Early Chain Housing Update

[Red Car]

I'm rebuilding an engine for my 65. I have an early 65 case with chain housings and covers for center lube cams. I intend to update to spray bar cams and would like to use updated tensioners with mechanical stops. I have a stack of books and have searched the archives, but haven't found any sources that discuss what I need to track down to make the changes. Are there any references out there? Do I need to use later housings and covers, or should I search for early covers from a spray bar engine that would fit my current housings? Would that make it tough to use better tensioners? Any suggestions would be appreciated - Mark

[304065]

A couple questions:

1) Why? People who value your 65 will appreciate the original cam lubrication. While the spraybar was an improvement (further improved in 1967) rebuilding the engine right is a $15,000 proposition that should be done as original once, there are plenty of cars running spraybars without the cams going flat; and

2) Mechanical tensioners are a retrograde step from properly installed 930 tensioners, idlers, sprockets, etc. They don't compensate for different operating conditions and need to be adjusted often

To answer your question, the early seven bolt covers from a late 901/01 motor (pre-weber, but post spraybar) will fit, as will those from a 901/05 (post-weber) or 901/06 (post "SSI" type exhaust and with a lesser cam profile). The change to a larger number of studs was made later, and you don't need to source the later chain boxes to make it work. (They do leak less however, but leaking is part of life for the very early cars) Late boxes have extra studs which your early case doesn't have, which means machining your case to make them fit. Ollies can do it but there goes your originality, see point #1.

There is no issue with using 930 style tensioners with the 901/05 boxes, I'm doing it and it works great. If you source REALLY late boxes you could use the Carrera tensioners with the oil lines- but they have limitations of their own, not the least of which is the oil supply. Get the 930 tensioners and the late idlers arms and call it cool.

Good luck!

[Flieger]

Center lube cams are better for the upper rev range. Spraybar is better for lower.

[Red Car]

I'm going to keep the engine as original as makes sense. I won't make any changes that can't be reversed, so no drilling for additional studs. I would prefer to use spray bar cams. It's not going to be a track car and I've built my trans with a ZD fifth gear for cruising. I'm glad 930 tensioners and idler arms will fit 7 stud housings. I'm going to put the travel stops on them as insurance. I think I need to source a set of late 7 stud covers. Is there anyone out there that has a set they'd be willing to sell? Thanks for the tips, this is a great list. - Mark

[tom1394racing]

Mark

I should have a pair of the chainbox covers you want. Send me a PM to follow-up.