Engine in F355 Belt Service...

BOOM BOOM!

 

.....or any old Jag, MG, Healey, Triumph etc...........................

 

Oops! Oh yea,,,,BOOM! BOOM!! Thanks mate

 

I enlarged the photo and then looked at my 355 for comparison.

What they have done here is jacked up the motor (unbolted the 4 engine mounts).... an inch or so .

At this point the crank nut is above the frame member and accessible to your impact gun.

The crank nut is removed and the crank pulley is pulled forward about an inch (till it hits the frame member).

This would leave more than enough room to install the timing belt with out twisting.

Also the tensioner bearings, tensioners and water pump are fully excessible for replacement if need be.....but I don't see how you can time the engine this way.
If you do this procedure you must be sure your car was properly timed the last time you had your belts replaced.

I'm not advocating this type of service for the 355.....just responding to the original inquiry.


Regarding the comments about an engine out on an Acura NSX.
Well the factory manual DOES NOT recommend this....the timing belt is to be replaced with the motor in the car and I HAVE done this (timing belt, tensioner bearings, valve adjustment).
This is not an easy job but it can be done by an experienced person with the right tools.
The first time it took me about 5 hours.....the second time I am sure I shaved over an hour off that time.

 

Toyota

 

I was having a casual conversation with the service manager of an independent service shop here in Houston about a year back. He mentioned the possibility of doing the belt replacement with the engine in. I promptly removed him from the list of shops that I will take my car to for a major service.

You don't want to take unnecessary short cuts when it comes to an expensive car like a Ferrari. The few $$$$ you save will bite you in the a$$ later on.

 

Like I said earlier, there is nothing wrong with shortcuts as long as they are good ones. The particular one in this discussion has been discussed many times ad naseum and is not one of the good ones. Also like I said before we are happy to try something new to find faster, better, higher quality, and more cost effective ways. Everyone benefits from that and in no way are we closed minded in that regard and so we did try that method. It is so full of shortcomings there isn't really any reason to waste my time listing them all. We just wont do it and feel anyone willing to accept the shortcomings of the procedure to be better suited to collecting toll at a bridge somewhere than being involved in Ferrari repair, be it professionally or as an avocation.

 

All my belt services have been engine out.

But the purpose of this discussion is to discuss the issues of an engine in t-belt replacement.
Every post on this topic dances around the alleged issues....so reviewing the last 2 years of posts does not clarify the issues....if anything they just cloud the issues more.

We already know that the timing belts (can be installed w/no twisting),t-belt pulley, tensioners & water pump can be replaced with the motor in......also the cam covers can be removed from the top if need be. As well, if the engine was properly 'timed' at the last belt change....it will still be properly 'timed' at the subsequent belt change.

If there are 'shortcomings' ,why can't you list them?

 

I deleted my responce so i am PMing you instead. Dont want the trouble.

 

I am offering a professional opinion for free. There are conditions. I am not being paid for it so I really don't feel like taking the time required to satisfy your every curiosity. If you were a client seriously discussing a service I would be happy to talk about in in a little greater detail. At the time we did it (several years ago) we did it to evaluate the procedure for our and our customers benefit. I did not feel like taking the time to document each and every aspect of the job I did not like for posterity or the people of this forum. Without said notes I really have no desire to get into detailed debate on the topic which is what these threads seem to turn into. If my opinion given in a very general way isn't enough, feel free to dismiss it.

If I do not donate enough time here already too bad, so sad.

 

How much time is saved by dropping the fuel tank as apposed to removing the engine cradle? Is it really that significant that it would overwhelm the ability to get to everything with ease and also do some cleaning/inspecting while its on the stand?

For a pro shop I can't see this saving much more than 2-3 hours???

 

OK, the timing belt service on all Ferraris is a pain, especially compared to a car with a chain driven motor. But the beauty of the 355 powerplant removed is almost worth the effort. I would rather the engine not need it, but I can honestly say I just want to get at the thing on a stand with a bunch of tooth brushes and work it until you could drink beer out of the intake runners (no, I am not advocating putting beer in the motor). And it doesn't get much easier, I mean the thing is designed to come out en bloc! Have you ever looked at a 512 TR with an eye to removing the motor? The 355 has its issues, but hot-diggity it is a fun car to drive and I think it is a pretty satisfying car to work on too. It's sure more fun working on the mechanical stuff than on the interior bits.

 

I'm going to help Brian out here (not that he needs my help in any way ) by stating the obvious big reason...

Most pros know that even if everything else is carefully left undisturbed, changing only the belts usually alters things just enough to require re-adjustment of the valve timing. The simple reason is that these belts are neither identical nor precise pieces of equipment ---- every one of them has enough variances in their dimensions (from belt-to-belt) to be significant. These are laid-up, molded pieces of fabric and rubber --- they are not tightly toleranced, machined, pieces of hard metal!

So, you are absolutely incorrect when you assert that the timing will remain unchanged when you do the belt change. I've never done belts on a 355, but I've done many on 308/328's and a Boxer or two, and I can assure that the differences in belts can cause as much as (2) full degrees of change on the cams. On a 308 engine, that is not necessarily the end of the world ---- but, on the much more performance-sensitive 355 valve train, that is a deal breaker!!!

So, all the other "nuances" aside, that alone is reason to always reset (or at least verify) valve timing with a belt change. As for how precisely this can be done with the engine in ---- well, that is a matter of subjective opinion. It's certainly doable on the 3x8's --- though very tedious. As for the 355, I wouldn't feel confident about doing it myself...

And, to quote Forrest Gump ---- "That's 'bout all I have t'say 'bout that..."

 

"wiping a diaper out".......My friend Peter, only you would put it this way. Gotta love that southern way of thinking!!!! Good on ya mate!
Thanks for the smile Pete
David

 

I don't believe there is any such variance (2 degrees?) on timing belt manufacturing tolerances as is suggested by 'finnerty'. The spacing of the 'cogs' is fixed and any minimal variance in the overall timing belt length is taken care of by the adjustment at the timing belt pulley.

If there were (significant variance) then every car in existence would require the engine being 'timed' with a belt change.......which of course, they do not. And it would not matter if the motor is high performance or not as most all motors out there are interference motors now with twin cam multivalve heads.

On a NSX the motor is set at TDC, cams pinned and the belt installed.

fyi: The NSX also has a 8300 rpm red line and IS NOT TIMED EVER (with regular belt changes), per the service manual.
With the NSX, if you are out even 1 tooth on the setup the engine will not go into Vtec....so a belt variance would not only result in no Vtec but also destruction of these high rev'g 4 valve heads (not to mention possible destruction of the titanium con rods....You don't want to ask how much these cost? Like most motors this is an interference motor.

And always use the manufacturers T-belt if you are concerned about product quality.
Always rotate the motor over manually after you have set the belt tension to ensure that all the pulley markings line up exactly and you will have no problems

 

Is belt variance real? I am just about to change my 348 belt and currently have not worked up the confidence to degree the cams... This would be kinda nice to know.

 

2 degrees on the camshaft ain't a whole lot, my friend... And, just the differences in allowable tooth widths, overall belt lengths, and new belt stretch (i.e., "set") will get you there in a hurry... Having actually seen the manufacturer's drawings / specs from both Gates an TRW for some of their "best" toothed belts (used for applications far more demanding than any car engine), I can tell you that the tolerances are quite large --- even for a molded part.

Yes, pinned --- but, with the timing marks lined up! Setting any engine to TDC at the crank and aligning the cam(s) with their timing marks IS IN FACT "timing" the engine. Do you have a service manual for any car that states NOT to do this? I'm pretty certain your NSX manual says somewhere to "ensure that the timing marks are lined up" when the belts are installed.

It has nothing whatsoever to do with which engine is more precise or "better". The simple reality is that Ferrari doesn't usually provide these marks externally on their engine castings, so you have to open some things up ---- like valve covers, for instance. And, even when marks are provided, they are notoriously inaccurate and cannot be blindly trusted. Every Ferrari shop manual states some form of the mantra "that using the marks is for reference and inspection only" ---- and "that using degree wheels and position indicators on the valves is how the timing should be set".

And, all engines are not equally robust to deviations from "right on the nut" valve timing. Most cars run perfectly well within a small range of valve timing ---- Ferrari's do not. The timing really needs to be exact for the engine to run at its peak. Again, this has nothing to do with either the quality or the performance of any engine compared to another ---- it's just a difference in design philosophies between Ferrari and most other performance car makers.

 

Unfortunately, I'm doing that thing of mine again where I don't communicate clearly enough

All I'm trying to say is that when you change belts, you need to make sure the timing is where it's supposed to be.

If you trust the index marks provided on the engine --- fine. If you don't trust them, then "degree the engine" --- fine too.

However, if you are trusting that two different belts are going to be closely matched enough to precisely re-create the same valve timing ---- and, that you don't need to verify the timing in any other way, then you will be disappointed.

Both Gates and TRW have great customer service departments for technical questions ---- someone feel free to give them a ring sometime. If you can find any of their belt design Engineers who disagree with what I just stated, I would be fascinated to hear about it!

 

BTW, DIYers ---

If you never pull the engine out of your Ferrari, you will miss out on one of the greatest perks of Ferrari ownership --- that white-knuckle, pissing-your-pants feeling you get as you move the engine over and across all that lovely and expensive bodywork...wondering all the way if you remembered to double check all your hoist chains and connections!!!!!!!! LOL

 

I hear you on that that one! Just got my engine out for the first time last saturday. As for cam degreeing - I think I am going to have to bite the bullet and got for it. I have heard too much on the subject now from fat cats that really seem to know what they are talking about. I think I know what fchatters like yourself and FBB are trying to get across - Ferrari engines (specifically) are finely tuned engines that react more strongly to very small differences in timing. Might be off on this one but its seems like this is what I am smelling...

 

Here is a thread started by FBB on degreeing 348 cams Troy. I am sure it will help you out.

http://www.ferrarichat.com/forum/showthread.php?t=148917&page=3

 

Thanks Pap.

 

It is standard practice on any motor when doing a belt change to turn the crank pulley to TDC and to line up the camshaft timing marks when changing the belts......and YES THIS IS timing the motor.
Which is precisely why this is an acceptable and precise method for belt replacement.
If your 355 motor has an excellent idle and passes an emission test barely registering, you can rest assured it is timed perfectly.
Under these circumstances you can simply install the timing belt (again lining up all timing marks on the crank pulley and cam shafts) and your 355 will still be perfectly timed.
Having worked on NSX's, Ferrari's, Porsches and numerous mundane import cars (vtec and variable cam timing though)....I can say with experience that this method is accurate. But it all depends on the skill of the tech working on the car. If however you have a car with a lumpy idle, poor emission readings, ect....then you MUST degree the motor to correct a previous layman messing with the cam timing (usually in the belief of increasing performance)

p.s. stretching of timing belts over time affects all timing alignements and it is of such small tolerance that it is not really relevant. the motors are designed to accept this tolerance.

 

+1000!!!! Enjoyed every minute of the engine out...and lucky for me, that included ALOT of minutes

 

Troy,

Don't even think twice about degreeing the cams when replacing the belt on your single belt driven quad overhead cam Ferrari engine. It is the correct procedure to follow when replacing the cam drive belt. Your engines performance and catalytic converters will love you for it.

??????

ps. The above mentioned Honda qualifies in the mundane catagory....

This statement is true for assembling engines and replacing cam drive belts (but in no way varifies "precise" camshaft phase timing)....

Assemble on the marks, degree to specification.

Replace chain, belt or belts on the marks, check and degree to specification.

WRONG!

You would know this if you actually check the cam timing on your belt changes as opposed to closing your eyes and sliding them on.... More often than not Ferrari's require adjustment if you desire the camshaft phase timing to be "perfectly timed" as you stated....

Emissions tests are performed after the catalytic converters, after the dirty emissions from the improperly timed engine are converted to cleaner emissions.... Hmmm, makes you wonder about all the fried cats and cat over temp. lights we hear about.

I would recommend diagnosing the problem with Ferrari sistima diagnosi equipment, checking the emissions before and after the cats and performing a compression and leak down test before discerning weather cam timing is the issue.

You may have to correct the cam timing due to a previous unqualified leyman not degreeing the cam phase timing while servicing your Ferrari. I know I have.....



There are correct and incorrect ways to do things... The perception of what is acceptable depends on the individual or technicians knowledge, skill, tools and integrity.