engine rebuild
As anyone who knows me well will testify I am a big fan of the Rover V8 engine. I have owned, in the past, thirteen Rover SD1 cars ten of which had the 3.5 litre V8 engine so it was no surprise that I fitted a RV8 to my first cobra replica, the sumo. With the AK though I decided to do something a little different, for me, and put in a Chevrolet engine instead. I decided to start with an early 350ci block and use stroker parts to take the capacity to 383 cubic inches or 6.3 litres! Unfortunately finding a decent 350 block was not as easy as I thought it would be, I eventually bought a block from Mike Huddart who also machined the bores +30 thou for me and fitted new cam bearings. With the block sorted I could then go through the thousands of combinations on the Summit Racing webpage to get the engine that I wanted. I decided to have an internally balanced engine so ensured that all the parts I ordered matched that. I also wanted to use my throttle bodies so went on the hunt for an inlet manifold that would take my four twin 50mm Jenvey throttle bodies. This was a nigh on impossible task as the throttle bodies that I had were of the IDF bolt pattern rather than the more common IDA. Some companies did use the IDF pattern on their manifolds but would only sell me one if I also bought an efi system off them too. I eventually found Inglese and they could supply me with an IDF pattern inlet manifold to suit my throttle bodies so one was ordered.
With all the parts ordered it was time to look at how to do the build, I decided to go in this order: –
Clean/paint block
Smooth out inlet tracts on manifold and heads
Port match heads/inlet manifold gaskets/inlet manifold
Fit crank and cam
Fit pistons and rods
Finish off bottom end (oil pump, sump etc.)
Fit timing gear and damper/waterpump etc.
Fit heads
Work out pushrod length
Fit inlet manifold and throttle bodies.
Fit flywheel, clutch and starter motor
Fit gearbox and prop
This account is not meant to be a step-by-step guide to building an engine but rather a log of how I did mine. There are only a few pictures to illustrate some points
Clean/paint block
Cleaning the block is one of the most important jobs to do as any dirt left here will get into the running engine and may destroy it, so I made sure I did this part properly. The block came from Huddarts reasonably clean with the coreplugs removed, but I knew that it had been machined so it was scrubbed with hot soapy water in all the nooks and crannies and bottle brushes were used to clean the oilways and holes etc. Then it was dried and treated to a spray with WD40 to keep rust at bay. I paid particular attention to cleaning the bores and used several rolls of cheap kitchen paper to keep scrubbing the bores until they were spotlessly clean. Once I was sure that the block was clean I fitted all the new coreplugs and threaded plugs, I checked to see whether Mike had removed the plug that sits below the oil pump and he had so fitted a new one there too. I had a quick check to see if there were any holes still in the block that weren’t covered by the coreplug kit I bought and spotted a few, so used some spare plugs that I had lying around (from Sarge’s build). Once I was certain that the block was sound I cleaned and painted it black with the same polyurethane paint and technique as with the suspension parts.
Smooth out inlet tracts on manifold and heads
I thought that the Victor Jnr heads that I had bought were a little to coarse in the inlet tracts so smoothed them off a little. The inlet manifold from Inglese was also smoothed off and the throttle body openings were enlarged slightly to ensure a perfect fit.
Port match heads/inlet manifold gaskets/inlet manifold
The inlet manifold gasket cut-outs were quite a bit smaller than the actual manifold holes so some time was spent here making sure that the holes lined up in both. The exhaust gaskets were done in the same way. I wanted to port match the inlet manifold to the heads but I waited until the heads were fitted so that I could get an accurate idea of how far the heads/manifold holes were out. I was pleasantly surprised that the holes were a perfect fit!
Fit crank and cam
At last I could start bolting things together! The crank was given a good clean and placed close to the block ready for fitting. The mains caps were put together in order and the new ARP head studs were fitted and screwed down. I fitted all the upper mains bearings (the ones with the holes in) and oiled them profusely, I then oiled the crank and lowered it into position rotating it as I went. I fitted the crank top half oil seal using a spot of silicone into the block and the corresponding half into the main cap then put the bearing in, oiled it well and fitted the cap into place. I fixed it down using ARP’s lube and torque figures and checked that the crank still rotated easily. The end of the crank was then hit with a soft mallet to seat the thrust bearing correctly. The other caps were fitted one by one ensuring that they were in the correct order and facing the correct way and the crank was turned after each cap was fitted to ensure there was no binding etc.
As I was using retrofit roller followers I needed to check the pushrod length and to do that I needed to fit the camshaft. I fitted the cam gear so I had something to hold onto while I fitted the cam then I oiled all the cam bearings well and the cam journal, I used cam lube on the last four lobes and inserted the cam into the block, then oiled the next journal and lubed the next four lobes and put the cam in further. This was done a further two times until the cam was fitted and all the lobes were lubed, I use this method as it stops getting lube/oil all over your hands while holding the cam to fit it. Once the cam was in place I removed the cam gear and put the crank gear in place then refitted the cam gear with the timing chain ensuring that the timing marks were in the right place. Once I was sure that the timing marks were correct I fitted the cam thrust button, lock plate and bolted it all down.
Work out pushrod length
I oiled a pair of roller followers and dropped them into place on cylinder number one, fitted a head with the bolts finger tight then I placed the pushrod length checking tool onto the follower, fitted a roller rocker and loosely fitted the rocker retaining nut. It was clearly obvious that the pushrod checker was too short so I lengthened it until the rocker tip was just on the edge of the valve stem. I blackened the valve tip with a marker then tightened the rocker nut to give the correct clearance and rotated the engine. I checked the corresponding mark on the valve tip and adjusted the pushrod checker to get the best and narrowest “stripe” possible. I locked off the pushrod checker and after re colouring the valve tips turned the engine over twice to double check and did the same on the inlet valve. I measured the pushrod checker and added the compressed gasket thickness and I need a set of pushrod’s 7.25” long.
Fit pistons and rods
The pistons and rods had been machined (balancing) so were thoroughly cleaned, then the pistons were fitted to the rods. My pistons had a front marking and needed to be fitted the correct way so that when in the block the crank fillet matched the larger cutaway in the rod big end. The rings were fitted next and gapped correctly and then it was time to install. The piston was generously lubricated with oil and the ring compressor was fitted, the bore was well oiled, the rod bearing was fitted and oiled then the piston was tapped into the bore. The crank journal was oiled and while the rod end was guided into place the piston was gently tapped until the rod was butting up to the crank. The bearing was fitted the rod cap put into place then torqued correctly. At this point I turned the engine over twice to ensure that there was no binding anywhere. Although when I specced the engine I ordered parts that were “stroker clearanced” until the engine is turned over with a piston, rod and cam installed you never quite know! Fortunately the engine turned perfectly and smoothly. The other pistons were then fitted the same way and the engine turned over twice after each fitting.
Finish off bottom end (oil pump, sump etc.)
The oil pump shaft was dropped into place then the oil pump retaining bolt was fitted followed by the oil pump itself. The pick-up was attached and bolted into place. Although I’ll detail here fitting the sump, it wasn’t actually fitted until after the front cover was fitted. As I’d heard how the Chevy sump gasket set-up can be difficult to seal I opted to fit a one piece after market seal, no sealant was needed I just fitted it and bolted the sump into place. I hope that it doesn’t leak!
Fit timing gear and damper/waterpump.
The timing gear has already been fitted to facilitate the pushrod length checking so that part was easy. I fitted a new damper seal to the front cover, fitted the front cover gasket (with a smear of silicone) then fitted the front cover itself remembering to also fit the timing pointer. The water pump gaskets were fitted with a smear of silicone and the pump fitted and bolted into place. I’ve not fitted any of the pulleys yet, I’ll do that when the engine is in the chassis. Finally I fitted the harmonic damper using a damper install tool which makes things so easy!
Fit Heads
A gasket was place on each side making sure it was the correct way up and each head was placed into position over its studs. The bolts were lubricated at the top by the washers with ARP lube and the bottom half inch or each bolt had thread sealant applied then the bolts were slotted into place. The thread sealant is required as the bolts reach into the water jacket. Seventeen bolts are used each side, eight small ones at the bottom edge by the sparkplug holes, two medium ones at the outside edges by the rocker gear and seven long bolts in the rest. All the bolts were torqued in the correct pattern in three stages till the final figure was obtained. My final job was to use a dial gauge and ensure that the timing pointer was reading correctly. It wasn’t it was reading two degrees BTDC so the timing pointer was “adjusted” to compensate.
Fit inlet manifold and throttle bodies.
I haven’t fitted these yet as I need to make some changes due to the Chevy spacing being different to the old Rover set-up they came from, watch this space!!!
Fitting the engine into the car was my next step. I decided to fit the engine first and then fit the gearbox after as the engine was taking up the space I needed to clean and paint the gearbox. To be honest fitting the engine wasn’t that hard a job. The hardest part was getting the engine off the stand, where the part that attaches to the block meets the stand it’s at an uphill angle and I couldn’t get the two bits apart (some grease on there next time!) I struggled that much with it that I hurt my back and had to spend a few hours on my back in the evening. Once the engine was free of the stand it swung nicely over the chassis and I slowly lowered it, moved it in a bit, lowered it etc. until it was in the right position over the chassis engine mounts. I had previously fitted the engine mounts onto the block and loosely fitted the rubber bobbins so once the engine was in position I lowered it a little at a time and guided the bobbins into there respective holes, job done!
Fit flywheel, clutch and starter motor
With the engine in place it was relatively easy to fit the next few parts. The flywheel only fits in one position due to the way the bolt holes are staggered so that was just a case of lining the holes up and fitting the bolts with a little loctite. Next came the starter motor which needs to have its alignment checked, with it bolted in place I checked the alignment and fitted the shims as necessary but noticed that the pinion only came out halfway across the flywheel teeth. I checked with the good folks on the cobra club forum and they seemed to think it wasn’t right but looking on the Real Steel website and their instructions are that it is correct and this starter motor should only have 50% pinion mesh!! Next it was time to fit the clutch, I made a clutch centralising tool by wrapping some tape around an old 1/2” drill bit and used it to ensure the friction disc was central then fitted the clutch cover making sure that the marks made by the balancing shop were lined up, again the bolts were fitted with a little loctite and torqued up nice and tight.
Fit gearbox and prop
The first thing I did was to prep the gearbox. I removed the gear linkage, took off the bottom mounting point and drained all the old fluid out. I then gave the ‘box a good clean and painted it in rust shops aluminium paint. The gear lever was cut off close to the ball joint and a threaded section welded on so that my gearlever will be removable once the car is finished (this is because I know how difficult it is to get the gearbox out with the lever in place and how difficult it is to get the gearlever out with my big hands!) and then painted black.
I had bought a Lakewood bell housing and had to cut the bottom and side returns off both the bellhouse and cover plate so that neither fouled the chassis or stuck too low towards the floor, I went through several cutting discs to do that! After the bellhouse had been painted it was time to mate the gearbox to it, AK supply a kit to do this but I had to do it my own way! I bought an adapter plate from Peter Jones, the cobra club magazine editor, which he has made to fit the Lakewood bell housing to the Jaguar Getrag gearbox I was using. I had previously dialled in the bellhouse and fixed it in position with weld on collars so knew that the large hole in the Lakewood bellhouse would be central, I had a piece of 6mm plate steel laser cut to fit in this hole and into that plate I had a smaller hole cut to fit round the Getrag input shaft support (still with me?) so with the plate in place (welded there) and everything bolted together the gearbox was central to the crank! The thrust bearing from the Chrysler clutch kit I bought was slightly too small to fit onto the input shaft so I had that turned down by 0.5mm and at the same time had a pilot bearing made to fit the Chevy crank and Getrag gearbox. The only other modification was a slight grinding of the Lakewood release arm to fit the Chrysler thrust bearing. All fitted it fits nicely together, and a fraction of the cost of a completed kit
I tried very hard to fit the gearbox to the engine but with the narrowed chassis it just wouldn’t go which was really annoying 🙂 I waited a day and enrolled the help of my top mate Sarge who spent a few hours with me taking the engine back out, marrying the gearbox and engine and then fitting them both back together again. I had to make a few “adjustments” to the AK gearbox mounts but it has all fitted together quite well.
