So I finished porting the heads on Saturday. Then on Sunday I cleaned the valves, lapped them and then installed the new valve springs. Here are some pictures of the completed work.
Glenn, I didn't shorten the valve guide because they are not very long and I was worried about how stable the large valve would be with the high spring pressures. I didn't want to compromise the stability of the valve and felt that the little bit of added cfm, if any, was worth the chance of the valve being able to rock in the seat. I'd rather have them last a long time.
Only comment--your intake port needs to be a little bigger (.060 or so ) than your intake port. This helps revision. You are on the right track, just need to to clean up the outer intake port at the gasket (leave port rough).
The exhaust port looks OK, but could use a little clean up- the smoother it is the less carbon build up. Other wise a very nice job.
__________________
64 Vette Roadster 400 ci
1990 F150 351 ci SuperCharged
48 Harley Pan Head 76 ci
2016 Nissan Altma
. . . your intake port needs to be a little bigger (.060 or so ) than your intake port. . . .
Uhhh . . .
__________________
Motorgen on To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Motorgen on To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Motorgen Project Car To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. (active)
Motorgen Project Car To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. (back burner)
Intake port on head vs. on intake manifold. Make the intake on the head larger than the intake on the intake manifold.
So you want the air/fuel mix to slow down and very slightly cool as it enters the head? Is there some other objective?
__________________
Motorgen on To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Motorgen on To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Motorgen Project Car To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. (active)
Motorgen Project Car To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. (back burner)
My only comment on this is the valve head/seat contact area. Last time I did a a valve job, a LONG time ago, when 3 angle seats were fairly new, it was desired to make the contact area as small as possible. Your lapped area looks rather large to me. Has the thinking been revised?
These heads are only two years old and I haven't had a valve job done on them. The angles are what Edelbrock used. The heads are Performer RPM rectangular ports and the seats have 3 angles and the valves have one. I'm sure there is more power in a good multi angle valve job but I don't have the cash to spend on it right now and the valves and seats are in good shape so I just lapped them.
These heads are only two years old and I haven't had a valve job done on them. The angles are what Edelbrock used. The heads are Performer RPM rectangular ports and the seats have 3 angles and the valves have one. I'm sure there is more power in a good multi angle valve job but I don't have the cash to spend on it right now and the valves and seats are in good shape so I just lapped them.
A 30 degree back cut on a exhaust valve helps the low lift flow. If you going for every little bit of horse power this will help. If not leave it alone. If you have Manley valves, if I remember our conversation correctly, then they should already have all the correct valve angles. I've done SIX angle cuts on my own heads when I had all the gear. But, that's just over kill.
__________________
64 Vette Roadster 400 ci
1990 F150 351 ci SuperCharged
48 Harley Pan Head 76 ci
2016 Nissan Altma
