t35 cylinder heads.

[george sutton]

your imput required SAP please,  reference mk1. valve guides.   WHAT please is the outside diameter (imp) of the guides ?  also, how much can one go up on the dia. and still be safe to use on these heads ??  george .s

[Clive]

Hi George,
This should start something,
Original  hole size in the head would have been 1/2 in. depending on the no of guide changes wear and tare the hole  could be well over size, are your guides loose?  I make mine so they are a light hammer fit say a thou o/s I fit them using a purpose made inserting tool . you ask how much o/s o/d can you go ,just go far enough for a tight fit you dont want to block up the ports any more than they are already!! i find a supply of good cast iron is Japanese car cam shafts
Regards
Clive

[george sutton]

hello again Clive, good point about over sizeing too much ,and blocking airflow.   measured the bit protruding into the valve mouth ,and i get 0.490" , so i guess they are 1/2" as std. Have now located some douglas ones that are well up on the outside dia.   so privided valve stem size is the same ill be able to turn them down.   Have also made up an extracter as they are very tight, i dont like hitting cast iron,. thanks for usefull info about old jap c/shafts.   Regards, Denis, george is my other name, (only use it when i'm in trouble).

[eddie]

Right then, George,
                               The original guides were .5005" dia x .835" long, then reduced by a couple of thou and then tapered where they protrude into the inlet port. The top of the guide has a 'head' .600" dia x .080". According to the handbook, the bore of the guide should be .343" - .344" and the valve stem is .341"dia - giving 2 - 3 thou clearance.
       Of course, the O.D. will be dependant on whether the heads have been reworked at any time.
               Hope this helps,
                                    Regards,
                                              Eddie.

[george sutton]

Eddie comes up trumps again, great stuff this.    the slight taper on the lead in explains why i got . 490 thou measured on the bit in the port. good news then that my guides are std..  It does supprise me though that the interference on the fit is only 1/2 thou.   If the heads get very hot , there's a possibility of movement on the guides,  Unless i locktight them ?. any way, from your info, it would seem that  my valves  arent too bad , but the guides ARe nack----ed.    unlike some though, I dont do jobs by half,   valves, springs, & guides, plus reseating will be done.   Thanks again guys, for the help, what a wonderful club this is!!. Denis (george) .S