Tight cam chain?

michipons

michipons

Hero member
Location
Palma de Mallorca
I am assembling my 3C engine.
Crank and head rebuild from Keith, they look great, even with new cam blocks. New gaskets. Head already torqued with 4 kg.

I am using the same timing chain as it looks in good condition, but when I mount it, is super tight! I would say it has the final good tension but without the tensioner! I had difficulties closing it. The first time I close it, was easy, but I had forgotten the "chain skate"¿? (black long piece), once I put it, it curves the chain already a bit and then is super hard to close. Once closed, the engine spins easily by hand from the alternator.

I have measured the chain play precisely, it has 4mm downwards and 3/4 upwards. So a total of 7/8mm.

Yes, I have checked that the chain is well-positioned in the crank sprocket (see photo).

Any ideas suggestions? can I consider it ok? My assumption is that the new cam blocks have risen the camshaft by few decimals...?

Miguel

IMG_0681.jpgIMG_0680.jpgIMG_0678.jpgIMG_0682.jpgIMG_0679.jpg
 
I'm sure Keith will know for sure, but definitely looks like the cam blocks ,they have a 02 on them ,I know they make them in plus sizes to gain room in older heads, plus combined with a new head gasket will tighten things up, I would think it should run in fine
 
Good point, i didn’t know there where oversized blocks… i thing I will keep going and after first 1000k I will check it and see how it developes.
He told me about mounting this chain: IWISG67SL 102 links, that is a bit “longer” than others. But no idea where to find it.
I have now a DID from Wolfang and the one mounted is Regina (old one).
Miguel
 
those are the cam blocks that we make and the 0.2 means that the axis of the camshaft has been lifted by 0.2mm
we machine the cam blocks in 0.0mm, 0.2mm and 0.4mm to use on heads that have been decked in the past, helps to gain shim thickness but also you cannot use them on heads that have not been machined/faced as lifting the camshafts means cam chain is difficult to close

I have always found that the DID is slightly longer than the IWIS cam chain
 
redax5 said:
those are the cam blocks that we make and the 0.2 means that the axis of the camshaft has been lifted by 0.2mm
we machine the cam blocks in 0.0mm, 0.2mm and 0.4mm to use on heads that have been decked in the past, helps to gain shim thickness but also you cannot use them on heads that have not been machined/faced as lifting the camshafts means cam chain is difficult to close

I have always found that the DID is slightly longer than the IWIS cam chain
Click to expand...
Thanks for the info Red! Well, mine was difficult to close but I could close it within 5 minutes of try and error… I assume that Keith is aware of everything and that all is ok despite the chain is somewhat tense…?
I have a DID chain from Wolfang, i might mount it… but after the experience with the lav500 I thought I would use the cam chains to their life end😁
 
Supposed to be 10 mm free play-5 up,5 down.When fitting new (Regina) I always found free play was on the tight side,not so different from your 7/8 mm total,so the tensioner was never brought into play,just tightened up enough to make gentle contact with the blade.These were new chains,so a little mileage would see them settle to the 10 mm recommended.
Fitted new Reginas every 15,000 miles.
Hopefully the DID should give similar results.
 
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