| Author | Message | ||
| Matt Lemus (Mlemus)
Intermediate Member Username: Mlemus Post Number: 2180 Registered: 8-2002 |
Time for "Threads of Flame and Shame"  | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1102 Registered: 12-2001 |
Mike, I already stopped so i wont need the thread. Thanks anyway. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 949 Registered: 11-2002 |
Hey Mike..SCREW YOU !!! I've contributed plenty freely and without posting lies or making up BS !! Where's all your help? | ||
| Mike Procopio (Pupz308)
Junior Member Username: Pupz308 Post Number: 97 Registered: 10-2002 |
Feckin A! Enough's enough, guys! Paul, JRV--very, very respecfully, you're not giving anything and you're taking away a lot from everybody on this board. For everyone's sake, I've taken initiative and created a thread where you can resume the discussion of your PERSONAL issues, entitled, "Container Thread for JRV and Paul Newman's Pissing Contest." You, and anyone else interested in following this debate, can find the thread here: http://www.ferrarichat.com/discus/messages/132929/206214.html?1045348703 All the best, Mike | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 948 Registered: 11-2002 |
>>As far as lying goes, you and a few others here know the truth about what I said and I expected you to deny it.<< paul, you are a vile and reprehesible liar! If I thought for one second you had a pot to piss in or a window to throw it out of, I would sue you for liable and slander in a heartbeat. For the life of me I can't imagine what prompts people like you to post lies about Ferrari's and other people on the internet. You are a pathetic low life scumbag. Are you being put up to this paul? are you really so patheticaly stupid as to be the mouth piece for some other liar with an agenda? It's obvious you can't provide proof of your vile, viscious lies otherwise I'm sure you would have long before now. How do I know with such certianty you'll never back up your lies with evidence paul, quite simple really, I've never been sued for 'anything' in the entire time I've been in business or in my entire carreer for that matter!!!! I think in you're case it's good luck to be brokedick pissant loser. | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1101 Registered: 12-2001 |
A thermal reactor muffler is a muffler with a chamber that is designed to increase temps to burn off HC, similar to a converter but not as affective. Its very big and heavy. | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1415 Registered: 1-2001 |
James A. -- do a search on "thermal reactor" (AND mode). The first thread has a '77 jpeg I picked up off eBay. I think it's really more a thermally insulated muffler/chamber rather than a catalytic converter (but cat converters are typically thermally insulated also for the same reason -- keeps the exh. gas temp up so the air injection process more fully completes). | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1100 Registered: 12-2001 |
Unfortunately JRV, you bring the worst out in me. If I can help someone, even one person then I get a sense of satisfaction out of it. You wont hear me relentlessly attack anyone who questions me or disproves me which is a flaw that you have shown here many times. As far as lying goes, you and a few others here know the truth about what I said and I expected you to deny it. What else would you say? You are right Paul? I doubt you would ever say something like that to anyone even on your death bed. Too much pride and no interpersonal skills. You have more ferrari knowledge than I because you have 30 years more experience in that limited exotic car field. Working on ferraris for a living isnt a big paying job(unless you are a thief) and prestige doesnt pay the bills. Given the chance to work at a ferrari dealer, I would turn it down. Im finished wasting space on this thread, feel free to talk to yourself or slam me more, I have thick skin, Ill survive. I would like to apologize to the rest of the members for the mud slinging that Ive done here. Paul. | ||
| James Angle (Jimangle)
New member Username: Jimangle Post Number: 33 Registered: 9-2002 |
I think a weak starter motor/weak battery could contribute to a low compression test as well. | ||
| James Angle (Jimangle)
New member Username: Jimangle Post Number: 32 Registered: 9-2002 |
What does the thermal reactor look like? Is it similar to a cat? It sounds like another name for a cat. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 941 Registered: 11-2002 |
>>Im not the one who lost a neglegence case regarding exotic car repairs or the lack there of, not to mention paying court costs<< Are you reffering to me paul? If you are you're a liar, and a very sick, sad, pathetic individual. I feel sorry for for a pathetic individual like you, but I feel even worse for the unfortunate people that you take money from pretending to be a knowledgable employee. Besides the fact you're nothing but a pathetic lowlife liar and a fraud, your refusal to come to terms with your own inadequacies is amazing. You thought you saw a chance to prove me wrong and how smart you are, instead you proved beyond a doubt how truly ignorant and sick you are. Until you grow up and accept personal responsibility for your own ignorance you will remain a pathetic nobody. Maybe you get away with BSing a few of your bubbas at work or at the local bar, but this is a different place where your type of crap is completely transparent and makes you look really stupid. | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1099 Registered: 12-2001 |
Im not the one who lost a neglegence case regarding exotic car repairs or the lack there of, not to mention paying court costs, LOL, I must be doing something right. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 939 Registered: 11-2002 |
Paul, here's what will help you, some sound friendly advise....go read some books or search the web and try to learn something. Not for my sake I could care less, but you are doing anyone who's car you work on a dis-service by bringing such a limited and innacurate knowledge base to the table. | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1098 Registered: 12-2001 |
Sorry JRV, I dont spend every waking hour on this site hanging on your every word but Im back now. I could have been specific on the wiped lobe by saying it wasnt completely round therefore it would still open the valve, just not fully. Hope that helps. | ||
| Frank Parker (Parkerfe)
Intermediate Member Username: Parkerfe Post Number: 1777 Registered: 9-2001 |
A compression check MUST be done with the engine at operating conditions. One done with a cold engine tells you nothing. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 129 Registered: 8-2001 |
I will have the dealer perform another test with a warm engine. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 936 Registered: 11-2002 |
>>>but the engine was cold.<< improper procedures can lead to incorrect and therefore useless test results. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 128 Registered: 8-2001 |
two more facts....the throttle was held open during the testing, but the engine was cold. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 127 Registered: 8-2001 |
Also, I just found out about 5 minutes ago that the compression was checked about 100 miles ago when the plugs were fouled and the car was running lethargic. A dealer checked the compression and it was fine. This is crazy............. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 126 Registered: 8-2001 |
Yes, Jim, the original "thermal reactor" (no cats on '77) muffler was on and it was deteriorated inside. The compression test was also done on a cold engine, and today I will ask my mechanic if the throttle was open during the test (which I am going to feel ridiculous doing since the guy has 30years experience with Ferraris - but everyone makes mistakes). Thanks again everyone for your input - I'll let you know what happens. Anthony | ||
| James Angle (Jimangle)
New member Username: Jimangle Post Number: 31 Registered: 9-2002 |
Anthony, You said that the original cat was on during the compression test? If the cat is somewhat clogged, it will effect your compression test. The engine is not breathing properly. A poorly running engine (running rich) will plug up a catalytic converter fast. That would explain the low numbers with only 6% leak down. That's the only explanation that would make sense. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 928 Registered: 11-2002 |
Steve, It's hard to say what might be wrong or if anything really is wrong. My best advice...redo the tests ..being careful to get accurate data following carefull proper procedures. If the compression really turns out to be low after a second careful test then a couple of other tests can be used to get to the bottom of 'why' and what would need to be done to correct the problem/problems. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 926 Registered: 11-2002 |
Jeff, yes a vacum gauge is another good tool and source of information. They can be used effectively on engines that share a common plenum. They don't work on a single cylinder however. | ||
| steve Lauren (Steve308gtsi)
New member Username: Steve308gtsi Post Number: 28 Registered: 5-2002 |
JRV, Do you think the valves may be out of adjustment causing low compression? I had a similar problem on a MB I worked on some years ago. Regards, Steve | ||
| jeff ryerson (Atheyg)
Junior Member Username: Atheyg Post Number: 161 Registered: 8-2002 |
Could you use a vaccuum test to see if the rings are bad also? running eng at idle rev to 2,000 then lift off throttle, guage should jump 5"hg if rings are good, if it falls from idle test readings rings are bad? Do vaccuum testers work well on Ferrari engines? | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 923 Registered: 11-2002 |
>>>Using the crank it until the cows come home technique would lead to a misdiagnosis or at the very least send you down the garden path.<<< Where'd ya go paul? Guess what I found "for you"...amazing what you can find on the web these days. Pay special attention to #8(The compression gauge will come up in puffs. Crank the engine until the needle doesn't climb anymore.) ...and BTW...a compression test is only ONE of MANY Tools and Tests needed to accurately diagois problems. But like most things, one must know how to use the tools properly, and have an understanding of what they are testing to draw inteligent conclusions. http://www.ac427.com/html/tech_comp_test.htm | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 922 Registered: 11-2002 |
Hey Paul, just for fun why don't you tell all your fans exactly how a compression test and a compression gauge work, from the engine side and gauge side . | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 920 Registered: 11-2002 |
I don't think so paul, if an intake cam doesn't open the valve then there will be no air filling the cynlinder to compress. How do Iknow this, very simple, practical first hand experience. A few years ago a customer wanted the compression checked on his Lamborghini V-12, it was low on the front 2 cylnders on each side...pulled it down, worn cam lobes on the front 2 cylinders on each side. I have the feeling some don't understand how a compression test works from both the engine and gauge side of the equation. | ||
| Bill White (Nc_newbie)
New member Username: Nc_newbie Post Number: 8 Registered: 2-2003 |
Newman, Good job coming up with a scenario where this would be the case, although it would be a RARE case in practice. Additionally, this would only be the case for one cylinder versus another not one engine vs. another since the gauge will rise faster on a larger displacement engine than on a smaller displacement engine. True a bad intake cam lobe would result in a low rise on a compression gauge for that cylinder as would any intake blockage on a given cylinder (exhaust blockage will not affect compression gauge readings). However, I do know where you are comming from because after you've used the same gauge for a while you know how many cranks you need to peak it out on a given engine and if takes more than that you probably have a weak or problem engine. Bill | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1097 Registered: 12-2001 |
Actually bill, a wiped out intake cam lobe will also cause a slow rise in compression with a perfectly good ring and valve seal. A compression test would help in this case but a leak down test would tell nothing. Using the crank it until the cows come home technique would lead to a misdiagnosis or at the very least send you down the garden path. A compression test can tell you more than just peak pressure. | ||
| TomD (Tifosi)
Advanced Member Username: Tifosi Post Number: 2729 Registered: 9-2001 |
oh boy, look forward to the reponses on that one  | ||
| Bill White (Nc_newbie)
New member Username: Nc_newbie Post Number: 7 Registered: 2-2003 |
I am not sure on the specifics but I know that you can run heavy oil (like straight 50w or 80w) in a car with "blow by" (ring or valve guide)problems to "cover up" the problem. If the pressure used during the leak down test is not sufficently high to break the surface tension between the rings and the cylinders then a problem engine with heavy oil could still read a low leak down. What was the starting pressure used for the leak down test? A low compression will still be seen on a compression gauge though. (BTW - I agree with JRV on the correct method of using a compression gauge). Compression gauges are for only telling peak pressure. Not trying to be PC but, Newman does have a point for "very leaky rings/valves". If you are loosing a significant amount of pressure through rings/valves during a compression test then the rate at which pressure builds behind the check valve in the pressure gauge is of relavence. This would only be the case though for a "very leaky piston". If this was observed, then hooking a battery booster to the battery when cranking should produce a higher reading by turning the starter faster... I've seen this on Rotax and Kawasaki jet engines after a rebuild before break-in. Sqirting oil into the piston a re-running the test will tell you whether it is valves or rings. I don't know if this piece of info applies, but I have seen many marine engines with low compression due to carbon build up still have plenty of "apparent" power. It is very difficult to feel the difference in power loss with out pushing the engine to the max or using a stop watch. Bottom line is you need to get to the bottom of this before buying the car. | ||
| Henryk (Henryk)
Member Username: Henryk Post Number: 465 Registered: 8-2001 |
JRV: I will look this weekend......it is supposed to get to a balmy 25 degrees.....it has been below zero for the last week. I will then post a thread "JRV; info on BBi" | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 125 Registered: 8-2001 |
Thanks so far everyone....did not mean to start any arguments! I'll ask my mechanic if he had the throttle open when he did the compression test - although it will surprise me big time if he screwed up a compression test...... Anthony | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 916 Registered: 11-2002 |
Henryk yes...I forgot to abswer on the other thread. The stock BB headers have access holes, so does the TR...for doing a cylinder by cyliner check when up against difficult problems. Don't need a photo just a description of the difference between them and the ones on your TR. | ||
| Henryk (Henryk)
Member Username: Henryk Post Number: 463 Registered: 8-2001 |
JRV: Thanks. Do you still want pictures of the BBi Tubi headers? | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 915 Registered: 11-2002 |
compression is determined by compression ratio...a comp ratio between 8 - 9.5 produces compression of approx. 145-165psi....maximimum satifactory difference highest to lowest is approx. 15psi or roughly 10% | ||
| Henryk (Henryk)
Member Username: Henryk Post Number: 461 Registered: 8-2001 |
Thanks JRV. Can you tell me what the compression should be on an 88TR? | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1096 Registered: 12-2001 |
JRV Im glad to see you still know everything there is to know and making friends left right and center. Henryk, the engine will still be warm enough to perform the test even if it takes half a day and a few beers. I would refer to the manual for the specs or the all knowing master with the infinite wisdom they call JRV might be willing to dispense some free of charge. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 914 Registered: 11-2002 |
Henryk, it's nice to have it warm yes, it won't cool down enogh to skew the test. Warm is nice to remove some of the varibles that can skew the information the test is designed to provide ie: the maximum pressure the cylinder can create..,the engine must be cranked until the maximum a cylinder has the ability to pump into the gauge is reached...the number is that cylinders compression reading.. I find it surprising that individuals are devising their own methods and theories in spite of the existence of instructions. The haven't read the book, aren't knowledable enough to write the book yet refuse to open the book and opt to develop "their personal theory of relativity".... | ||
| Henryk (Henryk)
Member Username: Henryk Post Number: 460 Registered: 8-2001 |
I have been told that the engine should be warm during a compression test. I want to do this on my TR this Spring. However, when the car is warmed up, it takes time to remove the 12 plugs, and then to check each cylinder. Won't the engine cool down, causing the compression, of the lattermost cylinders to be different from that of the first? BTW.....What should the compression be on an 88TR? | ||
| Henryk (Henryk)
Member Username: Henryk Post Number: 459 Registered: 8-2001 |
I have been told that the engine should be warm during a compression test. I want to do this on my TR this Spring. However, when the car is warmed up, it takes time to remove the 12 plugs, and then to check each cylinder. Won't the engine cool down, causing the compression, of the lattermost cylinders to be different from that of the first? | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 913 Registered: 11-2002 |
>>>When doing a compression test, not counting the strokes is asking for a misdiagnosis.<<< Completely and totally false...just as incorrect as you claiming Ferrari's have forged cranks. When the maximim compression a cylinder can achieve is reached the needle stops moving higher, not until. A cylinder cannot over pump a compression gauge. Paul it's very sad your ego gets in the way of your learning. You should spend some time learning how a tool works before trying to instruct others. Ken, believe what you want I don't care. But if you can inteligently argue how it's plausable get too it. Write out your theory in detail...love to read all about it. | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1095 Registered: 12-2001 |
When doing a compression test, not counting the strokes is asking for a misdiagnosis. Use the same number of "pumps" per cylinder to take out one more variable. Also, the first compression stroke should yeild the majority of your final reading. If its low and you crank until you are blue in the face to get the reading and the next cylinder gets there on 2 pumps, there is a problem even if the readings seem "ok" so I have to disagree on the comment of not counting strokes. | ||
| Ken (Allyn)
Member Username: Allyn Post Number: 720 Registered: 10-2001 |
JRV, am I correct that you say lots of gas in the cylinders from a flooding situation will not affect compression tests? Are you saying you've never run in to that, or you know for a fact it's just can't happen? I'm confused; I feel like my 31 year old engine has a 50/50 chance that the normal compression reading was the wrong one. Of course, since I burn no oil and have great power, and don't smoke, I figure it's got a lot of life left. But still.... | ||
| Bob Campen (Bob308gts)
Member Username: Bob308gts Post Number: 410 Registered: 9-2001 |
A good example of overlooking things, have a buddy with a Harley running good but a big problem with crankcase venting ( to much ). Took it to what were supposed to be the top guys in the area, both did some checks including a compression check and all checked out but the bike did the same thing, I asked if either had done a leakdown test neither had. At the end of the riding season he took it to a third guy to be checked out, first thing this guy checked was leakdown, came out at 45% ( compression rings mounted upside down ) sure shows don't assume anything is good without checking. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 912 Registered: 11-2002 |
To do a Proper & Correct compression test the throttle must be open...there is absolutely no need to count revolutions or strokes because you must crank until compression reading on gauge stops rising...when the compression gauge reading maxes out and no longer continues to climb...that's the compression on that cylinder. Paul, FYI..I've seen most things more than once...but I haven't seen bad readings on good engines or vice versa. When you test properly (not shoddily) with tools in good working order, following the correct and proper procedures ...one SHOULD obtain Quality Test Results..good or bad....tools and tests are not subjective...they simply define condition...When Done Correctly! When the results of proper quality testing are recorded and they don't make sense further investigation is in order. A quality "test" is defined as "Repeatible, Verifiable Results"...if the test results cannot be repeated and verified the data is GEGO. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 124 Registered: 8-2001 |
should the throttle be open or shut during a compression test? | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1094 Registered: 12-2001 |
JRV, do me a favour and save your typing finger for nostril duties, I dont need your explanation. | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1093 Registered: 12-2001 |
Anthony, without knowing how many compression strokes the mechanic used for the test and if the throttles were open or not its hard to answer why it reads low. I would suspect that if the leakdown is within spec, then a plugged exhaust will cause the low comp reading. Closed throttles will cause it to be low and a test with 3-4 compression strokes will also do this. It doesnt make sense. Maybe the guys gauge should be checked for calibration, who knows? Another compression test is in order. JRV, you seemed to not be able to comprehend the possibility of fuel washing a cylinder down being the cause of low compression. Im just enlightening you. Just because I havent done a study on the hows and whys, doesnt mean it isnt so. It happens and I find it difficult to believe that in your career spanning longer than my life that you havent seen this occur once. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 911 Registered: 11-2002 |
Paul, you're not comparing like situations, but I know how you love to argue so I'll ablige....nothing defies explanation in an engine, if one truly understands how and why they work...there are only answers that we haven't taken the time to find, understand and explain...that should be easy for you to grasp...due to time constraints I'll finish 'explaining things' later on. Ken, those numbers sound right on the money for a healthy QV engine. It even sounds like whoever took the readings knew how to check compression and used good tools . | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 123 Registered: 8-2001 |
Thanks, Paul. But I am still confused. Why would a leakdown test be acceptable in this case (6%)since you are still relying on the sealing properties of the rings, valves, while a compression test fails? | ||
| Ken Ross (Kdross)
Junior Member Username: Kdross Post Number: 238 Registered: 2-2002 |
JRV - what is an acceptable number on a 308QV engine for compression? A friend of mine got numbers between 151-155 on all 8 cylinders. Are these good numbers? Ken | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1092 Registered: 12-2001 |
Anthony, prior to rebuilding my engine, it was running on 7 due to an open in the #3 plug wire. A compression test reveiled 90psi before that cylinder had a good wire on it. After that was fixed, of course it ran better but the compression came up to 135 making no other changes. I suspect the cylinder was being washed with fuel causing this low reading. | ||
| Paul Newman (Newman)
Intermediate Member Username: Newman Post Number: 1091 Registered: 12-2001 |
Hi JRV, long time no argue. I have seen this before after an engine is apart and reassembled during a repair. We regularly use a cleaner to remove debris from a cylinder after a major top end repair and if you dont coat the cylinder with a shot of oil, it wont have compression and wont start. I know, its happened to me. Flooding would have the same effect. You can actually hear the engine spin effortlessly like the valves are all hung open. Why? the rings dont seal I guess. Another factor during the comp test is how many compression strokes were used to reach this number. I like to use 5-8 myself. With the throttles closed, I had a reading of 110psi, open I got 170psi. Both were performed on my engine after it was run for the first time since a rebuild. | ||
| Ken (Allyn)
Member Username: Allyn Post Number: 716 Registered: 10-2001 |
JRV, I personally have no idea. My mechanic said not to worry about it due to the fact I flooded it. After changing the oil and testing the compression somewhat later, all was well. Perhaps he just did the test poorly the first time? | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 122 Registered: 8-2001 |
JRV, Thanks, I understand. I also asked this same question at the time. Essentially a leakdown test and a compression test rely on the valves seating properly right? So, I asked how the one could be good and the other test poor. If a leakdown test is essentially using a closed-system (the cylinder with closed valves), how could it turn out okay while a compression test fails? I was present and viewed the gauge. I do not know what is going on. Ken - thanks, the car was running too rich, all the plugs were fouled, some not firing. Maybe there was raw fuel in the cylinders which explains this? Anthony | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 910 Registered: 11-2002 |
>> Seems the gas in the cylindars can give a false low reading.<< Oh really???? How does the gas stay in the cylinders when cranking over the engine with the plugs out? and supposing it magicaly can....what effect could the gas have on the engines ability to breathe in air, compress it and push it out? | ||
| Ken (Allyn)
Member Username: Allyn Post Number: 714 Registered: 10-2001 |
I once flooded my engine trying to start it not realizing my distributor was shorting. While it was in the shop, I had them do a compression chack and it was really low. I felt this was wrong because the engine ran strong and smoke free. Seems the gas in the cylindars can give a false low reading. Months later I had it done again and all was normal. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 909 Registered: 11-2002 |
Anthony, I'm just asking the question to resolve the inigma of contradictions. Normal as stated by all is 135-165....used engine..4%-12%... When I open a hood I have certian normal numbers I hope to see...or if I have a mechanic do the test I expect he will show me certian numbers when done....now if someone brings me numbers that don't compute...then what I really have is NO answers and only more questions that need explanation. When everything is real, then it can be explained in more or less simple terms... I'm only asking for a plausible explanation for implausible numbers, that's all. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 121 Registered: 8-2001 |
JVR, I am not a mechanic. I am only going by what experts are telling me (my mechanic and you). So, now I am confused. The vehicle did have it's crappy original thermal reactor exhaust on it when this was done. The exhaust has just been replaced with a new one. Could this have made a difference? | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 907 Registered: 11-2002 |
>>> He said he had seen this before. << Please share the circumstances where it's possible to get 6% and 90-120psi on a perfectly healthy Ferrari engine with no exhaust restriction and proper cam timing...I'd like to add that info to my personal knowledge base..in case I ever see it... | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 120 Registered: 8-2001 |
Thanks, guys. I just spoke with the mechanic. The cam timing was fine. He said he had seen this before. The ONLY reason I am considering this car knowing this is because a great abundance of good things were done to it recently by another well-known mechanic. The car basically was totally gone through and during the pre-purchase, my mechanic and I verified these things were actually done. Somewhere along the line someone fouled the plugs, it was then serviced at a Ferrari dealership who (like most dealerships) do not know what to do with a car without a computer. They tuned it improperly thus causing the plugs to foul again. My mechanic said the engine sounds fantastic and has great power. We will see............ Thank you, Anthony | ||
| Hans E. Hansen (4re_gt4)
Member Username: 4re_gt4 Post Number: 859 Registered: 4-2002 |
Consistent low compression can certainly indicate a problem elsewhere, such as cam timing as JRV suggested. May not be the valves/rings at all. Did the mechanic open the throttle when cranking? | ||
| Mike Procopio (Pupz308)
Junior Member Username: Pupz308 Post Number: 92 Registered: 10-2002 |
Altitude will play a role here in the compression, as it does with anything pressure and/or oxygen related. My 308 gets 133psi per cylinder, +/- 4 psi variance. I haven't done a leakdown. This is at 5000ft altitude. The conversion factor for 5000ft (from memory) is .8617, so (133/.8617) is 154psi at sea level, which is right in the range 308 2-valve owners have reported as healthy compression (150 to 160). I cannot speculate about the cause of your low compression, but I share your concern. I believe it is pretty much held that compression test and leakdown tests are strong indicators of an engine's health. An engine's health can also suggest the general car's condition, based on previous owners' driving habits. I know that you're close to getting this car, but I would take a step back and perhaps reconsider. There are 308s out there in with healthy compression, which in time you will find... Then again, depending on mileage, you might want to take the cost of a valve job off the car, and just do it now. New 308 owners usually end up spending a fair amount of money getting things sorted after they buy the car. Just my $.02. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 904 Registered: 11-2002 |
If the leakage was 6% yet the compression is 90-120psi I find it very very hard to believe it's carbon on the valve. I find those readings grouped together pretty hard to believe also. 6% leakage..the comp. would likely be 135-155 range at 90-120psi the leakage would likely be 25%-40% only one way I can think of off the top of my head that one could have actual numbers of 6% and 100+-psi would be if the cam timing was significantly off. Definately a case where the tests need to be run again by a different tester (mechanic) using different tools. | ||
| Anthony A. (Yank05)
Junior Member Username: Yank05 Post Number: 119 Registered: 8-2001 |
....to make a long story short.......... had a pre-purchase done recently on a carb. 308. Everthing checked out well except one major thing - compression. The compression was consistent, but pathetic in every cylinder (between 90 and 120). However, the leakdown test was superb (less than 6% in every cylinder). The mechanic (who has 30years experience and who I trust) pretty much thinks the low compression is due to extreme carbon deposits on the valves (the car was not running well for some time and the plugs were heavily sooted). This mechanic just tuned the car for the seller and said it is running well now. He feels with some driving, the carbon will burn off, thus raising the compression again. He feels that is it is very good car overall. Should I take this chance in buying the car, knowing that worst case can be a $4K valve job. Your thoughts please! Thank You, Anthony |