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Timing chain too short?


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Ratsun gurus I need you wisdom again.


I am in the process of changing from a U67 head to an A87 closed chamber head and have run into a roadblock. When attempting to install the cam gear i am coming up short. The timing chain will not allow the cam gear to go high enough to seat it on the cam. Its off by about 1/8th of an inch or half the width of the dowel on the end of the cam. I installed the cam tensioner retainer tool before removing the sprocket from the U67. Hopefully that didnt pop out, looking down inside the timing cover it does not appear that it did. I am at a loss. To my knowledge both heads are stock thickness. The only thing I can think of is the head gasket is too thick? It came out of DNJ Gasket Set FGS6033


Thank you in advance for any wisdom you can share.

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I had this once and the cam sprocket bolt would screw into the cam. By carefully tightening the bolt it forced the sprocket up and aligned it with the dowel and it slipped on. Make damn sure the hole and the dowel stay aligned so it's not crushed or distorted by the pinch.



Protect the gasket surface with a strip of wood and use a pry bar to force the cam sprocket up and onto the cam dowel.

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Thanks again Mike for the great advice. I got a long pry bar and a chunk of 2x4 pried up on the sprocket gently and it popped right on. Got everything reassembled and it’s running great. Now I can get the U67 upgraded with a new cam and some porting.

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The L head is pretty darn good as is. Polish away any casting marks and around the valve seats into the bowl area. Put the manifold gasket on the studs and scratch the port outlines into the soft aluminum with a nail. Use a carbide burr and remove metal out to this line you scratched. Now put the gasket onto the intake and do the same. Smooth back into the port walls about an inch. Does not have to be polished, rough is fine. Do the same with the cast iron exhaust. It's much harder and will be more work. When assembled flow in and out will match perfectly with no lip.


I would advise you use the 510's 4 into 2 exhaust manifold if you have it on the U67. Most important it will fit the car it came out of. It's a much better design than the ones used on the L20Bs.

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I will take all of that into consideration when I start work on the head. I am using the original 510 cast manifold now. I understand its as good as headers until I get into the upper limits of whats possible with an L series. My ultimate plan is to use the U67 with a freshly rebuilt Z22 block that I have. Unfortunately the car needs to remain drive-able while the work is done hence swapping the A87 onto the L20b.

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