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Richard Jemison
7,522 Posts
Discussion Starter #1
I get endless questions on engine building, cam issues and gearbox problems that I will share on this thread as others can benefit from the information.

I will start a similar one on the transmission / transaxle area for those type questions.

Richard Jemison
7,522 Posts
Discussion Starter #2 (Edited)
Cam Timing issues

In a message dated 7/4/2014 1:57:58 A.M. Central Daylight Time, johnxxxxxxxxxxxxxxx writes:
Dear Richard,

sorry to bother you with our Euro problems, I´ve a good friend how does hillclims with an Alfa GT 2000. He´s also a good mechanic but he made the same mistake all people around here make, he bought Catcams for he´s engine development, the 1030243 Catcam, I attach the data sheet of those cams. The problem, as allways, is that both cams are the same and what is happening is that the Ex valves are touching the pistons slithgly.

I told him many times to buy cams from you, but he forgot about that when he made the purchase (stupid him). I also told him about this problem that the valve will hit the piston due to to much overlap and lift on the Ex side and sugest him to use the C&B AR.120.292.S with 292º and 12mm of lift on the Ex side that he has.(no money left)

Some data of the Engine:

Motronic P&L

The usuall stuff, bottom end balanced, head ported & blueprinted, etc.......

Measured 10,5:1 CR (head was milled to get to the CR target)

Running with 48 DCO´s

Please would you recommend me LC´s to have a starting point to work with?

Many thanks for your time and regards.


If you look at not just the data but at the graph of the lobes you can see that at the lash setting which is .20mm (.008) the valve events have at least 75-80 degrees of overlap.
Far to much even for a race engine as all it will produce is very high RPM power.

Two things can be attempted to improve the setup so engine is better timed as to valve events and clear the internals.

First increase lash from .008 (.2mm) to .012 int (.25mm)and .014 exh.(.28mm) this will get the off the seat opening farther up the opening ramp and reduce the overlap.

Secondly, open the Lobe centers from 105 to 108 intake and 110 exhaust. This will improve both the excessive overlap and increase the Lobe Separation Angle to better match Alfa`s intake runner length.
It also advances the cams "centerline" improving mid range output. This could be done before taking the effort to change lash just to see the difference in output with only this change

The only way to really make improvements economically is to use a true exhaust design cam to correct valve timing events to make more torque and power.

His application requires a broad torque curve not peakey hp. These cams are not going to provide what he needs.



In a message dated 7/7/2014 1:35:43 A.M. Central Daylight Time, john.xxxxxxxxxxxxxxxxxx writes:

Thanks for that Richard!!

We´ve still the same problem, we can not go on the Ex cam to 110 LC because the valve touching piston, the pistons are Motronics but the valve pockets havent been worked (deepened) so they are still standard height, we have try lash of .50mm on the EX side and still touching so we are forced to go back to the C&B AR.120.292S on the Ex side (less lift).

So, having to use this combo, In Catcam & Ex C&B, should we start from the same set up? IN 108LC & EX 110LC??


John, you are doing it incorrectly if you are having P to V issues at 110 LCs.

On the intake side LC marks are Before Top Dead Center "BTDC" . The larger that LC (110 opposed to 102) the more RETARDED is the camshaft. (Cam is rolled counter clockwise to increase LCs(as viewed from in front of the engine). Valve clearance relative to the piston is increased.

On the exhaust side LC marks are After Bottom Dead Center (ABDC) the marks will increase on the exhaust side of the cap. (Not the intake side of the cap as on the intake)
Increasing the LC to 110 ADVANCES the cam (clockwise) so that the valve closes earlier and increases P to V clearance.

As to using another old high overlap on the exhaust side you wont get much performance benefit, but set the LC at 110 initially but close both based on info below.

Below is the short version of some of my setup info:

Initial timing and valve piston check:

This is very important as when cams advance the piston clearance reduces dramatically.
Set Intake and exhaust cams at initial LCs as indicated by provider set up instructions, and lash
By running the .050 plastic wire-tie between the Intake valve & piston, and .100 (or .080 ) on
the Exhaust side you can check if there is any interference and see that you have adequate
clearance between piston & valve. If by turning motor over by hand you feel some interferance
using a .050 thick wire-tie, (or .080 on Exhaust) but the motor continues to roll through, you are
If it locks up, retard the cam(intake side, (however you would advance the exhaust cam a degree or more to
get more clearance) a degree (or a couple of degrees) and try again until the clearance is found.
I suggest as a test to find this limit, you advance the intake cam until you do, and permanently
mark that point on the cam cap. That will be the point where the cam must NOT be advanced
Then do the same with the exhaust only retarding it until the limit is found.
Timing initially is dependant on design of cam lobe, & internal (pistons) components. Aggressive large duration cams will be more retarded.(intake) and advanced (exhaust) because of ramp & valve lift.
Tighten and instal lock nut on intake and bolt through sprocket and cam nut. Inspect carefully.
Roll the crankover by hand to verify timing.
When the intake cam is at the limit, or LC setting whichever is less advanced. You are there! That`s as good as it can get with your combination of components.

Richard Jemison
7,522 Posts
Discussion Starter #3
re: 1600 performance mods

In a message dated 6/25/2014 6:36:21 A.M. Central Daylight Time, writes:

Dear Richard,

Hope this email finds you well. I have been contemplating emailing you for a long time, but never did because I could not find the budget for the modifications. Yesterday I read your website again and just decided to do, also to prepare for the future.

My English is ok, but I don’t feel confident in calls etc. Therefore the email Sorry for that, I hope you don’t mind.


I have been in the possession of a Giulietta Sprint for approximately 15 years now. Once a 1300 normale (dcd carb) , it now has a 1600, light flywheel, veloce (1300) exaust manifold and dual webers. It makes about 106hp, 143NM on the rolling road. The pistons are standard. I am using the car / or my parents are /for road rallying in Europe. Endurance with a quick pace. ‘Bad’ fuel and mountains to climb. Picture attached!


I have a spare cylinder head that is lying there for a couple of years but is in good order. I heard via a local Alfa forum that you have some excellent cam (designs) for alfa engines that give real punch. I am focussing on buying these in the upcoming months, (if I understand correctly – via you is possible and cheaper? Than via webcams), but would like to make sure it all fits nicely together. If possible, I can now do some (small) mods to the existing cylinder head to come to a nice recipe for the Giulietta that can drive on 95 Octane and have a nice sweet engine that pulls.

I was thinking of raising compression a bit (to enough; maximum is 110,5mm I understand), maybe opening the ports a bit near the seats, if needed fitting a larger inlet valve and other valve guides. This combined with (one of?) your cams. I have a 10548 on the inlet now, and a 1600 standard on the exhaust. On the internet I see a lot of (very expensive) cylinder heads with additional HP etc, but I cannot afford this. However, I understand that you are the expert for ‘real’ tuning against fair pricing. So I hope you might be willing to guide me to some alternative ideas – any input is appreciated!?

With kind regards,

Arno xxxxxxxxxxx

Rotterdam - Netherlands

Van: [email protected] [mailto:[email protected]]
Verzonden: donderdag 26 juni 2014 16:18
Aan: arnoxxxxxxxxxxxxxxxxxcom

Onderwerp: Re: Giulietta 1600 Road endurance rally

Arno, it is very easy to improve the 1600 engines output without spending a lot of $$.

You really gain nothing with larger valves. Alfa used the same ones on the 1750 series. (But that was a get by interim motor until the 2 liter design and castings were finished)


Open the seats internally with a 75 degree cutter to the point that you are leaving a .040 seat surface for the very outer rim of the stock valve. Retain the 30 degree stock seat. No 3 angle cut! just the 30 degree seat to the 75 degree inner cut. Break the sharp edge at the junction just enough that it isn`t sharp. (Gases (fluids) do bot follow "curves" and the key to volumn increases is size/space). Larger valves are just an additional obstruction!

You will find that the 75 degree cutter will actually go past the bottom of the seat into the aluminum bowl blending the contact area perfectly.

Then remove the valve guides and open the port so that the port is a strait run to the bowl/valve seat on the sides from the manifold opening inward.

Replace the guides using the short bronze exhaust guides built for the stock 3.0 Liter V6 . Theses use the green viton seals and are perfect for both int and exh.

Set the guides so there is only 10.5mm to 11mm protruding above the aluminum bottom of the valve spring bore. This leaves room for any cam lift up to 13mm (which you do not need or want! for this application)

If you want to run cams with lift in excess of 11.3 MM you will need to notch the cam follower bores to clear the lobes. Again you don`t need to do so for your application as the small motors really benefit little from higher lifts than 11.3 for most applications.

For these small valve motors you do not need "performance" (stiffer) springs. Fresh stock factory springs sold for current 2 liter motors are fine for these stock smaller valves up to short runs past 7500 RPM. Less spring pressure, less valve train maintaince.

These heads can commonly be cut (surfaced) as much as .080 (2mm) from the stock thickness (4.410). Although to get your compression to a good usable range using stock 9.0 pistons (target CR 10.5) you only need to reduce the head thickness .050 (1.25mm) This will run happily on premium pump gas. If fuel quality is questionable cut the head 1mm to get about 10.2 to one which will run on our "regular" fuels.


The brain of the engine is the camshafts that control the valve events that determine the power producing range of the engine. Lots of overlap as old cams used (and all of Alfa`s stock cams used in "Nord" era engines, don`t make a wide power and torque band. As well using the same cam design on intake and the exhaust makes optimizing the power stroke impossible. Exhaust cams are specificly designed for that side of the engine. Critical in high output applications!

New designed cam lobes with greatly reduced overlap but more "open valve" duration make very broad power bands and far more power across the board than the old design cams.

I have attached a PDF file with full lobe profiles not only of my cams but all of Alfa`s production, the Autodelta performance cams, and many competitors cams which can be compared to see the differences in duration at specific lifts from .010 to max lift for all of them. This gives you definitive information that European cam builders give no one including their dealers.

For an application such as yours where lower RPM torque/power is needed to pull out of lower speed corners, and strong mid upper power I wouldn`t suggest more cam than the RjR429 intake and the RjR776 exhaust cam. Cams will come with correct timing and setup data to fit your application/use. FYI: LCs(LSAs) vary due to application and use, to make power where it is needed and useful. Cams/engines that only make decent power at high RPMs, will be a miserable driver on the street.

Attached are pics of stock seats from early type (1300/1600/1750 & 2liter motors & same design in all early motors 102/106/Montreal etc) engines before and after opening with 75 degree cutter. Seats in these are nothing but a section of steel or iron tube with a 30 degree seat cut! note valve guide differences


Dear Richard – wow. What an information – luckily you sent a translation with pics for dummiesJ.

I generally run in the powerband of 1700-6000 rpm. (depends on the ‘punch’). I have a fairly straight 140mn torgue curve. I will make a picture of the rolling road mapping when I am home. If you think that is the best combination, I would be interested in buying. What USD would those be shipped to NL?

What I wonder – would these cams also work in a ‘standard’head? (not sure if such cams will ruin dynamic compression). Otherwise, I would already run the cams in the car, and parallel do the head. (though time spent does not sound like a lot)




Use the comparison of the 10548-01 cam intake`s profile to the other intakes in the pdf file.
On the Alfa cams estimate .020 (.5mm) as typical lash. So the 10548-01 actual duration at true valve lift with .020 lash is appx 280 degrees of duration.
If you look at the RjR195 and lash for my cams will be .010-.012 then duration at .010 is 275,
The RjR 195 at .050 with lash is apx 240 deg where the 10548-01 is about 220 and etc. Compare the other and you can see the reduce corrected early lifts to reduce overlap, and the increased duration where the valves are truly flowing. Plus the increased lift getting the valve farther from the seat which improves flow at all ranges of cam duration.

The exhaust cam design`s (RjR1032) lesser early duration allows the exhaust Valve events to happen later (EXH opens later increasing the power stroke & reducing overlap) and with more duration & lift which improves extraction.

Actually I think with your application you should consider the RjR590 intake as it has a bit more lift but similar low off the seat #s.

As to camming engines the cams used in the 2 liter really don`t have much different requirments. Use and engine build are the key elements. The larger valves/seats & ports compensate for the displacement. These same cams would be excellent performance street cams. For more aggressive use for stock 2 liter motors the RjR429/776 exh would be a typical choice.

For some reason i cannot find the rolling road overview. Have requested a copy from the company, I hope they will sent me one soon. Once I have received, I would like to bother you once more, to facilitate the decision for the set. I did the comparison (see below) and understand (I think J) what you mean with the combination/ramp in terms of Torgue and HP.

What I would like to understand is the result of the 2 combinations versus my current setup – in terms of powerband and Torgue/rpm, maybe I just need to run the car differently J. Furthermore, I use a 123 ignition – would you happen to have a suggestion on the ‘best’ curve on the final combination of cams?

Sorry for all the questions – I do appreciate your time and efforts!
did a comparison and understand your input. So I agree that the 590 is a good alternative (with no other adjustments I assume). Then I think you advise 1032 on the exhaust. Correct?

So: then the combination would be

INLET: 590, exhaust, 1032

Shave 1 mm (to use with 95 octane)

75 degree valve cut

‘opening’ the ports

3.0 V6 exhaust guides with ‘green’ seals


Richard Jemison
7,522 Posts
Discussion Starter #4 (Edited)
Starter & Flywheel Application

The Starter and flywheel match problem continuously comes up....
Perhaps this will make the matching of starter designs to the ring gear designs more clear.....

Richard Jemison

Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 3,883
None of them are gear reduction.

The early 130 tooth is a common "wound" magnet type starter, the later "high Torque" smaller unit, is a permanant magnet type starter.

Starters from the early 1972 to 1974 cars or the starter from 1990-1994 can be interchanged.

NOTE! Starters from 1975 through 1989 are for 131 tooth and none of these can be fitted to the 130 tooth flywheel, including the small permanant magnet starter used in the mid/late `80`s. These part #s are:0001108024 or 031.

The Old type starter for 130 tooth ringgears is part # 0001211987.
The late model (90-94) smaller & lighter permanant magnet starter, is
part # 0-001-108081.

Both (actually all the 2 liter starters) are 9 tooth starters. Difference in ALL of the alfa starters is NOT tooth count but the gear centering position relative to the 3 bolt mounting position.
Richard Jemison
RJR Racing
Richard Jemison Racing

Premium Member
14,247 Posts
My spare is from an '88 and it has 9 teeth.

Richard Jemison
7,522 Posts
Discussion Starter #9
Un-nessary engine components / Stock cam timing

From another post of mine expanded a bit here.

You get benefit from the 10548-01 only because of the minor lift improvement and the small increase in duration that results from that lift. The lobe design is no more than a larger 9.6mm stock cam.

As I have said many times, both the 10548-01 and it`s smaller stock cousins have lobes designed for gentle lift and closings, and reduced wear to keep the cars out of the dealer`s shop through the warranty period. These are not "performance enhancers" just as the "S" cams in the V6 application where the only change is again only an enlarged intake lobe.

The correct timing of all the carbed Alfa`s was changed in a TSB from 102 (the stock mark) to 104 (both in & ex). That basically means the cam`s marks are positioned just outside (toward each side of the head) of the 102 mark on the cam cap. The marks should basically match the outside edge of the cap mark with the leading edge of the cam mark. This reduces the inherant excessive overlap due to the slow ramp rate. As well the wider LSA improves the valve timing events for better power (increased power stroke and combustion pressures).

However you set up Alfa stock cams the valve events won`t be as good as they can be because of lobe design.
Not until the TS did Alfa make an effort to improve the lobe profiles used on the intake and exhaust sides. Though the ramp rates are still slow (for the same reason as earlier versions) they do have less overlap and a different profile on each side to improve timing the valve events.

It amazes me the foolish manouvers used by engine "builders" to sell costly modifications to gullible Alfa owners for increasing output for non racing engines. It always starts in Europe. Big valves, Reducing the size of the exhaust seat/valve, small stem valves and their related parts etc. In an all out racing engine "some" of this is useful. In a performance street motor none of it is appropriate.
Here`s a perfect example forwarded to me by Bill Theobold.

2.0 Nord Trackday/Rally/Race Head – Big Valve | Classic Alfa Romeo spare parts and accessories

$6000.00 and 185 crank hp. Pitiful. Requires relocating the spark plug, inserting larger seats, all the components for converting to large valves with small stems and still makes no more HP than Ed`s stock size valve head using 40mm emission Webers.

If you have pi$$ away money go ahead and buy the Bling!
If you read the earlier post in this thread on head prep you can see how to do it without spendin lots of money.

Here`s a pic that can be used to explain why stock size valves on an opened stock seat will out flow oversized valves on that same seat. Note:

The outside diameter of the seat is 46mm.

Using any size oversize valve will come with a 45 degree seat. Typically with 45mm stainless valves as commonly sold
Opening the seat correctly with a 75 degree cutter leaving a 1mm seat width for the 45 degree valve to seat on leaves justover 44 mm internal width. This width seat is absolutely necessary as the 45 degree seat exerts a multiple of outward pressure in the seats "lip". Even with a wide .040 seat with these thin seats will spread at higher spring loads and seat pressures along with high RPM. You are also dealing with a heavier valve with larger versions which is not advantageous and increases seat stress as the seat is stopping the valve...

If you open the same stock seat with a 75 degree cutter to the inside diameter to fit a .5mm (.020) seat on a stock size 44 mm valve (43 mm at valve contact point. The 30 degree seat is far less damaging to the seat as less outward force. Using the stock 30 degree seat design you have only a
.020 (.5mm) overhang that the air/fuel mix has in its way into the chamber. As opposed to the 1mm overhang if using a 45 mm valve. Using 46mm valves on stock seats is beyond reason. Max flow isn`t about valve size but seat inside diameter and shape. The old 3 angle seats described in JK`s book is quite wrong for any performance application.

Note in the drawing the 46mm valve`s od is cut back to reduce the overhang...


274 Posts
"The old 3 angle seats described in JK`s book is quite wrong for any performance application."

So: as I couldn't remember seeing anything in Jim K's book about a 3 angle valve seat I went back to it and searched: From page 31, is this what you were referring to.?

Sorry about the crappy picture I used my iPhone.

B :cool:


4,874 Posts
I have a set of very good 2.5 heads I would like to use on a 3.0 short block I have. I've heard that it's possible to do that with some machining. What's involved in that, Richard, or is it even possible?

Richard Jemison
7,522 Posts
Discussion Starter #14 (Edited)
2.5 heads

I have a set of very good 2.5 heads I would like to use on a 3.0 short block I have. I've heard that it's possible to do that with some machining. What's involved in that, Richard, or is it even possible?
The only "interferance" with putting the 2.5 heads on a 3.0 liter engine is possibly the the oiling nipple in th block that fits into the head.
On early 2.5 heads the "nipple" was smaller than those in the 3.0 later motors. I think the later 2.5 blocks used the same nipple design as the 3.0 motors.

The combustion chamber is obviously smaller but does not interfere with the piston. With the 9.0 pistons the heads bump CR to just over 10.7 to 1. With "S" 10.0 pistons just over 12 to 1.

I used the "S" pistons, 2.5 Alfa Sei heads with good large porting and my typical valve seat mods and stainless valves, (Stock OD exh and 1mm oversize intake. With my cams and three 50 DCO Weber carbs engine made over 320 HP and was more than impressive performance wise!
Inexpensive to build and maintain.
Pics are of car right after building before the cold air boxes on the carbs.


4,874 Posts
Sounds pretty easy then. Just open up the pocket in the head for oil nipple and go. Or do you think I'll need to open up the valve like you did to get it to breathe at all? It is a late 164 L short block I have, so I assume that is 9.0 pistons. That should be fine. It's going in a 79 Spider, so about 2x the HP over the stock Nord should be more than plenty. I would love to use carbs on it, but I have decided to stick with the FI.

Thanks Richard!

Richard Jemison
7,522 Posts
Discussion Starter #17
Dropped Spindles/suspension changes & improvements

From another BB thread.............

Please excuse me for joining this conversation so late. I have enjoyed reading this thread but have a bump steer question. Changing the spindle height should also change the height and different "point in space" of the steering arm? This as I understand effects bump steer.
Alfaholics sells shorter and flatter steering arms, a good idea?
Actually when using "Dropped Spindles" it depends on the length increase at the bottom of the "upright".

To be clear the actual spindle isn`t moved. The upright below it is has to be lengthened which raises the spindle relative to the lower ball joint.

As well the additional length of the upright raises the upper "A" arm which will both raise the roll center, and additionally raising the upper arm does more, it increases camber gain as the wheel raises relative to the chassis (as it would be loaded during a corner on the outside, while the wheel inside the turn "droops" the camber is decreased. Both giving a better contact patch for the tires` tread at the road surface.

To maximize the latter (camber changes) the lower "A" arm should be positioned level with the road surface on street cars, and a bit (1/4" lower than level (on the spindle end) on race cars to maximize the negative camber gain on race applications on the loaded wheel when turning in at a corner.
The last thing you want on the suspension is a lower "A" arm that is higher on the spindle end that at the chassis. (What you get with shorter springs:no:)

Depending on the amount of "drop, (or length added below the spindle) which is a factor of wheel clearance, then steering arm modifications may or may not be wanted. On most modified spindles to fit stock wheels or those allowed by SCCA or Vintage groups about 3/4' to 1' is all that will fit. With that drop in ride height with a level lower "A" arm typically the stock steering arm on this ride height works great. (As an aside, where wheel rim does not allow but a small amount of lengthening the lower upright, the upright can be lengthened additionally at the top to farther raise the upper arm to get better suspension geometry for track applications). I have seen "dropped spindles" made by orgers where the top was "shortened" to keep the same upright length. This kills the suspension camber improvements you are after....

For drop spindles with greater ride height reductions a less upward incline is needed. IE straighter arm. If the car is lowered a lot with additional lower "A" arm droop (higher at the upright end than at the chassis) a more severly modified steering arm is needed (or the stock or straightened arms swapped sides (Left to the Right side and v v) with the steering link mounted on top rather than under. Or you can weld the hole closed and retaper from the bottom if you need to fine tune such)

The dropped spindle affects another steering factor in that you can tune the position (height) and change (increase) the "angle" of the modified steering arms position relative to the spindle`s straight ahead position) to increase the Ackerman angles, to make both front tires effective in cornering rather than the inside wheel offering no "positive" slip angle to the road`s surface. Commonly it`s just along for the ride. With the "dropped & lengthened upright improving the inside tires contact patch it should be used. (Commonly you see race cars with the inside tire/wheel at a severe neg camber angle with nothing but the inside edge of the tread being drug through the corner)

Using adjustable upper "A" arms is necessary to tune any front suspension correctly.

Pics of various type Alfa dropped spindles are in my website

Richard Jemison
7,522 Posts
Discussion Starter #18 (Edited)
Negative camber rear axle modification

Using high misalignment outer wheel bearings I have seen teams bend axle tubes to create negative camber on a live axle rear, I believe NASCAR boys do this but I am reading here that the Alfisti do this also?
Actually, using the 115 rear axle assembly with LSD internals the axles can be de-cambered about .5 degree (each side) and it is "accomodated" by the loose fitting drive sleeve in the LSD unit.

The proceedure I use is quite simple. It also allows some creation of minor amount of toe-in to keep the rear more stable under braking, or to effect thrust angle corrections of poorly built rear assemblies.

Anytime you heat a spot of metal and then quench it with water or wet cloth it shrinks. So you could heat till red hot "quarter" size spots from the axle tubes outward (at the tubes top) to draw the tube creating a gental curve upward bringing the bearing carrier to a negative camber on each side of the axle. This takes a while....
A simplier process is using a mig welder, to run a well defined bead from the inner mount of the axle tube along the top area of the tube out to the area of the lower locating arm brackets. after doing each side you will find a neg camber of .5 degree on each side.
I commonly place my weld bead just forward on the axle tube about 1/2 inch from top-center. This minor "offset" of the weld bead will give barely measurable toe-in of the two wheel positions.
To improve this "toe-in" or correct thrust angle differences, shorter beads can be ran along the front center (or rear center) of the tube to draw in the needed amount to perfect the alignment of the axle`s wheels. Major thrust angle problems are an issue with the lower arm lengths.

On my race cars I replace the lower arm rear bushing with a machined aluminum bushing and use a sprerical bearing rod end on the front to allow both alignment and movement of the axle up & down without binding.
This allows a stable lower arm for spring/shock mounting with no wobble as you will have using spherical bearings in both ends of the lower arm. (The CAS manual showed such on 101/750 design lower arms that had no spring mounts and had onlt front/rear loading so there was no issues there.)

You can see pics of these mods at post 186 (I think) at:
Richard Jemison
RJR Racing
Richard Jemison Racing
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