Hi all. A bit of background - I had a rebuilt 9:1 4.2 swapped into my '65 Mk2 in place of the original 8:1 3.8 and have been tweaking here and there to try and perfect the running and driving. I think I’m there, so thought I’d share some thoughts.
First - plugs. I have 2 x HD8’s which I run slightly rich. I’ve been chasing a slight miss at idle, and pulled the plugs. All of them were dark brown and gapped at .035. I read on here the gap should be .025, maybe slightly more with electronic ignition (I have 123distributor / flamethrower coil / NGK BPR5ES’s). Swapped out for .025 plugs thinking it would clear up the miss and car barely ran. Went back to original plugs at .035 and it runs normally again (albiet still with a slight miss). Lesson learned.
Second - exhaust. The original 1 3/4 system and stock silencers were almost silent, which I didn’t like at all. Also, the engine felt strangled above 1500 rpms. I did a lot of research on original style mufflers, etc. ended up getting Magnaflow straight-through generic mufflers and the sound is wonderful. Rumble at idle, trademark british trumpet under load, but quiet when cruising. And the engine breathes much better above 1500.
while you feel tune is good enuf…tips for perfection: next time plus are out…you can try 028 or 030. the 035 may be just a little open…and you could try the BP5ES…without the resistance, spark plug wires should also be low or no suppression…some modern plug wires have a LOT of suppression. (easy check is see if a 1.5 V continuity test light will light up…one end of plug wire to the other…) and…does it have the miss at even throttle while on the road? Sometimes an inoperative distributor vacuum unit can cause that…test the vac unit…
Nick
Nick - I also tried plugs at about .029 same issue, .035 is the sweet spot. I will check the wires when I get back to the garage later this week. The miss is only at idle, it’s smooth under load. I have a brand new 123 distributor so it seem unlikely it’s vacuum advance issues.
Ian - sounds good, very similar to mine. Did you find the engine pulled differently with the 2" kit? I opted to keep the 1 3/4 pipes but open mufflers, as Des Hammils book says for low end these engines pull better with smaller pipes that are straight thru vs. larger pipes.
Long story , but I don’t know !
When I put a 3.4 engine in my car first time around , I fittead a new standard system , 35 odd years past , the steel system rotted the boxes , so when I was looking for another went for a s/steel one !
I can tell you the car is a lot faster now !
The 3.4 engine I did have in it , come out of a racing Aston Martin DB2 , after a few years , the main rear oil seal had a bad leak , oil pressure was a bit down , and slight rattle from the timing chains , so time for another engine change .
Fully rebuilt 3.4 XJ6 engine come my way , for less then a crankshaft regrind
Went for the HS8 carbs , fittead a lightweight e-type flywheel , and the performance is notably much better then before !
Did you use the fidanza 13lb flywheel? I’m starting to investigate converting my car from the 700r4 to a 5 speed, so do not have a flywheel. I’ve read mixed to negative reviews on here about the lightened flywheel.
No , the flywheel come on the back of a 3.8 engine , turns out it is a Factory lightened E-Type flywheel .
This flywheel is around 16lb , it’s like most things , there are them that are for and them that are against , I do what I want to do , so far I am happy
Based on reading a bunch of archived posts it seems like some E types had a “lightened” flywheel like discussed above which was 16 or 18 lbs, then other versions between E, XK, Saloons were anywhere from 20-30+ lbs…
