Hello, I was hoping someone could help me. I have recently bought a low(ish) mileage (17,000kms) 348 GTB. It had a minor rear ender that damaged the rear guard, grill and oil tank. Because the oil tank was damaged I could not run the car but the guy selling (who I know personally) assured me that it was running fine did not stop hard in the accident and was just switched off. So I took the motor out sent the car to the panel shop and took the opportunity have a local Ferrari tech do the cam belt and changed filters etc. Got it all back together now and no:2 is dead. Did a compression test (all plugs removed, cold engine, 10 cranks per cylinder, throttle open.... everybody does them differently) 1: 160 2: 5 3: 156 4: 164 5: 198 6: 200 7: 197 8: 200 Lbs No:2 is chuffing out the exhaust. Because the right hand bank is consistently lower that the left I assume that the timing is out or the right bank has been run lean and one valve has died and the others are on the way? My question is firstly if anyone could tell me if the 348 has Sodium Valves? Also I have been told by 2 people that if I sort the timing out, No:2 may come back??? I find this hard to believe my experience is once a valve or seat is gone its gone but if someone could correct me I would be grateful. I also plan on removing the air injection system is there any problems with that? Also the Cats may disppear and was wondering if that confuses the temp sensors? Thanks For your help...
Sounds like all the classic symptoms of a burnt exh valve. If you can get a boroscope in there, you'll probably see a "V" burnt out of the exh valve(s) edge. Air injection removal should be Ok, but I'll defer to others for the 348. Ditto, the cats. The temp sensors just tell the temp of the cats. No cats, no temp, no warning lt's. But hold off 'till you get more input.
Thanks for your help and guesses on reason for the left bank being higher that the right do you think timing or other valves bad?
Checking the timing is (relatively) easy. A search will easily bring up the procedure. But it does kind of look like the other valves may be fried. IMHO, if you do one head, also do the other. Please let us know what happened when you get it apart.
Welcome to FerrariChat Ian and congrats on the 'new' 348!! When you put the engine back in the car, did the car start alright and run strong??
Outside observers like myself can only guess at your problem, but personally, I would say that it is just about impossible for your 348 to have a burned valve at 17,000km - it just doesn't make sense. If the seller told you that the engine was running fine before the accident, then it sure seems likely that the problem stems from the recent engine work. If you're really lucky, you may have an exhaust valve that is adjusted too tight and a cam belt that is off by a tooth or two on the 1/4 bank. No real damage. But it's quite possible that you have a bent exhaust valve on #2, caused by incorrect belt timing. What the heck, pull the cam covers and see if you can locate the problem. I'd recommend that you do NOT start the engine again, don't even crank it over on the starter until you have a better idea of what's wrong. If it DOES have a bent valve, don't take the risk of bending more of them. It would be nice if the mechanic had checked and saved the spark plugs from before the service. If it had a burned exhaust valve before the service, I would think that the plug would look different than the other 7. Good luck with this!
Before the engine was started for the first time it was obvious from the way it turned over that at least one cylinder was out even before it fired. It did start quite easily, turned over for about 10 turns stopped, turned over another 2 or 3 times and fired straight up, no mechanical noise at all, I have had cars before with shim and bucket cams that had sat for a while and had stuck buckets but they usually make a rattle in the cam box, there was no sign of that. Good point about the plugs I still have the old ones in the garage, will dig them out and have a look if there is any difference in them. I will also pull the cam covers off and have a look. I have just been going through some of the old invoice that came with the car and doing some detective work based on what I know now. At 13,655 Kms (2003) had cam belt done and at 14,555 Kms (2004) had 15,000 kms service which I assume included tuning. Then it was towed in with overheating at 15,564 kms (2004) had radiator cap and 1 hose replaced then the records stop and the car changes hand twice and puts on less than 2000kms in the next 4 years .. curious .. I think I will need to get the engine out and pull the heads off, once its fixed I will get it on a dyno to make sure I dont have one bank running leaner than the other. The person I bought it off had only had it a matter of weeks and was used to large capacity slow revving (Neanderthal) V8s so may not have noticed the miss??? But by the look of it probably the previous owners may have ..?
With compression readings like you reported, I'm pretty sure that the owner would "notice" the miss. To me, this still sounds like the mechanic messed it up. I still don't think you could get a BURNED valve in 17,000 km, unless the valves were horribly misadjusted from the factory. If the problem was due to engine overheating, it would affect both banks. If it was running really lean on the 1/4 bank, you'd get a warning light. The rev limiter should prevent damage from over-revving. I can't really understand why the car would have a belt service in 2003, then a 15K service less than one year and 1K later, unless the 15K service was just fluid changes. There is no "tuning" to perform. Was there any notice on the invoice for either of these services that something was amiss?
If the valve lash is ok, you can do all the timing checks, compression checks and leakdown checks in the world. The compression won't be coming back. Whether it has a burnt valve or a bent valve is water under the bridge, the head has to come off. You can speculate all you want about HOW it happened, but it still has to be fixed. Once the head is removed, THEN you can determine how it happened (burnt or bent, and maybe the cause). Just make sure to replace everything that is marginal now, (pulley fences, tensioner bearings, check valve guides for wear, etc.) so you won't be revisting this problem later on down the road.
Im with Jeff on this one, I think the Mechanic messed that cam timing up and you have a bent valve mate. Pull the heads off and inspect. You will soon see if it is a burnt valve, or poor workmanship. Sorry to hear of this bad experience Ian. Is this your first Ferrari mate?
try doing a cyl leak-down test,on #2 try backing off the valve adj,and see if it still leaks out the exhaust
Make sure the valve closes ... sometimes the valve adjustments tighten the valves / as in leaves them open .... open valve no compression.
The 348 has sodium valves. us$130ea. Many "cat" cars do since backpressure is used as a smog burner, thus keeping the exh valves very hot. Your compression number indicates more than just a burnt valve. Big open hole somewhere, hopefully but probably not misadjuted valves. G'luck mate, let us know what the news is. Maybe my spare motor has some parts that'll help.
Okay, I will just say it like I see it and let the chips fall where they may. I would be so GD fricken mad right now I would be throwing things. The time to fix that engine was when it was OUT of the car, not after the cars all fricken put back together. Even if it turns out to be a burned valve, it should have been discovered while he was wrenching on it, not after the fact.
"I could not run the car but the guy selling (who I know personally) assured me that it was running fine" I'd like a $100 bill for every time I've heard this. I'd be having a discussion with this individual! If you were given the indication by the seller that it was running fine, and that the sheet metal damage was supeficial; I imagine you in good faith gave the engine to it to the engine mechanic for what you felt were normal preventative measures, and not looking for any specific faults. Have the cam timing checked as it is taken apart to verify it is correct. If it is not then you have a reason to raise your voice. If the cam timing is correct, someone sold you a car in need of repair, regardless of the cause or severety. A valve certainly CAN burn in that mileage prior to your purchase, it could be caused by a sticking valve (guide) or bucket lifter, or an incorrectly adjusted valve. With all of the lower compression cylinders confined to one bank I would suspect an incorrectly timed cam, but (at this point) this would not account for the burned valve, it happend before. As stated fix it right, do it once. Rick
Thank all for your replies, I have managed to rescue 7 of the 8 plugs from the bin and can not find anything untoward. 2 appear slightly rich but none are burnt, have metal splatter, pitting or anything that would imediatly raise suspicions, as I said I have 7 of the 8 but I am sure if the 8th one looked bad when it was taken out someone would have said something. I have not taken off the cam boxes yet, but will try and get some time on the weekend. Have checked with the guy who changed the belt and says he did not degree the cams, just marked positions the old belt and put the new one back & checked all the timing marks. He did say that when he pulled the covers off he noticed that some one had been in there before??? Had to take the car down for registration, so just took it easy, on the way noticed a noise in the clutch, slight knock as the clutch took up in gear, so I guess that will be coming apart as well in the new year. Records show that the clutch was changed aprox 2000kms ago buy the same company that did the belt before so it will definetly need checking.
Sorry to agree, sounds like a burnt or bent valve. When engine is out I would strongly recommend inspecting exhaust headers and air injection pipes for any cracks. If it is a burnt valve, it may be explained by too cold of air entering exhaust port with the engine shut down hot. Also when engine is out and heads off, inspect the cylinder walls for any compremise in the nicosyl surface. Valve timing doesn't seem probable due to apparent single cylinder performance . Valve timing can be checked visually at the cam flanges thru the belt covers. Good luck
"....valve timing can be checked visually at the cam flanges through the belt covers...." We've been through this one before. The index marks on the cam GEARS may be correct after the initial assembly of the engine, but they will not necessarily be correct after the belt has been replaced. Since this engine has had the belt replaced (once? twice?) I definitely would not trust those marks to verify correct valve timing. The notches on the cams themselves and on the cam bearing caps will verify at least close valve timing, as they remain constant. But if the cams were "degreed" at the first belt change, then the relationship between the cams and the gears has been altered, and the inspection slots in the belt covers will no longer line up with the marks on the gears. By the way, Ian, did you get any kind of an itemized invoice from the person who did the last engine-out service? Do you know if the belt was actually replaced, not just "checked"? Have the tensioners been replaced? The water pump? What did he actually claim to have done?
The engine has had the belt changed twice, first in 2003 and recently in March this year. The car was imported to Australia from Hong Kong and the original work was done there. With regard to who it was I would not like to bad mouth anyone without proof of negligence. With the second cam belt change I supplied the belt and because of the low Kms since the last belt change I asked the local guy to check the tensioners, seals and guides etc and let me know. He reported that other than seeing that someone had been there in the past all looked tight, no oil leaks, tensioners appeared new (possibly done at last service), only a small crack on one of the bolt holes on the belt cover that was fixed with a bit of glue, but other than that fine. I had a look and took this pic after the belt was replaced and prior to buttoning up, was a bit dusty in there but cleaned this off. Water pump was not remover but had no sign of leaks etc. As you see everything is marked and he assures me that he assembled it checking the timing directly onto the cams not using the pulley wheels. Interesting what was said about the exhaust headers, when the engine was out after accident I noticed that one of the pipes was broken so I replaced the header. I put this down to damage in the accident but may have been the cause (or a symptom of) a burnt valve. Any way wont get much time on the car between now January so I would like to wish you all a merry Christmas and a happy new year. Image Unavailable, Please Login
If the header was broken and caused the possible burnt valve, I highly recommend checking the cylinder liners for wear when the heads come back off!! I have three 355 engines in the shop right now that all have bad liners, caused by header problems.
Pulled the cam box off the RH Bank, valves have not closed up so out come the motor, will post pics once it is done. Will check bores once the heads are off. Thanks again for all your posts.
