Maserati 4.9 V8 Engine

Didn't anticipate talking about head gaskets this soon, but I have a burnt valve in my L/H bank.

Does anyone have an accurate drawing of the 4.9 (Khamsin) head gasket? I'd like to have a copper one cut (I can have this done very easy and avoid sending a gasket half way around the world)

Thanks a mille,

Jack.

 

Hi Jack

Why do want a copper gasket when the linners patrude above the block? You will never get it to seal

Graeme

 

They are made of SOFT copper and i recommend that you anneal them before installing them, Maserati engines have problems with head gaskets and the Quattroporte 3 is worse because they have catalitic converters and that engine was never designed for back pressure. Over the years it's become apparentto to me that they have a problem in that area due to the number of cars i work on with head gasket failures.

 

Graeme,

The tolerance for potrusion of the liners is zero to 0,1mm, IIRC. I think this has as much to do with the bottom seal as with the top sealing against the gasket?

Why copper?
1)
I can have a gasket made around the corner
2)
It can be re-used should there be a problem
3)
It works out more economical than buying a gasket in Europe or the USA.

Negative is that the surfaces need to be flawless

Falta125:

We read a lot about this type of failure, but not that often in the Khamsin thread. If it can be done successfully I'd like the peace of mind. My car didn't have a failing gasket, it suffers a burnt exhaust valve; I am not a fan of repeating jobs, so if copper is safe I'd like to use it.

Best,

Jack.

 

Dear all Maserati Motor Experts

I have my 4.9 dismantled as you can see in my thread. I am told that it is in quite good nick but would need bearings etc. Question: Could I rebuild it? Or is it silly to try. I was thinking I could get a Maserati mechanic maybe to come and help me for a week at the key bits.

Let me know your thoughts.

Best

W

 

I'd say if you have the time, space and tools, absolutely. It's definitely nice to learn more about engines and how they work, and with a specialist to help you can (hopefully) avoid any potential pitfalls.

I've helped friends rebuild a few engines (not Italian exotica, US big iron and a Toyota), and as long as you are organized, clean and methodical you should be able to tackle the job. Obviously having an experts eye and guidance is always a plus, especially on an engine you don't want to have problems with down the line.

Make sure you have the service manual along with any factory bulletins/updates and go through it all section by section in your head before you start.

And maybe post a few pictures to keep us all posted on your progress, eh?

 

Hello William...

I agree with Quattroport3... Give it a shot... And, please post pictures...

Organization, Cleanliness, and being methodical are the main things!! Proper
tools will also be a big help. I also agree, it won't hurt to have a knowledgable
person assist/teach as progress occurs...

Mike

 

Thanks: I am looking into this option.

Best,

Jack.

 

I have a US spec QP3 and have some extra time on my hands.

What would be involved in converting a US engine to EU spec? I would expect that the smog stuff would go, but what else needs to be changed?

What advantages/disadvantages would result by doing so?

Does anyone here know what the differences are, specifically?

 

Just started to rebuild the heads on my 68 Ghibli and found the case hardening on the cam followers (cam buckets) looks suspect. The usual places seem to price them at about £32 or $32 each, can anyone suggest a more economic source? Jaguar XK ones seem to be about £5 each!
Thanks in advance

 

My mechanic said I should probably adjust the valve clearances and was going to go ahead and do it for me, until he saw in the service manual that the camshafts have to be removed.

He warned me that that would be a big and very expensive job, so I wanted to check here and see if anyone knows if the valves can be adjusted without pulling the cams.

Apparently what would normally be a 2-3 hour job in most cars ends up being a 10+ hour job on this engine. I guess it was good for the Italian employment statistics at the time ;-).

Anyone?

 

Only way to adjust the valve clearance is by replacing the valve shims. Only way to get to the valve shims is by removing the buckets. Only way to remove the buckets is to first remove the camshafts ...

The procedure is no different that adjusting valves on a Jaguar XK engine. Except Jaguar made the chain removal process much easier.

Ivan

 

ON the plus side he can change the cam timing at the side time if it needs to be put in euro spec.

 

Ok, thanks Ivan and Bob for confirming that for me.

I think I'll enjoy the few summer months there are with the car as it is, and make a plan for this winter where we do both the valves as well as the cam timing. It would be a good time to pull all the emissions stuff too and complete it's Eurofication.

 

Check the cam timing before trying to change it. You may find that it's already set to euro specs.

Just removing the cams to adjust the valves and then reassembling with the same tooth to tooth timing on the cams is not the same thing as fully timing the cams to a specific specification.

The late Stan Bishop wrote a very thorough white paper on how to time these engines.
See if you can find a copy of that.

 

For those that want to adjust the valves, I have been successful in adjusting all the valves except the #1&#8 without removing the cams. You can just unbolt them and lift them without changing the timing or removing the chains and remove the bucket tappets. If you need to adjust #1&8 then you have no choice but to remove the cams. When I do my valves I always increase the clearance on # 1&#8 by .002 inch because the clearance is closed up by the chain tension even when properly set. I believe this is stated in the Quartroporte engine manual.

 

Agree with the above advise. You should check for timing chain wear and replace the chains if in doubt. The timing chain master-links should be replaced as part of the job. Make sure the nuts holding the cam sprockets are properly torqued or the sprockets may come loose when the cams get hot and grow in length.

 

Doing the timing with the engine in the car is quite the job. One has to make bracketry to get the dial-indicators in their right position, with the probe aligned with the valves, and, like Will said already, the nuts on the cams need to be torqued correctly. Getting these nuts loose is another story, some have reported having to use big breaker-bars to get them off, and either way, undoing and torqueing these should happen without putting all that force on the chain. There is a hex at the back of the cams, but I prefer to do this in a well-mounted vice. That means the cams need to come off more than once during this job.
I am busy with this right now, and can hopefully post some pics after the weekend.

Best,

Jack.

 

To follow up on my previous post, I checked in the Service Manual, it specifies 0.03 - 0.05mm clearance, max 0.06mm on the intake side. If that's so, it would seem the mechanics measurement of 0.06mm is within spec. He thinks it sounds unusual.

So I checked in the User Manual, and it appears to give different valve clearance values.
It says (under engine details) 0.25 - 0.3mm if I'm reading it right.

Does anyone know with certainty the correct valve clearance specs?

Thanks!

 

If you go back and read the Service Manual again I think you will find the spec of .03-.05mm is the valve stem clearance to the valve guide. THe correct valve clearance for the cam to cam follower is .23-.25mm for the intake and .43-.45mm for the exhaust. These are the correct number for the 67000 and 67500 cams. Some of the older V8s had slightly different clearances. If you have older cams let me know the numbers and I can look up the recommended clearance.

 

In this light it is also important to note that the cam timing cannot be done correctly if not first the valve-lash is set properly.

Best,

Jack

 

Thanks Eugene & Jack,

assuming I want to have this done somewhere in the next few months, there isn't anyone here who can do it. So I can pay someone to learn (like the very competent Ferrari mechanic who does the stuff I'm not able to do myself) at the local labor rates ($$$$$), or I can take the car to someone who knows what they're doing and has done this many times before (and ideally has parts available, like shims and buckets and timing chains if needed), and pay normal labor rates ($$$).

Can anyone recommend a Maserati mechanic in northern Europe who could do this, who's experienced with the Maser V8 engine? Reputable, with parts available (if not on site, at least a day or two away)? I'm thinking Denmark, Northern Germany, Netherlands. Or I could put the car on a train and just take it to Modena, I suppose. That's the downside of living on the edge of the known universe. As great as MIE is, there always seems to be one additional thing missing every time we order parts, and we end up waiting an extra week or two for the last bits to arrive. I'd like to avoid that if possible.

I'm thinking I can have the valves done, and possibly remove the smog stuff and finish Eurofying the engine. As far as I recall, the camshafts are the same in the US/EU versions, just slightly different adjustments/timing.

So who's good to go to for this kind of work?

 

Setting valve-lash and cam timing on that engine is not that difficult if you just follow the instructions in the service manual. Yes, the European spec and US spec cars had the same camshafts. The wider valve clearances were done as a cheap way to change the timing of the valves opening and closing on US spec cars without having to come up with a different camshaft profile. The wider the gap between the lobe and tappet, the later the valve opens and the sooner it closes (all other things being equal).

Where the DIY mechanic is going to run into trouble is in setting up the carburetors, particularly older carbs with some wear and tear. The biggest problem with Webers is: People assume that when the engine doesn't run right, it must be due to those Webers and they start monkeying with them, usually wrecking the idle-mixture-screw seats in the soft carburetor bodies by tightening the mixture screws down hard.

You might find a professional willing to set up the carburetors if you've done the foundation work. Make sure the carburetors are clean throughout with all clean passages and having all new gaskets, working floats, new needle & seat assemblies, new accelerator-pump-diaphragms, no throttle-shaft wear, no warped surfaces, etc. Make sure the engine has correct cam-timing, correct timing-chain tension, correct valve-lash, correct ignition-timing and a healthy, working ignition-system with correct advance and retard function, fresh fuel with the correct pressure and flow, a working thermostat and cooling system, a free flowing exhaust system (no crushed pipes, holes, mouse nests in the mufflers or overheated catalytic converters). Unless all other systems work as they should, no amount of carburetor adjusting will help.

 

Hi Will,

thanks for your detailed and thoughtful reply, I appreciate it.

It's quite a bit more than I'm comfortable tackling on my own. I've adjusted valve clearances on little Japanese four-bangers as a youngster, but that was very straightforward, no need to remove any cams, etc.

There are competent mechanics here, but it's a cam-out 10-12 hour job. With the labour rates here it would cost a fortune.

When Jack started talking about dial indicator gauges and custom fab'ed brackets to hold them in place and taking the cams out mulitple times, plus I'd probably want to replace the timing chains and freshen up the tensioner, I recognized I was in over my head.

The engine runs fine. Let me qualify that. It runs very smoothly, idles nicely, revs consistently through the range without any significant changes in response, and produces a fair amount of power. One mechanic who had a look at it 2 years ago said that one of the timing chains was "ticking", probably a loose locking link and nothing to worry about. He did say that next time I had some engine work done I should have it checked and possibly replaced.

The problems I've been having have been primarily twofold (but related), poor power and poor mileage. We did a dyno run, although it was a bit difficult due to the slushbox, but we registered somewhere around 200-220HP if memory serves. The car drinks gas like there's no tomorrow, on average between 25-30l/100km (9-11MPG), while other owners report figures between 15-20l/100km (15-20MPG).

Actually I am much more comfortable working with the carburetors than the heads/valves, I guess I'm more adept with fine-mechanics than the bigger/heavier stuff. I rebuilt them last year, ran them through an ultrasonic bath and carb cleaner, replaced all gaskets, verified the floats worked and were set correctly, installed new needle valves (Grosse ball valves), new accelerator pump diaphragms, throttle shafts were good, repacked the bearings, checked bases for true, etc.

I've adjusted airflow (currently at 5.5kg/h @ 950rpm) across and between all barrels and they are pretty much dead-on matched, as well as idle mixture using a Colortune together with a digital tach along with my ears, finding the spot where the engine runs smoothest and quickest within the proper Colortune color range. I haven't yet used the exhaust analyzer, but will sometime this fall.

The mechanic who's been helping me measured the valve clearances (afaik this is identical to "lash") and found a few were out of spec, the worst was 0.06mm, and he said I should consider having them adjusted. He would have went ahead and taken care of it while he was at it until he realized that he'd have to remove the camshafts and timing chain to do so, and warned me it would be a big and expensive job. I don't know if the cam timing has been checked. I have had the compression checked, and all cylinders measure in the "good" range (between 11.25 - 13 bar) and are within 15% of each other.

He said that while I can still drive and enjoy the car, I should have the valves adjusted sooner rather than later and not wait too long before having it done. That's why I asked here.

The ignition timing is correct and factory spec, aside from the idle-retard controlled by the microswitch and solenoid valve (which pulls it back from 10-11degrees to 3-4, iirc), which is disconnected. The fuel pumps have been cleaned and checked and are delivering correctly, the filter/regulator is providing 2.5psi to the Webers and has a clean filter. The PO had removed the cats from the car, I had high-flow racing cats put back on. They don't overheat or reduce the wonderful sound the engine makes! The water pump was replaced a few months ago along with the thermostat, the fans come on at the right temp, etc.

No mouse nests either, I'm happy to say ;-).

As I mentioned, I'm quite happy getting parts from MIE to do work here (either myself or the local garage), but we always end up with "one more thing" or a missing part and have to wait another week (usually two) to get it. The mechanic I use is good, but this car is completely new to him and apparently Maserati does things quite a bit differently than Ferrari, which is is accustomed to. Add local labor costs on top and this would quickly cost more than an average QP3 on eBay...! I'm basically paying him to learn about the car.

I'd like to find someone who knows these engines and has parts, and can spend a few days getting everything right. That would be a great excuse for me to take a road trip/vacation to Germany, or Holland, or Denmark and have the car done while I'm there. As I tell my own customers, there's no substitute for experience. Following my own advice, I'd like to find someone who has proven experience working on these engines.