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crank case vent line
Posted: Sat Mar 29, 2008 1:27 pm
by anthony manzella
is it posilble that the hose fitting that joins the steel line which runs along the frame to the up rite tube to the carb , rott out [shead] the rubber jacket and cause a vaccume leak and make the M seam like it out of time have a small hesatation when powering up small inclines but on flat ground slowly get upto speed or should I start looking for something else

Re: crank case vent line
Posted: Sat Mar 29, 2008 7:48 pm
by MSeriesRebuild
anthony manzella wrote:is it posilble that the hose fitting that joins the steel line which runs along the frame to the up rite tube to the carb , rott out [shead] the rubber jacket and cause a vaccume leak and make the M seam like it out of time have a small hesatation when powering up small inclines but on flat ground slowly get upto speed or should I start looking for something else

Can you be more specific with your question?
Posted: Sun Mar 30, 2008 4:40 am
by M-Thrax
If your talkig about the 2 vent lines that run up the frame and cross over to the engine under the generator ( via 2 rubber hoses ) then the answer is no it will not affect the vacumn as they are plumbed into the airhorn before the carb ( upstream ). One is the vent for the master cyl and the other is fording vent for the gas tank
vaccum leak
Posted: Sun Mar 30, 2008 5:05 am
by anthony manzella
WELL HOW CAN I PUT IT H*LL I FOUND 2 BAD CYC #3&4 #3 is 20# and#4 is at10# hopefuly it's not going to be total rebuild but could use some good pointers I'am all eyes and ears

Posted: Sun Mar 30, 2008 8:21 am
by Lifer
The extremely low compression on #3 and #4 cylinders tells me that you've blown your head gasket between those two cylinders. This is the most common gasket failure and is an easy fix. You simply remove the head, clean off all old gasket material, install a new gasket, replace the head, and torque it down to specs. You'll be surprised how much better your truck will run once you turn that "4-banger" back into a 6-cylinder engine!

Re: vaccum leak
Posted: Sun Mar 30, 2008 9:37 am
by MSeriesRebuild
anthony manzella wrote:WELL HOW CAN I PUT IT H*LL I FOUND 2 BAD CYC #3&4 #3 is 20# and#4 is at10# hopefuly it's not going to be total rebuild but could use some good pointers I'am all eyes and ears

It is a possibility, but I'm not convinced your issue here is a blown head gasket. My reasoning is this, generally when a blown head gasket is the deal with 2 adjacent cylinders, the PSI reading for both is dead "0". A "0" reading for both is almost 100% certain blown head gasket. This being said, you need to verify that your test gauge is offering correct readings before you proceed. Since you have a 20 & 10 reading, that points more toward leaking (burned valves & seats) or severe ring/cylinder wall wear or damage. You can get a better idea of what may be going on using the following method, remove all spark plugs, individually put a tablespoon of engine oil in a plug hole & immediately re-test that hole for compression. Proceed with adding the oil to each plug hole 1 at a time & re-testing. If your PSI readings increase substantially after you added the engine oil, the problem is more concentrated to ring/ cylinder wall wear or damage. The oil will seal the rings temporarilly causing the compression to increase. If you see little or no change after adding oil & re-testing, this points to the valves being most of your problem. What were the readings on the other 4 cylinders? If they are at or below 100 PSI you are borderline, if they are below 90 PSI, forget it, a TOTAL rebuild is your only answer unless the 2nd test reveals the problem to be valves. Readings of 115 PSI or above with no more than a 5 PSI variation from 1 cylinder to another are considered acceptable to a good running engine. Lower readings are saying the engine is becoming tired & you need to be thinking overhaul in the not to distant future.
Let me add this, if by chance you find the head gasket to be the issue for cylinders 3&4 with good readings on the other 4 cylinders, don't think just replacing the gasket will fix the problem. There is an extremely high likelyhood that a low area in the head surface is the cause of the blow. Head gaskets don't blow for no reason when installed correctly on a flat surface. At the very least you would need to have the head resurfaced so it is perfectly flat before installing the new gasket.
If you will post the compression test result for each cylinder here for the original test & the new test after adding the oil, I can help you further with your diagnosis. Good luck.
Posted: Sun Mar 30, 2008 12:30 pm
by Lifer
As always, Charles has provided good advice. My suggestion was a "down and dirty" quick response. Charles' more in-depth analysis of the problem could well reveal that it's more than just a blown gasket. I recommend you perform the tests he described before pulling the head and that you have the head checked for warpage before reinstalling it. While there is still the possibility that you may be able to get by without a complete overhaul, be ready to accept the fact that a rebuild could be required. If time and money are not a major concern, get it rebuilt anyway. You won't be sorry you did.
vaccume leak
Posted: Sun Mar 30, 2008 2:29 pm
by anthony manzella
Lifer / Charels most surly thank you and will post compleat test numbers but it will take some few days as the person that helps me is starting a new job so we do'nt know how our hours are going to come together for a few days, BUT WILL POST NUMBERS. MUST SAY THIS SITE IS BETTER THAN GOING BARE AZZ NAKED , when things go south of the border.

posting #s
Posted: Sun Apr 13, 2008 5:13 pm
by anthony manzella
both our hours clash so I made the move saturday morring get to the rental plase and pick up a trailer to haul her off to the rebuilder wo'nt know anything for a few days my bet is on the valve seats so off she goes hopefully know something by monday of 4/21/08 in the mean time i'am dealing with my boat getting her to the finish line for august for my top speed run no dought i'll be getten pulled in two place's at once will let you all know what has happen in both cases
