Governed speed for 4BT?

[tk064]

A mechanic (maybe) was telling me that the top speed for a 4BT in automotive trim could be safely raised to 3600 rpm. This was allegedly due to the fact that automotive application typically run wide open for only a short time as compared to industrial which can be for a very extended time.



I always thought they would tear themselves up.



Do I need a new mechanic or what.



Thanks for any help

 

[Animal]

I'll agree with him!

As I understand it the 4BTA is the same as the 6BTA minus 2 cylinders. The going consensus is the 6BTA is fine to 4,000 RPM with 60lb. valve spring with some running as high as 6,000 RPM. Just make sure you use the 60lb. valve springs before going that high with the RPM's.

 

[rbalcom]

according to my repair manual... my 4bta cpl 986 is rated at 120hp/2500rpm and the only one with a higher rpm than mine is a cpl 762 105/2800rpm

i'll try to locate the differences in these two engines and get back to your question... ray

 

[HoleshotHolset]

Look for the CPL for the 150hp version of the 4BTA... . the marine version with the P-pump. I tend to think that it is rated a least a little higher... . most marine engines are.



Matt

 

[rbalcom]

According to this manual, cpl 741 is rated :150hp @2800

rated max boost is 31 inches Hg

peak torque boost is blank

going down the table... rated boost levels don't correlate to output hp/torque due to after cooling and charge air cooling, on these engines they lower compression ratios and boost levels due to the colder denser air mass... i'm assuming so they wont grenade...

 

[HoleshotHolset]

Max HP may be at 2800rpm, but I bet that it could handle at least 3000rpm on a regular basis... .

 

[philb4]

rpm

I have a 4bt in a 1 ton chevy and turn 3000 at the highway. Governer speed was set at 3200. I have 200,000 miles on this setup and the only repair to the engine was an alternator bracket that cracked. Engine is 105hp turned to 130 at rear wheels. Governed speed is as it came from cummins factory rebuilt.

 

[HoleshotHolset]

Phil,



Sounds to me like it will take a lick and keep on tickin'!!



Matt

 

[RGT]

4bt in chevy

philb4? if you read this I would like more info on your conversion, I have been thinking of doing the same...

 

[Steve Graham]

Philb4,

Whats the CPL on your 4BT?



steve

 

[philb4]

cpl and info

I will post cpl monday and e-mail me for info on 4bt swap.

 

[RGT]

ok, how do you email someone from the dicussion postings?

 

[philb4]

cpl#

My # is CPL767,built 6/8/94,sn 48105548. Thus far when asked for a CPL# it never looks up in the books.