| Author | Message | ||
     Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 20 Registered: 01-2003 |
I am preparing to Build an engine for my 96 Rover. I don't have a workshop manual yet. I have a question about the Cam Shaft bearings that are installed. Everything looks great.. except for the front Cam Bearing. It has five or more deep chunks in it. I am assuming these bearings are supposed to be finished? What is the diameter on a finished bearing? I know they are diff. sizes back to front. So what is the Dia. of the one closest to the Timing Cover? If they are not finished. How much does this process change the Diameter? They are normally made of a soft material. Correct? So is it possible to remove and replace with another one? Without taking out the crank or rods, ect? I need to know if any one has an opinion? Or advise on how to deal with this.Thanks for the help..   | ||
| Paul T. Schram (Paulschram) Senior Member Username: Paulschram Post Number: 1116 Registered: 02-2002 |
Joe: In the past when folks would actually pay to have engines rebuilt, rather than just swap boneyard engines, the machine shop I used back then would measure the camshaft by each individual journal and ream (for lack of a better term) each camshaft bearing to achieve the desired clearance. While I won't swear to the validity of it, this machine shop claimed that this was the only way to ensure that the critical tolerances of cam bearings were met. That said, I have wiped entire lobes off of cams from what could only have been excessive clearance on the cam bearings. You might e-mail the guys at RPI for their input. WHOAH! I just looked at your pictures more closely. The grooves in your bearings are certainly supposed to be there to promote oil flow. There is no way they could have worn that uniformly. As there is no copper visible, I'd assume your bearings are good. Have you measured the bearings and the cam to determine the clearance? That looks like the next step to me. Peace, Paul | ||
| Tbow (Tbow) Member Username: Tbow Post Number: 71 Registered: 12-2002 |
WHOAH.. What are you doing, and why are you rebuilding the engine? First, from the pictures, those bearings look fine. Second if you decide to rebuild the engine, think again. With the price of new pistons, rings, bearings (main, cam, and rods)plus the machine work, your going to be approaching over 1,200 dollars. You can get a BRAND NEW factory short block for 1,200 dollars. With a 12 month warranty!! I just went through the exact decision, and it was a no brainer. Total cost with the short block, parts and machine work on the heads around 2,000 dollars. | ||
| Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 21 Registered: 01-2003 |
This "is" the new block that I have ordered. I am trying to find out if the "grooves" in the Front camshaft bearing are typical? | ||
| Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 22 Registered: 01-2003 |
Paul.. They didn't "wear" that way. This is a new block I ordered. It looks more to me like they were "Grooved" by a tool. Am I not correct in assuming that the oil flows through the internal drilling in the cylinder block to the cam,tappets,camshaft journals,and rocker shafts? Thanks, Joe | ||
| Steve Hinton (Steve_h) New Member Username: Steve_h Post Number: 12 Registered: 02-2003 |
Joe, Those "grooves" are supposed to be there. Like Paul said, they are there to help the oil flow. Did'nt your short block come with a cam installed? Most times when people talk about a "short block" it comes with crank, rods, pistons, cam and lifters. Be careful when you put the cam in (and use lots of assembly lube) because the cam bearings are soft and it is very easy to nick them when trying to get the cam in. Hope this helps. | ||
| Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 23 Registered: 01-2003 |
No.. My block did not come with Cam or Lifters. Thanks for the information! | ||
| Paul T. Schram (Paulschram) Senior Member Username: Paulschram Post Number: 1117 Registered: 02-2002 |
Joe: At this point, it is time for you to measure the difference betwee OD and ID. Do you have a set of telescoping gauges and a good micrometer? If not, either buy a set of each, or drag your block and camshaft oyu intend to use ot your local automotive machine shop and ask them to do so for you. Without this piece of critical knowledge, you run the risk of oding as I did so many years ago (wiping lobes from camshaft). The clearance will be terrifically small, so if you are not confident I your measuring skills, it may well be best advised for you to pay someone to do this for you. FWIW-this (and main/rod bearing clearance measurements) will be the most precise task in the reassembly of your engine, in comparison, the rest are simple. Peace, Paul | ||
| Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 24 Registered: 01-2003 |
Thanks Paul! | ||
| Tbow (Tbow) Member Username: Tbow Post Number: 75 Registered: 12-2002 |
OK Joe that makes sense, it looked virtually brand new. Those groves are designed to sling oil on the front part of the cam to lubricate the timing chain. I just went through a new short block and rebuild heads myself on my 96 disco. I just went ahead and put a new camshaft and didn't worry about the clearances. With everything new, it's one less thing to worry about. In comparison, 250 for a camshaft is cheap when you add up everything else I paid for i.e. lifters, machine work on the heads, gaskets, valves, springs ect... My recommendation, don't be penny wise pound foolish.. new camshaft, and "forget about it".. Just my 2cents. | ||
| todd slater (Toddslater) Member Username: Toddslater Post Number: 239 Registered: 08-2002 |
Joe, Looking at your photo above on the left and in the center of the photo...there appears to be an un-natural chunk missing out of the block casting between the first two lifter bores. I ain't never seen nuttin like that not even other less sophisticated british stuff. Looks like something sploded through there. | ||
| Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 25 Registered: 01-2003 |
Oh it's un-natural. The chunks you are looking at. I would mark up to "Land Rover Craftmanship" Not finished very well. They left big chunks around the corners of where they cut the Drain holes in the valley. the drain holes are probably what you are looking at, from the bottom though. I need to remove the chunks and file or dremel the spots that are sticking up. Without dropping anything on to the crank. I might just leave it alone after re-moving the chunks. I don't want any metal flying around in there. I have given the new cam and lifters/Rods some thought. And will go that route.. Anyone got any hints/tolerances for setting pre-load on the tappets?Thanks again!   | ||
| Paul T. Schram (Paulschram) Senior Member Username: Paulschram Post Number: 1124 Registered: 02-2002 |
Pre-load on the tappets is not directly adjustable unless you wish to mill the rocker shaft mounting bosses. This is usually not necessary, nor advised unless you chop a huge chunk off of your heads, the heads and block were originally set up for the steel head gaskets, and you are now using the composition head gaskets. The lifters will absorb any variation you might find. As for not measuring cam shaft dimensions, do so at your own risk. The engine I destroyed multiple camshafts in was a brand new ,out-of-the-box SBC, and a brand new out-of-the-box camshaft. Peace, Paul | ||
| Joe Blanchard (Joeblanch) New Member Username: Joeblanch Post Number: 26 Registered: 01-2003 |
I am going to replace the Cam. But will still measure ID and OD of the Cam and Bearings. On the Tappet pre-load. I was refering to Rpi's website which suggested doing this. I will still measure this just to be sure. It would not hurt to be sure they are set up correctly.(hey.. they work with these Engines every day. I feel they would not put out any irrelevant info on how to set one up.) The heads I ordered have been milled to accept the composite gaskets with no loss of compresion. So maybe they have taken a chunk out of the heads. And the suggestion of measuring the pre-load would be in order. | ||
| todd slater (Toddslater) Member Username: Toddslater Post Number: 240 Registered: 08-2002 |
That is some very ugly "workmanship" indeed, and I use that term very loosely. A more apt description would be "hammer mechanic" at LR. | ||
| OLIVER CLOTHSOFF (Everythingleaks) Senior Member Username: Everythingleaks Post Number: 258 Registered: 10-2002 |
and they still build them this way as we speak. Amazing isn't it |
