The Morris 1275 in the Midget is ailing. I'm starting to plan the A15 build. Plan: A15 for MG Midget with mild cam, H89 head, GX intake with two SU HIF44, header. I have a couple of questions at the moment.

Can stock replacement lifters be used with mild performance cam in an A15? Lets say it's a Delta regrind, for example. I have a set of new replacement lifters.

I have a GX intake and an H89 head. I want to port match the ports to the intake (just port match, not gasket match). How far into the ports should I blend? For the record, I have a little porting experience, mostly bad. Some folks have a knack, I do not. At all. So go ahead and talk to me like a child. I do have the flange pattern CAD files that were given away recently and have printed them on clear material and I will be able to both make the ports and use the prints for reference. I just want to port match smoothly without creating problems with flow. I do not need a max-effort port.

The standard lifters will work with a moderate camshaft. They are in my A12 that has a 280 duration cam with .460 lift without issue for two seasons.

As for port matching just make sure you take a little at a time, the GX intake should have a larger port than the H89 head. Take a look on here there are some cutaway views of an H89 head that lets you know how much meat there is before you hit a water jacket. Start by getting rid if the step and just get a smooth transition. I'm not a porting expert by any means but I'd say maybe all of an inch into the head at most. If you are cleaning up the head also look at where the valve seats press into the head, these usually protrude 1 mm into the head all the way round. Smoothing that transition on my GX head made a noticeable difference.

On a more shameless note I have a complete A15 bottom end with JE forged pistons and Delta Cam that I may sell off (cheap) It appears I failed to properly torgue the head (threads in the block I should have cleaned more throughly) and the head gasket went. I believe the deck will need slight skim (rough spot where gasket burnt between cylinders), I'd let it go for less than the price of pistons, I have an overdrive 5 speed as well. I'm putting the A12 back in because I have a race this weekend and I've decided that rather than put the A15 back in I'd rather go to an L18 or more modern twin cam. Anyway PM me if your interested or send me an email.............I do mean cheap.

Tom

Rallytwit - I' have sent you a a PM re JE pistons

Tom,

Thanks for the lifter info & porting advice. My cam will be smaller than that.


Thanks for the engine offer. I would like to move ahead with my build as I have the pistons I want and forged slugs would be a waste for what I have planned. Hope you can move the short block

Somewhere on the site it thought there was the prep manual for Datsun Cherry, in it is the specs for porting. I know I have it down loaded, if it is not on here I can likely send it to you .

Yes what I have is more than what is needed for street, as for a street cam I think 260 duration with around .375 to .400 lift and 9.75 - 10 to 1 compression would work pretty well as far as performance, longevity and livability go.

Tom

Cool. I sent you a PM with my email.

Here is what the port mismatch looks like when I put your manifold onto my H89 head. Not too bad.

The water jacket is 6mm above the roof of the port and about 6 mm in from the gasket face ( look up head porting pictures) so to be safe I would not take more than about 2-3 mm. The scribe line looks like its 3-4 mm higher than the port.

Tom