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6 cy engine problem
84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed
popping out of carb. Found out that the # 1 cylinder exhaust valve and rocker/pushrod were not moving. Exchanged intake pushrod and rocker with the exhaust, same problem. Nuts and bridge are tight. Any opinions on problem......collapsed lifter, round camshaft lobe or other???? TIA Mike |
Re: 6 cy engine problem
Hi Mike,
You got it, round lobe. Camshaft break-in is extremely critical to prevent your new camshaft from flattening. Follow the camshaft break-in procedure religiously: http://engineparts.com/Motorhead/tec.../cambreak.html Your engine in 1929 had a side cover, to pull the lifter: http://www162.pair.com/nashram/nash/...rsonid=&carid= Unfortunately with better sand cores they did away with it and you have to pull the head to remove the lifters. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ MikeG wrote: > > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike |
Re: 6 cy engine problem
Hi Mike,
You got it, round lobe. Camshaft break-in is extremely critical to prevent your new camshaft from flattening. Follow the camshaft break-in procedure religiously: http://engineparts.com/Motorhead/tec.../cambreak.html Your engine in 1929 had a side cover, to pull the lifter: http://www162.pair.com/nashram/nash/...rsonid=&carid= Unfortunately with better sand cores they did away with it and you have to pull the head to remove the lifters. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ MikeG wrote: > > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike |
Re: 6 cy engine problem
Hi Mike,
You got it, round lobe. Camshaft break-in is extremely critical to prevent your new camshaft from flattening. Follow the camshaft break-in procedure religiously: http://engineparts.com/Motorhead/tec.../cambreak.html Your engine in 1929 had a side cover, to pull the lifter: http://www162.pair.com/nashram/nash/...rsonid=&carid= Unfortunately with better sand cores they did away with it and you have to pull the head to remove the lifters. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ MikeG wrote: > > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike |
Re: 6 cy engine problem
Hi Mike,
You got it, round lobe. Camshaft break-in is extremely critical to prevent your new camshaft from flattening. Follow the camshaft break-in procedure religiously: http://engineparts.com/Motorhead/tec.../cambreak.html Your engine in 1929 had a side cover, to pull the lifter: http://www162.pair.com/nashram/nash/...rsonid=&carid= Unfortunately with better sand cores they did away with it and you have to pull the head to remove the lifters. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ MikeG wrote: > > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike |
Re: 6 cy engine problem
Definitely a cam lobe that went flat. I had an interesting conversation with
an engineer at a cam company I deal with for circle track engines. He said that in the last few years cam failures have increased approximately 30% on non-roller camshafts. When I asked him why, he said that it was because many of the oils we buy for our vehicles no longer have sufficient zinc in them, which is critical to camshaft life. This was something I did not know, and I haven't researched the oils yet to determine which ones, if any, still have zinc in them. There is probably an additive available too. When you install a new cam, make sure that you use the proper assembly lube on the lifter faces and the cam lobes. The first 20 minutes of a camshaft's life are the most critical. There are proper break-in procedures available all over the net and from any cam manufacturer. The standard rule of thumb is to run the engine for 20 minutes at a minimum of 2000 RPM. I have also read that it is a good idea to vary the RPM between 2000 and 3000 by slowly revving the engine. I also run an extra quart of oil to promote more splash lubrication for the cam, but make sure you correct the oil level before driving, or you could have other problems. I was also told not to use synthetic oil for cam break-in, but I think you'll get mixed reviews on that. Chris "MikeG" <justme@idontknow.com> wrote in message news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ... > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike > > |
Re: 6 cy engine problem
Definitely a cam lobe that went flat. I had an interesting conversation with
an engineer at a cam company I deal with for circle track engines. He said that in the last few years cam failures have increased approximately 30% on non-roller camshafts. When I asked him why, he said that it was because many of the oils we buy for our vehicles no longer have sufficient zinc in them, which is critical to camshaft life. This was something I did not know, and I haven't researched the oils yet to determine which ones, if any, still have zinc in them. There is probably an additive available too. When you install a new cam, make sure that you use the proper assembly lube on the lifter faces and the cam lobes. The first 20 minutes of a camshaft's life are the most critical. There are proper break-in procedures available all over the net and from any cam manufacturer. The standard rule of thumb is to run the engine for 20 minutes at a minimum of 2000 RPM. I have also read that it is a good idea to vary the RPM between 2000 and 3000 by slowly revving the engine. I also run an extra quart of oil to promote more splash lubrication for the cam, but make sure you correct the oil level before driving, or you could have other problems. I was also told not to use synthetic oil for cam break-in, but I think you'll get mixed reviews on that. Chris "MikeG" <justme@idontknow.com> wrote in message news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ... > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike > > |
Re: 6 cy engine problem
Definitely a cam lobe that went flat. I had an interesting conversation with
an engineer at a cam company I deal with for circle track engines. He said that in the last few years cam failures have increased approximately 30% on non-roller camshafts. When I asked him why, he said that it was because many of the oils we buy for our vehicles no longer have sufficient zinc in them, which is critical to camshaft life. This was something I did not know, and I haven't researched the oils yet to determine which ones, if any, still have zinc in them. There is probably an additive available too. When you install a new cam, make sure that you use the proper assembly lube on the lifter faces and the cam lobes. The first 20 minutes of a camshaft's life are the most critical. There are proper break-in procedures available all over the net and from any cam manufacturer. The standard rule of thumb is to run the engine for 20 minutes at a minimum of 2000 RPM. I have also read that it is a good idea to vary the RPM between 2000 and 3000 by slowly revving the engine. I also run an extra quart of oil to promote more splash lubrication for the cam, but make sure you correct the oil level before driving, or you could have other problems. I was also told not to use synthetic oil for cam break-in, but I think you'll get mixed reviews on that. Chris "MikeG" <justme@idontknow.com> wrote in message news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ... > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike > > |
Re: 6 cy engine problem
Definitely a cam lobe that went flat. I had an interesting conversation with
an engineer at a cam company I deal with for circle track engines. He said that in the last few years cam failures have increased approximately 30% on non-roller camshafts. When I asked him why, he said that it was because many of the oils we buy for our vehicles no longer have sufficient zinc in them, which is critical to camshaft life. This was something I did not know, and I haven't researched the oils yet to determine which ones, if any, still have zinc in them. There is probably an additive available too. When you install a new cam, make sure that you use the proper assembly lube on the lifter faces and the cam lobes. The first 20 minutes of a camshaft's life are the most critical. There are proper break-in procedures available all over the net and from any cam manufacturer. The standard rule of thumb is to run the engine for 20 minutes at a minimum of 2000 RPM. I have also read that it is a good idea to vary the RPM between 2000 and 3000 by slowly revving the engine. I also run an extra quart of oil to promote more splash lubrication for the cam, but make sure you correct the oil level before driving, or you could have other problems. I was also told not to use synthetic oil for cam break-in, but I think you'll get mixed reviews on that. Chris "MikeG" <justme@idontknow.com> wrote in message news:pE8je.30320$VH2.14614@tornado.tampabay.rr.com ... > 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed > popping out of carb. Found out that the # 1 cylinder exhaust valve and > rocker/pushrod were not moving. Exchanged intake pushrod and rocker with > the exhaust, same problem. Nuts and bridge are tight. Any opinions on > problem......collapsed lifter, round camshaft lobe or other???? TIA Mike > > |
Re: 6 cy engine problem
Hey Bill I realy wanted to read that page,
http://engineparts.com/Motorhead/tec.../cambreak.html as I have under 80 miles on my remanned engine, but the link doesn't work, any others? "L.W. ("ßill") ------ III" <----------@cox.net> wrote in message news:428D1E01.4F6CDB78@cox.net... > Hi Mike, > You got it, round lobe. Camshaft break-in is extremely critical to > prevent your new camshaft from > flattening. Follow the camshaft break-in procedure religiously: > http://engineparts.com/Motorhead/tec.../cambreak.html Your engine in > 1929 had a side cover, to pull the lifter: > http://www162.pair.com/nashram/nash/...rsonid=&carid= > Unfortunately with better sand cores they did away with it and you have > to pull the head to remove the lifters. > God Bless America, ßill O|||||||O > mailto:-------------------- http://www.----------.com/ > > MikeG wrote: >> >> 84 CJ7 4.2L rebuilt engine installed 27K miles ago. Last week, noticed >> popping out of carb. Found out that the # 1 cylinder exhaust valve and >> rocker/pushrod were not moving. Exchanged intake pushrod and rocker >> with >> the exhaust, same problem. Nuts and bridge are tight. Any opinions on >> problem......collapsed lifter, round camshaft lobe or other???? TIA >> Mike |
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