| Author | Message | ||
| Ben Millermon (Brainsboy)
Member Username: Brainsboy Post Number: 301 Registered: 5-2001 |
Terry dont feel bad, I did that when I first got my ferrari and changed out a leaking oil seal | ||
| Walt Pfirman (Waltp)
New member Username: Waltp Post Number: 37 Registered: 7-2002 |
Terry, Glad that all is well and your car will be on the road soon. | ||
| Verell Boaen (Verell)
Member Username: Verell Post Number: 712 Registered: 5-2001 |
Terry - (WHEW!!!)That's great news!!! I had a belt jump off once while I was rotating the engine by hand to check the alignment(don't ask). Was so upset I couldn't bring my self to even try to evaluate the possible damage (was none) for a couple of days. GORDON - Snap-On gets $154.00 for the cam gear locking tool, and Baum tool asks even more: http://buy.snapon.com/catalog/pro_det.asp?P65=yes&qt=1&tool=all&catItem=true&INV_ONHAND=&FREIGHT=&qty=1&Item_id=57330&PartNo=ML4500&Price=154.95&ListPrice=154.95&FORMNAME=0&Desc=Tool%2C+Engine+Timing+%2F+Sprocket+Locking%2C+Universal&SUB_Cat_ID=1468384&SUB_Cat_NAME=Timing&Cat_ID=1468373&Cat_NAME=Engine+Service&group_id=1552&group_NAME=Timing&store=snapon-store&dir=catalog The other source is: www.baumtools.com At $154, I think I'll make my own 3x8 specific tool next time I'm doing a major. | ||
| John_Miles (John_miles)
Junior Member Username: John_miles Post Number: 58 Registered: 7-2001 |
Good to hear there was no damage. There are definitely indentations in the pistons -- they're just not quite deep enough to let you get away with much.  I wasn't as lucky as you were. Last spring, I managed to drop one of the airbox-mounting nuts into a carb throat without noticing it. That resulted in a $4K repair bill, along with a once-in-a-lifetime (I hope) look at the top end of a 308 engine: <img> <img> (Well, I tried to make thumbnail links, but the BBS software hosed them beyond repair. Click the tags above for detailed .JPGs.) As you can see, it's not hard to spot a nicked piston -- although any damage to your engine would probably have been less dramatic than mine. | ||
| Gordon Hollingsworth (Gordonh)
New member Username: Gordonh Post Number: 12 Registered: 5-2002 |
I'm interested in this special tool mentioned for installing the cam belts. What I had heard of before was a tool that would lock the camshafts in position correctly so that the belts could be changed and dowel pins installed in the correct holes. If this is the same tool, how do I get one? | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 480 Registered: 4-2002 |
I did a compression test tonight just to make sure there was no damage. I also inspected the pistons visually with the borescope. When I first looked at the #4 piston, the one I thought most likely to have had some contact, I was pretty bummed. Im not sure how I got this impression, but I thought the dome topped pistons did not have any cutout for valves in them. When I looked at the piston top, the valve relief coupled with some carbon buildup looked pretty much exactly like a piston mashed by a valve.... except there was no shiny metal showing. Then I installed the compression tester and hit the starter... and got only 120lb. My heart sank. Then I remembered that I had not opened the throttles.... I opened the throttles fully and tested again. Its fine. Here are the compression test results: Cylinders 1-4 164, 160, 158, 160 Cylinders 5-8 174, 168, 175, 160 I tested each cylinder twice. I also saw no shiny surfaces on any of the pistons when inspected with the borescope. An even, thin carbon coating with no scratchs or other marks that looked as if it could be made by contact with a valve. I believe I got away with it..... and call myself very lucky. | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 479 Registered: 4-2002 |
I have not run the car as yet, its not all the way back together. However, I dont think there is any chance there was any valve to piston contact. The tensioners were not locked down when I rotated the engine. The front bank pistons are all on the lower portion of their travel and these cams rotated fine as there were no front bank cam caps installed upside down. The rear bank belt skipped when the cams were bound by the flipped caps. The cam timing marks only moved less than .5 inch before the belt skipped. I was not applying a ton of force to the crank.... I knew if it was not rotating easily something was not right. It does rotate easily now that the caps are in the correct position. I dont think there could have been any damage. Right now I have a fuel tank out, the ignition all apart, no headers on the engine.... No real way to test compression. Should I worry and perhaps pull the fuse for the fuel pump and distributor and then try running the starter to take a compression test? | ||
| John_Miles (John_miles)
Junior Member Username: John_miles Post Number: 56 Registered: 7-2001 |
How's your compression looking after the accidental rotation? | ||
| Steve (Steve)
Member Username: Steve Post Number: 368 Registered: 2-2001 |
Verell the timing sprocket tool that I have is from snap-on but is the same as baum tool. BAsed on looking at my timing marks I am dead on so I would not expect to move the sprockets on the cams. So this being the case I assume that the cam locks are simpler to use vs. using cardboard under the cam bearing caps. | ||
| '75 308 GT4 (Peter)
Advanced Member Username: Peter Post Number: 2729 Registered: 12-2000 |
I'll continue to use the cardboard method in the future, but like Terry mentioned, I'll use more than one piece under one cap. Less clamping-force from the cap would be needed if multiple caps are being used (and therefore less chance of crackies happening  )... | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 478 Registered: 4-2002 |
Verell, This morning I went down, loosened the tensioners, rotated the engine 4 times watching the tensioners and then locked them down at their most extended point. Then I rotated the engine an additional 6 times. I put the flywheel at exactly TDC and rechecked the cam timing marks. The intake cams are PERFECT. The exhaust cams are off by an amount so small its barely perceptible to the eye... and this eye being a borescope focusing on it from less than an inch away. Its way less than 1/2 the width of the timing mark now. I cant see any reason to fight this thing for an adjustment so small it cannot be measured, so Im happy. Thanks again for the tips! I shot some photos of the binder clips in action and the Q/D crank pointer that you suggested and I'll post later. Terry | ||
| Verell Boaen (Verell)
Member Username: Verell Post Number: 696 Registered: 5-2001 |
Terry,If I remember right, I once calculated the timing marks in the cam caps as being about 1mm wide which corresponds to 3 or 4 degrees. If you're 1/2 timing mark off, you're off you have 2 choices. Either live with it, or you'll have to pull the cam-cam gear alignment pin & find a pair of holes that gives the desired alignment. I used 4 drill bits w/masking tape on the cutting ends as temporary pins, I believe the drill size is in the same thread as the binder clips suggestion. Steve: RE: twin cam locking tool - I assume you mean the one Baum sells for a few hundred? If you use the twin cam locking tool, how do you fine-tune the position of a cam gear on the cam? ie: Once I've pulled the pin out, How do I rotate the cam gear on the end of the cam? The cam gears are locked by the tool, and the cams are aligned where you want them. Am I overlooking some trick? | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 477 Registered: 4-2002 |
I used a piece of business card placed under 2 caps for each cam. I torqued the nuts down to "barely tight". No issues on the cams moving. When I had to remove one of the pully bolts, I put the cardboard under 2 more cam caps to make sure it didnt move when the impact wrench was applied. No problem. I really dont think the caps are at risk unless you were to use a really think piece of cardboard or you were to torque it down way too tight. So rather than a single piece of cardboard that is thick or tight.... use several thin ones with mild torque. On Verell's tip I also used the binder clips to hold the belts in place on the pulleys during fitting and I made a quick and dirty pointer for the crankshaft damper to show TDC. This made the job MUCH easier as rotating the engine to get exactly at TDC while working with the belts is made very simple. | ||
| Craig Dewey (Craigfl)
Member Username: Craigfl Post Number: 582 Registered: 1-2001 |
I was nervous about putting the cardboard shim under my cap ( for fear of cracking the cap like Peter said) so I did without it. It slipped once on me but if your careful, you'll catch this right away and move it back. The tool is probably the best way to go. | ||
| Steve (Steve)
Member Username: Steve Post Number: 366 Registered: 2-2001 |
Guys a quick question here? Is the cardboard you are talking about the piece of material you put under the cam bearing to stop the cams from jumping when you remove the old belt? Do you use this method on only 1 set (rear of car) cams? Why can't you use the twin cam locking tool to hold the cams from moving? I'm waiting for my belts and will put them on next week and want to make sure it goes easy. Thanks | ||
| '75 308 GT4 (Peter)
Advanced Member Username: Peter Post Number: 2724 Registered: 12-2000 |
Terry: "...Im thinking that being off perfect alignment by less than 1/2 the width of the timing mark is probably fine." It sure is. No worries there... | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 475 Registered: 4-2002 |
Terry<-------- (In his best Homer Simpson voice): "Dohhhhhh" After ready my original post and the first response, I went back downstairs and looked at the caps. Then of coarse I notice the numbers. And matching numbers on the head. And how the caps with the cam timing marks have the number on the same side as the number on the head. And how some of the other caps on the rear bank dont have the number facing the number on the head.... Swapped the caps around, re-installed belts, played with one pulley and pin a bit to get all the timing marks 100% exactly on, put tensioners in "tensioning" position and rotated engine. It rotates perfectly. Yes fellow fanatics.... I feel a bit like a moron ;) Anyhow, after rotating the engine 6 or 7 times and stopping back at TDC, I rechecked all the timing marks. When exactly on the TDC mark on the flywheel, both intake cams are precisely lined up. Both exhaust cams are off by a TINY FRACTION. I mean off by about 1/2 the width of the timing marks themselves. I am getting amazingly good looks at how the marks line up. The nifty new borescope fiber optic doohicky thing I got is WAY COOL. You can inspect from the front bank timing marks just as if your eyeball was focused exactly 1 inch away from the cam! Im thinking that being off perfect alignment by less than 1/2 the width of the timing mark is probably fine. Anyone disagree? BTW, thanks for all the help! You guys are great. Its nice to know there are knowledgable, helpful and understanding folks willing to lend a hand. Even if the question really only requires opening your eyes a bit! | ||
| '75 308 GT4 (Peter)
Advanced Member Username: Peter Post Number: 2721 Registered: 12-2000 |
Verell: "...The only other possibility i can thin of is that the cam caps were over-tighened down on the cardboard tabs & the caps were bent..." Not so, they crack when you over tighten them. Ask me how I know...  | ||
| Verell Boaen (Verell)
Member Username: Verell Post Number: 693 Registered: 5-2001 |
Terry, As others have said, the most likely thing that will lock the rear bank cams up like that is to have the cam caps upside down. DOWN SIDES: The only other possibility i can thin of is that the cam caps were over-tighened down on the cardboard tabs & the caps were bent. This would damage the caps, but not the cams or head. However, I suspect you only used 1 cardboard tab/cam, so if that cap were loosened, things should work as normal. THE REAL CAUSE FOR WORRY: Cross your fingers, I hope that the engine didn't actually rotate as far as you estimated. If I remember correctly, with the rear bank cams locked on PM1-4, there's only 35 degrees of safe crank rotation off of PM1-4 before there's interference between the rear bank's valves & pistons. | ||
| billy bob (Fatbillybob)
Member Username: Fatbillybob Post Number: 260 Registered: 8-2002 |
You are kinda lost here it seems. Go back and read up on your theory first to get a clear focus on what you are trying to achieve. ++WTF? I set both tensioners in the full loose position and remove the belts from the cam pulleys. I rotate the crank back to PM1-4. I rotate the front bank cams back to perfect alignment. I go to rotate the rear bank cams slightly back to alignment.... and neither of them will turn.++ You are not clear here. You may be 180 out of synch. #1 piston to TDC. Then cam marks align with cam journal marks. Cam cog pins should be out. Pin down cams w/ matchbook. put on belt. tension belts and insert cam cog pins into best hole. Rotate crank nut with 36mm wrench CW two turns to make sure all marks line up again. ++Both rear bank cams are just about locked tight in place, cannot be turned with hand pressure on the pulley alone.++ you may be hitting pistons jumping belts is a sure sign of possible disaster. ++The cap nuts have to be pretty loose for the cam to rotate with ease.++ you are binding on cam journals due to wear mismatch on the cam seats to journal caps ++Im thinking of leaving the cap nuts a bit loose, getting it all back together and all the timing marks lined up again, tightening the tensioner in the "tensioning" position and then rotating the engine several turns. If the cams turn ok and everything lines up well.... then I'll release the tensioner to rotate some more. Then after tightening the tensioner for the final time I will rotate again. THEN I will try to torque the cap nuts and see if the problem persists? And if its does.... I fear the heads need machining, the caps all replaced and new cams.++ This depends on how much destruction you have caused. In theory with a good motor the camshafts are perfectly round and the journals are line bored with caps in place. Therefore, in theory you can swap caps if everything is symetrically manufactured. However, this is never the case. The caps must go on the way they came off. Usually the number on the caps is close to the number on the head. Match up that way you may have caps backwards. Reassemble with assembly lube to the right torque. And give it a try that way. | ||
| JohnR. (Rivee)
Junior Member Username: Rivee Post Number: 189 Registered: 1-2002 |
Terry, as JRV said their are numbers 1-20 stamped on one side of the caps as well as on the head. Match the #'s to each other | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 1404 Registered: 11-2002 |
yes it matters which way they go on. Match the numbers stamped on the sides of the caps to the numbers stamped on the edge of the heads. | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 474 Registered: 4-2002 |
they could be.... I did keep the caps sorted properly so each one is in the same location it was removed from. But I'm not sure if they could be backwards or not. The seem to slip into place on the studs fine? Anyone know if the caps must go on a certain way and if so... which way? | ||
| Jack Habits (Ferraristuff)
Member Username: Ferraristuff Post Number: 343 Registered: 4-2003 |
I'm definitely not an expert on these engines but could it be that the caps are on backwards? There are engines where that matters. Jack | ||
| Terry Springer (Tspringer)
Member Username: Tspringer Post Number: 473 Registered: 4-2002 |
Im working on the cam belt change.... everything is going as planned, no issues. I get the belts on, have PM1-4 lined up perfectly and have all 4 cam marks lined up perfectly. I release the tensioners to apply tension, but dont lock them down. From the crankshaft pulley I go to rotate the engine. I turn it clockwise. It wont budge. I apply a little more pressure, it suddently turns but the rear bank cams both barely turn at all while the engine goes through a full 1/2 rotation and the rear cam belts jump several teeth. The front bank cams appear to rotate as normal. WTF? I set both tensioners in the full loose position and remove the belts from the cam pulleys. I rotate the crank back to PM1-4. I rotate the front bank cams back to perfect alignment. I go to rotate the rear bank cams slightly back to alignment.... and neither of them will turn. Both rear bank cams are just about locked tight in place, cannot be turned with hand pressure on the pulley alone. My cardboard tabs used to lock them in position have definitely been removed. I loosen up each cam cap in sequence significantly. When they have all been loosened a good bit, the cam will rotate properly. Same for both rear bank cams. I had torqued the cap nuts to 8 pounds. Next I loosened each cap in sequence again as if removing the cam completely. When almost all of the way off, I remove each cap in sequence, test its fit, apply fresh engine oil and place back in position. I then slowly and methodically, in sequence across the cam and back tighten the caps down and torque to "just barely tight". The cam seem to be very tight. The cap nuts have to be pretty loose for the cam to rotate with ease. WTF? Any ideas? What could be locking the rear cams in place this much? Im thinking of leaving the cap nuts a bit loose, getting it all back together and all the timing marks lined up again, tightening the tensioner in the "tensioning" position and then rotating the engine several turns. If the cams turn ok and everything lines up well.... then I'll release the tensioner to rotate some more. Then after tightening the tensioner for the final time I will rotate again. THEN I will try to torque the cap nuts and see if the problem persists? And if its does.... I fear the heads need machining, the caps all replaced and new cams. Any ideas? BTW: Verell.... your tip on using binder clips is great for the belt change! And yes I removed them prior to trying to rotate the engine. It is supposed to be rotated clockwise... right? Am I losing my mind?!?!?!? |
