steve260z Posted October 9, 2012 Share Posted October 9, 2012 (edited) Currently putting my 3.1L stroker together for the 2nd time. Got the engine mounted and discovered the machine shop left one exhaust manifold bolt off in the head. It all had to come out and apart. Upon putting it back together I've noticed something and wondering if I'm right or missing something. Using the "How to Rebuild Book", it calls for setting the 1 piston at TDC using a micro meter then placing the head on the block and you know the rest. Using a new timing chain and associated stuff why wouldn't the following method produce a correctly spot on TDC assembled motor? Set the #1 piston close to TDC, set the #1 valves closed on the head with lobes pointing up, set the new cam sprocket on the #1 dowel while correctly placing the 2 bright links on the chain on the crankshaft sprocket marker and cam sprocket. Now, since the cam and sprocket fit together via dowel and its a fixed distance between the cam and crankshaft sprocket because of the set number of links why wouldn't this result in perfect set up? Obviously, you would need to maybe rotate a bit after assembly to eliminate any slack in the chain but as long as the set up is close won't the end result be correct, due to the above reasons? ie...fixed length amount of chain, timing mark on the crankshaft sprocket and only 1 way to fit cam sprocket to cam. (I realize there are 3 ways to fit the cam sprocket but we're just talking all new parts here) Thanks steve Edited October 9, 2012 by steve260z Quote Link to comment Share on other sites More sharing options...
Ben's Z Posted October 9, 2012 Share Posted October 9, 2012 It probably wouldn't be off. Then again I have seen guys on OHV motors use TDC on #1 to dial in a cam. I am building my first engine ever as we speak. Quote Link to comment Share on other sites More sharing options...
AkRev Posted October 9, 2012 Share Posted October 9, 2012 Currently putting my 3.1L stroker together for the 2nd time. Got the engine mounted and discovered the machine shop left one exhaust manifold bolt off in the head. It all had to come out and apart. Upon putting it back together I've noticed something and wondering if I'm right or missing something. Using the "How to Rebuild Book", it calls for setting the 1 piston at TDC using a micro meter then placing the head on the block and you know the rest. Using a new timing chain and associated stuff why wouldn't the following method produce a correctly spot on TDC assembled motor? Set the #1 piston close to TDC, set the #1 valves closed on the head with lobes pointing up, set the new cam sprocket on the #1 dowel while correctly placing the 2 bright links on the chain on the crankshaft sprocket marker and cam sprocket. Now, since the cam and sprocket fit together via dowel and its a fixed distance between the cam and crankshaft sprocket because of the set number of links why wouldn't this result in perfect set up? Obviously, you would need to maybe rotate a bit after assembly to eliminate any slack in the chain but as long as the set up is close won't the end result be correct, due to the above reasons? ie...fixed length amount of chain, timing mark on the crankshaft sprocket and only 1 way to fit cam sprocket to cam. (I realize there are 3 ways to fit the cam sprocket but we're just talking all new parts here) Thanks steve I see your point, however you are doing a lot of assuming. You are assuming that no one has taken off anything from the head or the block. If you resurface the deck or the head you change the distance on those marks. (chain is the same lenght but distances from cam to crank is not) From the ones I have worked on, I think only one has been dead on with the marks when I went to dial it in. Take the time to dial it in, or you are just going to let Murphy's law take over you next few weekends. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 9, 2012 Share Posted October 9, 2012 Then again, later if there is a question....what will you have to do to make sure it's right? Quote Link to comment Share on other sites More sharing options...
steve260z Posted October 9, 2012 Author Share Posted October 9, 2012 No, I'm certainly not going to abide by Murphy. I dialed in TDC with a micro meter. The above just came about while I was putting it together. I did forget the issue of head/block shaving. That would play an important role. Steve Quote Link to comment Share on other sites More sharing options...
steve260z Posted October 13, 2012 Author Share Posted October 13, 2012 Just to note, mine lined up dead perfect. The p90 is unmolested and the 54 block was just lightly machined. Thanks to all and I'm getting this strioker back in and moving toward flipping the key! Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted October 14, 2012 Share Posted October 14, 2012 (edited) It would work just fine. The only reason any build book tells you to use a micrometer to set TDC, is to make sure it's TDC, and not a degree or two off of TDC. Lining up the timing marks should take care of any amount that the timing is off, since it's a set measured distance of the timing chain, between the marks of the crank gear and the cam gear. Edited October 14, 2012 by Six_Shooter Quote Link to comment Share on other sites More sharing options...
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