Hi Guys

I had hoped to be posting about how happy I am with having my 66 BB back in my garage after a 5 year resto but that is not the case. My first really big problem is a oil leak from the back that will require the motor to come out but meanwhile another oil problem has shown up.

There is very little if any oil getting to the top of the pass side of the motor and I am hearing of possibilities that I have the wrong parts in the motor. It was rebuilt by a very reputable shop who was told by me that the motor was from a 66 however the casting # (..351) proves it to be a 67. I did not realize this until after the motor was rebuilt and now I am hearing of different distributors and camshafts for the 67 square ports versus the 66 like mine.

If so I guess the fault is mine for informing him of the wrong year despite the casting # on the block.

Can anyone tell me if the camshafts and distributors were interchangeable or not between the 66 and 67 high hp 427's? I had always ordered parts thinking I had a 66 and bought a Mallory Unalite distributor for it back in the early 80's. Could I have the wrong distributor if I got one for a 66?

Thanks

Doug

 

'65 & '66 blocks used a grooved rear cam journal and grooved rear bearing to conduct oil to the lifters and top end. On later blocks ('67 up) there is a groove in the rear bearing boss (block) that does away with the grooved bearing/cam arrangement.

You most likely have an ungrooved cam/bearing in an early block that effectively cuts off oil to the top end.

Other than the groove deal the cams and distributors are interchangeable. Have a machine shop cut a groove in your cam journal and you will be in business.

The "very reputable shop" should have seen this one coming.

 

The camshafts are different. A 65/66 cam has a groove machined in the rear journal for oiling. If I remember correctly the rear cam bearing is different too. I can never remember details but if you don't match the cam to the block in one case you'll get an oil leak at that bearing.

 

Hi

Thank you both for the replies and that is probably where the oil leak is coming from. I have some dye in the oil but can't see exactly where but I am sure you are correct.

When I had the car on a dyno before the oil leak started it made 340 @ 5000 but then started falling off as soon as it went over 5000rpm. I had already told them I was dissatisfied with having a cam that petered out that early and especially so with a 4:11 rear end. He was surprised that the HP was that low and I am wondering if this would have restricted HP. If not then I need a different camshaft rather then just cutting the groove.

You would think so wouldn't you and especially so with the casting # right on the block.

Thanks

Doug

 

There's a little confusion here... You don't want the groove in the cam if you have a 67 block.

 

Hi

For sure I have a 67 block as the last three #'s are 351 and I appreciate that clarification. I just had a call from a friend who does not think that I am not getting any oil to the top end just because I have 6-700 miles on the motor with a lot of the latter ones at a fairly high rpm and nothing has blown. (Plus I have dyno time). I should have included that the replacement cam is a hyd (sorry about that) and things are relatively quiet. Tomorrow I plan to run it with a valve cover off and see how much oil is getting up there.

Thanks

Doug

 

I disagree somewhat.

A grooved cam in a '67 up block will not cause any harm. You will just get extra oil to the lifters/top end which may not be desireable. Big blocks suck enough oil past the guides to begin with.

This is a situation that pre-oiling with a 1/2" drill motor would have uncovered. Now you have to pull the motor, disassemble etc.

 

Seems pretty reasonable. You might be fine - I have no idea how bad oiling gets if parts are mismatched...

I got curious and dug out "How to Rebuild Your Big-Block Chevy".
It's old - but we're talking about old engines...

It says "Early, grooved camshafts can be used in later blocks. No modifications are necessary to the camshaft, but the rear cam bearing must be the later, non-grooved type. Before the rear cam bearing is installed, the oil hole must be soldered shut, redrilled to 0.060 - 1/16 in. is close enough - and then installed in the block. The original oil hole is too large and will allow a large internal oil leak that will disrupt engine oiling".

So a reasonable guess is that the engine builder got you a 66 cam but got the normal (67-up) cam bearings and you're sitting in the situation the book describes. Please post your results from tomorrow...

 

I think I would fire that shop, unless they are willing to make this right at their expense. They should know all about these kinds of problems and should be checking for them as they assemble, that is why you pay them the big money. Anyone can thow parts together, but the little gotchas are why I either have all parts checked by a pro as a set or assembled entirely by one. I think your shop let you down big time. No matter what year you told them it was they should have seen the block and bearings and cam were not a match set and said to you "What do you want us to do...here are your options .. xx xx xx. If we build it like this there will be a problem"

That being said if they will make it right I will cut them some slack since we are talking about a 40 year old motor and if they don't have people with some experience with the early 427 they might not have known, but then they should have said "hey we really don't know this motor that well maybe another shop would be better", or they should have done some serious reading up before final assembly.

I would be seriously annoyed.
Darren

 

You'd be surprised how many otherwise-capable shops aren't aware of the oiling difference between '65-'66 and '67-up 427 blocks; similar situation exists with the oiling difference between '55-'56 and '57-up small-blocks. You need to educate them first.

 

Seriously Annoyed? just a tad.

I have never had anyone do the right thing just because it was the right thing to do. On the other hand I am grateful to have the car back and the means to have it corrected no matter the consequences of past errors whether they be mine or other persons.

This project started in Ohio in 97 with the first shop stealing significant parts from the car while conducting a major criminal enterprise and working for the federal government all at the same time. The second shop went belly up on the job (not the shop just the quality of work they were doing for me and I had to have much of their work corrected. ) The third shop finished the car and in some respects did an excellent job but missed the mark in many others. The engine shop was my choice and I have had other work done by them satisfactorily.

Now I will have to wait until the middle of August at the earliest to correct the motor and other issues as there is no room at the shop here in SC because of jobs ahead of me.

Such is life. There is very little oil getting up top but I plan to drive the car back to my house today and keep it here until the next shop has time and room. Whatever damage done has already been done and a low rpm drive home should not make things any worse considering the miles and dyno that were at high rpm.

As the saga unfolds I will post accordingly with the anticipation of attending a cruise in at some time in the future.

Doug

 

Yup, I could "watch" the notch in the rear cam journal go past the oil guage port on my '56 Belair from the flop of the pointer on the pressure guage hung under the dash.

On driving with little or no oil to the lifters/top end, I'd trailer it. Cam may be gone anyway.

 

Yup, I could "watch" the notch in the rear cam journal go past the oil guage port on my '56 Belair from the flop of the pointer on the pressure guage hung under the dash.

On driving with little or no oil to the lifters/top end, I'd trailer it. Cam may be gone anyway.

 

had similar problem on 67-427. no oil to top when bought car. wore out valve guides. wrong rear cam bearing. some bubba had recently rebuilt motor. had to replace all guides and most of the valves.
your leak is probably different story.

don't think you can expect machine shops to know details like this. some do but you need to do your own homework.