Timing gear misalignment

[Steffo]

Hey guys,

My engine rebuild includes a new Stealth cam from V8D. When installing I noticed that the cam gear and crank gear misalign horizontally, approx 1-1,5 mm. You can clearly see the misalignment by eye, see picture.

If I don't do anything about this the chain wear will probably be quite excessive, or what do you think? Is it common that you have to grind off material from either the front end of the camshaft or the cam gear to make the gears align in these applications? Adding a shim behind the crank gear doesn't seem like a good option since the crank pulley then obviously will misalign to the other pulleys.

Any wise advice?

I have asked V8D to comment but haven't received any answer yet.

[TVR Beaver]

so are you saying the cam is too far out?.. won't it push in?.. have you a retainer fitted?..

[cinquecento]

Have you tried reversing the cam gear.. I recall I had the same issue some years ago.

[Steffo]

The cam is as far in as it goes, can't be pushed further. And yes, I have a retainer plate fitted. Turning the gear the other way around doesn't do any difference in this case, tried that also.

I will probably end up grinding off the extra mm from the cam gear. This engine was supposed to be running around May this year... This isn't exactly the first hassle I'm facing in this rebuild. But soon, very soon...

[TVR Beaver]

Yes, you could do that.. but watch how close the chain gets to bits... how much movement do you have in the cam?.. I think I had about 3 to 4 mm... what may be stopping it going deeper is the rear core plug.. has it been put in too deep?

[spend]

Many cams cause problems where the nose is relieved for the cam retainer, not just the z measurement for the face, but also the xy ods that the retainer sits on. Always wise to check & double check assembly & alignment + particularly that cam verniers don't foul anything & adjust properly also.

[DaveG]

I had a similar problem with a new cam a couple of years back. I resolved it with a 25thou washer. Can be purchased with right ID-OD from specialist suppliers or get your local machine shop to turn one up with correct thickness?

[Sardonicus]

Strange no such issues with a fitted thrust plate and KC adj vernier

[Steffo]

The cam sits nice and quite tight between block an retainer plate, I can hardly feel any horizontal play by hand when parts are smeared with engine oil. Luckily enough it's the flange in the front end that stops the cam from moving backwards, not the core plug in the back of the block.

I thought about the washer/shim option also, but that would obviously move the crank pulley assembly outwards so that it won't align perfectly to the rest of the pulleys. We're not talking huge distances here, but after all a bit more than 1 mm. Perhaps the alignment of the pulleys isn't that exact as standard, I'm not sure.

[Sardonicus]

Steffo said:

The cam sits nice and quite tight between block an retainer plate, I can hardly feel any horizontal play by hand when parts are smeared with engine oil. Luckily enough it's the flange in the front end that stops the cam from moving backwards, not the core plug in the back of the block.

I thought about the washer/shim option also, but that would obviously move the crank pulley assembly outwards so that it won't align perfectly to the rest of the pulleys. We're not talking huge distances here, but after all a bit more than 1 mm. Perhaps the alignment of the pulleys isn't that exact as standard, I'm not sure.

Not its not I have checked but not enough to cause issues that's why some low milers are still on their original serp belts of course if your out of this slight envelope that's where the tooth shedding occurs with serp style belts where as V belts just get thrown off the pulleys 1mm in belt alignment terms is bugger all IMO