the cam & chain installed loosed the valve adjusters all the way so that all the valves are closed, then the pistons won't hit the valves. The put the crank timing mark to zero- it will be at either #1 or #4 TDC- then look to see what position the cam is in- if the cam alignment dowel is straight up the cam is at #1TDC, if the dowel is straight down it's at #4TDC. If it's somewhere else you definitely have a cam timing problem. You need to get the engine to #1TDC or as close as you can. Now look at the dizzy rotor, see which terminal it's pointed at or closest to. Look at the cam sprocket, there should be a matchmark on the sprocket that aligns with a mark plate on the chain. This occurs only when the crank, chain & cam sprocket are at #1TDC.

What you ultimately need is for the crank & cam to be at #1TDC. You can pull the cam sprocket back off & rotate the cam independently of the crank & chain to get the dowel in the correct position. If the cam sprocket match marks don't align with the chain marks you can try moving the cam gear so that they do align by keeping strong tension on the side of the chain opposite the tensioner. When you get all the marks to align telling you you're at #1TDC rotate the engine at least two complete revolutions to make sure the marks return to the same alignment- this is with the valves still all closed. If the engine readily returns to #1TDC check that the dizzy rotor is pointing to the #1 plug wire terminal. If all matches set the valve lash. If you still don't have compression the problem is likely the gasket or installation, not timing.
Now, if your engine happened to be put together with the dizzy at #4 when the crank, chain & cam says it should be at #1 then you need to make the appropriate adjustments to the valve adjustment procedure. This may be your problem, the pertinent valves were adjusted as if the engine were at #1TDC when it was actually at #4. A quick tell should be if the #1 plug wire from the dizzy cap actually goes to the #4 plug.


This was the best advice I got! Thank you! I was so confused because the cam dowel was up but the distributor was pointing at number 4. "...if the cam alignment dowel is straight up the cam is at #1TDC" So after I decided that the engine had been put together different than what the book said, I went ahead and readjusted all the valve clearances starting with number four and the dowel pointing up (supposed to be number 1) and moving through the rest of the cylinders from that firing order.

Instant compressions of 125-135. After that it fired up after 4 or 5 tries, but I could tell it was gonna work right away.


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PostPosted: Sun Jul 08, 2018 11:20 am 
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Glad to hear you got her running Mike.
Thanks for the update!

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PostPosted: Sun Jul 08, 2018 1:44 pm 
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congrats! glad you got it going.

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