These are the results I just rec'd for the compression test: Motor cold open throttle. Do these #'s sound acceptable. 1. 242 2. 227 3. 210 4. 222 5. 240 6. 225 7. 190 8. 225
strange #'s; ideally you want them all closer together. I don't like the 50 psi spread...and a 240 max seems too high. I've never actually done the test myself so I'll let the pros here chime in as to how that could even be possible.
hmm 7 is really off from the others, check the exhaust valve on that one. I would try and something more average across the board.
Thanks Bruce I actually searche and read that last night. I guess I need to negotiate the car down to cover the possible repair job if things get worse..............or walk away.
cylinder #7 is was 19% right? Not perfect but we all expect this from 355's that haven't had the valves done. If everything else checks out and the car runs good negotiate the price down and do the valves on the next major. It is not that big of a deal. Too many people have OCD and want perfect numbers for a car that they will hardly drive anyway. Buy it at the right price, drive it and enjoy!!
This test is a little more tricky. All the race engines I've done have 0% leak down.....even with dyno time and one sprint race(2hrs). For race engines I allow no more than 2% per cylinder. It is important to watch how much pressure you use for the test,i.e. to much pressure can cause a valve that is slightly off its' seat to actually seal. The test is not just a visual observation focused on the guage.....you should be listening to the intake and exhaust systems, and opening the oil tank and inspecting. The important thing if you have a leak, is WHERE it is occuring. For street cars with some mileage I would like to see under 8%, and on a Ferrari somewhere less than 6%.....all cylinders within 2%. BTW,I would want the 6% leaking by the rings as opposed to the intake valves....lol
Hi Jeff, Thats correct 19% on #7 Im negotiating to have the repair done.................best case scenario seller flips the bill. I may go for the money deduction because its probably a good year away from having a major and just drive the car til then, shop says it runs great! I would actually feel better with the valve guides done and then do the major when I have the car in hand at my local shop. I know its kinda counterproductive but it makes me feel more comfortable about things.
Well looks like we are pulling the heads and re-doing the cvalve guides etc etc. the seller has agreed to split the repairs 50/50 So I still feel its a win for me............I'll have a low mileage 1 owner 355 with documented valve guide repairs. Obviously the belts will be done at the sam time so I'll basically have a fresh engine........ Anything else we should do while we are in the process?
