| Author | Message | ||
| Cable (Fe2_o3)
Rating: N/A |
As I said before I have a 671 with a valve problem. The head may or may not be rebuildable. It has the 4 valve design. Along with the coach I got a rebuilt 2 valve head. I'm interested in opinions on the two heads. My chief concerns are dependability, economy, power,and engine temp. I'm in this for the long haul. We plan to retire in her in a couple of years, so that is why dependability and economy are first on the list. We will have a toad. The engine has been over heated and suffered bent, burned, and broken valves with piston and ring damage in almost every cyl., so an inframe is in order. Budget is a large concern and will weigh heavily in our decision. My wife says I'm so tight only dogs hear me when I fart. All opinions except "Go get a motorhome" are welcome. Cable 4104-449 | ||
| RJ Long (Rjlong)
Rating: N/A |
Cable - IMHO, try and find a 4-valve head, maybe use the old as a core. The 4-valve's breathe better, so there's a slight performance increase over the two-valve. With N-70 injectors, your 6-71 should be putting out about 235 hp or so with the 4-valve head, per the DD spec sheet I have. About 210 with the two-valve. Economy should be about the same with either - a lot depends on how heavy your coach is, where you're driving it (worse in the mountains), and how far into the injectors you've got your right foot. As for dependability, the old 4104 is a tremendous proven workhorse, with an enviable reputation. Just run the correct straight 40 wt oil in it, change it regularly, lube the chassis as required, watch the temp gauge when climbing hills, and don't lug it. Take care of it, and it will take care of you.  Do you have a really good Detroit two-stroke guru to handle the in-frame? HTH, RJ PD4106-2784 Fresno CA | ||
| Al Petersen Rating: N/A |
My dad ran 1950 6-71 with 2 valve head and later models with the 4 valve head and we did not see much difference. The 4 valve head helps with polution control and does allow more power in the turbocharged versions, especially the boat engines. In a non turbo engine set at the 238hp range there is not much diff. with the heads. I would see if you can get an 8v-71 or 6v-92ta and 730 out of a transit bus. There are some good deals out there on this power package. You can get a transit bus with a low mileage engine for cheap. If you are going to use this bus full time and pull a toad.. the 6-71 does not have much power. You probably would be pulling it at full power with a toad and a loaded bus on any hill. Is that how it overheated? It is not bad to be cheap but don't be "stupid cheap" Good luck | ||
| Cable (Fe2_o3)
Rating: N/A |
RJ, I have the coach at Sonny's Place off of US.2 in Sultan, WA. So far he's been knowledgable and fair. If that changes every one will hear about it. The injectors in her now are 60's. I hope to find 65"s for the rebuild.. I don't know the scale weight yet, but she's not light. She has a 7.5 kw gen set, 75 gal propane tank, 200 gal fresh wa. with 200 gal. wastetanks. I should be able to boondock for several days. Al, I looked into bigger eng. and auto. trans. but it's out of the question. The cost of the equipment plus the cost of the swap was way more than the rebuild. And neither of us are that fond of cat food. Cable 4104-449 | ||
| TWO DOGS Rating: N/A |
will have to agree....look for a good engine...will be the cheapest thing...lots cheaper than a rebuild | ||
| Jim McArthur Rating: N/A |
Cable, I was just on HB Industries site. They have a complete 671 take out, they say in good shape for $1200. If its a good engine, certainly cheaper than a rebuild. Jim | ||
| Geoff (Geoff)
Rating: N/A |
Does the 2-valve head have all the rocker arms and fuel lines etc.so it can bolt right on?-- if so, then I would just use it. If you have to buy all the hardware for it I would look for another 4 valve head instead. --Geoff '82 RTS CA | ||
| mel 4104 Rating: N/A |
cable if that motor has been cooked as bad as you say then you are in for a complete out of frame rebuild if you was the rebuild to last. it is not just a matter of putting on another head and driving it away with a smile on your face. just rember you get what you spend and as to being cheap most good mec. when they hear the tight squeek they will tell you in a nice way to beat it go some where else. and the guys that work for less know their own value. as to the heads the 2 v. has the same area as the4 v to allow air in the piston the difference is 2 areas at different points which gives better fuel effencyand burn. | ||
| John Rigbyjj
Rating: N/A |
Cable, I have a 671 two valve head N-70 injectors advanced timing n my 4104. I feel the bus will out run any 4-valve head engined 4104 on the road.Excludindg RDW,S 671TA. Could be wrong. MY only problem has always been overheating with this engine and the previous one ( I have had the coach 18 years. But last year I installed a new radiator core with more though put.Cost $690.00 Have not had heating problems since. John | ||
| DMDave Rating: N/A |
If you ever want to add a jake brake you will need the 4 valve head. something to think about especially with a heavy coach and a toad. | ||
| mel 4104 Rating: N/A |
NO you do not need a 4 valve head as you can put jakes on a 2valve head which i have had on my 4104 for the last 10 years when i put a jake brake system on it. what you need are the caps that go on the bridges, they are hard to find and can be expensive and then again you might just find a set of them on a shelf some whee as i did and they work great just the same as on the 4 valve head as my brotherin law has a 4104 with a 4 valve head and when we traveled to gether there was no difference in the two coaches as to jake operation. good luck on your search. |