6-71 Detroit diesel questions

Gambles · Oct 26, 2016

Didn't want to hijack the other two-stroke threads, so here is my questions:
I've got a '71 Chevy C90 truck with the 6-71 Detroit two-stroke. Knowing nothing about the Detroit two-strokes, is it possible or easy to bolt on a 4-valve head? Any real advantages?
Second, since my truck has a canister oil filter, would a spin-on oil filter base be as simple as bolting on an oil filter base that accepts spin on oil filters?

Al Baker(pumpman) · Oct 26, 2016

If your engine is a 1971 you all ready have a 4 valve head. Yes, there is a adapter to make it a spin on. Most times these leak,,, Al

Ian Beale · Oct 27, 2016

What's another one then?

From following discussions below

roaddevil49 · Oct 27, 2016

2 valve head, there were two types of liners for the 71 engines, "S " & "N ", with all parts interchangable. Not sure if the 92' s could be had with ether liner,being a newer engine they would have the "N "s.p

guido · Oct 27, 2016

Hello Gambles,

A set of injectors with a good tune up will wake up all the horses under the hood. You could get bigger injectors for a bit more power. Of course you should change all the filters as well.

Guido.

buickanddeere · Oct 27, 2016

As previously stated the N series improves starting and adds a wee bit of power. A natural aspirated 6-71 should have C70 injectors . The "C" injector have an improved spray pattern.
Iirc there is also a cam follower spring and valve spring upgrade for the 71's and well as the 53's.
2300rpm for full rated and 2450rpm fast idle. Many engines are set too low at 1800-1900rpm Max which makes the spread between tea mission gears too far apart.

buickanddeere · Oct 27, 2016

Run the injection timing at the old advanced levels instead of retarded to lower NOX emissions but lowers power and efficiency.

JOCCO · Oct 27, 2016

The filter yes there are adapters and you can move them to a different place. Kind of surprised your engine is a 2 valve head as that is going back a long way. I would pull cover and look also look at injector it will have number on it. If you know little about them get a good manual or find some one who does to help you. I know good luck with that these days.

guido · Oct 27, 2016

Hello buickanddeere,

The c70 injectors were used on a four valve head with adv. timing. For standard timing they used C60. The C70 timed at 1.484 while the C60 timed at 1.460. I don't remember much about the 2 valve heads as all our engines were 4 valve heads.

Guido.

Gambles · Oct 27, 2016

As another poster noted, it probably IS a 4-valve motor. I've not had a valve cover off on it...yet.

buickanddeere · Oct 27, 2016

The C injectors were just California emission injectors that had an even better spray pattern than the N series injectors. The old S series injectors were a dismal set of drippers.

6-71 Detroit diesel questions

Gambles

Well-known Member

Al Baker(pumpman)

Member

Ian Beale

Member

roaddevil49

Member

guido

Well-known Member

buickanddeere

Well-known Member

buickanddeere

Well-known Member

JOCCO

Well-known Member

guido

Well-known Member

Gambles

Well-known Member

buickanddeere

Well-known Member

Similar threads