53 Series Detroit Cams?

[VicS]

A while back there was a discussion about these cams. It was stated that there were high lift cams in a 2 valve head, and low lift cams in 4 valve heads. So I want to update to a 4 valve head with big valves! I just tore out the cam from a 3-53 motor with a 4 valve head. Have the cam from a 2 valve 2-53 motor, laying beside it. Both of these engines have the latest detroit picture cast on the side of the block. I measure both cams with a caliper at 1.82 on the exhaust. and 1.80 on the fuel lobe. I can tell no difference. Granted I can't see or measure the duration. What am I not seeing. The cam grinder from Washington, said he didn't know of any difference, but if I would send him both he would grind the 2 cyl to the 3 cyl specs. Thanks for any replies Vic
 

[wi50]

What is the rocker arm ratio for the 2 valve and 4 valve. Maybe you heard a rumor and maybe the difference is in the rockers.

I don"t know that total lift would be all that important for this application, though I don"t have any experience with a Detroit. Do both engines use the same lifter diameter? It would be nice to map the cams and see not so much what the duration is, but how fast the ramp is on the cam as well as exhaust valve timeing.
 

[johns]

Hey Vic, the most knowledgeable and accurate person on Detroits is Scott Franklin. He's on the Oliver board from time to time and he's overhauled several in 53,71,92 series. if you want send me an email and I'll get you his number.
 

[buickanddeere]

There are two different four valve cams. The later is the low lift low velocity cam which stresses the valve train less.
The ramp velocity is still slower on the early four valve cam than the two valve cam.
You will have to set up a degree wheel and a dial indicator to see the difference.
There are various codes stamped on the cam to identify which version it is. There is a chart in DD service manuals to figure which.
A four valve 2-53 was never released from the factory but I know of at least one. Problem was it was built with the factory high lift-high velocity cam. Rpms above the normal 2400rpm limit for a 2-53 are not recomended.
Now if you have the 2-53 cam ground to low lift-low velocity. And use valve and cam followers as heavy as or heavier than the latest factory spring updates. Then 3200-3600rpm is no problem,
 

[VicS]

Thanks guys for the responses, I would have got back sooner, but caught the flu, like really bad. I measured them (cams) in every place I could with the tools I have. The cams I have are both from late model engines. Thanks again Vic
 

[VicS]

johns; Here is my E mail, tvfarm@hotmail.com my ph no. is 618 838 2225