| Author |
Message |
1975GT4Don (1975gt4don)
New member
Username: 1975gt4don
Post Number: 25
Registered: 1-2002
| | Posted on Friday, March 08, 2002 - 1:45 pm: | |
Jeff/and the others, I guess we are fortunate enough to have such a wonderful site such as this, so that others can save $$$$ by avoiding costly mistakes. I love helping others because I always get it ten-fold down the road.
OK, so how to avoid the mistake I made. Easy, to check proper clutch freeplay, is to go and sit inside the car, push down on the clutch pedal. The clutch pedal should travel approximately one-half of an inch before you feel the clutch pedal start to engage the pressure plate. If you do not feel this freeplay, you should rectify the problem asap or else. The adjustments on the 2 valve 308 are very tricky, since the clutch is not hydraulic, but mechanical, and I recommend having a Ferrari mechanic do it. It won't cost much, maybe 30 minutes of labor tops. It took me 2 hours to do it myself and with the rapid wear of the 308 clutches, periodic checking of the freeplay becomes a larger part of maintenance. Refer to your shop AND parts manual on the 308 for the clutch linkage layout. There are at least two adjustment points on the linkage that are very sensitive in setting clutch freeplay. It is basically trial and error. If you are turning the adjustment nut the wrong way, you will know to go the opposite way on the next attempt. it will probably take you around 2 hours to get the hang of it.
**********more importantly*******************
To the prospective buyer of a 308. Since a 308 engine CAN function properly for a while WITHOUT one thrust washer/bearing missing and laying on the oil pan somewhere, how can one diagnose if this problem exists without taking the oil pan out?
Easier than you think :-) Although you will need two people to visualize this. First, one person must get inside of the car to push down on the clutch pedal and the 2nd person must sit and watch thru the engine compartment with the hood up, to watch the crankshaft move.
So here it goes: get a mallet or soft faced hammer. Ask the other person to go in and push down the clutch pedal to the floor. The other person will tap on the crankshaft pulley to insure that the crank is at the point closest to the clutch assembly. Once this is done, ask the other person inside of the car to let their foot off the clutch pedal completely. IF the thrust washer(s)/bearing(s) has fallen off of the crank, the additional crankshaft endplay will become apparent due to the crankshaft shifting about a 1/4 of a inch or so towards the right hand side (away from the clutch housing). If this happens, engine removal time! Remember that the crank has two thrust washers. On my instance, only one fell out and was damaged. If both thrust washers fell out, the complete engine would be a coffee table. The connecting rods would bend due to the excessive crankshaft travel moving back and forth everytime the clutch is engaged, then disengaged, not to mention that the oil holes(galley's) would become misaligned thereby causing immediate oil lubrication problems and rod bending. Spinning a main bearing(s) is unavoidable at this point as well. As all of us know here, Ferrari engine blocks are not that cheap. |
Jeff 77 GTB (Jbk)
Junior Member
Username: Jbk
Post Number: 59
Registered: 4-2001
| | Posted on Friday, March 08, 2002 - 11:14 am: | |
GT4Don, thanks for the heads-up. So in addition to wearing out the clutch, not having it adjusted right risks major damage. Another case where lack of knowledge can be dangerous to the DIYer. I'm going to be careful to keep mine adjusted right. |
David Jones (Dave)
Junior Member
Username: Dave
Post Number: 66
Registered: 4-2001
| | Posted on Friday, March 08, 2002 - 8:39 am: | |
I too am with Ric on this one.
Gapless rings are great....
Re-using rings is out...
And I hate to be this way But,
If a new set of rings is beyond your budget,
you might consider a less expensive play toy. |
Richelson (Richelson)
Member
Username: Richelson
Post Number: 529
Registered: 12-2001
| | Posted on Friday, March 08, 2002 - 6:54 am: | |
How can you tell if you have adequate free play in your clutch? I have never heard about this. |
Robert Davis (H2oquick)
Junior Member
Username: H2oquick
Post Number: 120
Registered: 8-2001
| | Posted on Thursday, March 07, 2002 - 8:22 pm: | |
I am with Ric...I have used the total seal rings in racing applications....they are great and probably better than the factory or any other aftermarket rings. Do not reuse rings if you are doing an engine rebuild (IMHO). Especialy if your are doing any cylinder honing or replacement, there is a chance they will never seat properly...end result HIGH oil consumption, smoking...you know all the normal Ferrari things. |
Ric Rainbolt (Ricrain)
New member
Username: Ricrain
Post Number: 20
Registered: 2-2002
| | Posted on Thursday, March 07, 2002 - 5:36 pm: | |
I have used and strongly recommend Total Seal rings. In addition to having the "gapless" 2nd ring (less leakdown = more power), they have fitments already available for 308's. You can get them from Norwood's. Call 972-831-8111 and ask for James.
I've seen the Deeves sets and the oil scraper is not adequate for higher RPM applications, IMHO. |
1975GT4Don (1975gt4don)
New member
Username: 1975gt4don
Post Number: 24
Registered: 1-2002
| | Posted on Thursday, March 07, 2002 - 4:20 pm: | |
Michael, nope. It is presently a dark blue with white leather interior, it has a wing also. 24K miles on the Countach, 50 state car with BAR sticker, carburated. A shame. The paint is not original and it looks to be painted over the original light blue color. Bobileff is having a hard time finding the next oversize on the main bearings and other parts. I am glad I don't own one. They used to be my dream car. |
Michael Fennell (Mfennell70)
New member
Username: Mfennell70
Post Number: 32
Registered: 7-2001
| | Posted on Thursday, March 07, 2002 - 4:10 pm: | |
Don,
Is that a white/white Countach without a wing? If so, it led a tough life.
|
1975GT4Don (1975gt4don)
New member
Username: 1975gt4don
Post Number: 23
Registered: 1-2002
| | Posted on Thursday, March 07, 2002 - 3:40 pm: | |
Frank, I was afraid you were going to ask that! :-) The engine suffered from something that I do not think has been talked about yet on this forum, not to my knowledge. The reason why I had to rebuild the engine, was that the thrust washer/bearing on the crankshaft that determines the endplay on the crankshaft, dropped into my oil pan one infamous day. The reason this did this? Not having the proper endplay on the clutch! Expensive lesson! What happens, is that the pressure plate exerts axial constant force upon the crankshaft nonstop, pushing the crankshaft up against the block via the thrust washer(or bearing as some call it). The heat generated by this constant friction was inevitable---the thrust washer dug into the block slightly then spun around a few times splitting apart in the process. The block had to be removed, remachined and welded. That is the only part of the rebuild I did not do myself. As I found out to my luck, is that the oil gally's on the main bearings and crankshaft allow for oil passage even without the thrust washer!!! Do you know what kind of damage to my engine would have occured if this happened? I don't want to talk about that. The main bearings were barely worn as well as the piston rings, cylinder walls, cams, etc. The machinist told me I had at least another 100K to go on the engine before a rebuild was necessary. I change my oil every 2500 miles. Overkill, but good nonetheless and can only help an engine. There is a lamb countach sitting in pieces as I write this in Bobileff Motor Car in San Diego, an 82. This guy bought it off of the internet against Bobileffs advice after he inspected the car. He only paid 50K for the lambo. However, 1,000 miles later, the engine is sitting in pieces on Bobileff's workbench awaiting new main bearings, reground crank, new cams, machine work on the block, etc. The guy is in $30K so far, without installing the engine back into his Countach. The reason for this failure? INSUFFICIENT FREEPLAY IN CLUTCH. Expensive lesson to be learned. |
Frank Parker (Parkerfe)
Member
Username: Parkerfe
Post Number: 676
Registered: 9-2001
| | Posted on Thursday, March 07, 2002 - 3:01 pm: | |
Don, if your car only had 50k miles and the bores were not worn, why did you rebuild the engine ? |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2113
Registered: 2-2001
| | Posted on Thursday, March 07, 2002 - 2:24 pm: | |
Mitchell, I meant DO NOT use the old rings. Do as Steve and Don have suggested. Remove the wear ring at the top of the cylinder and Glaze Bust, hone,going up and down to create a crosshatch pattern on the cylinder wall. Install new rings putting the pistons back in their orig. cylinders. It's too much work to screw it up for the price difference. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 70
Registered: 11-2001
| | Posted on Thursday, March 07, 2002 - 12:45 pm: | |
Thanks
I will use the Deves rings and rehone the liners.
Mitchell |
1975GT4Don (1975gt4don)
New member
Username: 1975gt4don
Post Number: 21
Registered: 1-2002
| | Posted on Thursday, March 07, 2002 - 12:37 pm: | |
mitchell, do not reuse your old rings. When I rebuilt my 75 with only 50K on the clock, my cylinder bores barely showed any wear at all, but the bores were honed with new rings installed, otherwise, your old rings would never reseat properly and you would have a large compression loss with oil consumption problems. If you don't have the money to buy new rings now, wait until you do. I know it sucks to have the car sit, but it is better to have the car sit, than to have to pull the engine again. Honing breaks the glaze of the cylinder lining and introduces the crosshatching marks into each cylinder bore that facilitates oil lubrication---the oil will use the crosshatching marks to aid in lubricating the engine. |
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 576
Registered: 1-2001
| | Posted on Thursday, March 07, 2002 - 12:19 pm: | |
Mitchell's '75 has cast iron liners so conventional "stone" honing is OK -- but isn't ridge-reaming also needed? |
Mark C. Gordon (Markg)
Junior Member
Username: Markg
Post Number: 130
Registered: 2-2001
| | Posted on Thursday, March 07, 2002 - 12:11 pm: | |
I used Deves rings exclusively in all past rebuilds I have done (Datsun, Porsche); they are great rings, but you will neeed to have cylinders re-honed to break glaze to get proper seat (if Ferrari bores can be honed - some aluminum engine bores can't; other chat board members will know...).
Make sure pistons go back into same bores as they came out of. I feel re-using rings in a rebuild is kind of risky if it can be avoided. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 69
Registered: 11-2001
| | Posted on Thursday, March 07, 2002 - 11:07 am: | |
I called Deves and asked for pricing. THey quoted $30 per cylinder. So, it is affordable, but still expensive. I will try what you said to see if there is a cheaper way. |
Edward Gault (Irfgt)
Member
Username: Irfgt
Post Number: 892
Registered: 2-2001
| | Posted on Thursday, March 07, 2002 - 10:51 am: | |
You can take your old rings to any knowledgeable independent parts house and let them measure the rings and along with the bore size you can get a generic set of rings for a very economical price. I would do this before I reused th old rings. I do not recommend reusing old rings but I have seen it done with favorable results in certain applications. In fact there is a current problem with certain 1999-2001 Corvettes and the factory says to replace only the middle ring and reuse the others to correct the problem and if you use the whole set of rings that you take the center ring from you could make the problem worse. Damndest thing I have ever heard but true. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 68
Registered: 11-2001
| | Posted on Thursday, March 07, 2002 - 10:06 am: | |
Magoo
I am re-using the liners as they are. So your argument of the rings now are seated mean they should be reused. No? |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2112
Registered: 2-2001
| | Posted on Thursday, March 07, 2002 - 9:47 am: | |
The rings are now matched to the bore and seated. I would never use old rings over again in any overhaul on any engine. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 67
Registered: 11-2001
| | Posted on Thursday, March 07, 2002 - 9:14 am: | |
What is the board's opinion on the topic of re-using piston rings if they are still in specs. A set of new piston rings for my GT4 would run ... almost $1000 and that is ... beyond my budget. Deeves will probably sell a ring set for one cylinder so I can just replace a few rings if they are out of specs. |