Revese Rotation?

Jim,

I know that in the case of the ford engines that CC used they all came reverse rotation. My 1965 Mustang is a 260 reverse rotation and I'm in the middle of having it rebuilt at the machine shop. Lots of special parts in these motors that are marine and reverse rotation specific - some that come to mind are:

Camshaft
Distributor
Timing cover (obvious)
Exhaust manifolds (obvious)
Oil pan
Oil pump pickup
Crankshaft
Front and rear main seals
Starter
Pistons face the rear of the engine

The cylinders are numbered the same as all ford sb v8's

The firing order is different than a std rotation engine.

My advice to you is to leave the cam alone and add a 4bbl carb and a decent intake.

-Coop

I do not think all of what colinc says is true. My thoughts:

1. Not ALL Correct Crafts used reverse rotation engines. My 77 Martinique is LH whereas my 93 Nautique is RH.
2. Not all reverse rotation engines are created equal, but maybe so for PCM. If the camshaft is driven by a gear, then the camshaft, oil pump and distributor rotate in the same direction as a conventional engine.
3. For the life of me, I cannot figure why the exhaust manifold or oil pan would be different for a reverse rotation engine. Likewise for the timing chain/gear cover.
4. The firing order for reverse rotation engines is easy to figure out. Simply swap positions of the #1 and #8 wires at the distributor cap.
5. Do not forget about the water pump, it is special to reverse rotation.
6. The timing mark tab position does not change (if I remember correctly and think about it a bit...you would still attach the timing light to the #1 wire).

With everything I have said above, please know that the only reverse rotation engine I have rebuilt was a Chevy 350. Ford engines may be different. Bottom line, just check how the engine is assembled and note special parts. If the engine is reverse rotation and the camshaft is chain driven, then yes, all parts are special and thus more costly.

Well, in regards to the cam my commmon sense tells me it must be different to be ground to run in the reverse durection, BUT, I could be wrong. Thinking about it is like looking in the mirror to shave.

It does seem to me though the tab that has the timing marks on it must be on the other side of the engine or setting the timing would be very wierd. So, I dont know if a special timing cover is therefore needed or not - but that's academic. The cam is all that looms in my future for now. How much is a "Marine" cam? And, my prop is right hand - is my engine therefore reverse rotation?

cam is different i got mine from comp cams. these people are confusing. its not as difficult as it sounds. i just had to do a total rebuild. and my timing marks are on the flywheel. btdc and atdc do change places.

Jim,
I've dedicated a disproportionate (hrs vs. results) chunk of the last 5 years pursuing your same goal. But ultimately the results have been very rewarding in terms of fun. I've got a 70' Mustang 302 powered hull like yours shown in the diaries. I've got to run my two chocolate kids to the vet this AM, but afterwards I can give you a complete lowdown on every step we took, good and worthless, on picking up a solid 10 mph topend. The additional speed also comes with an unsuspected bonus; incredible low end power and pull.   

Jim,
I think everyone's covered the reverse rotation issue quite well. You've got a reverse engine now, so just make sure that any new parts that are rotation related are indeed reverse parts. They are all available so don't make any exceptions.

The upgrades that we made were to a 210 HP Interceptor which was the 4V version. It originally ran 45 mph. I'm assuming yours is either a 165 or 190 HP model. In order of actual upgrades performed here's what we've done:
* Short block No. 1: rebuilt short block with flat top pistons and original 302 heads with no modifications; SpeedPro cam: Lift .444"/452", Duration 206-221 @ 050". Edelbrock Perf RPM intake. Original Interceptor square small dia exhausts and 2-1/4" exhaust hose. +/- 50 mph. This piston and low perf head combo netted about 9.5-10.0 compression. We weren't real pleased with this package especially when a head cracked. Don't ask.
* Short block No 2: Same block, installed Keith Black KB-116 pistons and 351 heads with the exhausts mildly ported. This woke the boat up very well in term of bottom end torque. +/- 10.5 Comp Ratio. No other changes. 53 mph.
* Had previously removed saturated foam from exhaust hose area, so decided to replace 2-1/4" hose and thru-hull fittings with 2-7/8"-3" material. The sound really arrived along with one MPH to 54. I felt this was a good move as the initial expansion of the foam had actually compressed the original hose in a few small areas. I've found that upgrading to the larger exhaust without other engine mods will not net you much if anything, but it sure will sound better. By that time however, Holman Moody and Chrysler engines were already using the bigger exhaust and hose in the Mustangs.
* Acquired another set of 351 heads and did extensive exhaust port and intake bowl porting. I did this myself under the close supervision of a retired Ford engineer, but wouldn't suggest paying someone to do this for the additional mph to 55 mph. The previous heads had the mild exhaust porting so basically cylinder head upgrades netted us 2 mph.
* Finally replaced the original power-robbing log manifolds (These were the later factory cast iron units and not the classic Interceptor logo pieces) so there was no value to holding on to them. I found a set of no-longer-available Barr Marine aluminum center rise exhausts which were easily ported to match the enlarged head ports. Another quick mph to 56 MPH and that's where we sit today.   Please note that these are corrected GPS verified speeds as I was saddened to learn several months back that the newer model Teleflex speedo currently used on this boat many others read a bit high. With one person on board, the gauge shows 58-59 and with a large buddy in the back it'll touch 60. I corrected my posting several months back.

Recommendations? How fast do you want to go and how much money are you willing to spend?
You've said you'd go as far as the cam and carb. I agree. I couldn't be more pleased with the cam we're using. You could go with a more agressive one, but I wouldn't suggest it unless you plan on upgrading much more. You can pick up a Edelbrock intake and 600 CFM marine carb for a combined $500-max new. Tons of good used intakes on ebay, or I'll sell you a factory cast iron for $25. But just going with a carb and intake isn't going to cut it. So if you're doing a partial tear down with the cam install, I would recommend enlarging the historically small Ford head exhaust ports as well as the exhaust manifolds to match. If you've got the Interceptor alum manifolds, I'd keep them for nostalgias sake and you can port them easily. Those changes I estimate would net you 30-40 HP and 4-5 mph. After that you get into more engine internals and head upgrades which will increase your costs somewhat. How far do you want to go? As you've quickly seen, this web-site will support you. Let's get at it!    

BTW, reidp, where did you get the SpeedPro cam and how is your idle? Rough? How's the low end torque? Did the cam seem to reduce your low end? Is it a hydraulic lifter cam?

Jim:

Not try to beat the reverse rotation issue into the ground, but have you determined whether or not the camshaft is driven via a gear and NOT a chain? I thought all reverse rotation engines utlized a gear to drive the camshaft, but I could be wrong. My point is that if the camshaft is gear driven, then it turns the SAME direction as a conventional rotation engine. This means that the distributor and oil pump also turn conventionally and thus the distributor uses a conventioal drive gear. So, it follows that the major components specific to reverse rotation would be: crank seals, circulation pump and starter. I really do not know if the crank is different via oil ports oriented the opposite direction.

Again, the firing order is achieved by taking the conventional rotation firing order and then swapping the #1 and #8 plug wires at the distributor. Since timing is taken from the #1 wire (which has been relocated) the timing reference point stays on the port side of the engine.

I hope this helps.

Some cam grinds firing orders are different, to lessen the wear on the critical areas of the crank. You just dont' move wires, that is why there is different firing orders. Manufactures preference.

SS 201 Bill,
Could you call me or give me your number again when you get a chance. I lost it somehow. Thanks. 704-451-5080

The best way to find out about the Motor..
If it is the PCM...
Call Mark at PCM in little Mountain S.C.
1-803-345-1337 ext---4..
he could tell you about the PCM Motor's

The 450CFM carb will not make it run lean unless it is jetted too lean. If so, just increase the size of your main jets to enrich your mixture as much as you want.

The spark plug check is always a good idea when you make changes, but keep in mind your running conditions prior to plug removal. Read the plugs after idling for a while to get an idea of your idle mixture (and idle enrichment screws setting). Then read them again after running at speed to get an idea of your main jet size. If you ever read them after a cold idle, they will show some black carbon, but that is normal because you are running on a “choked” enriched mixture – so only check them after your engine has had ample time to warm up.

Most Automotive shop manuals have a couple pages of good color photos of spark plugs with descriptions of how to "read" them. Black is too rich, white is too lean, light brown (rust) is perfect. One thing to keep in mind is that they can change colors throughout the operation of your boat. They might get some black carbon on them when your engine is cold and choked, and then (ten minutes later) if you have undersized jets they might burn off the carbon and turn white. Then, if your idle mixture screws are set too rich, they might turn black again while you are idling around for five minutes while loading onto your trailer. So, just because they are white when you get home, doesn't necessarily mean your jets are too small - you might just need to back out your idle enrichment screws a tad.

The technicians at Holley's tech support line could probably recommend a good starting point for jet size if you give them all of your specs and upgrades. Then, go play for a couple of hours and just after some hard running, kill the engine and check the plugs (without doing ANY idling).

With the additives in gas sometimes takes time to color. Add some octane booster and it will color the tips red then read how much color, jet as necessary. Those GT 40 heads are usually 63 CC.