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| Replacing Cam Pulleys | Rating: 
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| Posted: 06-25-2008 03:32 am |
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1st Post |
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Joel Member
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Ok, I took a look at my timing belt and it's looking worn. I know it was a bit tight but didn't want to mess w/ it. Besides, I had a 'professional' take care of it for me... I have a couple of problems so I figure I might as well do some 'while I'm there jobs'. The pulleys on the cams are looking worn. Where the belt travels (about 1/4" from the front of the pulley) it's worn down probably 1/32-1/16". The belt is looking a bit tattered so it's gotta go. I figure I might as well replace the pulleys. And if I'm replacing the cam pulleys - I might as well do the crank pulley too and get the round tooth belt. The other issue is that I know the oil pump pulley isn't running 100% true. I don't remember why - I didn't change it - remember I paid the expert. I'll call him back up and ask if he remembers. It's been at least a year so I bet he doesn't. Anything I should do 'while I'm there'? Is it worth the effort to replace the tensioner? Just the parts - pulleys, belt, etc are about 700 bucks so I figure a little more couldn't hurt too much. The car has just over 100k on it. The story was the top end was redone before i bought it - but you never know what was really done. I drive the bejeezus out of this car and don't want anything to break at triple digit speeds.....
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| Posted: 06-25-2008 03:24 pm |
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2nd Post |
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edward_davis Member 
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Joel, You might as well replace the tensioner bearings while you're in there. They're not very expensive, and you should replace them every other belt anyway... You can probably keep the tensioner pulley itself, since it is smooth and runs against the smooth side of the belt. I'm not sure, but I think you'll have to replace the toothed pulley for the distributor, too, if you switch to the rounded tooth belt. Hope that helps, Edward
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| Posted: 06-25-2008 08:01 pm |
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3rd Post |
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jcdean Member
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Dave Been Engineering has a complete "kit" for the toothed belt change out for a not too terrible price.
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| Posted: 06-29-2008 02:35 pm |
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4th Post |
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jgreen Member
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Although, wonderful people on the phone, my experience with Dave Bean Engineering has been challenging to say the least. They seem very unorganized. I ordered an HTD pulley set ( green dot) from them........ the process was a nightmare. They sent the wrong parts th first time and during the exchange for correct parts ( they had to back order), they took 3 and 1/2 months to refund the difference as they somhowhow managed to "double charge' me for a couiple of incorrect pulleys. Advice: 1) Tom is very knowledgeable but seems memory and organizationally challenged. 2) The billing department is a mess...... pay with a credit card...... that way you will have a decent paper trail as to what was purchased and the date..... dave Bean won't have a clue as they are unorganized and at times took as much as 3 weeks to get a call back. 3) If something is backordered.... wait until the part comes in before ordering.... DO NOT PREPAY... EVER. Their records are terrible and most likely, the stuff will come in and they will sell it to someone else and forget all about you as you wait patiently for a call. Their back order system is not computer driven.... it is people driven. They will forget all about you until you remind them and fax them a receipt. Just call every week until the parts come in and you will have a much better experience. Just my experience, not necessarily the experience of others.
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| Posted: 06-29-2008 11:24 pm |
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5th Post |
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dwalls1 Member
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FWIW In my conversations with Delta Motorsports they indicated that worn pulleys were not a problem that warranted expensive replacement. They did recommend replacing the idler pulley bearings and the belt at the same time.
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| Posted: 06-30-2008 03:34 am |
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6th Post |
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Judson Manning Member 
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Generally speaking, everything aluminum used on the 907 is very soft including the cam sprockets. Early sprockets will be shiny and a definate wear pattern will be visible on the teeth. The more the wear, the less grip = BANG! time for a new set of valves. Later cam sprockets were of another (harder) aluminum alloy or treated with a hard anodized coating. Of the ones I've seen, they appear dark grey or gunmetal in appearance similar to the HTD variants. I say 'later' but I recently saw a GT with shiny sprockets...
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| Posted: 07-01-2008 04:59 pm |
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7th Post |
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Brett Gibson JH5 20497 Member
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Judson, at the last couple of Nationals here in the East I have been checking belt tension with this gauge from Mcmaster Carr on a large number of cars, what seem's to be a ideal tension measurement is between 95 and 100 lbs on a warm engine, when I see shiny pulley's the belts are usually over tight, 120 plus, I even found a car this year running slack at 55 to 60 lbs, seem's the cars will run in a wide range but but once you go over 100 lbs they tend to whine, havent yet run into a car with the half moon belt yet, I would be intrested on what reading works bets for that. Dial Pull-Style Belt Tension Indicator 40 to 180 Pound Range, 1/2" to 1" Belt Width P/N#60275K21 Brett.
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| Posted: 07-01-2008 05:12 pm |
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8th Post |
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Joel Member
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Now that's a pretty expensive little tool....
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| Posted: 07-03-2008 11:17 pm |
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9th Post |
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Greg Fletcher Administrator 
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Just an FYI- our excellent JH Shop Manual does list a measurement for timing belt tension- whoo hooo, it's 35 Kp! It's in the RM service pages. –Update– the Kp (kiloponds, now that's useful) conversion to pounds of force comes out to 77.161 and it actually seems to work, at least on my car. Later Lotus publications state that 90 pounds is the "correct" pound force measurement on the Kent Moore gauge device, BUT this measurement is for the later, hardened pulleys. The Jensen Healey uses the softer aluminum pulleys, so consider a timing belt tension more appropriate to the material used.
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| Posted: 08-19-2008 02:01 am |
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10th Post |
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dwalls1 Member
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I'm hoping someone has time to answer what is probably a rhetorical dumb question. When I changed the cam belt on 17798; for some reason I thought the belt would center itself on the pulleys. Now it is running towards the back of the pulleys. Is this a problem? Should I loosen the tensioner idler and slide the belt out to the center of the pulleys? What are the odds of getting the belt loose enough to slip a cog on a pulley? I know that's three questions, but would appreciate anyones input. I hate to fool with it as it is running so sweet and sounding so nice with the new exhaust. Thank You in advance for your time, Dale
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| Posted: 08-19-2008 06:51 am |
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11th Post |
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subwoofer Member
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My timing belt stays towards the rear of the pulley, I can't really see any reason why that should be a problem as long as it doesn't rub anywhere along the way. The previous, worn, belt also settled in the exact same position, so I doubt loosening up the belt and moving it will have any lasting effect whatsoever. -- Joachim
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| Posted: 08-19-2008 12:14 pm |
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12th Post |
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Brett Gibson JH5 20497 Member
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I have seen the belt run on both the front and back sides of the pulley's, dont recall seeing one run in the center, but I would'nt rule it out, I believe one cause of were the belt runs is wether it is running on the front or back side of the tensioner. What I mean by that is, the belt runs clockwise, so the best position for the tensioner is running on the up side of the belt, easier to set tension, but it also can run on the back side, a bit more difficult to set but can be done. probably not saying this well but I hope it's not to cloudy, anyhow as long as it stay's put and you have decent tension I would'nt worry about it. Brett
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| Posted: 08-19-2008 01:51 pm |
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13th Post |
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dwalls1 Member
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Thanks a bunch guys, My mind is eased, I am continuing to monitor the belt for wear on the backside and tension. At this time it doesn't appear to be rubbing on anything. The belt I removed did run closer to the center of the pulleys, but apparently that is not requisite. Thanks again, Dale
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| Posted: 04-28-2011 06:28 pm |
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14th Post |
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sjensen24 Member
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I have decided to replace the timing gears (cams and distributor). removing the cam gears looks easy. The distributor gear appears to be attached with an allen connection, which does not thrill me. I would welcome any advice on the whole project of changing these gears. thanks.
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| Posted: 04-28-2011 10:21 pm |
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15th Post |
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dwalls1 Member
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My first thought when I read that you had the allen head screw on the distributor shaft, was make sure you have the right allen wrench. It's metric and just close enough to an SAE to get us in trouble. Clean the socket out good and make sure your wrench is inserted fully. When reinstalling the sprocket use blue Loctite on the shaft and screw. It may be worth removing the radiator to have room to use a hammer impact on that allen screw. The cam sprockets come off pretty easy as I recall. Good Luck.
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| Posted: 04-29-2011 05:28 am |
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16th Post |
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pbahr Member 
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For the HTD Lotus belts and gears, you could try R.D.Enterprises. Ray Psulkowski is a well respected Lotus parts dealer. rdent@rdent.com I've had good luck at Bean as well.
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| Posted: 04-29-2011 01:28 pm |
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17th Post |
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Dan (Florida) Member
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In the late 80's Nissan used basically the same setup on the vg30i v-6 engine for a couple of years before going to a chain drive. The pulley size and pitch were the same and the belt is the same except the pulleys are steel and are mounted different. I had the same problem with the belt almost sunk into the aluminum pulleys. The local u-pull it yard supplied the pulleys at $5-10 apiece and a machinist freind made me a set of spacers and offset drive keys so that everything lines up . All thats left is to mark the timing marks from the old to the new pulleys by stacking the old on top of the new and lining up the key slots. I thought it was easy but there are folks here who think that this is a dangerous thing for the uninitiated. At any rate you can google nissan vg30i to see them or look in the photo gallery under florida cars for pic's of mine. If your belt is moving forward or backward on the pulley, suspect the idler pulley(the little one with no teeth). Itis supposed to be arched in the middle to keep the belt centered. it may be worn or loose/ misaligned or have bad bearings.
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| Posted: 05-03-2011 02:40 pm |
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18th Post |
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sjensen24 Member
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I purchased new gears from Delta and got them in the mail yesterday. I spent some time looking over the car. I may have gone overboard a bit by purchasing the distributor gear. Looking at the car more closely, I see that the exhaust gear is badly worn, the intake gear not so bad and the distibutor gear not much. I could return the distributor gear ($190) and save myself some trouble. It may be paranoia but I still don't like that allen screw. Also,I have electronic ignition so getting the distributor lined up correctly is not as intuitive as with the points. If I leave the old gear on I think I can just mark the gear position relative to the distributor body and be OK. Any suggestions?
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