*Notes*
1.) Timing gear – The 4AGE timing gear must be used with the Porsche timing belt. The spacing of the teeth on the timing gear is different between the 4AGE and 7AFE. The 7AFE teeth are spaced farther apart and the gear is also bigger. The TDC timing mark on the 4AGE and 7AFE timing gear are in the same spot even thought they differ in size, they will both line up to the timing mark on the oil pump, this will give you a sure TDC for the crank. (Refer to pictures)
2.) Knock sensor and water pipes - Bigport application: You don’t need to use the knock sensor if you don’t have the need for one. The water pipes will bolt right in place and everything will line up, you will not have to modify anything to the water pipes unlike the application for the AE86 rwd. In case you do need to use a knock sensor you will have to custom the smaller water pipe (cut and re-weld or use a water hose to bend around it to clear the knock sensor). Smallport application: The smaller pipe for the smallport comes bent from factory to clear the knock sensor so you don’t have worry about it. The smaller water pipe for the smallport and bigport doesn’t bolt up in the same places on the 4AGE, if you don’t have a problem with that then you can mix and match the pipes.
3.) Head bolts/studs – Use the head bolts for the 4AGE. If using ARP head studs for the 4AGE, the distributor shaft will hit the bolt. The distributor shaft must be grinded down a bit to have clearance between the stud and distributor.
4.) Timing belt cover - If you plan on using the 4AGE timing belt covers you must cut a few parts off of the covers to fit. There will be a gap between the mid and bottom sections, this will be normal due to the taller 7AFE block.
5.) Adjustable cam gears - It’s not necessary to use adjustable cam gears, you can get away with using the OEM ones but your camshafts will be way off timing. Best advise is to use adjustable cam gears so you can set the camshafts as close to spec as possible. After spending a lot of time figuring out how I was going to set the camgears to I finally came to a setting that works, I was able to get the cams to sit at the factory setting and the crank to TDC without the camgears being so advanced or retarded. Crank the engine by hand a few times to see if it will line up to the factory indicator markings. But still with the adjustable camgears your cams will still be off, best is if you use a degree wheel kit and dial in the camshafts correctly.
6.) Exhaust header – You won’t be able to use the OEM 4AGE exhaust manifold without the bottom down pipe being modified. The reason is that the 7AFE oil pan is a two piece and it comes down a lot lower which the OEM 4AGE exhaust manifold cannot clear, also the 7AFE block itself hangs down a bit lower as well. So your option is to get your hands on an aftermarket header. I used the KBD header that I had used for my 4AGE (KBD, OBX, Pacesetter or any other header for the 4AGE FWD). You will have to customize the bottom pipe to clear the oil pan. I had to cut and re-weld the A-pipe a bit longer so that it will hang lower to clear the oil pan, I believe it was extended down by 2.5"-3".
7.) Flywheel - You have a choice to use either the 7AFE 212mm or 4afe 200mm 6 bolt flywheel, 4AGE flywheel wont work since it used 8 bolts instead of 6 bolts like the 7AFE and 4AFE. Depending on which flywheel you choose, you also will have to use the corresponding clutch kit for it; 4AGE and 4AFE use the same clutch kit for the 200mm flywheel. A few people has gone a ways to make the mounting of the flywheel to crank stronger by drilling and inserting 3 dowel pins onto the crank which strengthens the crank to flywheel relationship.
8.) Pistons - You can use either pistons from the 7AFE or 4AGE. Compression varies from which pistons you’re using. The 7AFE is supposed to use a 20mm pressed wrist pin. When using full floating 4AGE pistons and wrist pins the machinist had a hard time slipping them into the pistons by hand, maybe I had a bad set of pistons or that they were just too virgin. The small end of the 7AFE rod was bored out a bit in order for the pin to slip through when being pressed to avoid any hesitation of the pin getting stuck when being pressed in. Also note that you can’t use the earlier bigport 4AGE pistons and wrist pin due to it using an 18mm wrist pin.
9.) Head gasket - The head gasket between the two is not identical but is very similar and they each uses most or all of the cut-outs for oil and water galleys. The OEM 4AGE head gasket is 1.2mm while the 7AFE OEM head gasket is 0.6mm and it’s a metal gasket. I am using the 7AFE metal head gasket and so far everything seems good, the water temperature is still the same as when I had the original 4AGE in the car. I recommend the use of the 4AGE head gasket instead, it has cut-outs for the 2 big water port that the 7AFE gasket does not have on the gasket but uses on the block. If you want higher compression then use either the 7AFE (.6mm OEM) or a thinner 4AGE (.8mm, .5mm TRD) head gasket.
10.) Oil pump – It’s been mentioned that the 7AFE oil pump is a higher volume oil pump and pumps out more oil. The 4AGE oil pump is a lesser volume but pumps faster and can withstand higher revs. The decision is up to you on which one you want to use, as for me I stuck with the 7AFE one since it was in good condition with minimal scaring on the internal gear and housing.
11.) Timing belt tensioner – The 7AFE belt tensioner is bigger and it gives more tension to the belt which is needed when using the Porsche 944 belt. The 4AGE tensioner is smaller and doesn’t give tension to the belt so the 7AFE tensioner must be used.
12.) Oil pan and oil cooler – There is no alternative to using another oil pan not unless you get a custom one made. If you want to use the OEM oil cooler which was essentially on the car for the AE82 with 4AGE then the 7AFE oil pan has a bolt that you can unscrew and use a barb fitting for the oil return line (I believe the threading is a M14x1.25). Also you will need to use the oil filter sandwich assembly from the 4AGE onto the 7AFE if you’re going use the oil cooler, it fits and bolts up perfectly, don’t forget to also take off the dowel pin for the oil sandwich plate. (Refer to pictures)
13.) Alternator adjusting bracket – With the 7AFE block being taller you will not be able to mount the alternator to the adjusting bracket which is mounted onto the water outlet on the cylinder head. You will have to use only one of the two screws to hold it to tighten the belt, which is the screw closest to the alternator. You will have to extend the 2nd hole a bit farther down so that it will line up to the hole on the water outlet.
14.) Transmission dust shield - There are two different types of dust shields that you can use depending on which transmission you are using. The transmission plate for the C50 places the starter in the front of the engine under the header. The C52, C56, C160 has two openings so that you can place it under the exhaust manifold or under the intake manifold. Best is to use the corresponding dust plate for the transmission that you are going to use to avoid any problems. When using the dust shield you won’t be able to the lower piece of the dust shield which covers the flywheel from the bottom of the transmission, also there will be a gap between the transmission and the oil pan. The 7AFE oil pan has an opening on it so that you can remove the rubber cover on the 7AFE flywheel dust shield to get to the flywheel to torque converter bolts for the 7AFE application, you can find a way to cover it or you can just leave it open like I did. As for the gap, it won’t cause any harm so you can just let it be. Im believe that you can also use the 7AFE transmission dust shield but it will locate the starter to the back, I kept my starter located on the front.
15.) Power steering pump and bracket - When installing the p/s pump bracket I noticed that there were a mounting hole missing for the third mounting screw on the 7AFE. It looks to be unsafe to just have the bracket being held by two bolts. I went ahead and installed the p/s bracket and pump anyways to see how it will hold up, it seems to be holding up pretty good. Make sure you torque it down and maybe use lock washers.
16.) Cylinder head – The valve stem seals should be replaced and the head should be resurfaced since you have the head off already. Also you can take this time to get the head cleaned.
17.) Cylinder block – The block should be resurface along with the head for a proper seating of the head gasket especially if you’re going to use a metal head gasket. Also take into consideration to replacing all the freeze plugs.
18.) Connecting Rods – I took my 7A rods to the machine shop to have them refurbish and shot peened. Shot peening the rods will strengthen them a bit. Buy and use brand new rod bolts.
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